Ultra-deepwater shallow gas reservoir overlying hydrate stratum drilling and production simulation experiment device

Abstract

The invention provides a drilling and production simulation experiment device for an overlying hydrate stratum of an ultra-deep water shallow gas reservoir. A reaction kettle is filled with a water-containing soil body and provides a closed pressure space, a gas injection assembly supplies methane gas, and a temperature control assembly adjusts the temperature to a range required by hydrate generation. The drill bit guiding assembly can be pre-buried in a water-containing soil body in advance according to the number, depth and relative position of horizontal wells of a multi-branch well needing to be simulated so as to guide the well drilling assembly to drill multi-branch well holes. The temperature and pressure measuring assembly is arranged in the kettle to collect data; the gas-liquid separation component is used for separating exploiting materials and metering the gas production amount; the data acquisition assembly acquires temperature, pressure and gas production amount data, automatically generates a plane cloud picture, a report form and a curve graph, and inverts real-time changes of hydrate generation and production. The device can simulate a multi-branch well mining scene with a main well being a vertical well, the number, depth, extension length, spacing and relative position of the branch wells are controlled through the drill bit guiding assembly, and the influence of different branch well parameters on the mining effect is researched.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development engineering technology, and in particular to a drilling and production simulation experimental device for overlying hydrate formations in ultra-deep water shallow gas reservoirs. Background Technology

[0002] Natural gas hydrates, as a highly efficient potential energy source with vast reserves and clean combustion, are of great significance for optimizing the energy structure through commercial exploitation. More than 90% of the world's natural gas hydrate resources are found in deep-sea sediments at depths exceeding 800 meters. The ultra-deep-water environment in which they exist has complex characteristics of low temperature and high pressure, posing extremely high demands on extraction technologies.

[0003] In terms of extraction methods, traditional single vertical wells suffer from low gas production rates due to limited contact area with the reservoir, making it difficult to meet economic requirements. Meanwhile, the ultra-long horizontal well approach, proposed to increase the drainage area, faces challenges such as high drilling costs, significant technical difficulties, and limited production enhancement effects in low-permeability reservoirs. In recent years, multi-branch well technology has been considered a highly promising approach to increasing production and efficiency. This technology, by drilling multiple branch wells into the main wellbore, can precisely adapt to the spatial distribution of heterogeneous hydrate reservoirs such as banded formations, achieving three-dimensional, networked drainage and significantly expanding the hydrate decomposition area, thus theoretically enabling a substantial increase in production capacity. Combining multi-branch wells with a rational well network layout and reservoir stimulation technology is considered one of the key directions for breaking through current production bottlenecks, improving the cost-effectiveness of extraction, and promoting commercialization.

[0004] From technology research and development to field application, it is essential to rely on indoor physical simulation devices that can highly replicate the real environment and processes for pilot experiments and mechanism studies. However, current experimental devices used for simulating natural gas hydrate drilling and production have limited functionality and cannot flexibly and accurately adjust and simulate the core engineering parameters of multi-branch wells, such as the number of branch wells, spatial orientation, spacing, drilling depth, and well network layout, making it difficult to support the optimization design research of complex well structures. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a drilling and production simulation experimental device for ultra-deepwater shallow gas reservoirs with overlying hydrate formations, aiming to solve the problem that current experimental devices used for simulating natural gas hydrate drilling and production have limited functionality and cannot flexibly and accurately adjust and simulate the core engineering parameters of multi-branch wells.

[0006] This invention provides a drilling and production simulation experimental device for ultra-deepwater shallow gas reservoirs overlying hydrate formations, comprising: A reaction vessel, wherein the interior is filled with water-bearing soil and provides a closed pressure environment for the formation of hydrates; The gas injection assembly has its outlet end connected to the reactor and is used to introduce methane gas into the reactor. A temperature control component, used to regulate the temperature inside the reactor; A drill bit guiding assembly is pre-embedded in the water-bearing soil of the reactor. It includes multiple vertical guiding rails, multiple turning guiding rails, and multiple horizontal guiding rails. The multiple vertical guiding rails are connected end to end in the vertical direction. The multiple horizontal guiding rails are used to set at different target depths and extend in different horizontal directions. The horizontal guiding rails are connected to the vertical guiding rails through the turning guiding rails. The turning guiding rails are connected between two adjacent vertical guiding rails. A drilling assembly, disposed on top of the reactor, is used to drill a wellbore along the extending directions of the vertical guide rail, the steering guide rail, and the horizontal guide rail; A temperature measurement component, comprising multiple temperature acquisition units arranged within the internal space of the reactor; A pressure measurement assembly, comprising multiple pressure acquisition units arranged within the internal space of the reactor; A gas-liquid separation assembly, which is connected to the reaction vessel, is used to separate the gas and liquid from the extracted material and to measure the amount of natural gas extracted. The data acquisition component is used to acquire the temperature value collected by the temperature acquisition unit, the pressure value collected by the pressure acquisition unit, and the gas extraction volume measured by the gas-liquid separation component. Based on the temperature value and the pressure value, it automatically generates a planar cloud map, raw data report, analysis report, and curve graph to invert the real-time changes in hydrate formation and extraction.

[0007] According to the drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formation provided by the present invention, the static pressure of the reactor is greater than or equal to 30 MPa.

[0008] According to the drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formation provided by the present invention, the temperature measurement component further includes multiple probes, which are distributed along the circumference and longitudinal direction of the reactor, and each probe extends radially along the reactor, with multiple temperature acquisition units provided on each probe.

[0009] According to the drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formation provided by the present invention, the multiple probes are distributed in five layers, and each layer contains five probes, and each probe is equipped with five temperature acquisition units.

[0010] According to the drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formation provided by the present invention, the pressure acquisition unit is disposed on the inner side wall of the reactor, and a plurality of the pressure acquisition units are arranged along the depth direction of the reactor.

[0011] The drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate strata provided by the present invention includes a soil pressure gauge and a resistivity acquisition unit pre-embedded in the water-bearing soil body. Both the soil pressure gauge and the resistivity acquisition unit are communicatively connected to the data acquisition component.

[0012] According to the drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formations provided by the present invention, the drilling assembly includes a lifting device, a rotary drive device, a drill pipe, a drill bit, and a drilling fluid circulation and filtration device. The rotary drive device is connected to the reaction vessel through the lifting device. The drill pipe is driven by the rotary drive device. The drill bit is connected to the bottom of the drill pipe. The outlet of the drilling fluid circulation and filtration device is connected to the drill bit through the drill pipe. The inlet of the drilling fluid circulation and filtration device is connected to the wellbore. The drilling fluid circulation and filtration device is used for solid-liquid separation and re-transports the separated liquid back to the drill bit.

[0013] According to the drilling and production simulation experimental device for ultra-deepwater shallow gas reservoir overlying hydrate formations provided by the present invention, the gas-liquid separation component includes a filter, a back pressure valve, a gas-liquid separator, a gas flow meter, and a weighing device. The filter, the back pressure valve, and the inlet of the gas-liquid separator are connected in sequence. The upstream end of the filter is connected to the reaction vessel. The gas flow meter is connected to the gas outlet of the gas-liquid separator. The weighing device is used to measure the mass of the liquid separated by the gas-liquid separator.

[0014] According to the drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formation provided by the present invention, the drilling fluid circulation filtration device includes a solid-liquid separator, a circulation pump and a preheater. The inlet of the solid-liquid separator is connected to the drilling fluid outlet of the reaction vessel. The circulation pump is connected between the liquid outlet of the solid-liquid separator and the preheater. The downstream end of the preheater is connected to the drill bit through the drill pipe.

[0015] According to the drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formation provided by the present invention, the temperature control component includes a jacket and a circulating cooling device. The jacket is sleeved on the outside of the reaction vessel, and the circulating cooling device is used to drive circulating water to circulate between the jacket and the circulating cooling device, and to cool the circulating water when it passes through the circulating cooling device.

[0016] The present invention has the following advantages due to the adoption of the above technical solutions: The present invention provides a drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations, comprising a reaction vessel, a gas injection component, a temperature control component, a drill bit guiding component, a drilling component, a temperature measurement component, a pressure measurement component, a gas-liquid separation component, and a data acquisition component. The reaction vessel is filled with water-bearing soil and provides a sealed pressure environment for hydrate formation. The gas injection component supplies methane gas into the reaction vessel, and the temperature control component regulates the temperature within the reaction vessel to the range required for hydrate formation. The drill bit guiding component is pre-embedded within the water-bearing soil of the reaction vessel and includes multiple vertical guide rails, steering guide rails, and horizontal guide rails. The multiple vertical guide rails are connected sequentially end-to-end along the vertical direction, and the multiple horizontal guide rails are set at different target depths and extend along different horizontal directions. The horizontal guide rails are connected to the vertical guide rails via steering guide rails, which connect adjacent vertical guide rails. The drilling component is used to drill a wellbore along the extension directions of the vertical guide rails, steering guide rails, and horizontal guide rails. The temperature measurement component includes multiple temperature acquisition units arranged inside the reactor. Similarly, the pressure measurement component includes multiple pressure acquisition units arranged inside the reactor. The gas-liquid separation component is connected to the reactor body and is used for gas-liquid separation of the extracted material and for measuring the amount of natural gas extracted. The data acquisition component obtains the temperature values ​​collected by the temperature acquisition units, the pressure values ​​collected by the pressure acquisition units, and the amount of gas extracted measured by the gas-liquid separation component. Based on the temperature and pressure values, it automatically generates planar cloud maps, raw data reports, analytical reports, and graphs to invert the real-time changes during hydrate formation and extraction. The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations provided by this invention can simulate the production scenario of multi-branch wells where the main well is a vertical well. Based on the simulated multi-branch well production scenario, the number, depth, extension length, spacing, and relative position of the branch wells are determined. Based on the number, depth, extension length, spacing, and relative position of the branch wells, a drill bit guide assembly is preset in the reaction vessel. During drilling, the drill bit is drilled along the drill bit guide assembly. The influence of different numbers, spacing, and relative positions of branch wells on the production effect can be systematically studied. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the internal structure of a reaction vessel provided in an embodiment of the present invention; Figure 2This is a partially enlarged view of a drill bit guiding assembly provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the external structure of a reaction vessel provided in an embodiment of the present invention; Figure 4 This is a top view of a reaction vessel provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formations provided in an embodiment of the present invention.

[0019] Figure label: 110: Vessel body; 120: Vessel lid; 200: Gas injection assembly; 300: Circulating refrigeration device; 410: Vertical guide rail; 420: Turning guide rail; 430: Horizontal guide rail; 510: Rotary drive device; 520: Drill rod; 531: Solid-liquid separator; 532: Circulating pump; 533: Preheater; 600: Probe; 610: Temperature acquisition unit; 700: Pressure acquisition unit; 810: Filter; 820: Back pressure valve; 830: Gas-liquid separator; 840: Gas flow meter; 850: Weighing device. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0025] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0026] The present invention provides a drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations, comprising a reaction vessel, a gas injection component, a temperature control component, a drill bit guiding component, a drilling component, a temperature measurement component, a pressure measurement component, a gas-liquid separation component, and a data acquisition component. The reaction vessel is filled with water-bearing soil and provides a sealed pressure environment for hydrate formation. The gas injection component supplies methane gas into the reaction vessel, and the temperature control component regulates the temperature within the reaction vessel to the range required for hydrate formation. The drill bit guiding component is pre-embedded within the water-bearing soil of the reaction vessel and includes multiple vertical guide rails, steering guide rails, and horizontal guide rails. The multiple vertical guide rails are connected sequentially end-to-end along the vertical direction, and the multiple horizontal guide rails are set at different target depths and extend along different horizontal directions. The horizontal guide rails are connected to the vertical guide rails via steering guide rails, which connect adjacent vertical guide rails. The drilling component is used to drill a wellbore along the extension directions of the vertical guide rails, steering guide rails, and horizontal guide rails. The temperature measurement component includes multiple temperature acquisition units arranged inside the reactor. Similarly, the pressure measurement component includes multiple pressure acquisition units arranged inside the reactor. The gas-liquid separation component is connected to the reactor body and is used for gas-liquid separation of the extracted material and for measuring the amount of natural gas extracted. The data acquisition component obtains the temperature values ​​collected by the temperature acquisition units, the pressure values ​​collected by the pressure acquisition units, and the amount of gas extracted measured by the gas-liquid separation component. Based on the temperature and pressure values, it automatically generates planar cloud maps, raw data reports, analytical reports, and graphs to invert the real-time changes during hydrate formation and extraction. The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations provided by this invention can simulate the production scenario of multi-branch wells where the main well is a vertical well. Based on the simulated multi-branch well production scenario, the number, depth, extension length, spacing, and relative position of the branch wells are determined. Based on the number, depth, extension length, spacing, and relative position of the branch wells, a drill bit guide assembly is preset in the reaction vessel. During drilling, the drill bit is drilled along the drill bit guide assembly. The influence of different numbers, spacing, and relative positions of branch wells on the production effect can be systematically studied.

[0027] The following is combined with Figures 1 to 5 This invention describes a drilling and production simulation experimental apparatus for overlying hydrate formations in ultra-deep water shallow gas reservoirs.

[0028] An embodiment of the present invention discloses a drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formations, comprising a reaction vessel, a gas injection component 200, a temperature control component, a drill bit guiding component, a drilling component, a temperature measurement component, a pressure measurement component, a gas-liquid separation component, and a data acquisition component.

[0029] The reactor includes a vessel body 110 and a vessel lid 120. After the vessel lid 120 is opened, equipment such as a drill bit guide assembly, a temperature measuring assembly, and a pressure measuring assembly can be installed inside the vessel body 110, and water-bearing soil can be filled into the vessel body 110. After the vessel lid 120 is closed, a closed pressure space for hydrate formation is formed inside.

[0030] The outlet of the gas injection assembly 200 can be connected to the bottom of the reactor and the interior of the reactor to supply methane gas into the reactor. The pressure inside the reactor can be adjusted by adjusting the gas injection pressure of the gas injection assembly 200 to meet the pressure requirements for hydrate formation.

[0031] The temperature control unit is used to regulate the temperature inside the reactor so that the temperature inside the reactor reaches the temperature required for hydrate formation.

[0032] The drill bit guiding assembly is pre-embedded in the water-bearing soil of the reactor vessel, and includes multiple vertical guide rails 410, multiple turning guide rails 420, and multiple horizontal guide rails 430. The vertical guide rails 410 are connected end to end in the vertical direction. The horizontal guide rails 430 are used to set at different target depths and extend in different horizontal directions. The horizontal guide rails 430 are connected to the vertical guide rails 410 through the turning guide rails 420, and the turning guide rails 420 are connected between two adjacent vertical guide rails 410.

[0033] In use, first determine the length of the vertical shaft, the number of horizontal shafts, and the depth of each horizontal shaft. Based on the determined length of the vertical shaft, the number of horizontal shafts, and the depth of each horizontal shaft, determine the number of vertical guide rails 410 and the number of vertical guide rails 410 of different lengths, so that the length of all vertical guide rails 410 spliced ​​together can reach the length of the vertical shaft, and ensure that there is a joint of vertical guide rail 410 at a position slightly above the corresponding depth of each horizontal shaft. The horizontal guide rails 430 are set at the target depth along a preset direction. The steering guide rail 420 includes three connecting ends: one end connects to the bottom of the upper vertical guide rail 410, one end connects to the top of the lower vertical guide rail 410, and one end connects to the horizontal guide rail 430.

[0034] The drilling assembly is located on top of the reactor and is used to drill a wellbore along the extension direction of the vertical guide rail 410, one of the turning guide rails 420, and the horizontal guide rail 430 corresponding to the turning guide rail 420.

[0035] The temperature measurement component includes multiple temperature acquisition units 610, which are arranged inside the reactor body 110 to collect the temperature inside the reactor body 110.

[0036] The pressure measurement component includes multiple pressure acquisition units 700, which are arranged inside the vessel body 110 of the reactor to collect pressure throughout the vessel body 110.

[0037] The gas-liquid separation component is connected to the vessel body 110 and is used to separate the gas and liquid from the extracted material and to measure the amount of natural gas extracted.

[0038] The data acquisition component is used to acquire the temperature value collected by the temperature acquisition unit 610, the pressure value collected by the pressure acquisition unit 700, and the gas extraction volume measured by the gas-liquid separation component. Based on the temperature and pressure values, the data acquisition component automatically generates planar cloud maps, raw data reports, analysis reports, and curves, and inverts the formation of hydrates and their real-time changes during extraction.

[0039] The drilling and production simulation experimental device for ultra-deepwater shallow gas reservoirs with overlying hydrate formations provided by this invention can simulate the production scenario of multi-branch wells with a vertical main well. The number, extension length, spacing, and relative position of the branch wells can be flexibly adjusted to change the structure of the multi-branch wells. The device can systematically study the impact of the number, spacing, and relative position of the branch wells on the production effect. At the same time, it can explore the hydrate decomposition rate and gas production variation law under different depths and different formation soil combinations, providing multi-scenario and multi-dimensional optimization solutions for commercial production.

[0040] In addition, the drilling pressure and rotation speed of the drilling components are adjustable, as are the particle density and water content of the water-bearing soil filling the reactor. Therefore, it is also possible to study the effects of different drilling parameters and formation parameters on hydrate decomposition rate and gas production.

[0041] Currently, some experimental devices have low pressure resistance ratings, only 15MPa, which cannot reproduce the ultra-deepwater high-pressure environment. The drilling and production simulation experimental device for ultra-deepwater shallow gas reservoir overlying hydrate formation disclosed in the embodiments of the present invention uses a stainless steel barrel-shaped container with a static pressure resistance of 30MPa, an inner diameter of 2.0m, a height of 5.5m, and an internal effective volume of 69080L. Compared with the traditional 15MPa pressure-resistant device, it can accurately reproduce the ultra-deepwater high-pressure environment and is used for natural gas hydrate preparation and multi-branch well drilling simulation tests.

[0042] In some embodiments, the temperature measurement assembly further includes multiple probes 600, which are distributed along the circumference and longitudinal direction of the reactor, and each probe 600 extends radially along the reactor. Each probe 600 is provided with multiple temperature acquisition units 610.

[0043] Specifically, 25 probes 600 can be set up, distributed in five layers at different depths in the vessel body 110. Each layer includes five probes 600, which are radially distributed with the axis of the vessel body 110 as the axis, and the interval between two adjacent probes 600 is 72 degrees. Five temperature acquisition units 610 are evenly distributed along the axis of each probe 600, for a total of 125 units.

[0044] It should be noted that the probe 600 should be positioned appropriately away from the wellbore to prevent the drill bit from damaging the temperature acquisition unit 610 during drilling.

[0045] In some embodiments, the pressure acquisition unit 700 is disposed on the inner sidewall of the reactor and a plurality of pressure acquisition units 700 are arranged along the depth direction of the reactor.

[0046] For example, ten pressure acquisition units 700 can be set up and evenly distributed on the inner wall of the reactor along the depth direction.

[0047] The drilling and production simulation experimental device for ultra-deep water shallow gas reservoir overlying hydrate formations provided by this invention can effectively improve data visualization performance through dense distribution of temperature and pressure measuring points, thereby enhancing the ability to capture dynamic changes in the formation temperature and pressure field.

[0048] In some embodiments, a soil pressure gauge and a resistivity acquisition unit are also pre-embedded in the aquifer. The data collected can be used to reveal the mechanism and law of wellbore collapse in multi-branch wells with shallow gas overlying hydrate layers.

[0049] In some embodiments, the drilling assembly includes a lifting device, a rotary drive device 510, a drill pipe 520, a drill bit, and a drilling fluid circulation and filtration device. The lifting device is positioned above the reactor vessel. The rotary drive device 510 is connected to the movable end of the lifting device and moves up and down with the lifting device. The rotary drive device 510 is driveably connected to the drill pipe 520, and the front end of the drill pipe 520 is connected to the drill bit. The drilling fluid circulation and filtration device is used to deliver drilling fluid to the bottom of the well through the drill pipe 520 and the drill bit. Drill fluid that returns and carries cuttings is returned to the drilling fluid circulation and filtration device for filtration. After filtering out solid particles in the drilling fluid, the drilling fluid returns to the bottom of the well for circulation.

[0050] Specifically, the drilling fluid circulation filtration device includes a solid-liquid separator 531, a circulation pump 532, and a preheater 533. The inlet of the solid-liquid separator 531 is connected to the reaction vessel and further connected to the wellhead. The drilling fluid returning from the wellhead and carrying solid debris undergoes solid-liquid separation in the solid-liquid separator 531. The separated liquid is transported to the preheater 533 for preheating through the circulation pump 532. The preheated drilling fluid is then transported to the bottom of the well through the drill pipe 520 and the drill bit.

[0051] In some embodiments, the gas-liquid separation assembly includes a filter 810, a back pressure valve 820, a gas-liquid separator 830, a gas flow meter 840, and a weighing device 850. The wellhead, the filter 810, the back pressure valve 820, and the inlet of the gas-liquid separator 830 are connected in sequence. The gas outlet of the gas-liquid separator 830 is connected to the gas flow meter 840. The extracted material in the well is filtered by the filter 810 and then enters the gas-liquid separator 830 for gas-liquid separation. The separated natural gas is measured by the gas flow meter 840, and the separated liquid is discharged through the liquid outlet of the gas-liquid separator 830 and weighed by the weighing device 850 to obtain the mass of the liquid.

[0052] In some embodiments, the temperature control assembly includes a jacket and a circulating cooling device 300. The jacket is fitted over the outside of the reactor, and the circulating cooling device 300 drives circulating water to circulate between the jacket and the circulating cooling device 300, cooling the circulating water as it passes through the circulating cooling device 300. As the circulating water flows through the jacket, it exchanges heat with the interior of the reactor to bring the temperature inside the reactor up to the temperature required for hydrate formation.

[0053] The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations provided by this invention allows for flexible increases or decreases in the number of branch wells according to actual production needs. The extension length can be precisely adjusted within the range of 0-900mm. It supports customizable spacing and relative positions between branch wells to meet the simulation requirements of different well network layouts. The depth of the branch wells can be freely set, and the water-bearing soil combination within the reactor can be adjusted as needed, such as by adjusting the sand particle size or water ratio, to adapt to more actual formation conditions. It supports precise adjustment of drill bit speed from 0-100r / min and drilling pressure from 0-50kN, allows for manual replacement of drill rods of different sizes (520), real-time monitoring of drilling speed, and a maximum drilling stroke ≤900mm to avoid impact to the reactor bottom. This device overcomes the limitations of traditional devices that can only simulate a single radial horizontal well with fixed parameters.

[0054] The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations provided by this invention has the following beneficial effects: The simulation of working conditions is more accurate and closer to reality: the 30MPa pressure-resistant, large-capacity reactor, equipped with temperature control components, can perfectly reproduce the low-temperature and high-pressure environment of ultra-deep water above 800 meters. At the same time, the gas injection component accurately simulates the underlying shallow gas, and solid hydrate crystals are generated in the upper part. The adjustability of the number, extension length, spacing, relative position and depth of branch wells, combined with the free control of the formation soil combination, enables the simulation working conditions to cover various actual production scenarios from simple to complex, solving the problem of the disconnect between simulation and reality in traditional equipment.

[0055] More comprehensive monitoring and analysis: The full-area deployment of 125 temperature acquisition units (610), 10 pressure acquisition units (700), and earth pressure gauges and resistivity acquisition units, combined with cloud map inversion technology, can accurately capture changes in temperature and pressure fields and formation stress distribution, providing high-precision data support for wellbore stability analysis and branch well layout optimization, making up for the shortcomings of traditional devices in terms of single monitoring dimensions and weak data visualization.

[0056] The research dimensions are richer: the multi-functional adjustable drilling system supports flexible simulation of multi-branch well structures, multiple drilling parameters, and multiple formation combinations. It can systematically study the impact of the number, spacing, and relative position of branch wells on the production effect, and explore the hydrate decomposition rate and gas production variation law under different depths and different formation soil combinations, providing multi-scenario and multi-dimensional optimization solutions for commercial production.

[0057] More efficient resource utilization: The drilling fluid circulation filtration device enables the recycling of drilling mud, reducing experimental costs and environmental impact, which is in line with the concept of green experimentation.

[0058] Enhanced commercial adaptability: Focusing on the cost reduction and efficiency improvement advantages of multi-branch wells, it can directly provide experimental basis for well structure design, branch well layout optimization, and drilling parameter debugging for the commercial exploitation of ultra-deepwater hydrates, helping to achieve an increase in production capacity.

[0059] The following is a specific embodiment that describes the operation method of the drilling and production simulation experimental device for overlying hydrate formations in ultra-deep water shallow gas reservoirs provided by the present invention.

[0060] 1. Pressure test: After sealing the vessel lid 120, fill the vessel body 110 with nitrogen gas to a pressure of 30 MPa. After the gas injection is completed, sprinkle a small amount of soapy water at the connection between the drilling assembly and the vessel lid 120, and observe whether there are any air bubbles leaking at the interface. If no air bubbles appear, it proves that the seal is good, and the pressure can be released for the next step of the experiment.

[0061] 2. Drilling fluid preparation 3. Measure the density of soil particles. 4. Preparation of experimental soil: Based on the soil moisture content sampled from the deep well site, mix the soil with water to prepare experimental soil with a target moisture content of 31.7%. Record the mass of the soil before each pouring into the reactor.

[0062] 5. Set the branch well parameters according to the experimental plan: determine the number of branch wells, the depth of each branch well, the extension length, the spacing and relative position, and arrange the vertical guide rail 410, the turning guide rail 420 and the horizontal guide rail 430 based on the information determined above.

[0063] 6. Arrange temperature acquisition unit 610, pressure acquisition unit 700, earth pressure gauge and resistivity acquisition unit.

[0064] 7. Sand Filling: During the process, the mass of sand added each time needs to be weighed. After filling approximately 10cm of sand, compact the sand with a tamper. When filling, pay close attention to the protection and avoidance of the lines of the resistivity acquisition unit, earth pressure gauge, temperature acquisition unit 610, and pressure acquisition unit 700.

[0065] 8. Install the vessel lid 120: Hoist the vessel lid 120 above the vessel body 110, connect the data transmission lines of each data acquisition unit to the interface at the bottom of the vessel lid 120, and then lower the vessel lid 120 to install it with the vessel body 110. After the vessel lid 120 is installed, connect the earth pressure gauge, resistivity acquisition unit, temperature acquisition unit 610, and pressure acquisition unit 700.

[0066] 9. Sealing of vessel body 110: Connect the drilling assembly to the vessel cover 120 and fix the sealing screws.

[0067] 10. Gas Injection: Inject methane gas into the vessel body 110 at a displacement of Q. i The injection time is t. i The injected environmental pressure is P i The temperature is T i .

[0068] 11. Cooling: Reduce the temperature of the vessel 110 using the temperature control component, and record and observe the data from the earth pressure gauge, resistivity acquisition unit, temperature acquisition unit 610, and pressure acquisition unit 700. During this period, the formation of hydrates will cause the pressure of the vessel 110 to decrease. Once the pressure of the vessel 110 stabilizes, the hydrate formation is considered complete.

[0069] 12. Multi-branch well drilling simulation: Adjust the drilling fluid and reaction vessel to the target temperature, set the back pressure parameter, start the drilling assembly, start the multi-branch well rotary drilling, adjust the drill bit speed and drilling pressure according to the experimental plan, control the maximum drilling stroke ≤900mm, and record the quality of water collected in the gas-liquid separator 830 and the gas production at regular intervals. Note that the recording frequency should be more frequent at the beginning and less frequent at the end to match the characteristics of hydrate decomposition rate.

[0070] To study the impact of different branch well layouts or formation combinations, repeat the above steps, adjusting only the corresponding branch well parameters or formation combinations.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations, characterized in that, include: A reaction vessel, wherein the interior is filled with water-bearing soil and provides a closed pressure environment for the formation of hydrates; Gas injection assembly (200), the gas outlet of the gas injection assembly (200) is connected to the reactor and is used to introduce methane gas into the reactor; A temperature control component, used to regulate the temperature inside the reactor; A drill bit guiding assembly is pre-embedded in the water-bearing soil of the reactor. It includes multiple vertical guide rails (410), multiple turning guide rails (420), and multiple horizontal guide rails (430). The multiple vertical guide rails (410) are connected end to end in the vertical direction. The multiple horizontal guide rails (430) are used to be set at different target depths and extend in different horizontal directions. The horizontal guide rails (430) are connected to the vertical guide rails (410) through the turning guide rails (420). The turning guide rails (420) are connected between two adjacent vertical guide rails (410). A drilling assembly, disposed on top of the reactor, is used to drill a wellbore along the extension directions of the vertical guide rail (410), the turning guide rail (420), and the horizontal guide rail (430); A temperature measurement component, comprising a plurality of temperature acquisition units (610), wherein the plurality of temperature acquisition units (610) are arranged in the internal space of the reactor; A pressure measurement assembly, comprising a plurality of pressure acquisition units (700), wherein the plurality of pressure acquisition units (700) are arranged in the internal space of the reactor; A gas-liquid separation assembly, which is connected to the reaction vessel, is used to separate the gas and liquid from the extracted material and to measure the amount of natural gas extracted. The data acquisition component is used to acquire the temperature value acquired by the temperature acquisition unit (610), the pressure value acquired by the pressure acquisition unit (700), and the gas extraction volume measured by the gas-liquid separation component, and automatically generate a planar cloud map, raw data report, analysis report and curve based on the temperature value and the pressure value, and invert the real-time changes in hydrate formation and extraction.

2. The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations according to claim 1, characterized in that, The static pressure of the reactor is greater than or equal to 30 MPa.

3. The drilling and production simulation experimental device for ultra-deepwater shallow gas reservoirs overlying hydrate formations according to claim 1, characterized in that, The temperature measurement assembly also includes multiple probes (600), which are distributed along the circumference and longitudinal direction of the reactor, and each probe (600) extends radially along the reactor. Each probe (600) is provided with multiple temperature acquisition units (610).

4. The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations according to claim 3, characterized in that, The multiple probes (600) are distributed in five layers, and each layer contains five probes (600), and each probe (600) is provided with five temperature acquisition units (610).

5. The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations according to claim 1, characterized in that, The pressure acquisition unit (700) is disposed on the inner wall of the reactor, and a plurality of the pressure acquisition units (700) are arranged along the depth direction of the reactor.

6. The drilling and production simulation experimental device for ultra-deepwater shallow gas reservoirs overlying hydrate formations according to claim 1, characterized in that, A soil pressure gauge and a resistivity acquisition unit are pre-embedded in the water-bearing soil, and both the soil pressure gauge and the resistivity acquisition unit are communicatively connected to the data acquisition component.

7. The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations according to claim 1, characterized in that, The drilling assembly includes a lifting device, a rotary drive device (510), a drill pipe (520), a drill bit, and a drilling fluid circulation filtration device. The rotary drive device (510) is connected to the reactor via the lifting device. The drill pipe (520) is driven by the rotary drive device (510). The drill bit is connected to the bottom of the drill pipe (520). The outlet of the drilling fluid circulation filtration device is connected to the drill bit via the drill pipe (520). The inlet of the drilling fluid circulation filtration device is connected to the wellbore. The drilling fluid circulation filtration device is used for solid-liquid separation and to re-transport the separated liquid to the drill bit.

8. The drilling and production simulation experimental device for ultra-deepwater shallow gas reservoirs overlying hydrate formations according to claim 1, characterized in that, The gas-liquid separation assembly includes a filter (810), a back pressure valve (820), a gas-liquid separator (830), a gas flow meter (840), and a weighing device (850). The inlets of the filter (810), the back pressure valve (820), and the gas-liquid separator (830) are connected in sequence. The upstream end of the filter (810) is connected to the reaction vessel. The gas flow meter (840) is connected to the gas outlet of the gas-liquid separator (830). The weighing device (850) is used to measure the mass of the liquid separated by the gas-liquid separator (830).

9. The drilling and production simulation experimental device for ultra-deep water shallow gas reservoirs overlying hydrate formations according to claim 7, characterized in that, The drilling fluid circulation filtration device includes a solid-liquid separator (531), a circulation pump (532), and a preheater (533). The inlet of the solid-liquid separator (531) is connected to the drilling fluid outlet of the reactor. The circulation pump (532) is connected between the liquid outlet of the solid-liquid separator (531) and the preheater (533). The downstream end of the preheater (533) is connected to the drill bit through the drill pipe (520).

10. The drilling and production simulation experimental device for ultra-deepwater shallow gas reservoirs overlying hydrate formations according to claim 1, characterized in that, The temperature control assembly includes a jacket and a circulating cooling device (300). The jacket is fitted on the outside of the reactor. The circulating cooling device (300) is used to drive circulating water to circulate between the jacket and the circulating cooling device (300) and to cool the circulating water as it passes through the circulating cooling device (300).

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