A shale free gas content determination method, device and storage medium

Abstract

The application discloses a shale free gas content determination method and device and a storage medium. The method comprises the following steps: acquiring basic data capable of reflecting free gas content corresponding to each type of pore in a target area; calculating shale adsorbed gas volume in the target area according to the basic data; calculating free gas content of each type of pore by using the basic data; and determining shale free gas content in the target area based on each free gas content and the shale adsorbed gas volume. As known from the above, the present application classifies pores in which free gas exists, considers the factor that free gas contents in different types of pores are different, and also considers the proportion of free gas and adsorbed gas, thereby improving the accuracy and reliability of shale free gas content determination in the target area. The present application can provide a basis for accurately recognizing shale gas resource potential and finding a favorable exploration area of shale gas, and has important practical significance for shale gas exploration and deployment decision-making.

Description

Technical Field

[0001] This invention relates to the field of shale gas exploration technology, and in particular to a method, apparatus and storage medium for determining the free gas content in shale. Background Technology

[0002] Shale gas resources have enormous potential and will become an important component of future natural gas production growth. Shale gas mainly exists in adsorbed and free states in low-porosity and low-permeability mudstone and shale. Free gas refers to natural gas existing in a free state within the pores and microfractures of mudstone and shale. Free gas is a crucial component of shale gas, especially deep overpressured shale gas. Therefore, accurately determining the free gas content is of great significance in understanding shale gas resource potential and identifying favorable shale gas exploration areas.

[0003] Currently, in the industry, the pore volume defined in traditional petroleum geology is typically used to determine the free gas content of shale. However, marine shale reservoirs are mainly composed of organic pores, brittle mineral pores, and clay mineral pores, and different types of pores store different amounts of free gas. Therefore, the current process for determining the free gas content of shale does not take into account the differences in shale free gas content caused by different pore types, which can easily lead to poor reliability of the determined shale free gas content. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a scheme for determining the free gas content of shale, so as to improve the accuracy and reliability of determining the free gas content of shale.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for determining the free gas content in shale, comprising:

[0006] Obtain basic data reflecting the free gas content of each type of pore within the target area; the types include at least one of organic pores, brittle mineral pores, and clay mineral pores;

[0007] Calculate the volume of shale-adsorbed gas within the target area based on the aforementioned basic data;

[0008] The free gas content of each type of pore is calculated using the aforementioned basic data;

[0009] The free gas content of shale in the target area is determined based on the content of each free gas and the volume of shale adsorbed gas.

[0010] Optionally, the basic data includes: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0011] Optionally, calculating the shale adsorbed gas volume within the target area based on the basic data includes:

[0012] The volume φ of shale adsorbed gas in the target area is calculated according to the following expression. a :

[0013]

[0014] Among them, G a ρ represents the adsorbed gas content in shale. b ρ is the density of the rock. s Let M be the density of natural gas adsorbed on the rock, and M be the apparent atomic weight of the natural gas.

[0015] Optionally, calculating the free gas content of each type of pore using the basic data includes:

[0016] The proportion of mesopores and macropores in the organic pore volume is calculated based on the pore size of the organic pores.

[0017] The free gas content in the organic pores is calculated based on the pore ratio, the porosity of the organic pores, and the formation volume factor of the natural gas.

[0018] Optionally, calculating the free gas content in the organic pores based on the pore ratio, the porosity of the organic pores, and the formation volume factor of the natural gas includes:

[0019] The free gas content G in the organic pores is calculated according to the following expression. fo :

[0020]

[0021] Where, φ org ρ represents the porosity of the organic pores, α represents the proportion of mesopores and macropores in the organic pores, and ρ represents the porosity of the organic pores. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0022] Optionally, calculating the free gas content of each type of pore using the basic data includes:

[0023] Calculate the free gas content G in the pores of brittle minerals using the following expression. fi :

[0024]

[0025] Where, φ i Porosity of brittle minerals, Sw is the reservoir water saturation, and ρ b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0026] Optionally, calculating the free gas content of each type of pore using the basic data includes:

[0027] Calculate the free gas content G in the pores of clay minerals using the following expression. fc :

[0028]

[0029] Where, φ c ρ represents the porosity of clay minerals, Sw represents the reservoir water saturation, and ρ represents the pore size. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0030] Optionally, determining the shale free gas content within the target area based on the content of each free gas and the volume of shale adsorbed gas includes:

[0031] The shale free gas content G in the target area is calculated according to the following expression. f :

[0032]

[0033] Where, φ org φ represents the porosity of organic pores. i φ represents the porosity of brittle mineral pores. c ρ represents the porosity of clay mineral pores. b ρ is the density of the rock. s Here, ρ is the density of adsorbed natural gas in the rock, a is the proportion of mesopores and macropores in the organic pores, Sw is the reservoir water saturation, M is the apparent atomic weight of natural gas, and G is the density of adsorbed natural gas in the rock. a B represents the adsorbed gas content in shale. g This is the formation volume factor for natural gas.

[0034] To solve the above-mentioned technical problems, the present invention provides a device for determining the free gas content of shale, comprising:

[0035] The data acquisition module is used to acquire basic data reflecting the free gas content of various types of pores within the target area; the types include at least one of organic pores, brittle mineral pores, and clay mineral pores;

[0036] The volume calculation module is used to calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0037] The pore free gas calculation module is used to calculate the free gas content of various types of pores using the basic data.

[0038] The shale free gas determination module is used to determine the shale free gas content in the target area based on the content of each free gas and the volume of shale adsorbed gas.

[0039] Optionally, the basic data includes: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0040] Optionally, the volume calculation module is specifically used to calculate the shale adsorbed gas volume φ in the target area according to the following expression. a :

[0041]

[0042] Among them, G a ρ represents the adsorbed gas content in shale. b ρ is the density of the rock. s Let M be the density of natural gas adsorbed on the rock, and M be the apparent atomic weight of the natural gas.

[0043] Optionally, the pore free gas calculation module includes:

[0044] The porosity calculation unit is used to calculate the porosity ratio of mesopores and macropores in organic pores based on the pore size of organic pores.

[0045] An organic pore free gas calculation unit is used to calculate the free gas content in organic pores based on the pore ratio, the porosity of the organic pores, and the formation volume factor of the natural gas.

[0046] Optionally, the organic pore free gas calculation unit is used to calculate the free gas content G in the organic pores according to the following expression. fo :

[0047]

[0048] Where, φ org ρ represents the porosity of the organic pores, α represents the proportion of mesopores and macropores in the organic pores, and ρ represents the porosity of the organic pores. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0049] Optionally, the pore free gas calculation module is specifically used to calculate the free gas content G in the pores of brittle minerals according to the following expression. fi :

[0050]

[0051] Where, φ iPorosity of brittle minerals, Sw is the reservoir water saturation, and ρ b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0052] Optionally, the pore free gas calculation module is specifically used to calculate the free gas content G in the pores of clay minerals according to the following expression. fc :

[0053]

[0054] Where, φ c ρ represents the porosity of clay minerals, Sw represents the reservoir water saturation, and ρ represents the pore size. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0055] Optionally, the shale free gas determination module is specifically used to calculate the shale free gas content G in the target area according to the following expression. f :

[0056]

[0057] Where, φ org φ represents the porosity of organic pores. i φ represents the porosity of brittle mineral pores. c ρ represents the porosity of clay mineral pores. b ρ is the density of the rock. s Here, ρ is the density of adsorbed natural gas in the rock, a is the proportion of mesopores and macropores in the organic pores, Sw is the reservoir water saturation, M is the apparent atomic weight of natural gas, and G is the density of adsorbed natural gas in the rock. a B represents the adsorbed gas content in shale. g This is the formation volume factor for natural gas.

[0058] To address the aforementioned technical problems, the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the aforementioned method.

[0059] To address the aforementioned technical problems, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method.

[0060] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0061] When determining the free gas content of shale using the method of this invention, the basic data of each type of pore in the target area are first obtained; then the volume of shale adsorbed gas in the target area is calculated based on the basic data; then the free gas content of each type of pore is calculated using the basic data; and finally, the free gas content of shale in the target area is determined based on the free gas content and the volume of shale adsorbed gas.

[0062] As can be seen from the above, the present invention classifies the pores in which free gas exists, taking into account the different free gas contents in different types of pores. At the same time, it also takes into account the ratio of free gas to adsorbed gas, thereby improving the accuracy and reliability of determining the free gas content of shale in the target area. It can provide a basis for accurately understanding the potential of shale gas resources and finding favorable shale gas exploration areas, and has important practical significance for shale gas exploration deployment decisions. Attached Figure Description

[0063] The scope of this disclosure can be better understood by reading the following detailed description of exemplary embodiments in conjunction with the accompanying drawings. The accompanying drawings are:

[0064] Figure 1a A schematic diagram showing the spatial volume occupied by gas adsorbed in marine shale;

[0065] Figure 1b A schematic diagram showing the free gas content in the organic pores of marine shale;

[0066] Figure 1c A schematic diagram showing the free gas content in the pores of brittle minerals in marine shale;

[0067] Figure 1d A schematic diagram showing the free gas content in the pores of marine shale clay minerals;

[0068] Figure 1e A schematic diagram of the free gas content in marine shale reservoirs;

[0069] Figure 2 This is a first flowchart of a method for determining the free gas content in shale provided in an embodiment of the present invention;

[0070] Figure 3 This is a schematic diagram illustrating the relationship between various basic data and burial depth provided in the embodiments of the present invention;

[0071] Figure 4 This is a second flowchart of the method for determining the free gas content in shale provided in an embodiment of the present invention;

[0072] Figure 5 This is a third flowchart of the method for determining the free gas content in shale provided in an embodiment of the present invention;

[0073] Figure 6This is a fourth flowchart of the method for determining the free gas content in shale provided in an embodiment of the present invention;

[0074] Figure 7 The fifth flowchart of the method for determining the free gas content in shale provided in the embodiments of the present invention;

[0075] Figure 8 The sixth flowchart of the method for determining the free gas content in shale provided in the embodiments of the present invention;

[0076] Figure 9 A structural diagram of a shale free gas content determination device provided in an embodiment of the present invention;

[0077] Figure 10 This is an internal structural diagram of the pore free gas calculation module provided in an embodiment of the present invention;

[0078] Figure 11 A structural diagram of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0079] To make the objectives, technical solutions, and advantages of the present invention clearer, the implementation method of the present invention will be described in detail below with reference to the accompanying drawings and embodiments, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0080] Among existing technologies, China possesses enormous shale gas resource potential. With the commercial development of shale gas in the southern Sichuan Basin and the increasing proportion of natural gas in the energy consumption structure, shale gas is becoming a crucial replacement area for future natural gas production growth in China. According to the latest resource assessment results from China National Petroleum Corporation (CNPC), my country's recoverable onshore shale gas resources amount to 12.85 × 10⁻⁶. 12 m 3 Of which, the recoverable resources of marine shale gas are 8.82 × 10⁻⁶. 12 m 3 The proportion is 69%; the recoverable resources of shale gas in the marine-continental transitional facies are 2.37 × 10⁻⁶. 12 m 3 The proportion is 18%; the recoverable resources of continental shale gas are 1.66 × 10⁻⁶. 12 m 3 That accounts for 13%.

[0081] Shale gas mainly exists in adsorbed and free states in low-porosity, low-permeability mudstone and shale. Free gas refers to natural gas existing in a free state within the pores and microfractures of mudstone and shale. Generally, within a certain temperature range, the free gas content increases steadily with increasing pressure. Since formation pressure is often positively correlated with burial depth, shale formations at greater burial depths contain a larger amount of free gas. Please refer to [link / reference]. Figures 1a to 1eIn shale reservoirs at a depth of 1150m, the content of free gas and adsorbed gas is roughly equivalent. However, at a depth of around 2800m, the free gas content in shale increases significantly, exceeding twice the content of adsorbed gas. Therefore, free gas is a crucial component of shale gas, especially deep overpressured shale gas. Accurately assessing the free gas content is essential for understanding shale gas resource potential and identifying favorable exploration targets.

[0082] Currently, in the industry, the pore volume defined in traditional petroleum geology is typically used to determine the free gas content of shale. However, marine shale reservoirs are mainly composed of organic pores, brittle mineral pores, and clay mineral pores, and different types of pores store different amounts of free gas. Therefore, the current process for determining the free gas content of shale does not take into account the differences in shale free gas content caused by different pore types, which can easily lead to poor reliability of the determined shale free gas content.

[0083] Therefore, embodiments of the present invention provide a method, apparatus, and storage medium for determining the free gas content in shale, so as to improve the accuracy and reliability of determining the free gas content in shale.

[0084] The method for determining the free gas content in shale provided in the embodiments of the present invention will be described below.

[0085] Example 1

[0086] like Figure 2 The diagram shown is a first flowchart of a method for determining the free gas content in shale provided by an embodiment of the present invention. This method may include the following steps:

[0087] Step S101: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0088] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas. Figure 3 The diagram shows the relationship between the basic data and burial depth provided in the embodiments of the present invention; Table 1 shows a set of basic data for determining the free gas content of marine shale, as follows:

[0089] Table 1

[0090]

[0091] Step S102: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0092] Step S103: Calculate the free gas content of each type of pore using the basic data.

[0093] Step S104: Determine the shale free gas content in the target area based on the free gas content and the shale adsorbed gas volume.

[0094] As can be seen from the above, the present invention classifies the pores in which free gas exists, taking into account the different free gas contents in different types of pores. At the same time, it also takes into account the ratio of free gas to adsorbed gas, thereby improving the accuracy and reliability of determining the free gas content of shale in the target area. It can provide a basis for accurately understanding the potential of shale gas resources and finding favorable shale gas exploration areas, and has important practical significance for shale gas exploration deployment decisions.

[0095] Furthermore, this invention addresses the characteristics of shale reservoirs, which exhibit diverse pore types and complex microstructures. Considering the controlling effect of pore type and microstructure on shale free gas content, it establishes a method for evaluating shale free gas content. The scheme provided by this invention can quickly and accurately establish an effective model for marine shale free gas content. Moreover, this method can quantitatively evaluate shale free gas content based on pore development characteristics, temperature, and pressure conditions in the study area, revealing the shale free gas content and laying the foundation for understanding the shale gas resource potential of the study area.

[0096] Example 2

[0097] like Figure 4 The diagram shown is a second flowchart of a method for determining the free gas content in shale provided by an embodiment of the present invention. This method may include the following steps:

[0098] Step S201: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0099] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0100] Step S202: Calculate the volume φ of shale adsorbed gas in the target area according to expression (1). a :

[0101]

[0102] Among them, G a ρ represents the adsorbed gas content in shale. bρ is the density of the rock. s Let M be the density of natural gas adsorbed on the rock, and M be the apparent atomic weight of the natural gas.

[0103] Step S203: Calculate the free gas content of each type of pore using the basic data.

[0104] Step S204: Determine the shale free gas content in the target area based on the content of each free gas and the volume of shale adsorbed gas.

[0105] It should be noted that, Figure 4 Steps S201, S203, and S204 in the method embodiment shown are the same as those in the previous examples. Figure 2 Steps S101, S103, and S104 in the method embodiment shown are similar; for details, please refer to [link / reference]. Figure 2 The method embodiments shown are not described in detail here.

[0106] Figure 4 The method embodiments shown, in addition to having Figure 2 In addition to all the advantages of the method embodiment shown, a specific method for calculating the volume of adsorbed gas in shale within the target area is also provided, which helps to improve the accuracy of subsequent calculations of shale free gas content.

[0107] Example 3

[0108] like Figure 5 The diagram shown is a third flowchart of a method for determining the free gas content in shale provided by an embodiment of the present invention. This method may include the following steps:

[0109] Step S301: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0110] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0111] Step S302: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0112] Step S303: Calculate the proportion of mesopores and macropores in the organic pores based on the pore size of the organic pores;

[0113] Step S304: Calculate the free gas content in the organic pores based on the pore ratio, the porosity of the organic pores, and the formation volume factor of the natural gas.

[0114] In one implementation, calculating the free gas content in the organic pores based on the pore ratio, the porosity of the organic pores, and the formation volume factor of the natural gas includes:

[0115] The free gas content G in the organic pores is calculated according to expression (2). fo :

[0116]

[0117] Where, φ org ρ represents the porosity of the organic pores, α represents the proportion of mesopores and macropores in the organic pores, and ρ represents the porosity of the organic pores. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0118] Step S305: Determine the shale free gas content in the target area based on the free gas content and the shale adsorbed gas volume.

[0119] It should be noted that, Figure 5 Steps S301, S302, and S305 in the method embodiment shown are the same as those in the previous step. Figure 2 Steps S101, S102, and S104 in the method embodiment shown are similar; for details, please refer to [link / reference]. Figure 2 The method embodiments shown are not described in detail here.

[0120] Figure 5 The method embodiments shown, in addition to having Figure 2 In addition to all the advantages of the method embodiment shown, a specific method for calculating the free gas content in organic pores is also provided, which helps to improve the accuracy of subsequent calculations on the free gas content of shale.

[0121] Example 4

[0122] like Figure 6 The diagram shown is a fourth flowchart of a method for determining the free gas content in shale provided by an embodiment of the present invention. This method may include the following steps:

[0123] Step S401: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0124] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0125] Step S402: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0126] Step S403: Calculate the free gas content G in the pores of brittle minerals according to expression (3). fi :

[0127]

[0128] Where, φ i Porosity of brittle minerals, Sw is the reservoir water saturation, and ρ b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0129] Step S404: Determine the shale free gas content in the target area based on the free gas content and the volume of shale adsorbed gas.

[0130] It should be noted that, Figure 6 Steps S401, S402, and S404 in the method embodiment shown are the same as those in the previous step. Figure 2 Steps S101, S102, and S104 in the method embodiment shown are similar; for details, please refer to [link / reference]. Figure 2 The method embodiments shown are not described in detail here.

[0131] Figure 6 The method embodiments shown, in addition to having Figure 2 In addition to all the advantages of the method embodiment shown, a specific method for calculating the free gas content in the pores of brittle minerals is also provided, which helps to improve the accuracy of subsequent calculations on the free gas content of shale.

[0132] Example 5

[0133] like Figure 7 The diagram shown is a fifth flowchart of a method for determining the free gas content in shale provided by an embodiment of the present invention. This method may include the following steps:

[0134] Step S501: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0135] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0136] Step S502: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0137] Step S503: Calculate the free gas content G in the pores of clay minerals according to expression (4). fc :

[0138]

[0139] Where, φ c ρ represents the porosity of clay minerals, Sw represents the reservoir water saturation, and ρ represents the pore size. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0140] Step S504: Determine the shale free gas content in the target area based on the free gas content and the volume of shale adsorbed gas.

[0141] It should be noted that, Figure 7 Steps S501, S502, and S504 in the method embodiment shown are the same as those in the previous step. Figure 2 Steps S101, S102, and S104 in the method embodiment shown are similar; for details, please refer to [link / reference]. Figure 2 The method embodiments shown are not described in detail here.

[0142] Figure 7 The method embodiments shown, in addition to having Figure 2 In addition to all the advantages of the method embodiment shown, a specific method for calculating the free gas content in the pores of clay minerals is also provided, which helps to improve the accuracy of subsequent calculations on the free gas content of shale.

[0143] It should also be noted that the specific methods for calculating the free gas content of various types of pores using basic data in Examples 2 to 5 above can be combined with each other, and will not be listed one by one here.

[0144] Example 6

[0145] like Figure 8 The diagram shown is a sixth flowchart of a method for determining the free gas content in shale provided by an embodiment of the present invention. This method may include the following steps:

[0146] Step S601: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0147] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0148] Step S602: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0149] Step S603: Calculate the shale free gas content G in the target area according to expression (5). f :

[0150]

[0151] Where, φ org φ represents the porosity of organic pores. i φ represents the porosity of brittle mineral pores. c ρ represents the porosity of clay mineral pores. b ρ is the density of the rock. s Here, ρ is the density of adsorbed natural gas in the rock, a is the proportion of mesopores and macropores in the organic pores, Sw is the reservoir water saturation, M is the apparent atomic weight of natural gas, and G is the density of adsorbed natural gas in the rock. a B represents the adsorbed gas content in shale. g This is the formation volume factor for natural gas.

[0152] Step S604: Determine the shale free gas content in the target area based on the free gas content and the volume of shale adsorbed gas.

[0153] It should be noted that, Figure 8 Steps S601, S602, and S604 in the method embodiment shown are the same as those in the previous embodiment. Figure 2 Steps S101, S102, and S104 in the method embodiment shown are similar; for details, please refer to [link / reference]. Figure 2 The method embodiments shown are not described in detail here.

[0154] Figure 8 The method embodiments shown, in addition to having Figure 2 In addition to all the advantages of the method embodiments shown, a specific method for calculating free gas in shale with different pore types is also provided, which helps to improve the accuracy of subsequent calculations of shale free gas content.

[0155] Corresponding to the above method embodiments, the present invention provides a device for determining the free gas content of shale. The device for determining the free gas content of shale provided in the embodiments of the present invention will be described below.

[0156] Example 7

[0157] like Figure 9 The diagram shown is a structural diagram of a shale free gas content determination device provided in an embodiment of the present invention. The device includes the following modules:

[0158] The data acquisition module 710 is used to acquire basic data reflecting the free gas content of various types of pores within the target area; the pore types include at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0159] The volume calculation module 720 is used to calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0160] The pore free gas calculation module 730 is used to calculate the free gas content of various types of pores using the basic data.

[0161] Shale free gas determination module 740 is used to determine the shale free gas content in the target area based on the content of each free gas and the volume of shale adsorbed gas.

[0162] As can be seen from the above, the present invention classifies the pores in which free gas exists, taking into account the different free gas contents in different types of pores. At the same time, it also takes into account the ratio of free gas to adsorbed gas, thereby improving the accuracy and reliability of determining the free gas content of shale in the target area. It can provide a basis for accurately understanding the potential of shale gas resources and finding favorable shale gas exploration areas, and has important practical significance for shale gas exploration deployment decisions.

[0163] In one implementation, the basic data includes: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0164] In one implementation, the volume calculation module 720 is specifically used to calculate the shale adsorbed gas volume φ in the target area according to the following expression. a :

[0165]

[0166] Among them, G a ρ represents the adsorbed gas content in shale. b ρ is the density of the rock. s Let M be the density of natural gas adsorbed on the rock, and M be the apparent atomic weight of the natural gas.

[0167] In one implementation, such as Figure 10 As shown, the pore free gas calculation module 730 includes:

[0168] The pore proportion calculation unit 731 is used to calculate the pore proportion of mesopores and macropores in organic pores based on the pore size of organic pores.

[0169] Organic porosity free gas calculation unit 732 is used to calculate the free gas content in organic porosity based on the porosity ratio, the porosity of the organic pores and the formation volume factor of the natural gas.

[0170] Specifically, the organic pore free gas calculation unit 732 is used to calculate the free gas content G in the organic pores according to the following expression. fo :

[0171]

[0172] Where, φ org ρ represents the porosity of the organic pores, α represents the proportion of mesopores and macropores in the organic pores, and ρ represents the porosity of the organic pores. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0173] In another implementation, the pore free gas calculation module 730 is specifically used to calculate the free gas content G in the pores of brittle minerals according to the following expression. fi :

[0174]

[0175] Where, φ i Porosity of brittle minerals, Sw is the reservoir water saturation, and ρ b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0176] In another implementation, the pore free gas calculation module 730 is specifically used to calculate the free gas content G in the pores of clay minerals according to the following expression. fc :

[0177]

[0178] Where, φ c ρ represents the porosity of clay minerals, Sw represents the reservoir water saturation, and ρ represents the pore size. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0179] In one embodiment of the present invention, the shale free gas determination module is specifically used to calculate the shale free gas content G in the target area according to the following expression. f :

[0180]

[0181] Where, φ org φ represents the porosity of organic pores. i φ represents the porosity of brittle mineral pores.c ρ represents the porosity of clay mineral pores. b ρ is the density of the rock. s Here, ρ is the density of adsorbed natural gas in the rock, a is the proportion of mesopores and macropores in the organic pores, Sw is the reservoir water saturation, M is the apparent atomic weight of natural gas, and G is the density of adsorbed natural gas in the rock. a B represents the adsorbed gas content in shale. g This is the formation volume factor for natural gas.

[0182] When determining the free gas content of shale using the method of this invention, the basic data of each type of pore in the target area are first obtained; then the volume of shale adsorbed gas in the target area is calculated based on the basic data; then the free gas content of each type of pore is calculated using the basic data; and finally, the free gas content of shale in the target area is determined based on the free gas content and the volume of shale adsorbed gas.

[0183] As can be seen from the above, the present invention classifies the pores in which free gas exists, taking into account the different free gas contents in different types of pores. At the same time, it also takes into account the ratio of free gas to adsorbed gas, thereby improving the accuracy and reliability of determining the free gas content of shale in the target area. It can provide a basis for accurately understanding the potential of shale gas resources and finding favorable shale gas exploration areas, and has important practical significance for shale gas exploration deployment decisions.

[0184] Example 8

[0185] To address the aforementioned technical problems, the present invention provides a computer device, such as... Figure 11 As shown, it includes a memory 810, a processor 820, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method described above.

[0186] The computer device may be a desktop computer, laptop, handheld computer, or cloud server, etc. The computer device may include, but is not limited to, the processor 820 and the memory 810. Those skilled in the art will understand that... Figure 11 This is merely an example of a computer device and does not constitute a limitation on the computer device. It may include more or fewer components than shown, or combine certain components, or different components. For example, the computer device may also include input / output devices, network access devices, buses, etc.

[0187] The processor 820 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0188] The memory 810 can be an internal storage unit of the computer device, such as a hard drive or RAM. The memory 810 can also be an external storage device of the computer device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory 810 can include both internal and external storage units. The memory 810 is used to store the computer program and other programs and data required by the computer device. The memory 810 can also be used to temporarily store data that has been output or will be output.

[0189] The method implemented by the processor when executing the computer program includes the following steps:

[0190] Step S101: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0191] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0192] Step S102: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0193] Step S103: Calculate the free gas content of each type of pore using the basic data.

[0194] Step S104: Determine the shale free gas content in the target area based on the free gas content and the shale adsorbed gas volume.

[0195] In one scenario, the method implemented by the processor when executing the computer program may include the following steps:

[0196] Step S201: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0197] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0198] Step S202: Calculate the volume φ of shale adsorbed gas in the target area according to the following expression. a :

[0199]

[0200] Among them, G a ρ represents the adsorbed gas content in shale. b ρ is the density of the rock. s Let M be the density of natural gas adsorbed on the rock, and M be the apparent atomic weight of the natural gas.

[0201] Step S203: Calculate the free gas content of each type of pore using the basic data.

[0202] Step S204: Determine the shale free gas content in the target area based on the content of each free gas and the volume of shale adsorbed gas.

[0203] In another scenario, the method implemented by the processor when executing the computer program may include the following steps:

[0204] Step S301: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0205] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0206] Step S302: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0207] Step S303: Calculate the proportion of mesopores and macropores in the organic pores based on the pore size of the organic pores;

[0208] Step S304: Calculate the free gas content in the organic pores based on the pore ratio, the porosity of the organic pores, and the formation volume factor of the natural gas.

[0209] In one implementation, calculating the free gas content in the organic pores based on the pore ratio, the porosity of the organic pores, and the formation volume factor of the natural gas includes:

[0210] The free gas content G in the organic pores is calculated according to the following expression. fo :

[0211]

[0212] Where, φ org ρ represents the porosity of the organic pores, α represents the proportion of mesopores and macropores in the organic pores, and ρ represents the porosity of the organic pores. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0213] Step S305: Determine the shale free gas content in the target area based on the free gas content and the shale adsorbed gas volume.

[0214] In another scenario, the method implemented by the processor when executing the computer program may include the following steps:

[0215] Step S401: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0216] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0217] Step S402: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0218] Step S403: Calculate the free gas content G in the pores of brittle minerals according to the following expression. fi :

[0219]

[0220] Where, φ i Porosity of brittle minerals, Sw is the reservoir water saturation, and ρb B represents the density of the rock. g This is the formation volume factor for natural gas.

[0221] Step S404: Determine the shale free gas content in the target area based on the free gas content and the volume of shale adsorbed gas.

[0222] In another scenario, the method implemented by the processor when executing the computer program may include the following steps:

[0223] Step S501: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0224] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0225] Step S502: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0226] Step S503: Calculate the free gas content G in the pores of clay minerals according to the following expression. fc :

[0227]

[0228] Where, φ c ρ represents the porosity of clay minerals, Sw represents the reservoir water saturation, and ρ represents the pore size. b B represents the density of the rock. g This is the formation volume factor for natural gas.

[0229] Step S504: Determine the shale free gas content in the target area based on the free gas content and the volume of shale adsorbed gas.

[0230] In another scenario, the method implemented by the processor when executing the computer program may include the following steps:

[0231] Step S601: Obtain basic data reflecting the free gas content of each type of pore within the target area; the pore type includes at least one of organic pores, brittle mineral pores, and clay mineral pores.

[0232] In a preferred embodiment, the basic data may include: porosity of various types of pores, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas.

[0233] Step S602: Calculate the volume of shale adsorbed gas in the target area based on the basic data.

[0234] Step S603: Calculate the shale free gas content G in the target area according to the following expression. f :

[0235]

[0236] Where, φ org φ represents the porosity of organic pores. i φ represents the porosity of brittle mineral pores. c ρ represents the porosity of clay mineral pores. b ρ is the density of the rock. s Here, ρ is the density of adsorbed natural gas in the rock, a is the proportion of mesopores and macropores in the organic pores, Sw is the reservoir water saturation, M is the apparent atomic weight of natural gas, and G is the density of adsorbed natural gas in the rock. a B represents the adsorbed gas content in shale. g This is the formation volume factor for natural gas.

[0237] Step S604: Determine the shale free gas content in the target area based on the free gas content and the volume of shale adsorbed gas.

[0238] Example 9

[0239] This application also provides a computer-readable storage medium, which may be a computer-readable storage medium included in the memory described in the above embodiments; or it may be a standalone computer-readable storage medium not assembled into a computer device. The computer-readable storage medium stores one or more computer programs, which, when executed by a processor, implement the methods described above.

[0240] If the integrated module / unit is implemented as 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, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory 810, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electrical carrier signals and telecommunication signals.

[0241] As the device embodiment is basically similar to the method embodiment, it is described in a relatively simple way. For relevant details, please refer to the description of the method embodiment.

[0242] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0243] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0244] It should be understood that the terminology used in this application specification is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this application specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0245] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0246] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if the described condition or event is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once the described condition or event is detected," or "in response to the detection of the described condition or event."

[0247] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for determining the free gas content in shale, characterized in that, include: Obtain basic data reflecting the free gas content of each type of pore within the target area; The types include at least one of organic pores, brittle mineral pores, and clay mineral pores, and the basic data include: porosity of each type of pore, pore size of organic pores, reservoir water saturation, shale adsorbed gas content, rock density, rock adsorbed natural gas density, formation volume factor of natural gas, and apparent atomic weight of natural gas. Calculate the volume of shale-adsorbed gas within the target area based on the aforementioned basic data; The free gas content of various types of pores is calculated using the aforementioned basic data, including: calculating the proportion of mesopores and macropores in the organic pores based on the pore size; calculating the free gas content of the organic pores based on the pore proportion, the porosity of the organic pores, and the formation volume factor of the natural gas; and calculating the free gas content in the pores of brittle minerals according to the following expression. : ,in, Porosity refers to the porosity of brittle mineral pores. Reservoir water saturation For rock density, The formation volume factor for natural gas is given; the free gas content in the pores of clay minerals is calculated using the following expression. : ,in, Porosity refers to the porosity of clay mineral pores. Reservoir water saturation For rock density, Let be the formation volume factor for natural gas; calculate the shale free gas content within the target area using the following expression. : ,in, Porosity of organic pores Porosity refers to the porosity of brittle mineral pores. Porosity refers to the porosity of clay mineral pores. For rock density, The density of natural gas adsorbed on the rock, The proportion of mesopores and macropores in organic pores. Reservoir water saturation For natural gas, The content of adsorbed gas in shale. This is the formation volume factor for natural gas; The free gas content of shale in the target area is determined based on the content of each free gas and the volume of shale adsorbed gas.

2. The method for determining the free gas content in shale according to claim 1, characterized in that, The calculation of the shale adsorbed gas volume within the target area based on the basic data includes: The volume of shale-adsorbed gas in the target area is calculated using the following expression. : ， in, The content of adsorbed gas in shale. For rock density, The density of natural gas adsorbed on the rock, The apparent atomic weight of natural gas.

3. The method for determining the free gas content in shale according to claim 1, characterized in that, The calculation of the free gas content in the organic pores based on the porosity, the porosity of the organic pores, and the formation volume factor of the natural gas includes: The free gas content in the organic pores is calculated according to the following expression. : ， in, Porosity of organic pores The proportion of mesopores and macropores in organic pores. For rock density, This is the formation volume factor for natural gas.

4. A device for determining the free gas content in shale using the method of claim 1, characterized in that, include: The data acquisition module is used to acquire basic data reflecting the free gas content of various types of pores within the target area; the types include at least one of organic pores, brittle mineral pores, and clay mineral pores; The volume calculation module is used to calculate the volume of shale adsorbed gas in the target area based on the basic data. The pore free gas calculation module is used to calculate the free gas content of various types of pores using the basic data. The shale free gas determination module is used to determine the shale free gas content in the target area based on the content of each free gas and the volume of shale adsorbed gas.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1 to 3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 3.

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