Method and device for analyzing and processing activity rate of seabed shallow fluid and medium

Abstract

The invention discloses a seabed shallow fluid activity rate analysis processing method and device and a medium, which take basic theories of fluid kinematics and thermodynamics as guidance, give full play to parameter advantages of'temperature 'elements, establish a heat convection conduction model, and depend on actually measured ground temperature data of a near-seabed stratum with lower acquisition cost to analyze and process the seabed shallow fluid activity rate. Meanwhile, by combining hydrate stability domain ground temperature data obtained through hydrate phase equilibrium simulation and similar seabed reflection layer inversion, average ground temperature gradient calculation in a hydrate stability domain close to a seabed stratum and below the seabed is carried out, and finally the vertical migration rate of the seabed shallow fluid is calculated by utilizing a Beckey (Pe) equation, so that a foundation is laid for revealing the activity behavior of the seabed shallow fluid. And a basis is provided for evaluating potential ecological environment and geological disaster influences. According to the embodiment of the invention, the seabed shallow fluid activity rate can be conveniently and accurately analyzed and processed, and the method can be widely applied to the technical field of data processing.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and in particular to a method, device and medium for analyzing and processing the activity rate of shallow-layer fluid on the seafloor. Background Art

[0002] In nature, affected by regional tectonic and sedimentary activities, deep fluids in the strata migrate to shallow layers along fluid channels such as gas chimneys and structural faults under the drive of overpressure, causing deep matter and energy to circulate in the shallow seabed. The intense gas-bearing fluid activity in the continental margin can sometimes directly act on the seabed, playing an important role in controlling the marine carbon cycle and ecosystem evolution. In addition, the activity of gas-bearing fluids in the strata often means that there is sufficient gas supply in the underlying sediments. Carrying out relevant geological exploration work has important indicative significance for serving marine oil and gas, especially the exploration of shallow seabed natural gas hydrates.

[0003] As an important parameter to characterize the characteristics of fluid activity, the fluid migration rate is often obtained through two methods: survey observation or numerical simulation calculation. Among them, survey observation is direct, and can be subdivided into geophysical survey, geochemical survey and seabed in-situ observation according to the survey method. In geophysical survey, the deep fluid activity rate is qualitatively inferred based on the seismic wave reflection intensity, distribution range, amplitude shape and the degree of deformation of the overlying strata caused; in geochemical survey, the fluid activity rate is inferred based on the characteristics of typical ions (such as sulfate ions) in the pore water of the sedimentary strata below the seabed; in seabed in-situ observation, in-situ monitoring equipment deployed on the seabed is often used to directly monitor the leakage of seabed fluids.

[0004] Numerical simulation is an effective method for indirectly estimating fluid migration rate and is widely used in geological exploration practice. Specifically, numerical simulation is mainly based on the principles of fluid kinematics and seepage mechanics. By carrying out numerical modeling and programmed calculations on specific geological parameters such as "formation pressure", "pressure gradient", "rock permeability" and "rock density", it can simulate and predict the intensity and migration direction of fluid activity.

[0005] Although the method of obtaining fluid migration rate based on direct investigation and observation is highly reliable, it is not realistic for large-scale promotion and application due to the huge cost of offshore implementation and high geological, engineering and environmental risks. Most existing technical solutions are guided by the basic principles of fluid mechanics, relying on existing survey data, and indirectly estimating fluid activity intensity and fluid migration rate through numerical simulation methods, providing key scientific parameters for guiding deep oil and gas exploration. Fluid migration rate is mainly obtained through two methods: "direct" investigation and observation or "indirect" numerical simulation calculation. Although the use of investigation and observation to obtain fluid migration rate is highly reliable, its significant disadvantages are high economic cost, long observation period and certain geological, engineering and environmental risks, and it does not have the prospect of widespread promotion and application. Existing numerical simulation technology methods also have certain shortcomings or application limitations in actual application scenarios. Summary of the invention

[0006] The present invention aims to solve the problem of related technical limitations at least to a certain extent. To this end, the present invention proposes a method, device and medium for analyzing and processing the activity rate of shallow seabed fluid, which can conveniently and accurately analyze and process the activity rate of shallow seabed fluid.

[0007] On the one hand, an embodiment of the present invention provides a method for analyzing and processing the flow rate of shallow seafloor fluid, comprising the following steps:

[0008] Obtain the seismic reflection time of the target position in the seismic profile of the target area, and establish a fluid leakage geological model based on the seismic reflection time; the target position includes the seabed position, the seabed-like reflection layer and the root position of the fluid leakage channel; the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel;

[0009] Based on the fluid seepage geological model and the temperature data of the target location, a heat convection conduction model is established;

[0010] Based on the heat convection conduction model, the formation temperature field function is transformed to obtain the function of the geothermal gradient changing with the burial depth;

[0011] Acquire formation temperature measurement data, and obtain the top boundary temperature gradient value of the near-seabed formation based on the formation temperature measurement data processing; the top boundary of the near-seabed formation characterizing the fluid leakage geological model;

[0012] The formation pressure of the seafloor-like reflector is obtained, and the phase equilibrium temperature of the bottom boundary of the hydrate stability domain is obtained by solving the hydrate phase equilibrium equation based on the formation pressure, and then the average geothermal gradient of the hydrate stability domain is obtained by combining the measured seafloor temperature at the seafloor position;

[0013] The average geothermal gradient is substituted into the variation function, and then combined with the Berkeley equation to derive the vertical migration rate of the fluid.

[0014] Optionally, the seismic reflection time includes a first reflection time at the seabed, a second reflection time at a seabed-like reflection layer, and a third reflection time at the root of the fluid leakage channel; establishing a fluid leakage geological model based on the seismic reflection time includes the following steps:

[0015] The seabed depth of the seabed position is obtained according to half of the product of the first reflection time and the first velocity; the first velocity represents the propagation speed of the seismic wave in the seawater;

[0016] The first depth is obtained according to half of the product of the difference between the second reflection time and the first reflection time and the second velocity; the second velocity represents the propagation velocity of the seismic wave in the shallow seabed; the first depth represents the depth of the seabed-like reflection layer below the seabed position;

[0017] A second depth is obtained according to half of the product of the difference between the third reflection time and the first reflection time and the second velocity; the second depth represents the depth of the root position of the fluid leakage channel below the seabed position;

[0018] A fluid seepage geological model is established based on the seafloor depth, the first depth, and the second depth;

[0019] Among them, the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel; the vertical distance of the fluid leakage geological model is equal to the second depth.

[0020] Optionally, the temperature data includes a top boundary temperature of the top boundary and a bottom boundary temperature of the bottom boundary; based on the fluid leakage geological model combined with the temperature data of the target position, a heat convection conduction model is established, including the following steps:

[0021] Based on the top boundary temperature and the bottom boundary temperature, the thermal convection conduction model is established by combining the Berkeley number and the vertical distance of the fluid leakage geological model; the vertical distance represents the depth distance between the top boundary and the bottom boundary;

[0022] Among them, the heat convection conduction model represents the data relationship between the burial depth and its corresponding depth temperature; the expression of the heat convection conduction model is:

[0023]

[0024] Where, T z represents the depth temperature corresponding to the burial depth z; T 0 Indicates the top boundary temperature; T L represents the bottom temperature; L represents the vertical distance; e is a mathematical constant; β represents the Berkeley number.

[0025] Optionally, performing formation temperature field function transformation based on the heat convection conduction model to obtain a function of geothermal gradient variation with burial depth includes the following steps:

[0026] Based on the heat convection conduction model, the partial derivative function of the formation temperature field with respect to the burial depth is calculated, and the functional relationship between the geothermal gradient and the burial depth in the heat convection conduction model is established;

[0027] Among them, the expression of the functional relationship is:

[0028]

[0029] In the formula, The symbol for the partial derivative function; T represents the symbol for temperature;

[0030] Based on the functional relationship, the burial depth is approximately 0 as a constraint condition to obtain the temperature function of the near-seafloor strata;

[0031] The expression of temperature function is:

[0032]

[0033] Substitute the temperature function into the functional relationship and obtain the change function through functional transformation;

[0034] The expression of the change function is:

[0035]

[0036] Optionally, obtaining formation temperature measurement data, and obtaining a top boundary temperature gradient value of a near-seafloor formation based on the formation temperature measurement data, comprises the following steps:

[0037] Obtain in-situ temperature data and location information of the temperature probe of the shallow seabed to obtain formation temperature measurement data;

[0038] The temperature probe is placed in the shallow layer of the seabed by a gravity column, and the gravity column carries a plurality of temperature probes; the shallow layer of the seabed represents a shallow layer within a preset depth below the seabed position;

[0039] The least squares method is used to perform linear fitting on the in-situ temperature data corresponding to different location information to obtain the apparent geothermal gradient value of the near-seabed stratum, which is used as the top boundary temperature gradient value.

[0040] Optionally, the formation pressure of the seafloor-like reflective layer is obtained, and the phase equilibrium temperature of the bottom boundary of the hydrate stability domain is obtained by solving the hydrate phase equilibrium equation based on the formation pressure, and then the average geothermal gradient of the hydrate stability domain is obtained in combination with the measured seafloor temperature at the seafloor position, including the following steps:

[0041] The underwater depth of the quasi-bottom-sea reflector is determined based on the fluid seepage geological model, and then the hydrostatic pressure of the quasi-bottom-sea reflector is calculated in combination with the pore fluid density of the sedimentary strata; the hydrostatic pressure is used as the formation pressure;

[0042] The fluid seepage geological model includes the seafloor depth at the seafloor position and the first depth of the seafloor-like reflective layer below the seafloor position; the underwater depth is obtained based on the sum of the seafloor depth and the first depth; the hydrostatic pressure is obtained by multiplying the underwater depth, the pore fluid density and the gravitational acceleration;

[0043] The hydrate phase equilibrium simulation function is constructed using the preset phase equilibrium simulation software, and the formation pressure is substituted into the hydrate phase equilibrium simulation function to solve and obtain the phase equilibrium temperature of the bottom boundary of the hydrate stability domain;

[0044] Based on the phase equilibrium temperature at the bottom of the hydrate stability zone and the measured seabed temperature at the seabed, the average geothermal gradient of the hydrate stability zone is obtained by partial derivative calculation.

[0045] The expression of the average geothermal gradient is:

[0046]

[0047] In the formula, represents the symbol of the partial derivative function; T represents the symbol of temperature; z represents the burial depth; T BSR represents the phase equilibrium temperature; T 0 Represents the measured seafloor temperature; Z BSR Indicates the first depth.

[0048] Optionally, the average geothermal gradient is substituted into the variation function, and then the vertical migration rate of the fluid is derived in combination with the Berkeley equation, including the following steps:

[0049] Substitute the average effect position point corresponding to the average geothermal gradient into the variation function to obtain the first function;

[0050] The expression of the change function is:

[0051]

[0052] In the formula, represents the symbol of the partial derivative function; T represents the symbol of temperature; z represents the burial depth; L represents the vertical distance of the heat convection conduction model; e is a mathematical constant; β represents the Berkeley number;

[0053] The expression of the average geothermal gradient is:

[0054]

[0055] Where, T BSR represents the phase equilibrium temperature; T0 Represents the measured seafloor temperature; Z BSR Indicates the first depth of the seafloor-like reflector below the seafloor position;

[0056] The expression of the first function is:

[0057]

[0058] Where, 0.5Z BSR is the average effect location point;

[0059] Substituting the Berkeley equation into the first function yields the second function;

[0060] The expression of Berkeley's equation is:

[0061]

[0062] Where φ represents the formation porosity; ρ w represents the density of sediment pore fluid; C w represents the heat capacity of sediment pore fluid; V z represents the vertical migration rate of fluid; λ represents the average thermal conductivity of formation sediment;

[0063] The expression of the second function is:

[0064]

[0065] The measured parameters are introduced into the second function to derive the vertical migration rate of the fluid; the measured parameters include the measured values ​​of formation porosity, sediment pore fluid density, sediment pore fluid heat capacity and average thermal conductivity of formation sediments.

[0066] On the other hand, an embodiment of the present invention provides an analysis and processing device for the activity rate of a shallow seabed fluid, comprising:

[0067] The first module is used to obtain the seismic reflection time of the target position in the seismic profile of the target area, and establish a fluid leakage geological model based on the seismic reflection time; the target position includes the seabed position, the seabed-like reflection layer and the root position of the fluid leakage channel; the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel;

[0068] The second module is used to establish a heat convection conduction model based on the fluid leakage geological model and the temperature data of the target location;

[0069] The third module is used to transform the formation temperature field function based on the heat convection conduction model to obtain the function of the geothermal gradient changing with the burial depth;

[0070] The fourth module is used to obtain formation temperature measurement data, and obtain the top boundary temperature gradient value of the near-seabed formation based on the formation temperature measurement data processing; the top boundary of the near-seabed formation characterizing the fluid leakage geological model;

[0071] The fifth module is used to obtain the formation pressure of the seabed reflector layer, and obtain the phase equilibrium temperature of the bottom boundary of the hydrate stability domain by solving the hydrate phase equilibrium equation based on the formation pressure, and then combine the measured seabed temperature at the seabed position to obtain the average geothermal gradient of the hydrate stability domain;

[0072] The sixth module is used to substitute the average geothermal gradient into the variation function, and then derive the vertical migration rate of the fluid in combination with the Berkeley equation.

[0073] On the other hand, an embodiment of the present invention provides an electronic device, including: a processor and a memory; the memory is used to store programs; the processor executes the program to implement the above-mentioned method for analyzing and processing the activity rate of shallow seabed fluid.

[0074] On the other hand, an embodiment of the present invention provides a computer storage medium, in which a program executable by a processor is stored. When the program executable by the processor is executed by the processor, it is used to implement the above-mentioned analysis and processing method of the shallow seabed fluid activity rate.

[0075] The embodiment of the present invention establishes a fluid leakage geological model based on the seismic reflection time by acquiring the seismic reflection time of the target position in the seismic profile of the target area; the target position includes the seabed position, the seabed-like reflection layer and the root position of the fluid leakage channel; the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel; a heat convection conduction model is established based on the fluid leakage geological model combined with the temperature data of the target position; the formation temperature field function is transformed based on the heat convection conduction model to obtain a function of the change of the geothermal gradient with the burial depth; the formation temperature measurement data is acquired, and the top boundary temperature gradient value of the near-seabed formation is obtained based on the formation temperature measurement data; the near-seabed formation represents the top boundary of the fluid leakage geological model; the formation pressure of the seabed-like reflection layer is acquired, and the phase equilibrium temperature of the bottom boundary of the hydrate stability domain is obtained by solving the hydrate phase equilibrium equation based on the formation pressure, and then the average geothermal gradient of the hydrate stability domain is obtained by combining the measured seabed temperature of the seabed position; the average geothermal gradient is substituted into the change function, and then the vertical migration rate of the fluid is derived by combining with the Berkeley equation. The present invention is guided by the basic theories of fluid kinematics and thermodynamics, gives full play to the parameter advantage of the "temperature" factor, establishes a heat convection conduction model, relies on the measured geothermal data of the near-seabed strata with low acquisition cost, and combines the hydrate phase equilibrium simulation and the hydrate stability domain geothermal data obtained by the inversion of the quasi-seabed reflector layer to carry out the calculation of the average geothermal gradient in the near-seabed strata and the hydrate stability domain below the seabed, and finally uses the Berkeley (Pe) equation to calculate the vertical migration rate of the shallow seabed fluid, which provides a basis for revealing the shallow seabed fluid activity behavior and evaluating the potential ecological environment and geological disaster impact. The embodiment of the present invention can conveniently and accurately analyze and process the shallow seabed fluid activity rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0077] Figure 1 This is a schematic diagram of an implementation environment for analyzing and processing the activity rate of shallow-layer fluid on the seafloor provided by an embodiment of the present invention;

[0078] Figure 2 It is a flow chart of a method for analyzing and processing the activity rate of shallow-layer fluid on the seafloor provided by an embodiment of the present invention;

[0079] Figure 3 A schematic diagram of a fluid activity geological model established based on seismic profile characteristics provided by an embodiment of the present invention;

[0080] Figure 4 A schematic diagram of the expanded flow of step S400 provided in an embodiment of the present invention;

[0081] Figure 5 A schematic diagram of a data relationship curve for calculating the phase equilibrium temperature of the bottom boundary of the hydrate stability domain through phase equilibrium simulation provided in an embodiment of the present invention;

[0082] Figure 6 A schematic diagram of a data relationship curve for calculating the boundary geothermal gradient of a fluid leakage model provided in an embodiment of the present invention;

[0083] Figure 7 A schematic diagram of a data relationship curve for calculating the vertical migration rate of formation fluid using the Pe (Berkeley) equation provided in an embodiment of the present invention;

[0084] Figure 8 A schematic diagram of the overall process of a method for analyzing and processing the activity rate of shallow seabed fluid provided by an embodiment of the present invention;

[0085] Fig. 9 A schematic diagram of the structure of a device for analyzing and processing the activity rate of shallow-layer fluid on the seafloor provided by an embodiment of the present invention;

[0086] Fig.10 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0087] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0088] It should be noted that, although the functional modules are divided in the system schematic diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flow chart. The terms "first / S100", "second / S200", etc. in the specification, claims and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0089] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0090] To facilitate the understanding of the technical solution of the present invention, the meanings of the parameters that may be cited in the embodiments of the present invention and their technical principles are first explained:

[0091] Hydrate: A mineral crystal formed by the combination of water molecules and gas molecules under low temperature and high pressure conditions. It is often found in marine environments or terrestrial permafrost zones and is a potential clean energy source with huge energy (hydrates in this invention specifically refer to hydrates in marine environments).

[0092] BSR: Bottom Simulation Reflection, represents the reflection interface between hydrate-bearing sediments and the underlying hydrate-free layer. BSR is an important indicator of hydrate occurrence in geophysical exploration, and is also a thermodynamic interface. It is generally believed that the area above BSR is within the hydrate stability domain, where hydrates can be stably present; the area below BSR is beyond the hydrate stability domain, where hydrates cannot exist stably.

[0093] Hydrate phase equilibrium curve: usually expressed in the form of a pressure (P)-temperature (T) diagram, refers to the equilibrium state of coexistence of hydrate (solid phase), liquid water and free gas under specific temperature and pressure conditions. The hydrate phase equilibrium curve is the equilibrium boundary between the hydrate stable zone and the unstable zone.

[0094] Hydrate stability domain: refers to a specific area below the seafloor where the temperature and pressure conditions are within the thermodynamically stable range for hydrate formation. The bottom boundary of the hydrate stability domain is numerically equal to the intersection value of the geothermal gradient line and the hydrate phase equilibrium curve. The hydrate stability domain is mainly controlled by geological factors such as seawater depth, seafloor temperature and pressure, geothermal gradient, pore fluid salinity, and natural gas alkane gas composition.

[0095] Gas chimney: A geophysical manifestation of gas in sedimentary strata, which resembles a "chimney". Gas chimneys are important channels for the migration of deep gas-bearing fluids to shallow layers. The migration to shallow layers is accompanied by a significant heat transfer effect, which leads to changes in the shallow geothermal field of the seabed. The intensity of gas-bearing fluid activity and the disturbance of the geothermal field can be qualitatively inferred based on the shape and scale of gas chimneys.

[0096] Geothermal field: Geothermal field is the manifestation of the earth's internal heat energy on the crust through rocks with different thermal conductivity. Under the surface, the stratum temperature increases regularly with the increase of burial depth, that is, the geothermal temperature increases accordingly with each increase in burial depth.

[0097] Geothermal gradient: A parameter that measures the vertical transfer rate of stratum temperature, usually expressed as the degree of temperature drop per kilometer (℃ / km).

[0098] Thermal conductivity: also known as "thermal conductivity" or "thermal conductivity", is the amount of heat transferred by a unit temperature gradient through a unit heat conduction surface in a unit time, with the unit W / (m·K). The thermal conductivity of sediments is directly or indirectly related to lithology, geological age, burial depth, and compaction degree. The thermal conductivity of deep-sea sediments is mainly related to hydrostatic pressure, sediment compaction degree, and the resulting porosity changes.

[0099] Heat transfer: refers to the physical phenomenon of heat energy transfer caused by temperature difference. There are three basic forms of heat transfer: heat conduction, heat radiation and heat convection. Heat conduction is the heat transfer phenomenon when there is no macroscopic movement in the medium, which can occur in solids, liquids and gases. Strictly speaking, pure heat conduction is only in solids; heat convection is the process of transferring energy from a higher temperature part to a lower temperature part by the flow of liquid or gas. Under shallow geological conditions on the seabed, the transfer of energy in deep strata is mainly achieved through heat conduction and heat convection.

[0100] Peclet Number (Pe for short) indicates the ratio of convection to diffusion in a fluid gradient field environment. In fluid theory, the larger the Pe, the more significant the role of convection in the fluid migration process.

[0101] It is understandable that the analysis and processing method of the shallow seabed fluid activity rate provided by the embodiment of the present invention can be applied to any computer device with data processing and computing capabilities, and this computer device can be various terminals or servers. When the computer device in the embodiment is a server, the server is an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN (Content Delivery Network), and big data and artificial intelligence platforms. Optionally, the terminal is a smart phone, tablet computer, laptop computer, desktop computer, etc., but is not limited to this.

[0102] To facilitate the understanding of the technical solution of the present invention, the technical feature terms that may appear in the embodiments of the present invention are first explained:

[0103] like Figure 1 FIG. 1 is a schematic diagram of an implementation environment provided by an embodiment of the invention. Figure 1 The implementation environment includes at least one terminal 102 and a server 101. The terminal 102 and the server 101 can be connected to a network wirelessly or wired to complete data transmission and exchange.

[0104] Server 101 can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers. It can also be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN (Content Delivery Network), as well as big data and artificial intelligence platforms.

[0105] In addition, the server 101 can also be a node server in the blockchain network. Blockchain is a new application model of computer technologies such as distributed data storage, peer-to-peer transmission, consensus mechanism, and encryption algorithm.

[0106] The terminal 102 may be a smart phone, a tablet computer, a laptop computer, a desktop computer, a smart speaker, a smart watch, etc., but is not limited thereto. The terminal 102 and the server 101 may be directly or indirectly connected via wired or wireless communication, which is not limited in the embodiment of the present invention.

[0107] Based on the example Figure 1 In the implementation environment shown, an embodiment of the present invention provides a method for analyzing and processing the activity rate of shallow seabed fluid. The following is explained using the example of applying the method for analyzing and processing the activity rate of shallow seabed fluid in the server 101. It can be understood that the method for analyzing and processing the activity rate of shallow seabed fluid can also be applied to the terminal 102.

[0108] Reference Figure 2 , Figure 2 The flowchart of the method for analyzing and processing the activity rate of shallow seabed fluid applied to the server provided in the embodiment of the present invention, the execution subject of the method for analyzing and processing the activity rate of shallow seabed fluid can be any of the aforementioned computer devices (including servers or terminals). Figure 2 , the method comprises the following steps:

[0109] S100, obtaining the seismic reflection time of the target position in the seismic profile of the target area, and establishing a fluid leakage geological model based on the seismic reflection time;

[0110] The target positions include the seabed position, the seabed-like reflective layer and the root position of the fluid leakage channel; the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel;

[0111] It should be noted that the seismic reflection time includes the first reflection time of the seabed position, the second reflection time of the seabed-like reflection layer and the third reflection time of the root position of the fluid leakage channel; in some embodiments, establishing a fluid leakage geological model based on the seismic reflection time may include the following steps: obtaining the seabed depth of the seabed position according to half of the product of the first reflection time and the first velocity; the first velocity represents the propagation velocity of seismic waves in seawater; obtaining the first depth according to half of the product of the difference between the second reflection time and the first reflection time and the second velocity; the second velocity represents the propagation velocity of seismic waves in the shallow seabed; the first depth represents the depth of the seabed-like reflection layer below the seabed position; obtaining the second depth according to half of the product of the difference between the third reflection time and the first reflection time and the second velocity; the second depth represents the depth of the root position of the fluid leakage channel below the seabed position; establishing a fluid leakage geological model based on the seabed depth, the first depth and the second depth; wherein the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel; the vertical distance of the fluid leakage geological model is equal to the second depth.

[0112] For example, in some specific implementations, a specific embodiment with typical fluid leakage activity characteristics is taken as an example:

[0113] In the seismic profile, read the seismic reflection time corresponding to the seismic reflection event axis at the seabed position, recorded as t 0 , unit s;

[0114] In the seismic profile, read the seismic reflection time corresponding to the BSR position, recorded as t BSR , unit s;

[0115] In the seismic profile, read the seismic reflection time corresponding to the root position of the fluid leakage channel (such as gas chimney, tubular channel, mud diapir / mud volcano) (i.e. the position where the fluid begins to leak or diffuse), recorded as t L , unit s;

[0116] In a specific embodiment, the propagation speed of seismic waves in seawater is v=1500 m / s; the propagation speed of seismic waves in the shallow seabed is v=1600 m / s.

[0117] Specifically, the seafloor depth D sea (i.e. water depth), BSR burial depth Z below the seabed BSR , the depth L of the root of the fluid leakage channel is recorded as:

[0118] D sea =(1500*t 0 ) / twenty one)

[0119] Z BSR =1600*(tBSR -t 0 ) / twenty two)

[0120] L=1600*(t L -t 0 ) / twenty three)

[0121] According to the above parameters, a gas-bearing fluid leakage geological model is established. The geological model environment is set as a stratum that is permeable to both heat and fluid, and the heat and fluid migration directions are both vertical. The seabed is taken as the top boundary of the fluid leakage geological model, and the root position of the fluid leakage channel is taken as the bottom boundary of the fluid leakage geological model. The model height, that is, the vertical distance between the "top boundary" and the "bottom boundary", is L (e.g. Figure 3 shown).

[0122] S200, establishing a heat convection conduction model based on the fluid leakage geological model and the temperature data of the target location;

[0123] It should be noted that the temperature data includes the top boundary temperature of the top boundary and the bottom boundary temperature of the bottom boundary; in some embodiments, step S200 may include the following steps: based on the top boundary temperature and the bottom boundary temperature, a thermal convection conduction model is established in combination with the Berkeley number and the vertical distance of the fluid leakage geological model; the vertical distance represents the depth distance between the top boundary and the bottom boundary; wherein the thermal convection conduction model represents the data relationship between the burial depth and the corresponding depth temperature; the expression of the thermal convection conduction model is:

[0124]

[0125] Where, T z represents the depth temperature corresponding to the burial depth z; T 0 Indicates the top boundary temperature; T L represents the bottom temperature; L represents the vertical distance; e is a mathematical constant; β represents the Berkeley number.

[0126] For example, in some specific implementations, a one-dimensional thermal convection conduction numerical model of the temperature field is established based on the geological model, which is expressed as:

[0127]

[0128] In formula 4:

[0129] L: height of the heat convection conduction model, m;

[0130] z: Depth at any position z in the heat convection conduction model (z≤L), m;

[0131] T 0 : Seafloor temperature, i.e. the top temperature of the heat convection conduction model ℃;

[0132] TL : bottom temperature of the heat convection conduction model, ℃;

[0133] T Z : Temperature at depth z in the heat convection conduction model, °C;

[0134] β: Pe (Berkeley number).

[0135] Specifically, the seafloor temperature T is measured by carrying a temperature probe on a gravity column. 0 The system can measure, record and store data in the form of electronic documents, and directly retrieve data for numerical calculation.

[0136] S300, transforming the formation temperature field function based on the heat convection conduction model to obtain a function of the change of the geothermal gradient with the burial depth;

[0137] It should be noted that, in some embodiments, step S300 may include the following steps:

[0138] Based on the heat convection conduction model, the partial derivative function of the formation temperature field with respect to the burial depth is calculated, and the functional relationship between the geothermal gradient and the burial depth in the heat convection conduction model is established;

[0139] Among them, the expression of the functional relationship is:

[0140]

[0141] In the formula, The symbol for the partial derivative function; T represents the symbol for temperature;

[0142] Based on the functional relationship, the burial depth is approximately 0 as a constraint condition to obtain the temperature function of the near-seafloor strata;

[0143] The expression of temperature function is:

[0144]

[0145] Substitute the temperature function into the functional relationship and obtain the change function through functional transformation;

[0146] The expression of the change function is:

[0147]

[0148] For example, in some specific implementations, the partial derivative function of the formation temperature field with respect to the burial depth is calculated, and the functional relationship between the geothermal gradient and the burial depth of the heat convection conduction model is established, which is recorded as:

[0149]

[0150] For the near-seafloor strata (i.e., the top boundary of the geological model, when the burial depth z≈0), Formula 5 is expressed as:

[0151]

[0152] Substituting formula 6 into formula 5 and replacing some constant terms on the right side of the equation, we get:

[0153]

[0154] Further functional transformation of formula 7 gives formula 8:

[0155]

[0156] S400, obtaining formation temperature measurement data, and obtaining a top boundary temperature gradient value of a near-seafloor formation based on the formation temperature measurement data;

[0157] Among them, the near-seafloor strata represent the top boundary of the fluid seepage geological model;

[0158] It should be noted that in some embodiments, Figure 4 As shown, step S400 may include the following steps: S401, obtaining in-situ temperature data and position information of a temperature probe of the shallow layer of the seabed to obtain formation temperature measurement data; wherein, the temperature probe is carried by a gravity column and placed at the shallow layer of the seabed, and the gravity column carries multiple temperature probes; the shallow layer of the seabed represents the shallow strata within a preset depth below the seabed position; S402, using the least squares method to perform linear fitting on the in-situ temperature data corresponding to different position information to obtain the apparent geothermal gradient value of the near-seabed stratum, and use the apparent geothermal gradient value as the top boundary temperature gradient value.

[0159] For example, in some specific embodiments, the geothermal gradient of the near-seafloor formation, i.e., the geothermal gradient of the top boundary of the model, is expressed as express.

[0160] Specifically, the geothermal gradient of the near-seabed stratum is obtained by collecting in-situ temperature data of the shallow seabed layer (generally the shallow stratum within 5m below the seabed) through a gravity column carrying a temperature probe, and combining the position information of the temperature probe, the least squares method is used to linearly fit the in-situ stratum temperature at different burial depths of the near-seabed stratum to obtain the apparent geothermal gradient value of the near-seabed stratum, which is recorded as:

[0161]

[0162] Where, T i , T k are the measured formation temperatures of the near-seafloor formations recorded by the i-th and k-th temperature probes carried by the gravity column, respectively;

[0163] Where, X i , Xk are the depths below the seabed where the i-th and k-th temperature probes carried by the gravity column are located, respectively.

[0164] Specifically, i,k is generally less than 6, that is, the number of temperature probes carried by the gravity column is generally less than 6;

[0165] Specifically, X i , X k Generally less than 5m, that is, the temperature probe carried by the gravity column penetrates less than 5m below the seabed;

[0166] Specifically, during the temperature measurement of near-seabed formations, temperature probes are installed on gravity sampling tubes at different angles and fixed spacing values, and the relative distances between the temperature probes are measured before and after entering the water to ensure that the temperature probes do not shift.

[0167] Specifically, since the temperature measurement probe may not be completely upright when penetrating into the sediment, but may be at a certain angle to the vertical direction, it is necessary to perform inclination correction of the temperature measurement probe to calculate the actual geothermal gradient value.

[0168] Specifically, the temperature measurement probe position information, the measured in-situ temperature information, and the temperature measurement probe inclination information all come from field measurement records and are stored in the form of electronic documents, and the data information can be directly retrieved for numerical calculations.

[0169] S500, obtaining the formation pressure of the seafloor-like reflective layer, and obtaining the phase equilibrium temperature of the bottom boundary of the hydrate stability domain by solving the hydrate phase equilibrium equation based on the formation pressure, and then obtaining the average geothermal gradient of the hydrate stability domain in combination with the measured seafloor temperature at the seafloor position;

[0170] It should be noted that, in some embodiments, step S500 may include the following steps: determining the underwater depth of the seafloor-like reflective layer based on the fluid seepage geological model, and then calculating the hydrostatic pressure of the seafloor-like reflective layer in combination with the pore fluid density of the sedimentary stratum; using the hydrostatic pressure as the formation pressure;

[0171] The fluid seepage geological model includes the seafloor depth at the seafloor position and the first depth of the seafloor-like reflective layer below the seafloor position; the underwater depth is obtained based on the sum of the seafloor depth and the first depth; the hydrostatic pressure is obtained by multiplying the underwater depth, the pore fluid density and the gravitational acceleration;

[0172] The hydrate phase equilibrium simulation function is constructed using the preset phase equilibrium simulation software, and the formation pressure is substituted into the hydrate phase equilibrium simulation function to solve and obtain the phase equilibrium temperature of the bottom boundary of the hydrate stability domain;

[0173] Based on the phase equilibrium temperature at the bottom of the hydrate stability zone and the measured seabed temperature at the seabed, the average geothermal gradient of the hydrate stability zone is obtained by partial derivative calculation.

[0174] The expression of the average geothermal gradient is:

[0175]

[0176] In the formula, represents the symbol of the partial derivative function; T represents the symbol of temperature; z represents the burial depth; T BSR represents the phase equilibrium temperature; T 0 Represents the measured seafloor temperature; Z BSR Indicates the first depth.

[0177] For example, in some specific embodiments, the formation pressure at the BSR position is calculated, and then the bottom phase equilibrium temperature of the hydrate stability domain is calculated by solving the hydrate phase equilibrium equation (i.e., the PT equation).

[0178] Specifically, the formation pressure at the BSR position is approximately equal to the hydrostatic pressure at that position, expressed as:

[0179] P BSR =ρ*g*H=ρ*g*(D sea +Z BSR ) (10)

[0180] Where, ρ: pore fluid density of sedimentary formation, 1035 kg / m 3 ;

[0181] g: acceleration due to gravity, 9.8 m / s 2 ;

[0182] D sea : depth of overlying seawater, m;

[0183] Z BSR : burial depth of BSR below the seafloor, m.

[0184] Specifically, the phase equilibrium simulation software CSMGEM was used to carry out numerical simulation calculations on the bottom boundary of the hydrate stability domain. By inputting parameters such as the alkane gas composition of the hydrate decomposition gas and the salinity of the pore water, a hydrate phase equilibrium simulation function was constructed. The formation pressure P at the BSR position obtained based on Formula 10 was converted into BSR Substitute it into the hydrate phase equilibrium simulation function to obtain the formation temperature at the BSR position, that is, the phase equilibrium temperature T at the bottom boundary of the hydrate stability region. BSR (like Figure 5 shown).

[0185] Specifically, the test work on the alkane gas composition of the hydrate decomposition gas and the salinity of the pore water are completed on site during the hydrate drilling voyage. The corresponding test data are stored in the form of electronic documents, and the data can be directly retrieved for numerical simulation calculations.

[0186] Specifically, according to the measured seafloor temperature T 0 and the bottom phase equilibrium temperature T of the hydrate stability region BSR , calculate the average geothermal gradient of the hydrate stability zone (such as Figure 6 As shown), recorded as:

[0187]

[0188] S600. Substitute the average geothermal gradient into the variation function, and then derive the vertical migration rate of the fluid in combination with the Berkeley equation.

[0189] It should be noted that, in some embodiments, step S600 may include the following steps: substituting the average effect position point corresponding to the average geothermal gradient into the variation function to obtain a first function; wherein the expression of the variation function is:

[0190]

[0191] In the formula, represents the symbol of the partial derivative function; T represents the symbol of temperature; z represents the burial depth; L represents the vertical distance of the heat convection conduction model; e is a mathematical constant; β represents the Berkeley number;

[0192] The expression of the average geothermal gradient is:

[0193]

[0194] Where, T BSR represents the phase equilibrium temperature; T 0 Represents the measured seafloor temperature; Z BSR Indicates the first depth of the seafloor-like reflector below the seafloor position;

[0195] The expression of the first function is:

[0196]

[0197] Where, 0.5Z BSR is the average effect location point;

[0198] Substituting the Berkeley equation into the first function yields the second function;

[0199] The expression of Berkeley's equation is:

[0200]

[0201] Where φ represents the formation porosity; ρ w represents the density of sediment pore fluid; C w represents the heat capacity of sediment pore fluid; V z represents the vertical migration rate of fluid; λ represents the average thermal conductivity of formation sediment;

[0202] The expression of the second function is:

[0203]

[0204] The measured parameters are introduced into the second function to derive the vertical migration rate of the fluid; the measured parameters include the measured values ​​of formation porosity, sediment pore fluid density, sediment pore fluid heat capacity and average thermal conductivity of formation sediments.

[0205] For example, in some specific implementations, the geothermal gradient derived from Formula 11 is is the average geothermal gradient value of the hydrate stability domain, and its value is half of the hydrate stability domain, that is, the average effect position point is 0.5Z BSR .

[0206] In a specific embodiment, according to the model boundary conditions, Formula 8 is expressed as:

[0207]

[0208] Combined with the definition formula of Pe (Berkeley) equation:

[0209]

[0210] The specific expression of formula 12 is as follows:

[0211]

[0212] In formula 14:

[0213] The geothermal gradient value of the near-seafloor strata, ℃ / km, is calculated by formula 9;

[0214] The average geothermal gradient of the hydrate stability zone, °C / km, is calculated by formula 11;

[0215] Z BSR : Depth of the BSR below the seafloor, m, calculated by Formula 2;

[0216] ρ w : Sediment pore fluid density, 1035kg / m 3 ;

[0217] C w: Heat capacity of sediment pore fluid, 4186 J·kg -1 ·K -1 ;

[0218] φ: formation porosity, dimension is 1;

[0219] λ: average thermal conductivity of stratum sediments, W·m -1 ·K -1 ;

[0220] V z : vertical migration rate of fluid in the heat convection conduction model, m / s;

[0221] Specifically, the formation porosity φ can be calculated using sonic logging, density logging or neutron porosity logging curves obtained by hydrate logging while drilling.

[0222] Specifically, the average thermal conductivity λ of the sediment can be obtained by conducting thermal conductivity tests on sediment samples obtained by gravity piston sampling and hydrate drilling.

[0223] V z As the only variable to be solved, the vertical migration rate of the fluid is obtained by numerical calculation through formula 14 (e.g. Figure 7 shown).

[0224] In order to explain the principle of the technical solution of the present invention in detail, the overall process of the present invention is described below in combination with some specific embodiments. It is easy to understand that the following is an explanation of the technical principle of the present invention and cannot be regarded as a limitation of the present invention.

[0225] First of all, it should be noted that the method of obtaining fluid migration rate based on direct survey and observation is highly reliable, but due to the huge cost of offshore operation and high geological, engineering and environmental risks, it is not realistic for large-scale promotion and application. Existing technical solutions (such as the following example) are mostly guided by the basic principles of fluid mechanics, relying on existing survey data, and indirectly estimating fluid activity intensity and fluid migration rate through numerical simulation methods, providing key scientific parameters for guiding deep oil and gas exploration.

[0226] The fluid migration rate is mainly obtained through "direct" survey observation or "indirect" numerical simulation calculation. Although the use of survey observation to obtain fluid migration rate is highly reliable, its significant disadvantages are high economic cost, long observation period and certain geological-engineering-environmental risk hazards, and it does not have the prospect of widespread promotion and application. However, the existing numerical simulation technology methods also have certain shortcomings or application limitations, which are mainly reflected in the following three aspects:

[0227] (1) The existing technical solutions mainly target deep strata (usually buried thousands of meters below the seafloor), and focus on the "secondary migration" of liquid petroleum hydrocarbons in consolidated rocks and the accumulation process in the dominant reservoir. Compared with the fluid activity behavior of shallow seafloor strata with the characteristics of "shallow burial depth" (usually buried less than 200m below the seafloor), "loose and unconsolidated", "developed pore structure" and "active fluid micro-leakage", the two have obvious differences in fluid migration conditions, driving mechanisms and numerical simulation methods, resulting in the limitations of existing technical solutions when applied to the study of shallow seafloor fluid activity.

[0228] (2) Existing technical solutions usually use formation "pressure" factors, especially fluid overpressure factors, as key control variables for geological modeling and fluid migration rate calculation. However, for shallow seabed sediments, the pore fluid pressure is almost the same as the hydrostatic pressure, and there is no significant formation overpressure effect. In addition, shallow seabed fluid activity is mostly micro-seepage, and the intensity of fluid activity is significantly weaker than that of deep fluids. Therefore, the existing solutions based on formation pressure factors to carry out modeling and estimate the direction of formation fluid activity and migration rate through "overpressure" anomalies are no longer applicable.

[0229] (3) Existing technical solutions and numerical simulation methods involve many types of parameters, and key geological parameters such as "formation pressure", "deep rock permeability", "rock density", etc. need to be obtained through deep well drilling, coring testing, etc. Due to the difficulty of data collection and the high cost of parameter acquisition, they are not suitable for large-scale application.

[0230] Taking into account the limitations of the existing technical methods in terms of application conditions, the present invention focuses on the leakage behavior of gas-bearing fluids in shallow submarine strata (generally less than 200 m below the seabed, generally located in the hydrate stability domain). Based on the fact that the migration of gas-bearing hot fluids causes the migration of deep material energy and the disturbance of shallow submarine geothermal fields, the present invention is guided by the basic theories of fluid kinematics and thermodynamics, gives full play to the parameter advantages of the "temperature" factor, and establishes a one-dimensional thermal convection conduction model of the temperature field. Relying on the measured geothermal data of near-seabed strata with low acquisition costs, and combining the geothermal data of the hydrate stability domain obtained by hydrate phase equilibrium simulation and BSR inversion, the average geothermal gradient calculation in the near-seabed strata and the hydrate stability domain below the seabed is carried out. Finally, the Berkeley (Pe) equation is used to calculate the vertical migration rate of shallow submarine fluids, which provides a basis for revealing the activity behavior of shallow submarine fluids and evaluating the potential ecological environment and geological disasters.

[0231] In some specific application scenarios, such as Figure 8 As shown, the technical solution of the present invention can be implemented as follows:

[0232] Step 1: Establish a geological model of gas-bearing fluid leakage and determine the model boundary conditions based on seismic reflection characteristics.

[0233] In this embodiment, a typical fluid leakage activity area in a certain sea area is taken as the research object.

[0234] Specifically, in a specific embodiment of developing deep gas chimney activity, exemplary,

[0235] In the seismic profile, read the seismic reflection time t at the seabed location 0 : 2.56s;

[0236] In the seismic profile, read the seismic reflection time t at the BSR position BSR : 2.75s;

[0237] In the seismic profile, read the seismic reflection time t at the root of the gas chimney L : 3.5s.

[0238] According to the propagation speed of seismic waves in seawater v = 1500m / s; the propagation speed of seismic waves in the shallow seabed v = 1600m / s, the seabed depth (i.e. water depth), the burial depth of BSR below the seabed, and the root depth of the fluid leakage channel are calculated respectively:

[0239] D sea =(1500*t 0 ) / 2=(1500*2.56) / 2=1920m (1)

[0240] Z BSR =1600*(t BSR -t 0 ) / 2=1600*(2.75-2.56) / 2=152m (2)

[0241] L=1600*(t L -t 0 ) / 2=1600*(3.5-2.56) / 2=752m (3)

[0242] According to the calculated D sea , Z BSR , L and other parameter values, and establish a gas-bearing fluid leakage geological model. The geological model environment is a stratum that is permeable to both heat and fluid, and the directions of heat and fluid migration are both vertical.

[0243] The height L of the established geological model is 752m, and the BSR is located 152m below the top boundary of the geological model.

[0244] Step 2: Based on the geological model, establish a one-dimensional thermal convection conduction numerical model of the temperature field.

[0245] In a specific embodiment of developing deep gas chimney activities, illustratively, a one-dimensional thermal convection conduction numerical model of the temperature field is established based on the geological model, which is recorded as:

[0246]

[0247] Substituting the geological model parameters calculated based on step 1 into formula 4, the numerical model expression of the one-dimensional thermal convection conduction of the temperature field is obtained as follows:

[0248]

[0249] In formula 4-1,

[0250] L: height of one-dimensional heat convection conduction model, 752m;

[0251] z: Depth of any position z in the heat convection conduction model (z≤752m), m;

[0252] T 0 : Seafloor temperature, i.e. the top temperature of the heat convection conduction model, 2.64℃;

[0253] T L : bottom temperature of the heat convection conduction model, °C;

[0254] T z : the formation temperature at depth z in the heat convection conduction model, °C;

[0255] β is the value of Pe (Berkeley number), and its dimension can be 1.

[0256] Specifically, in this embodiment, the seafloor temperature T 0 The temperature probe is carried by a gravity column to complete the measurement, and the data is recorded and stored in the form of electronic documents, and the data can be directly retrieved for numerical calculations.

[0257] Step 3: Carry out geothermal field function transformation to obtain the function of geothermal gradient changing with burial depth.

[0258] In this embodiment, by calculating the partial derivative function of the formation temperature field with respect to the burial depth, a functional relationship between the geothermal gradient and the burial depth in the heat convection conduction model is established, which is in the following form:

[0259]

[0260] Substituting the geological model parameters calculated in step 1 into formula 5, the functional relationship between the geothermal gradient and the burial depth of the heat convection conduction model is obtained as follows:

[0261]

[0262] For the near-seafloor strata (i.e., the top boundary of the geological model, when the burial depth z≈0), Formula 5-1 is expressed as

[0263]

[0264] Substitute Formula 6 into Formula 5-1 and replace some constant terms on the right side of the equation:

[0265]

[0266] Further functional transformation of formula 7 gives formula 8

[0267]

[0268] Step 4: Calculate the geothermal gradient value of the near-seabed formation based on the formation temperature measurement data.

[0269] In this embodiment, the geothermal gradient of the stratum near the seabed, i.e., the geothermal gradient of the top boundary of the model, is express.

[0270] Specifically, the geothermal gradient of the near-seabed strata is obtained by collecting in-situ temperature data of the shallow seabed layer (generally the strata shallower than 5m below the seabed) through a gravity column carrying a temperature probe, and combining the temperature probe position information, the least squares method is used to perform linear fitting of the in-situ stratum temperatures at different burial depths of the near-seabed strata to obtain the geothermal gradient of the near-seabed strata.

[0271]

[0272] In this embodiment, the in-situ temperature information of the near-seafloor formation recorded by the temperature probe carried by the gravity column is: T 1 :2.809℃;T 2 :2.893℃;T 3 :2.986℃;T 4 :3.064℃;T 5 :3.154℃;T 6 :3.248℃; where T 1 , T 2 , T 3 , T 4 , T 5 , T 6 These are the measured formation temperatures of the near-seafloor formations recorded by the 1st, 2nd, 3rd, 4th, 5th, and 6th temperature probes carried by the gravity column;

[0273] In this embodiment, the buried depth information recorded by the temperature probe carried by the gravity column is: 1 :1.025m;X 2 :1.825m;X 3 :2.625m;X 4:3.425m;X 5 :4.225m;X 6 :5.025m. Among them, X 1 , X 2 , X 3 , X 4 , X 5 , X 6 These are the depths below the seabed where the 1st, 2nd, 3rd, 4th, 5th and 6th temperature probes carried by the gravity column are located.

[0274] Based on formula 9, the apparent geothermal gradient of the near-seafloor strata is obtained by linear fitting.

[0275] Specifically, during the temperature measurement of the near-seafloor formation, the temperature probes were installed on the gravity sampling tube at different angles and fixed spacing values ​​and fixed by screws. The relative distances between the temperature probes were measured before and after entering the water to ensure that the temperature probes were not displaced.

[0276] Specifically, since the temperature measuring probe has a certain angle with the vertical direction when it penetrates into the seabed sediment, the actual geothermal gradient of the near-seabed stratum can be obtained after the inclination correction of the temperature measuring probe.

[0277] Specifically, the temperature measurement probe position information, the measured in-situ temperature information, and the temperature measurement probe inclination information all come from field measurement records and are stored in the form of electronic documents, and the data information can be directly retrieved for numerical calculations.

[0278] Step 5: Estimate the equilibrium temperature of the hydrate bottom phase based on the BSR burial depth and calculate the average geothermal gradient value of the hydrate stability domain.

[0279] In this embodiment, the formation pressure at the BSR position in the model is calculated, and the hydrate phase equilibrium equation (ie, PT equation) is solved to calculate the bottom boundary phase equilibrium temperature of the hydrate stability region.

[0280] In this embodiment, the formation pressure at the BSR position is approximately equal to the hydrostatic pressure at the position, which is expressed as:

[0281] P BSR =ρ*g*H=ρ*g*(D sea +Z BSR ) (10)

[0282] Specifically, the model parameter calculation results in step 1 are substituted into formula 10 to calculate the formation pressure at the BSR position:

[0283] P BSR =ρ*g*H=ρ*g*(D sea +ZBSR )=1035*9.8*(1920+152)=21.02Mpa(10-1)

[0284] In formula 10-1:

[0285] ρ: density of pore fluid in sedimentary formation, 1035 kg / m 3 ;

[0286] g: acceleration due to gravity, 9.8 m / s 2 ;

[0287] D sea : Sea depth, 1920m;

[0288] Z BSR : The burial depth of the BSR below the seabed is 152m.

[0289] Specifically, the alkane gas composition of the hydrate decomposition gas in this embodiment is:

[0290] CH 4 :97.5%;C 2 H 6 :2.49%;C 3 H 8 : 0.01%; pore water salinity: 35‰.

[0291] In this embodiment, the gas composition of hydrate decomposition, pore water salinity and other related test contents are all completed on-site during the hydrate drilling voyage, and the test results are stored in the form of electronic documents, and the data can be directly retrieved for numerical simulation calculations.

[0292] In this embodiment, the hydrate decomposition gas alkane gas composition and pore water salinity parameter information are input into the phase equilibrium simulation software CSMGEM to carry out hydrate phase equilibrium simulation, that is, to construct the hydrate phase equilibrium function.

[0293] Furthermore, the BSR position obtained based on Formula 10-1 is placed at the ground pressure P BSR Substituting into the hydrate phase equilibrium simulation function, the formation temperature at the BSR position is calculated, that is, the bottom boundary phase equilibrium temperature T of the hydrate stability domain. BSR :17.93℃.

[0294] In this embodiment, according to the measured seabed temperature T 0 and the bottom phase equilibrium temperature T of the hydrate stability region BSR , calculate the average geothermal gradient of the hydrate stability zone, expressed as:

[0295]

[0296] Step 6: Use the Pe (Berkeley) equation and combine it with the model boundary geothermal gradient value to calculate the vertical migration rate of the formation fluid.

[0297] In this embodiment, the geothermal gradient derived from formula 11 is is the average geothermal gradient value of the hydrate stability domain, and its value is half of the hydrate stability domain, that is, the average effect position point is 0.5Z BSR .

[0298] In a specific embodiment, according to the model boundary conditions, Formula 8 is expressed as:

[0299]

[0300] The result calculated by formula 2, formula 9, and formula 11 is Substituting into formula 12, the specific expression is as follows:

[0301] 100.59 / 114.1=e β(76 / L) (12-1)

[0302] Combined with the definition formula of Pe (Berkeley number):

[0303]

[0304] The expression of formula 12-1 is:

[0305]

[0306] In this embodiment, the specific information of each parameter in Formula 14 is as follows:

[0307] ρ w : Sediment pore fluid density, 1035kg / m 3 ;

[0308] C w : Heat capacity of sediment pore fluid, 4186 J·kg -1 ·K -1 ;

[0309] φ: porosity of shallow seafloor sedimentary strata, 0.4;

[0310] Specifically, in this embodiment, the φ value is calculated using the hydrate while drilling sonic logging information;

[0311] λ: Average thermal conductivity of shallow seafloor sediments, 1.2 W·m -1 ·K -1 .

[0312] Specifically, in this embodiment, the λ value is obtained based on gravity piston sampling and thermal conductivity testing of hydrate drilling sediment samples.

[0313] In this embodiment, V z is the only variable to be solved in formula 14. Through numerical calculation, the vertical migration rate of the fluid is obtained as V z : 3.62cm / year.

[0314] In this example, the calculated fluid leakage activity rate is comparable to the fluid activity rate in the hydrate drilling area on the northeastern slope of the South China Sea that has been confirmed by drilling. This result reveals that the study area may also have the potential for hydrate development.

[0315] In summary, the present invention aims to solve the scientific and technological problems existing in the process of marine geological exploration, such as "high cost of deep-sea in-situ data acquisition and observation", "difficult to predict the activity rate of shallow seabed fluid", and "uncertain potential engineering geological risks". Based on the basic theories of fluid kinematics and thermodynamics, the present invention gives full play to the parameter advantages of the "temperature" element of the formation, relies on the near-seabed measured geothermal data with low acquisition cost and combines the hydrate phase equilibrium simulation and BSR inversion to obtain the hydrate stability domain geothermal data. By establishing a one-dimensional thermal convection conduction model of the temperature field, and carrying out the calculation of the average geothermal gradient of the near-seabed formation and the hydrate stability domain below the seabed, the Berkeley (Pe) equation is finally used to complete the calculation of the vertical migration rate of the shallow seabed fluid.

[0316] The embodiment of the present invention is based on the principles of fluid kinematics and thermodynamics, giving full play to the parameter advantage of the "temperature" factor, relying on the near-seabed measured formation temperature data with relatively low acquisition cost, and combining the hydrate stability domain geothermal data obtained by phase equilibrium simulation and BSR inversion. By establishing a one-dimensional heat convection conduction model, and carrying out the calculation of the average geothermal gradient in the near-seabed formation and the hydrate stability domain below the seabed, the Berkeley (Pe) equation is finally used to achieve the vertical migration rate of the shallow seabed fluid, which provides a basis for clarifying the shallow seabed fluid activity behavior and evaluating the potential ecological environment and geological disaster impacts. Specifically, the technical solution of the present invention includes at least the following innovative points:

[0317] Innovation point 1: Based on the concepts of fluid kinematics and thermodynamics, the present invention estimates the vertical migration rate of shallow seabed fluid by constructing a one-dimensional thermal convection conduction model of the temperature field, thus making up for the deficiency that traditional technology cannot directly monitor the laws of fluid activity in the strata below the seabed.

[0318] The present invention first establishes a fluid leakage geological model based on the comprehensive analysis of geological elements, and on this basis proposes a one-dimensional heat convection conduction model and forms a vertical temperature field function of the formation. Afterwards, the vertical spatial geothermal field disturbance of the shallow seabed is used as a breakthrough point. By calculating the in-situ geothermal gradient of the near-seabed formation, the bottom boundary equilibrium temperature of the hydrate stability domain and the average geothermal gradient in the stable domain are calculated in combination with the hydrate phase equilibrium equation, and finally the vertical migration rate of the shallow seabed fluid is calculated using the Berkeley equation. The entire technical process is based on the basic principles of fluid kinematics and thermodynamics, and uses measured data such as the average geothermal gradient of the near-seabed formation and the hydrate stability domain below the seabed as boundary conditions to carry out model numerical calculations. The method has a high scientificity. In addition, this method effectively overcomes the limitation that traditional observation (monitoring) methods cannot directly obtain the characteristics of fluid activity in the formation below the seabed.

[0319] Key point 2: The present invention constructs the shallow seabed fluid field based on the formation "temperature" factor, breaking through the traditional technical paradigm of inferring the laws of deep fluid activity based on the formation "pressure" factor in previous technical solutions, and is innovative in the basic modeling theory and application scenarios.

[0320] Existing technologies are mostly developed around deep oil and gas systems, and focus on the formation "pressure" factor, especially the influence of formation "overpressure" on the fluid migration and accumulation process, but formation "overpressure" is almost non-existent in shallow seabed formations. However, the thermal convection generated during the migration of deep high-temperature gas-bearing fluids and its disturbance to the shallow seabed geothermal field can form an effective geological record, which provides a theoretical basis and favorable conditions in technical methods for obtaining the shallow seabed fluid activity rate by establishing a one-dimensional thermal convection conduction numerical model of the temperature field with the "temperature" element as the entry point in this embodiment. In practical applications, the shallow seabed temperature field is easier to obtain by seabed geothermal measurement; the important geophysical indicator (BSR) of hydrate occurrence is also more significant in the study area, which provides a reliable basis for the construction of hydrate phase equilibrium equations, the determination of equilibrium temperature and the calculation of the average geothermal gradient in the hydrate stability domain. Based on the "temperature" element, the present invention realizes the effective integration of geothermal field information, geochemical information and geophysical information under the constraints of fluid thermodynamics theory, and improves the accuracy of numerical simulation results. This technical method is highly applicable in studying shallow seabed strata, especially in the absence of fluid "overpressure" to study the laws of fluid activity.

[0321] Key point 3: The present invention is mainly based on seismic survey data and near-seabed temperature measurement data with relatively low acquisition cost, which effectively reduces the cost of acquiring in-situ formation parameters of deep formations. The technical method is cost-effective and has spatial scalability.

[0322] Traditional methods mainly obtain key geological parameters of fluid activity by deploying in-situ observation equipment for fluid leakage activity on the seabed or based on hydrate drilling and related downhole detection equipment. The outstanding features of the above technical methods are high construction cost, long period of key geological science parameter acquisition, and certain geological, engineering and environmental risks, which do not meet the conditions for large-scale implementation and application. The present invention is mainly based on the acquisition of low-cost shallow seabed geothermal measurement data and hydrate seismic survey data. By constructing a one-dimensional thermal convection conduction model of the temperature field, the quantitative calculation of fluid activity rate is achieved, which effectively reduces the cost of obtaining key geothermal parameter information in deep layers, especially hydrate layers. The present invention and technical process effectively make up for the technical limitations of traditional methods that can only obtain fluid activity information through high-cost hydrate drilling, long-term seabed in-situ observation, etc. The technical method has high economic benefits and expanded applicability.

[0323] In view of this, compared with the prior art, the present invention includes at least the following beneficial effects: Based on the basic principles of fluid kinematics and thermodynamics, the present invention establishes a fluid thermal convection conduction model based on the "temperature" element through the organic combination of seismic survey data (mainly BSR reflection characteristics) and near-seabed geothermal measurement data and information mining. The technical advantage of this method is to carry out numerical simulations under the constraints of actual geological models and boundary conditions, avoiding errors in the understanding of fluid activity laws that may be caused by the scarcity of deep formation drilling test data, and providing a basis for revealing the shallow seabed fluid activity behavior and then evaluating potential ecological environments and geological disasters. In addition, the present invention and technical process get rid of the path dependence of traditional technical methods that only rely on high-cost drilling, long-term seabed in-situ observations, etc. to obtain fluid activity information, reducing the cost of obtaining formation science parameter information, and has good prospects for expanding applications.

[0324] It should also be noted that the leakage of gas-bearing fluids in the continental margin is common, which plays an important role in indicating energy accumulation, marine carbon cycle and ecosystem evolution. The relevant research has great scientific significance and economic value. The present invention breaks through the traditional technical paradigm and key parameter acquisition limitations of the previous technical schemes based on the "pressure" factor of the formation to infer deep fluid activities. Based on the actual working conditions and application scenarios of the shallow seabed strata, according to the basic theory of fluid kinematics and thermodynamics, the special advantages of the "temperature" factor are fully utilized. Relying on the shallow seabed measured geothermal data with low acquisition cost and combining the hydrate phase equilibrium simulation and BSR inversion to obtain the equilibrium temperature of the hydrate stability domain, a one-dimensional heat convection conduction model is established, and the average geothermal gradient calculation is carried out in the near-seabed strata and the hydrate stability domain below the seabed, and finally the vertical migration rate of the shallow seabed fluid is calculated using the Berkeley equation, which provides a basis for clarifying the behavior of shallow seabed fluid activity and evaluating the potential ecological environment and geological disasters. The present invention and technical process effectively make up for the technical limitations of previous technical solutions that can only obtain fluid activity information through high-cost hydrate drilling, long-term seabed in-situ observation, etc., and have high economy and expanded applicability, and provide new ideas and methods for serving hydrate energy resource exploration and geological disaster assessment.

[0325] On the other hand, Fig. 9 As shown, the embodiment of the present invention provides an analysis and processing device 900 for the activity rate of a shallow-layer fluid on the seafloor, which may include:

[0326] The first module 901 is used to obtain the seismic reflection time of the target position in the seismic profile of the target area, and establish a fluid leakage geological model based on the seismic reflection time; the target position includes the seabed position, the seabed-like reflection layer and the root position of the fluid leakage channel; the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel;

[0327] The second module 902 is used to establish a heat convection conduction model based on the fluid leakage geological model and the temperature data of the target location;

[0328] The third module 903 is used to transform the formation temperature field function based on the heat convection conduction model to obtain the function of the change of geothermal gradient with burial depth;

[0329] The fourth module 904 is used to obtain formation temperature measurement data, and obtain the top boundary temperature gradient value of the near-seabed formation based on the formation temperature measurement data processing; the near-seabed formation represents the top boundary of the fluid leakage geological model;

[0330] The fifth module 905 is used to obtain the formation pressure of the seabed reflection layer, and obtain the phase equilibrium temperature of the bottom boundary of the hydrate stability domain by solving the hydrate phase equilibrium equation based on the formation pressure, and then obtain the average geothermal gradient of the hydrate stability domain in combination with the measured seabed temperature at the seabed position;

[0331] The sixth module 906 is used to substitute the average geothermal gradient into the variation function, and then derive the vertical migration rate of the fluid in combination with the Berkeley equation.

[0332] The contents of the method embodiments of the present invention are all applicable to the device embodiments. The functions specifically implemented by the device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0333] On the other hand, an embodiment of the present invention further provides an electronic device, the electronic device comprising a memory and a processor, the memory storing a computer program, and the processor implementing the above-mentioned method for analyzing and processing the activity rate of the shallow seabed fluid when executing the computer program. The electronic device can be any intelligent terminal including a tablet computer, a car computer, etc.

[0334] It can be understood that the contents of the above method embodiments are all applicable to the present device embodiments, the functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0335] like Fig.10 As shown, Fig.10 The hardware structure of an electronic device 1000 of another embodiment is illustrated. The electronic device 1000 includes:

[0336] The processor 1001 may be implemented by a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (application-specific integrated circuit, aSIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present invention;

[0337] The memory 1002 may be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 1002 may store an operating system and other application programs. When the technical solution provided in the embodiment of this specification is implemented by software or firmware, the relevant program code is stored in the memory 1002, and the processor 1001 calls and executes the network node population optimization method of the embodiment of the present invention;

[0338] Input / output interface 1003, used to implement information input and output;

[0339] The communication interface 1004 is used to realize the communication interaction between the device and other devices. The communication can be realized through a wired manner (such as USB, network cable, etc.) or a wireless manner (such as mobile network, WIFI, Bluetooth, etc.);

[0340] A bus 1005 , which transmits information between various components of the device (e.g., the processor 1001 , the memory 1002 , the input / output interface 1003 , and the communication interface 1004 );

[0341] The processor 1001 , the memory 1002 , the input / output interface 1003 and the communication interface 1004 are connected to each other in communication within the device via the bus 1005 .

[0342] The electronic device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0343] The contents of the method embodiments of the present invention are all applicable to the electronic device embodiments. The functions specifically implemented by the electronic device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0344] Another aspect of an embodiment of the present invention further provides a computer-readable storage medium, wherein the storage medium stores a program, and the program is executed by a processor to implement the above method.

[0345] It should be noted that the computer-readable medium shown in the embodiment of the present invention may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disk read-only memory (Compact Disc Read to Only Memory, CD to ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, device or device. In the present invention, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer readable signal media may also be any computer readable medium other than computer readable storage media, which may send, propagate, or transmit programs for use by or in conjunction with an instruction execution system, apparatus, or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0346] The contents of the method embodiments of the present invention are all applicable to the computer-readable storage medium embodiments. The functions specifically implemented by the computer-readable storage medium embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0347] The embodiment of the present invention also discloses a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. A processor of a computer device can read the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the computer device executes the above method.

[0348] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0349] It should be noted that, although several modules of the device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to an embodiment of the present invention, the features and functions of two or more modules or units described above can be embodied in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into being embodied by multiple modules or units.

[0350] Through the description of the above implementation, it is easy for those skilled in the art to understand that the example implementation described here can be implemented by software, or by software combined with necessary hardware. Therefore, the technical solution according to the implementation of the present invention can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD to ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the implementation of the present invention.

[0351] In some selectable embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided by way of example, for the purpose of providing a more comprehensive understanding of technology. The disclosed method is not limited to the operation and logic flow presented herein. Selectable embodiments are expected, wherein the order of various operations is changed and the sub-operation of a part for which is described as a larger operation is performed independently.

[0352] In addition, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise specified, one or more of the functions and / or features can be integrated into a single physical device and / or software module, or one or more functions and / or features can be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the present invention. More specifically, in view of the properties, functions and internal relationships of the various functional modules in the device disclosed herein, the actual implementation of the module will be understood within the conventional skills of the engineer. Therefore, those skilled in the art can implement the present invention set forth in the claims without excessive experimentation using ordinary techniques. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0353] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0354] The logic and / or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable instructions for implementing logical functions, and may be embodied in any computer-readable medium for use by an instruction execution device, apparatus or device (such as a computer-based device, a device including a processor, or other device that can fetch instructions from an instruction execution device, apparatus or device and execute the instructions), or in conjunction with such instruction execution device, apparatus or device. For purposes of this specification, "computer-readable medium" may be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution device, apparatus or device, or in conjunction with such instruction execution device, apparatus or device.

[0355] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0356] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution device. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0357] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0358] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0359] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A method for analyzing and processing the activity rate of shallow seabed fluid, characterized in that: The following steps are involved: Acquire the seismic reflection time of the target position in the seismic profile of the target area, and establish a fluid leakage geological model based on the seismic reflection time; the target position includes the seabed position, the seabed-like reflection layer and the root position of the fluid leakage channel; the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel; Based on the fluid leakage geological model and the temperature data of the target location, a heat convection conduction model is established; Based on the heat convection conduction model, the formation temperature field function is transformed to obtain the function of the geothermal gradient changing with the burial depth; Acquire formation temperature measurement data, and obtain a top boundary temperature gradient value of a near-seafloor formation based on the formation temperature measurement data; the near-seafloor formation represents the top boundary of the fluid leakage geological model; Acquire the formation pressure of the quasi-bottom-seafloor reflector layer, obtain the phase equilibrium temperature of the bottom boundary of the hydrate stability domain by solving the hydrate phase equilibrium equation based on the formation pressure, and then obtain the average geothermal gradient of the hydrate stability domain in combination with the measured seabed temperature at the seabed position; The average geothermal gradient is substituted into the variation function, and then combined with the Berkeley equation to derive the vertical migration rate of the fluid.

2. The method for analyzing and processing the activity rate of shallow seabed fluid according to claim 1, characterized in that: The seismic reflection time includes a first reflection time at the seabed, a second reflection time at the seabed-like reflection layer, and a third reflection time at the root of the fluid leakage channel; and establishing a fluid leakage geological model based on the seismic reflection time includes the following steps: Obtaining the seabed depth of the seabed position according to half of the product of the first reflection time and a first velocity; the first velocity represents the propagation velocity of seismic waves in seawater; A first depth is obtained according to half of the product of the difference between the second reflection time and the first reflection time and a second velocity; the second velocity represents the propagation velocity of seismic waves in the shallow seabed; the first depth represents the depth of the seabed-like reflection layer below the seabed position; A second depth is obtained according to half of the product of the difference between the third reflection time and the first reflection time and the second velocity; the second depth represents the depth of the root position of the fluid leakage channel below the seabed position; The fluid leakage geological model is established based on the seabed depth, the first depth and the second depth; Among them, the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel; the vertical distance of the fluid leakage geological model is equal to the second depth.

3. The method for analyzing and processing the activity rate of shallow seabed fluid according to claim 1, characterized in that: The temperature data includes the top boundary temperature of the top boundary and the bottom boundary temperature of the bottom boundary; the heat convection conduction model is established based on the fluid leakage geological model combined with the temperature data of the target position, including the following steps: The heat convection conduction model is established based on the top boundary temperature and the bottom boundary temperature in combination with the Berkeley number and the vertical distance of the fluid leakage geological model; the vertical distance represents the depth distance between the top boundary and the bottom boundary; The heat convection conduction model represents the data relationship between the burial depth and the corresponding depth temperature; the expression of the heat convection conduction model is: Where, T z represents the depth temperature corresponding to the burial depth z; T0 represents the top temperature; T L represents the bottom temperature; L represents the vertical distance; e is a mathematical constant; β represents the Berkeley number.

4. The method for analyzing and processing the activity rate of shallow seabed fluid according to claim 3, characterized in that: The method of transforming the formation temperature field function based on the heat convection conduction model to obtain a function of the change of the geothermal gradient with the burial depth includes the following steps: Calculating the partial derivative function of the formation temperature field with respect to the burial depth based on the heat convection conduction model, and establishing a functional relationship between the geothermal gradient and the burial depth in the heat convection conduction model; Wherein, the expression of the functional relationship is: In the formula, The symbol for the partial derivative function; T represents the symbol for temperature; Based on the functional relationship, the burial depth is approximately equal to 0 as a constraint condition to obtain a temperature function of the near-seafloor formation; Wherein, the expression of the temperature function is: Substituting the temperature function into the functional relationship, and obtaining the change function through functional transformation; Wherein, the expression of the change function is:

5. The method for analyzing and processing the activity rate of shallow seabed fluid according to claim 1, characterized in that: The step of obtaining formation temperature measurement data and obtaining a top boundary temperature gradient value of a near-seafloor formation based on the formation temperature measurement data includes the following steps: Acquire in-situ temperature data and position information of a temperature probe of a shallow seabed layer to obtain the formation temperature measurement data; Wherein, the temperature probe is carried by a gravity column and placed at the shallow surface layer of the seabed, and the gravity column carries a plurality of the temperature probes; the shallow surface layer of the seabed represents a shallow stratum within a preset depth below the seabed position; The in-situ temperature data corresponding to the different position information are linearly fitted using the least square method to obtain the apparent geothermal gradient value of the near-seabed stratum, and the apparent geothermal gradient value is used as the top boundary temperature gradient value.

6. The method for analyzing and processing the activity rate of shallow seabed fluid according to claim 1, characterized in that: The step of obtaining the formation pressure of the quasi-bottom-seafloor reflector layer, obtaining the phase equilibrium temperature of the bottom boundary of the hydrate stability domain by solving the hydrate phase equilibrium equation based on the formation pressure, and then obtaining the average geothermal gradient of the hydrate stability domain in combination with the measured seafloor temperature at the seafloor position, comprises the following steps: Determine the underwater depth of the seafloor-like reflective layer based on the fluid seepage geological model, and then calculate the hydrostatic pressure of the seafloor-like reflective layer in combination with the pore fluid density of the sedimentary strata; and use the hydrostatic pressure as the formation pressure; The fluid leakage geological model includes the seafloor depth of the seafloor position and the first depth of the seafloor-like reflective layer below the seafloor position; the underwater depth is obtained based on the sum of the seafloor depth and the first depth; the hydrostatic pressure is obtained by multiplying the underwater depth, the pore fluid density and the gravitational acceleration; A hydrate phase equilibrium simulation function is constructed using a preset phase equilibrium simulation software, and the formation pressure is substituted into the hydrate phase equilibrium simulation function to solve and obtain the phase equilibrium temperature of the bottom boundary of the hydrate stability domain; Based on the phase equilibrium temperature at the bottom boundary of the hydrate stability zone and the measured seabed temperature at the seabed position, the average geothermal gradient of the hydrate stability zone is obtained by partial derivative calculation; The expression of the average geothermal gradient is: In the formula, represents the symbol of the partial derivative function; T represents the symbol of temperature; z represents the burial depth; T BSR represents the phase equilibrium temperature; T0 represents the measured seafloor temperature; Z BSR Indicates the first depth.

7. The method for analyzing and processing the activity rate of shallow seabed fluid according to claim 1, characterized in that: Substituting the average geothermal gradient into the variation function and then deriving the vertical migration rate of the fluid in combination with the Berkeley equation comprises the following steps: Substituting the average effect position point corresponding to the average geothermal gradient into the variation function to obtain a first function; Wherein, the expression of the change function is: In the formula, represents the symbol of the partial derivative function; T represents the symbol of temperature; z represents the burial depth; L represents the vertical distance of the heat convection conduction model; e is a mathematical constant; β represents the Berkeley number; The expression of the average geothermal gradient is: Where, T BSR represents the phase equilibrium temperature; T0 represents the measured seafloor temperature; Z BSR Indicates the first depth of the seafloor-like reflector below the seafloor position; The expression of the first function is: Where, 0.5Z BsR is the average effect location point; Substituting the Berkeley equation into the first function to obtain a second function; The expression of the Berkeley equation is: Where φ represents the formation porosity; ρ w represents the density of sediment pore fluid; C w represents the heat capacity of sediment pore fluid; V z represents the vertical migration rate of fluid; λ represents the average thermal conductivity of formation sediment; The expression of the second function is: The measured parameters are introduced into the second function to derive the vertical migration rate of the fluid; the measured parameters include the measured values ​​of the formation porosity, the sediment pore fluid density, the sediment pore fluid heat capacity and the average thermal conductivity of the formation sediment.

8. An analytical processing device for the activity rate of shallow seabed fluid, characterized in that: include: The first module is used to obtain the seismic reflection time of the target position in the seismic profile of the target area, and establish a fluid leakage geological model based on the seismic reflection time; the target position includes the seabed position, the seabed-like reflection layer and the root position of the fluid leakage channel; the top boundary of the fluid leakage geological model is the seabed position, and the bottom boundary of the fluid leakage geological model is the root position of the fluid leakage channel; The second module is used to establish a heat convection conduction model based on the fluid leakage geological model and the temperature data of the target location; The third module is used to transform the formation temperature field function based on the heat convection conduction model to obtain the function of the change of geothermal gradient with burial depth; The fourth module is used to obtain formation temperature measurement data, and obtain the top boundary temperature gradient value of the near-seabed formation based on the formation temperature measurement data; the near-seabed formation represents the top boundary of the fluid leakage geological model; The fifth module is used to obtain the formation pressure of the quasi-seafloor reflector layer, obtain the phase equilibrium temperature of the bottom boundary of the hydrate stability domain by solving the hydrate phase equilibrium equation based on the formation pressure, and then obtain the average geothermal gradient of the hydrate stability domain in combination with the measured seafloor temperature at the seafloor position; The sixth module is used to substitute the average geothermal gradient into the variation function, and then derive the vertical migration rate of the fluid in combination with the Berkeley equation.

9. An electronic device, characterized in that: including a processor and a memory; The memory is used to store programs; The processor executes the program to implement the method according to any one of claims 1 to 7.

10. A computer storage medium storing a program executable by a processor, characterized in that: The program executable by the processor is used to implement the method according to any one of claims 1 to 7 when executed by the processor.

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