Method and apparatus for determining EUR of shale gas wells

Abstract

The present application discloses a method and device for determining the EUR of a shale gas well, belonging to the technical field of shale gas development. The method comprises: dividing a plurality of EUR levels in a target well area, determining the average recovery rate corresponding to each EUR level; obtaining the well-controlled reserves of a target gas well in a first target stage, wherein the first target stage is a well site demonstration stage, a drilling stage, or a fracturing stage; based on the average recovery rate corresponding to each EUR level and the well-controlled reserves of the target gas well, determining the estimated final recoverable reserves EUR of the target gas well in the first target stage at each EUR level. The method provided in the embodiment of the present application can calculate the EUR of a gas well in the well site demonstration stage, the drilling stage, or the fracturing stage.

Description

Technical Field

[0001] The present application relates to the technical field of shale gas development, and in particular to a method and device for determining the EUR of a shale gas well. Background Art

[0002] China's shale gas is widely distributed in marine shales and has broad prospects for exploration and development. For shale gas with large resources, the evaluation of EUR (Estimated Ultimate Recovery) is particularly important in order to accurately assess its development potential and develop it at scale. EUR is related to gas well production, work system, and deployment and adjustment of development well networks, and is the basis for efficient and scientific development of shale gas fields.

[0003] However, currently there are a large number of methods that can be used to calculate the EUR of a gas well after it is put into production, but there is no method to calculate the EUR of a gas well before it is put into production. Summary of the invention

[0004] The embodiment of the present application provides a method and device for determining the EUR of a shale gas well, which can calculate the EUR of a gas well in the well site demonstration stage, the drilling stage or the fracturing stage. The technical solution is as follows:

[0005] In one aspect, an embodiment of the present application provides a method for determining a shale gas well EUR, the method comprising:

[0006] In the target well area, multiple EUR levels are divided and the average recovery factor corresponding to each EUR level is determined;

[0007] Obtaining the well-controlled reserves of a target gas well in a first target stage, wherein the first target stage is a well location demonstration stage, a drilling stage, or a fracturing stage;

[0008] Based on the average recovery factor corresponding to each EUR level and the well-controlled reserves of the target gas well, the estimated ultimate recoverable reserves EUR of the target gas well in the first target stage at each EUR level are determined.

[0009] Optionally, before determining the average recovery factor corresponding to each EUR grade, the method further includes:

[0010] Selecting a first number of gas wells from all gas wells in the target well area that have been in production for more than one year, and determining the EUR of each gas well;

[0011] Based on the EUR of each gas well, the gas wells are ranked, and the first second number of gas wells are regarded as gas wells with excellent EUR grades; the last third number of gas wells are regarded as gas wells with poor EUR grades; and the other gas wells except the gas wells with excellent EUR grades and the gas wells with poor EUR grades are regarded as gas wells with medium EUR grades.

[0012] Optionally, determining the average recovery factor corresponding to each EUR grade of the target well area includes:

[0013] A fourth number of gas wells are selected from the gas wells with an excellent EUR grade, and an average EUR and an average well-controlled reserve are determined based on the EUR and the well-controlled reserve of each gas well, and an average recovery factor corresponding to the excellent EUR grade is determined based on the average EUR and the average well-controlled reserve;

[0014] Randomly select a fifth number of gas wells from the gas wells with a medium EUR level, determine an average EUR and an average well-controlled reserve based on the EUR and well-controlled reserve of each gas well, and determine an average recovery factor corresponding to the medium EUR level based on the average EUR and the average well-controlled reserve;

[0015] Among the gas wells with poor EUR grades, the sixth number of gas wells are randomly selected, and the average EUR and the average well-controlled reserves are determined based on the EUR and the well-controlled reserves of each gas well. Based on the average EUR and the average well-controlled reserves, the average recovery factor corresponding to the poor EUR grade is determined.

[0016] Optionally, when the first target stage is the well location demonstration stage, obtaining the well-controlled reserves of the target gas well in the first target stage includes:

[0017] According to formula G x =0.01*A g *h*ρ y *C x , and obtain the adsorbed gas geological reserves of the first type of reservoir in the target gas well, where G x represents the adsorbed gas geological reserves of the first type of reservoir in the target gas well, A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, and ρ y represents the shale mass density of the first type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the first type of reservoir in the target gas well, Z i represents the original gas deviation factor of the first type of reservoir in the target gas well;

[0018] According to the formula The free gas geological reserves of the first type of reservoir in the target gas well are obtained, where G yrepresents the free gas geological reserves of the first type of reservoir in the target gas well, A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, represents the effective porosity of the first type of reservoir in the target gas well, S gi represents the original gas saturation of the first type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the first type of reservoir in the target gas well;

[0019] Adding the adsorbed gas geological reserves of the first type of reservoir in the target gas well to the free gas geological reserves of the first type of reservoir in the target gas well to obtain the well-controlled reserves of the first type of reservoir in the target gas well;

[0020] Among them, according to the formula Ag = 2*L a *L far , and obtain the gas-bearing area of ​​the first type of reservoir in the target gas well, where A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, L a represents the theoretical horizontal length of the first type of reservoir in the target gas well, L far It represents the controlled half-length of the first type of reservoir in the target gas well in the horizontal direction.

[0021] Optionally, when the first target stage is the drilling stage, obtaining the well-controlled reserves of the target gas well in the first target stage includes:

[0022] According to formula G xn =0.01*A gn *h*ρ y *C x , to obtain the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, where G xn A represents the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, and ρ y represents the shale mass density of the nth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the nth type of reservoir in the target gas well, Z i represents the original gas deviation factor of the nth type of reservoir in the target gas well;

[0023] According to the formula Get the free gas geological reserves of the nth type of reservoir in the target gas well, where G yn A represents the free gas geological reserves of the nth type of reservoir in the target gas well, gnrepresents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, represents the effective porosity of the nth type of reservoir in the target gas well, S gi represents the original gas saturation of the nth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the nth type of reservoir in the target gas well;

[0024] Adding the adsorbed gas geological reserves of the n-th type of reservoir in the target gas well to the free gas geological reserves of the n-th type of reservoir in the target gas well to obtain the well-controlled reserves of the n-th type of reservoir in the target gas well;

[0025] According to formula A gn =2*L b *F n *L far , and obtain the gas-bearing area of ​​the nth type of reservoir in the target gas well, where A gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, L b represents the actual horizontal length of the nth type of reservoir in the target gas well, L far represents the horizontal control half-length of the nth type of reservoir in the target gas well, F n It represents the drilling rate of the nth type of reservoir in the target gas well.

[0026] Optionally, when the first target stage is the fracturing stage, obtaining the well-controlled reserves of the target gas well in the first target stage includes:

[0027] According to formula G xm =0.01*A gm *h*ρ y *C x , to obtain the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, where G xm represents the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, A gm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, and ρ y represents the shale mass density of the mth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the mth type of reservoir in the target gas well, Z i represents the original gas deviation factor of the mth type of reservoir in the target gas well;

[0028] According to the formula Get the free gas geological reserves of the mth type of reservoir in the target gas well, where G ymrepresents the free gas geological reserves of the mth type of reservoir in the target gas well, A gm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, represents the effective porosity of the mth type of reservoir in the target gas well, S gi represents the original gas saturation of the mth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the mth type of reservoir in the target gas well;

[0029] Adding the adsorbed gas geological reserves of the mth type of reservoir in the target gas well to the free gas geological reserves of the mth type of reservoir in the target gas well to obtain the well-controlled reserves of the nth type of reservoir in the target gas well;

[0030] According to formula A gm =2*L c *R m *L far , and obtain the gas-bearing area of ​​the mth type of reservoir in the target gas well, where A gn represents the gas-bearing area of ​​the mth type reservoir in the target gas well, L represents the horizontal length of the mth type reservoir in the target gas well after drilling, and L far represents the controlled half length of the m-th type of reservoir in the target gas well in the horizontal direction, R m It represents the fracturing rate of the mth type of reservoir in the target gas well.

[0031] Optionally, the method further comprises a second target stage;

[0032] The method further comprises:

[0033] When the second target stage is the drainage stage, the EUR of the target gas well in the drainage stage is determined based on a pre-stored regression formula, as well as the test production of the target gas well, the average wellhead pressure, the pressure drop from the opening to the wellhead of the test device, and the maximum constant return rate.

[0034] Optionally, the method further includes:

[0035] When the second target stage is a fast decline stage or a slow decline stage, the EUR of the target gas well in the fast decline stage or the slow decline stage is determined based on the hyperbolic decline curve.

[0036] In one aspect, an embodiment of the present application provides a device for determining EUR of a shale gas well, the device comprising:

[0037] The first determination module is configured to divide a target well area into a plurality of EUR levels and determine an average recovery factor corresponding to each EUR level;

[0038] An acquisition module is configured to acquire the well-controlled reserves of a target gas well in a first target stage, wherein the first target stage is a well location demonstration stage, a drilling stage, or a fracturing stage;

[0039] The second determination module is configured to determine the estimated ultimate recoverable reserves EUR of the target gas well in the first target stage at each EUR level based on the average recovery factor corresponding to each EUR level and the well-controlled reserves of the target gas well.

[0040] Optionally, the device further comprises a division module, wherein the division module is configured to: select a first number of gas wells from all gas wells in the target well area that have been in production for more than one year, and determine the EUR of each gas well;

[0041] Based on the EUR of each gas well, the gas wells are ranked, and the first second number of gas wells are regarded as gas wells with excellent EUR grades; the last third number of gas wells are regarded as gas wells with poor EUR grades; and the other gas wells except the gas wells with excellent EUR grades and the gas wells with poor EUR grades are regarded as gas wells with medium EUR grades.

[0042] Optionally, the first determining module is configured to:

[0043] A fourth number of gas wells are selected from the gas wells with an excellent EUR grade, and an average EUR and an average well-controlled reserve are determined based on the EUR and the well-controlled reserve of each gas well, and an average recovery factor corresponding to the excellent EUR grade is determined based on the average EUR and the average well-controlled reserve;

[0044] Randomly select a fifth number of gas wells from the gas wells with a medium EUR level, determine an average EUR and an average well-controlled reserve based on the EUR and well-controlled reserve of each gas well, and determine an average recovery factor corresponding to the medium EUR level based on the average EUR and the average well-controlled reserve;

[0045] Among the gas wells with poor EUR grades, the sixth number of gas wells are randomly selected, and the average EUR and the average well-controlled reserves are determined based on the EUR and the well-controlled reserves of each gas well. Based on the average EUR and the average well-controlled reserves, the average recovery factor corresponding to the poor EUR grade is determined.

[0046] Optionally, when the first target stage is the well location demonstration stage, the acquisition module is configured to:

[0047] According to formula G x =0.01*A g *h*ρ y *C x , and obtain the adsorbed gas geological reserves of the first type of reservoir in the target gas well, where G xrepresents the adsorbed gas geological reserves of the first type of reservoir in the target gas well, A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, and ρ y represents the shale mass density of the first type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the first type of reservoir in the target gas well, Z i represents the original gas deviation factor of the first type of reservoir in the target gas well;

[0048] According to the formula The free gas geological reserves of the first type of reservoir in the target gas well are obtained, where G y represents the free gas geological reserves of the first type of reservoir in the target gas well, A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, represents the effective porosity of the first type of reservoir in the target gas well, S gi represents the original gas saturation of the first type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the first type of reservoir in the target gas well;

[0049] Adding the adsorbed gas geological reserves of the first type of reservoir in the target gas well to the free gas geological reserves of the first type of reservoir in the target gas well to obtain the well-controlled reserves of the first type of reservoir in the target gas well;

[0050] Among them, according to the formula Ag = 2*L a *L far , and obtain the gas-bearing area of ​​the first type of reservoir in the target gas well, where A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, L a represents the theoretical horizontal length of the first type of reservoir in the target gas well, L far It represents the controlled half-length of the first type of reservoir in the target gas well in the horizontal direction.

[0051] Optionally, when the first target stage is the drilling stage, the acquisition module is configured to:

[0052] According to formula G xn =0.01*A gn *h*ρ y *C x , to obtain the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, where G xn A represents the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, gnrepresents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, and ρ y represents the shale mass density of the nth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the nth type of reservoir in the target gas well, Z i represents the original gas deviation factor of the nth type of reservoir in the target gas well;

[0053] According to the formula Get the free gas geological reserves of the nth type of reservoir in the target gas well, where G yn A represents the free gas geological reserves of the nth type of reservoir in the target gas well, gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, represents the effective porosity of the nth type of reservoir in the target gas well, S gi represents the original gas saturation of the nth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the nth type of reservoir in the target gas well;

[0054] Adding the adsorbed gas geological reserves of the n-th type of reservoir in the target gas well to the free gas geological reserves of the n-th type of reservoir in the target gas well to obtain the well-controlled reserves of the n-th type of reservoir in the target gas well;

[0055] According to formula A gn =2*L b *F n *L far , and obtain the gas-bearing area of ​​the nth type of reservoir in the target gas well, where A gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, L b represents the actual horizontal length of the nth type of reservoir in the target gas well, L far represents the horizontal control half-length of the nth type of reservoir in the target gas well, F n It represents the drilling rate of the nth type of reservoir in the target gas well.

[0056] Optionally, when the first target stage is the fracturing stage, the acquisition module is configured to:

[0057] According to formula G xm =0.01*A gm *h*ρ y *C x , to obtain the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, where G xm represents the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, Agm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, and ρ y represents the shale mass density of the mth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the mth type of reservoir in the target gas well, Z i represents the original gas deviation factor of the mth type of reservoir in the target gas well;

[0058] According to the formula Get the free gas geological reserves of the mth type of reservoir in the target gas well, where G ym represents the free gas geological reserves of the mth type of reservoir in the target gas well, A gm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, represents the effective porosity of the mth type of reservoir in the target gas well, S gi represents the original gas saturation of the mth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the mth type of reservoir in the target gas well;

[0059] Adding the adsorbed gas geological reserves of the mth type of reservoir in the target gas well to the free gas geological reserves of the mth type of reservoir in the target gas well to obtain the well-controlled reserves of the nth type of reservoir in the target gas well;

[0060] According to formula A gm =2*L c *R m *L far , and obtain the gas-bearing area of ​​the mth type of reservoir in the target gas well, where A gn represents the gas-bearing area of ​​the mth type reservoir in the target gas well, L represents the horizontal length of the mth type reservoir in the target gas well after drilling, and L far represents the controlled half length of the m-th type of reservoir in the target gas well in the horizontal direction, R m It represents the fracturing rate of the mth type of reservoir in the target gas well.

[0061] Optionally, the device further includes a second target stage, and the device further includes a third determining module, and the third determining module is configured to:

[0062] When the second target stage is the drainage stage, the EUR of the target gas well in the drainage stage is determined based on a pre-stored regression formula, as well as the test production of the target gas well, the average wellhead pressure, the pressure drop from the opening to the wellhead of the test device, and the maximum constant return rate.

[0063] Optionally, the device further includes a fourth determining module, and the fourth determining module is configured to:

[0064] When the second target stage is a fast decline stage or a slow decline stage, the EUR of the target gas well in the fast decline stage or the slow decline stage is determined based on the hyperbolic decline curve.

[0065] According to the technical solution provided in the embodiment of the present application, the well-controlled reserves of the target gas well in the well site demonstration stage, the drilling stage or the fracturing stage are different. The EUR corresponding to each EUR level of the target gas well in the well site demonstration stage, the drilling stage or the fracturing stage can be estimated based on the average recovery rate corresponding to each EUR level and the well-controlled reserves of the target gas well in the well site demonstration stage, the drilling stage or the fracturing stage, thereby solving the problem in the prior art that the EUR of the gas well before production cannot be calculated. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0067] Figure 1 is a flow chart of a method for determining EUR of a shale gas well provided in an embodiment of the present application;

[0068] Figure 2 It is a structural schematic diagram of determining the EUR of a shale gas well provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0070] Figure 1 is a flow chart of a method for determining EUR of a shale gas well provided in an embodiment of the present application. Figure 1 , the embodiment comprises:

[0071] Step 101: In the target well area, multiple EUR levels are divided, and the average recovery factor corresponding to each EUR level is determined.

[0072] Optionally, the steps of dividing into multiple EUR grades are: among all the gas wells in the target well area that have been in production for more than one year, select a first number of gas wells, and determine the EUR of each gas well; based on the EUR of each gas well, sort the gas wells, and take the first second number of gas wells as gas wells with excellent EUR grades; take the last third number of gas wells as gas wells with poor EUR grades; and take the other gas wells except the gas wells with excellent EUR grades and the gas wells with poor EUR grades as gas wells with medium EUR grades.

[0073] The difference in horizontal section lengths between every two gas wells selected from the first number of gas wells is smaller than a preset value, that is, the horizontal section lengths of the first number of gas wells are comparable.

[0074] For example, in the target well area, 100 gas wells with comparable horizontal section lengths are selected, and these 100 gas wells are sorted, and the first 30 gas wells are regarded as gas wells with excellent EUR grades, the last 30 gas wells are regarded as gas wells with poor EUR grades, and the remaining 40 wells are regarded as gas wells with medium grades.

[0075] It should be noted that for each gas well, under normal circumstances, the horizontal section length of each gas well should be within a fixed range, that is, the horizontal section lengths of gas wells under normal circumstances are equivalent. In abnormal circumstances, there will be gas wells with too long or too short horizontal sections in the target well area. These situations are only special cases. In order to improve the accuracy of classification, the EUR level cannot be classified based on these abnormal gas wells.

[0076] Optionally, after being divided into multiple EUR grades, the steps of determining the average recovery factor corresponding to each EUR grade of the target well area are as follows: among the gas wells with excellent EUR grade, a fourth number of gas wells are selected, and based on the EUR and well-controlled reserves of each gas well, the average EUR and the average well-controlled reserves are determined, and based on the average EUR and the average well-controlled reserves, the average recovery factor corresponding to the excellent EUR grade is determined; among the gas wells with medium EUR grade, a fifth number of gas wells are randomly selected, and based on the EUR and well-controlled reserves of each gas well, the average EUR and the average well-controlled reserves are determined, and based on the average EUR and the average well-controlled reserves, the average recovery factor corresponding to the medium EUR grade is determined; among the gas wells with poor EUR grade, a sixth number of gas wells are randomly selected, and based on the EUR and well-controlled reserves of each gas well, the average EUR and the average well-controlled reserves are determined, and based on the average EUR and the average well-controlled reserves, the average recovery factor corresponding to the poor EUR grade is determined.

[0077] Among them, the fourth number, the fifth number and the sixth number may be equal or unequal.

[0078] In implementation, a fourth number of gas wells are selected from the gas wells classified as having an excellent EUR grade. The EUR of each gas well is obtained, and the sum of the EUR of each gas well is divided by the fourth number to obtain an average EUR. The well-controlled reserves of each gas well are obtained, and the sum of the well-controlled reserves of each gas well is divided by the fourth number to obtain an average well-controlled reserve. The average EUR and the average well-controlled reserve are multiplied to determine the average recovery factor corresponding to the excellent EUR grade. A fifth number of gas wells are selected from the gas wells classified as having a medium EUR grade. The EUR of each gas well is obtained, and the sum of the EUR of each gas well is divided by the fifth number to obtain an average EUR. The well-controlled reserves of each gas well are obtained, and the sum of the well-controlled reserves of each gas well is divided by the fifth number to obtain an average well-controlled reserve. The average EUR and the average well-controlled reserve are multiplied to determine the average recovery factor corresponding to the medium EUR grade. A sixth number of gas wells are selected from the gas wells classified as having a poor EUR grade. The EUR of each gas well is obtained, and the sum of the EUR of each gas well is divided by the sixth number to obtain the average EUR. The well-controlled reserves of each gas well are obtained, and the sum of the well-controlled reserves of each gas well is divided by the sixth number to obtain the average well-controlled reserves. The average EUR and the average well-controlled reserves are multiplied to determine the average recovery factor corresponding to the EUR grade difference.

[0079] It should be noted that the well-controlled volume of the gas well can be obtained through the static method, and the gas abundance in the logging data can be obtained. The well-controlled reserves of the gas well can be obtained by multiplying the well-controlled volume and the gas abundance.

[0080] Step 102: Acquire the well-controlled reserves of the target gas well in the first target stage.

[0081] Among them, the first target stage is the well site demonstration stage, the drilling stage or the fracturing stage.

[0082] Optionally, when the first target stage is the well location demonstration stage, the step of obtaining the well-controlled reserves of the target gas well is: when the first target stage is the well location demonstration stage, according to formula G x =0.01*A g *h*ρ y *C x , and obtain the adsorbed gas geological reserves of the first type of reservoir in the target gas well, where G x A represents the geological reserves of adsorbed gas in the first type of reservoir in the target gas well. g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, and ρ y represents the shale mass density of the first type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the first type of reservoir in the target gas well, Z i It represents the original gas deviation factor of the first type of reservoir in the target gas well. According to the formula Get the free gas geological reserves of the first type of reservoir in the target gas well, where G y A represents the free gas geological reserves of the first type of reservoir in the target gas well, g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, represents the effective porosity of the first type of reservoir in the target gas well, S gi represents the original gas saturation of the first type of reservoir in the target gas well, B gi Represents the original shale gas volume coefficient of the first type of reservoir in the target gas well. Add the adsorbed gas geological reserves of the first type of reservoir in the target gas well to the free gas geological reserves of the first type of reservoir in the target gas well to obtain the well-controlled reserves of the first type of reservoir in the target gas well. According to the formula Ag = 2*L a *L far , and obtain the gas-bearing area of ​​the first type of reservoir in the target gas well, A g Indicates the gas-bearing area of ​​the first type of reservoir in the target gas well, L a represents the theoretical horizontal length of the first type of reservoir in the target gas well, L far It represents the controlled half-length of the first type of reservoir in the target gas well in the horizontal direction.

[0083] Optionally, when the first target stage is the drilling stage, the step of obtaining the well-controlled reserves of the target gas well is: when the first target stage is the drilling stage, according to formula G xn =0.01*A gn *h*ρ y *C x , and obtain the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, where G xn A represents the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, and ρ y represents the shale mass density of the nth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the nth type of reservoir in the target gas well, Z i It represents the original gas deviation factor of the nth type of reservoir in the target gas well. According to the formula Get the free gas geological reserves of the nth type of reservoir in the target gas well, where G yn A represents the free gas geological reserves of the nth type of reservoir in the target gas well, gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, represents the effective porosity of the nth type of reservoir in the target gas well, S gi represents the original gas saturation of the nth type of reservoir in the target gas well, Bgi represents the original shale gas volume coefficient of the nth type of reservoir in the target gas well; the adsorbed gas geological reserves of the nth type of reservoir in the target gas well are added to the free gas geological reserves of the nth type of reservoir in the target gas well to obtain the well-controlled reserves of the nth type of reservoir in the target gas well. gn =2*L b *F n *L far , and obtain the gas-bearing area of ​​the nth type of reservoir in the target gas well, where A gn Indicates the gas-bearing area of ​​the nth type of reservoir in the target gas well, L b Indicates the actual horizontal length of the nth type of reservoir in the target gas well, L far represents the horizontal control half-length of the nth type of reservoir in the target gas well, F n It indicates the drilling rate of the nth type of reservoir in the target gas well.

[0084] Optionally, when the first target stage is the drilling stage, the step of obtaining the well-controlled reserves of the target gas well is: when the first target stage is the fracturing stage, according to formula G xm =0.01*A gm *h*ρ y *C x , and obtain the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, where G xm A represents the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, gm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, and ρ y represents the shale mass density of the mth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the mth type of reservoir in the target gas well, Z i It represents the original gas deviation factor of the mth type reservoir in the target gas well. According to the formula Get the free gas geological reserves of the mth type of reservoir in the target gas well, where G ym A represents the free gas geological reserves of the mth type of reservoir in the target gas well, gm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, represents the effective porosity of the mth type of reservoir in the target gas well, S gi represents the original gas saturation of the mth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the mth type reservoir in the target gas well. The adsorbed gas geological reserves of the mth type reservoir in the target gas well are added to the free gas geological reserves of the mth type reservoir in the target gas well to obtain the well-controlled reserves of the nth type reservoir in the target gas well. gm =2*Lc *R m *L far , and obtain the gas-bearing area of ​​the mth type of reservoir in the target gas well, where A gn represents the gas-bearing area of ​​the mth type reservoir in the target gas well, L represents the horizontal length of the mth type reservoir in the target gas well after drilling, and L far represents the horizontal control half-length of the m-th type of reservoir in the target gas well, R m It represents the fracturing rate of the mth type of reservoir in the target gas well.

[0085] It should be noted that the fracturing rate is the effective fracturing wellbore length divided by the total length of the wellbore in the reservoir, that is, the effective fracturing wellbore length / the total length of the wellbore in the reservoir.

[0086] Step 103: Based on the average recovery factor corresponding to each EUR level and the well-controlled reserves of the target gas well, the estimated ultimate recoverable reserves EUR corresponding to each EUR level of the target gas well in the first target stage are determined.

[0087] In implementation, the average recovery factor corresponding to each EUR level is multiplied by the well-controlled reserves of the target gas well to obtain the estimated ultimate recoverable reserves EUR corresponding to each EUR level of the target gas well in the first target stage.

[0088] In the embodiments of the present application, the well-controlled reserves of the target gas well in the well site demonstration stage, the drilling stage or the fracturing stage are different. The EUR corresponding to each EUR level of the target gas well in the well site demonstration stage, the drilling stage or the fracturing stage can be estimated based on the average recovery rate corresponding to each EUR level and the well-controlled reserves of the target gas well in the well site demonstration stage, the drilling stage or the fracturing stage, thereby solving the problem in the prior art that the EUR of the gas well before production cannot be calculated.

[0089] Optionally, after obtaining the EUR corresponding to each EUR grade of the gas well before exploitation in the well site demonstration stage, drilling stage or fracturing stage, the EUR corresponding to different gas wells at the same stage and the same EUR grade can be analyzed. For example, if the EUR corresponding to the EUR grade of gas well A in the drilling stage is better than the EUR corresponding to the EUR grade of gas well B in the drilling stage, then the drilling effect of gas well A is better than the drilling effect of gas well B. If the EUR corresponding to the EUR grade of gas well A in the fracturing stage is worse than the EUR corresponding to the EUR grade of gas well B in the fracturing stage, it can be known that the fracturing technology used in gas well A is not applicable, while the fracturing technology used in well area B is applicable.

[0090] Optionally, select any well, determine the EUR change of the gas well at each stage according to the EUR corresponding to the same EUR level in the well location demonstration stage, drilling stage and fracturing stage, and analyze and obtain the main influencing factors of EUR. For example, at the same EUR level, if the EUR corresponding to the drainage stage is relatively small, it means that there are factors affecting the gas well productivity in this stage, and then determine the factors affecting the gas well productivity.

[0091] Optionally, when the second target stage is the drainage stage, the EUR of the target gas well in the drainage stage is determined based on a pre-stored regression formula, as well as the test production of the target gas well, the average wellhead pressure, the pressure drop from the opening to the wellhead of the test device, and the maximum constant return rate.

[0092] Among them, the pre-stored regression formula is Y=aQ+bP+cK+dF+e, wherein Y represents the EUR of the drainage stage, Q represents the test production, P represents the average wellhead pressure, K represents the degree of pressure reduction at the wellhead of the open channel test device, F represents the maximum constant return rate, and a, b, c, d and e represent constants.

[0093] It should be noted that the method for determining a, b, c, d and e is: obtain the EUR, test production, average wellhead pressure, the degree of pressure reduction at the wellhead of the open-channel test device and the maximum constant return rate of different gas wells in the drainage and production stage, and analyze the changing relationship between the test production, average wellhead pressure, the degree of pressure reduction at the wellhead of the open-channel test device, the maximum constant return rate and EUR, establish a regression curve, and determine the regression formula as well as a, b, c, d and e in the regression formula.

[0094] Optionally, when the second target stage is a fast decline stage or a slow decline stage, the EUR of the target gas well in the fast decline stage or the slow decline stage is determined based on the hyperbolic decline curve.

[0095] In the rapid decline stage, when the target gas well enters the rapid decline stage, the EUR of the target gas well is calculated based on the production data using the hyperbolic decline curve, where the hyperbolic decline curve is a curve about time and production. At this time, the time after the gas well enters the rapid decline stage is required, and this time is brought into the hyperbolic decline curve to obtain the EUR of the target gas well in the rapid decline stage.

[0096] In the slow decline stage, when the target gas well enters the slow decline stage, the EUR of the target gas well is calculated based on the production data using the hyperbolic decline curve, where the hyperbolic decline curve is a curve about time and production. At this time, the time after the gas well enters the slow decline stage is required, and this time is brought into the hyperbolic decline curve to obtain the EUR of the target gas well in the rapid decline stage.

[0097] Optionally, the EUR and the corresponding horizontal section length corresponding to each gas well are obtained in advance, and the EUR and the corresponding horizontal section length corresponding to each gas well are divided to obtain the unit length EUR corresponding to each gas well, and then the unit length EUR corresponding to each gas well in the gas field is obtained. Based on the unit length EUR corresponding to each gas well in the gas field, each gas well in the gas field is sorted, and the seventh number of gas wells ranked in the front are regarded as gas wells with excellent unit length EUR level, and the eighth number of gas wells ranked in the back are regarded as gas wells with poor unit length EUR level, and the other gas wells are regarded as gas wells with medium unit length EUR level. Among them, the number of gas wells in the gas field is multiplied by the first ratio set in advance to obtain the seventh number, and the number of gas wells in the gas field is multiplied by the second ratio set in advance to obtain the eighth number.

[0098] For each unit length EUR level, the unit length EUR corresponding to all gas wells in the unit length EUR level are added together to get the sum, and the sum is divided by the number of all gas wells in the unit length EUR level to obtain the average unit length EUR corresponding to the unit length EUR level.

[0099] By the above method, the average unit length EUR of each gas field in each unit length EUR level is obtained, and the development effect of the gas field is evaluated by the average unit length EUR of each gas field in each unit length EUR level. The average unit length EUR at the same unit length EUR level is compared. If the average unit length EUR is higher at the same unit length EUR level, the development effect of the gas well corresponding to the average unit length is better. If the average unit length EUR is higher at the same unit length EUR level, the development effect of the gas well corresponding to the average unit length is worse.

[0100] Optionally, at the same unit length EUR level, the reduction rate of the unit length EUR of the gas well in two adjacent stages is obtained. The reduction rate of the unit length EUR of the gas well in two adjacent stages is compared with the reduction rate of the gas field in the same two stages to obtain a comparison result. For example, when the unit length EUR level is excellent, the unit length EUR corresponding to the demonstration stage is subtracted from the unit length EUR corresponding to the drilling and completion stage, and then divided by the unit length EUR corresponding to the demonstration stage to obtain the reduction rate of the unit length EUR. If the reduction rate is positive, it means that the unit length EUR is reduced in the drilling and completion stage, and a poorer reservoir other than the optimal reservoir designed in the well location demonstration stage is encountered; if the reduction rate is negative, it means that the drilling and completion stage obtains a better reservoir than the well location demonstration stage; if the reduction rate is equal to 0, it means that the drilling and completion stage is consistent with the well location demonstration design. The reduction rate of EUR per unit length of a gas field represents the overall technological level of the gas field. If the difference between the reduction rate of EUR per unit length of a gas well and that of a gas field is greater than 20% of the EUR per unit length of the gas field, it means that the encounter rate of high-quality reservoirs during drilling and completion is far lower than the technological level of the gas field or that there are reservoir changes that are significantly different from the understanding of the well location justification.

[0101] Among them, the unit length EUR corresponding to all wells in the gas field in the demonstration stage is obtained, and the unit length EUR corresponding to all wells in the demonstration stage is averaged to obtain the first average unit length EUR. The unit length EUR corresponding to all wells in the gas field in the drilling and completion stage is obtained, and the sum and average are obtained to obtain the second average unit length EUR. The first average unit length EUR corresponding to the demonstration stage is subtracted from the second average unit length EUR corresponding to the drilling and completion stage, and divided by the second average unit length EUR corresponding to the demonstration stage to obtain the reduction rate of the unit length EUR.

[0102] It should be noted that the reduction rates between other stages can also be calculated by the above method.

[0103] Figure 2 This is a schematic diagram of a structure for determining the EUR of a shale gas well provided in an embodiment of the present application. The device comprises:

[0104] The first determination module 201 is configured to divide a target well area into multiple EUR levels and determine an average recovery factor corresponding to each EUR level;

[0105] An acquisition module 202 is configured to acquire the well-controlled reserves of a target gas well in a first target stage, wherein the first target stage is a well location demonstration stage, a drilling stage, or a fracturing stage;

[0106] The second determination module 203 is configured to determine the estimated final recoverable reserves EUR of the target gas well at each EUR level in the first target stage based on the average recovery factor corresponding to each EUR level and the well-controlled reserves of the target gas well.

[0107] Optionally, the device further comprises a division module, the division module being configured to: select a first number of gas wells from all gas wells in the target well area that have been in production for more than one year, and determine the EUR of each gas well;

[0108] Based on the EUR of each gas well, the gas wells are ranked, and the first second number of gas wells are regarded as gas wells with excellent EUR grades; the last third number of gas wells are regarded as gas wells with poor EUR grades; and the other gas wells except the gas wells with excellent EUR grades and the gas wells with poor EUR grades are regarded as gas wells with medium EUR grades.

[0109] Optionally, the first determining module 201 is configured to:

[0110] A fourth number of gas wells are selected from the gas wells with an excellent EUR grade, and an average EUR and an average well-controlled reserve are determined based on the EUR and the well-controlled reserve of each gas well, and an average recovery factor corresponding to the excellent EUR grade is determined based on the average EUR and the average well-controlled reserve;

[0111] Randomly select a fifth number of gas wells from the gas wells with a medium EUR level, determine an average EUR and an average well-controlled reserve based on the EUR and well-controlled reserve of each gas well, and determine an average recovery factor corresponding to the medium EUR level based on the average EUR and the average well-controlled reserve;

[0112] Among the gas wells with poor EUR grades, the sixth number of gas wells are randomly selected, and the average EUR and the average well-controlled reserves are determined based on the EUR and the well-controlled reserves of each gas well. Based on the average EUR and the average well-controlled reserves, the average recovery factor corresponding to the poor EUR grade is determined.

[0113] Optionally, when the first target stage is the well location demonstration stage, the acquisition module 202 is configured to:

[0114] According to formula G x =0.01*A g *h*ρ y *C x , and obtain the adsorbed gas geological reserves of the first type of reservoir in the target gas well, where G x A represents the geological reserves of adsorbed gas in the first type of reservoir in the target gas well. g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, and ρ y represents the shale mass density of the first type of reservoir in the target gas well, Cx represents the shale adsorbed gas content of the first type of reservoir in the target gas well, Z i represents the original gas deviation factor of the first type of reservoir in the target gas well;

[0115] According to the formula Get the free gas geological reserves of the first type of reservoir in the target gas well, where G y A represents the free gas geological reserves of the first type of reservoir in the target gas well, g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, represents the effective porosity of the first type of reservoir in the target gas well, S gi represents the original gas saturation of the first type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the first type of reservoir in the target gas well;

[0116] Adding the adsorbed gas geological reserves of the first type of reservoir in the target gas well to the free gas geological reserves of the first type of reservoir in the target gas well to obtain the well-controlled reserves of the first type of reservoir in the target gas well;

[0117] Among them, according to the formula Ag = 2*L a *L far , and obtain the gas-bearing area of ​​the first type of reservoir in the target gas well, where A g Indicates the gas-bearing area of ​​the first type of reservoir in the target gas well, L a represents the theoretical horizontal length of the first type of reservoir in the target gas well, L far It represents the controlled half-length of the first type of reservoir in the target gas well in the horizontal direction.

[0118] Optionally, when the first target stage is the drilling stage, the acquisition module 202 is configured as follows:

[0119] According to formula G xn =0.01*A gn *h*ρ y *C x , and obtain the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, where G xn A represents the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, and ρ y represents the shale mass density of the nth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the nth type of reservoir in the target gas well, Z i represents the original gas deviation factor of the nth type of reservoir in the target gas well;

[0120] According to the formula Get the free gas geological reserves of the nth type of reservoir in the target gas well, where G yn A represents the free gas geological reserves of the nth type of reservoir in the target gas well, gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, represents the effective porosity of the nth type of reservoir in the target gas well, S gi represents the original gas saturation of the nth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the nth type of reservoir in the target gas well;

[0121] Adding the adsorbed gas geological reserves of the n-th type of reservoir in the target gas well to the free gas geological reserves of the n-th type of reservoir in the target gas well, to obtain the well-controlled reserves of the n-th type of reservoir in the target gas well;

[0122] According to formula A gn =2*L b *F n *L far , and obtain the gas-bearing area of ​​the nth type of reservoir in the target gas well, where A gn Indicates the gas-bearing area of ​​the nth type of reservoir in the target gas well, L b Indicates the actual horizontal length of the nth type of reservoir in the target gas well, L far represents the horizontal control half-length of the nth type of reservoir in the target gas well, F n It indicates the drilling rate of the nth type of reservoir in the target gas well.

[0123] Optionally, when the first target stage is the fracturing stage, the acquisition module 202 is configured as follows:

[0124] According to formula G xm =0.01*A gm *h*ρ y *C x , and obtain the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, where G xm A represents the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, gm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, and ρ y represents the shale mass density of the mth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the mth type of reservoir in the target gas well, Z i represents the original gas deviation factor of the mth type of reservoir in the target gas well;

[0125] According to the formula Get the free gas geological reserves of the mth type of reservoir in the target gas well, where G ym A represents the free gas geological reserves of the mth type of reservoir in the target gas well, gm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, represents the effective porosity of the mth type of reservoir in the target gas well, S gi represents the original gas saturation of the mth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the mth type of reservoir in the target gas well;

[0126] The adsorbed gas geological reserves of the m-th type of reservoir in the target gas well are added to the free gas geological reserves of the m-th type of reservoir in the target gas well to obtain the well-controlled reserves of the n-th type of reservoir in the target gas well;

[0127] According to formula A gm =2*L c *R m *L far , and obtain the gas-bearing area of ​​the mth type of reservoir in the target gas well, where A gn represents the gas-bearing area of ​​the mth type reservoir in the target gas well, L represents the horizontal length of the mth type reservoir in the target gas well after drilling, and L far represents the horizontal control half-length of the m-th type of reservoir in the target gas well, R m It represents the fracturing rate of the mth type of reservoir in the target gas well.

[0128] Optionally, the device further includes a second target stage, and the device further includes a third determining module, and the third determining module is configured to:

[0129] When the second target stage is the drainage stage, the EUR of the target gas well in the drainage stage is determined based on the pre-stored regression formula, the test production of the target gas well, the average wellhead pressure, the pressure drop from the opening to the wellhead of the test device and the maximum constant return rate.

[0130] Optionally, the device further includes a fourth determining module, and the fourth determining module is configured to:

[0131] When the second target stage is a fast decline stage or a slow decline stage, the EUR of the target gas well in the fast decline stage or the slow decline stage is determined based on the hyperbolic decline curve.

[0132] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including a program code, and the program code can be executed by a processor in a terminal or a server to complete the media resource playback method in the above embodiment. For example, the computer-readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a compact-disc read-only memory, a magnetic tape, a floppy disk, an optical data storage device, etc.

[0133] A person skilled in the art will appreciate that all or part of the steps for implementing the above embodiments may be accomplished by hardware or by hardware associated with a program code, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0134] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining EUR of a shale gas well, characterized in that: The method comprises: Select a first number of gas wells from all gas wells in the target well area that have been in production for more than one year, and determine the EUR of each gas well; Based on the EUR of each gas well, the gas wells are ranked, and the first second number of gas wells are regarded as gas wells with excellent EUR grades; the last third number of gas wells are regarded as gas wells with poor EUR grades; and the other gas wells except the gas wells with excellent EUR grades and the gas wells with poor EUR grades are regarded as gas wells with medium EUR grades; A fourth number of gas wells are selected from the gas wells with an excellent EUR grade, and an average EUR and an average well-controlled reserve are determined based on the EUR and the well-controlled reserve of each gas well, and an average recovery factor corresponding to the excellent EUR grade is determined based on the average EUR and the average well-controlled reserve; Randomly select a fifth number of gas wells from the gas wells with a medium EUR level, determine an average EUR and an average well-controlled reserve based on the EUR and well-controlled reserve of each gas well, and determine an average recovery factor corresponding to the medium EUR level based on the average EUR and the average well-controlled reserve; Randomly select a sixth number of gas wells from the gas wells with poor EUR grades, determine an average EUR and an average well-controlled reserve based on the EUR and well-controlled reserve of each gas well, and determine an average recovery factor corresponding to the poor EUR grade based on the average EUR and the average well-controlled reserve; Obtaining the well-controlled reserves of a target gas well in a first target stage, wherein the first target stage is a well location demonstration stage, a drilling stage, or a fracturing stage; Based on the average recovery factor corresponding to each EUR level and the well-controlled reserves of the target gas well, the estimated ultimate recoverable reserves EUR corresponding to each EUR level of the target gas well in the first target stage are determined.

2. The method according to claim 1, characterized in that When the first target stage is the well location demonstration stage, the step of obtaining the well-controlled reserves of the target gas well in the first target stage includes: According to formula G x =0.01*A g* h*ρ y *C x , and obtain the adsorbed gas geological reserves of the first type of reservoir in the target gas well, where G x represents the adsorbed gas geological reserves of the first type of reservoir in the target gas well, A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, and ρ y represents the shale mass density of the first type of reservoir in the target gas well, C x Indicates the shale adsorbed gas content of the first type of reservoir in the target gas well; According to formula G y =0.01*A g *h*φ*S gi / B gi , and obtain the free gas geological reserves of the first type of reservoir in the target gas well, where G y represents the free gas geological reserves of the first type of reservoir in the target gas well, A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, h represents the effective thickness of the first type of reservoir in the target gas well, φ represents the effective porosity of the first type of reservoir in the target gas well, S gi represents the original gas saturation of the first type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the first type of reservoir in the target gas well; Adding the adsorbed gas geological reserves of the first type of reservoir in the target gas well to the free gas geological reserves of the first type of reservoir in the target gas well to obtain the well-controlled reserves of the first type of reservoir in the target gas well; Among them, according to the formula Ag=2*L a *L far , and obtain the gas-bearing area of ​​the first type of reservoir in the target gas well, where A g represents the gas-bearing area of ​​the first type of reservoir in the target gas well, L a represents the theoretical horizontal length of the first type of reservoir in the target gas well, L far It represents the controlled half-length of the first type of reservoir in the target gas well in the horizontal direction.

3. The method according to claim 1, characterized in that When the first target stage is the drilling stage, the step of obtaining the well-controlled reserves of the target gas well in the first target stage includes: According to formula G xn =0.01*A gn* h*ρ y *C x , to obtain the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, where G xn represents the adsorbed gas geological reserves of the nth type of reservoir in the target gas well, A gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, and ρ y represents the shale mass density of the nth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the nth type of reservoir in the target gas well; According to formula G yn =0.01*A gn *h*φ*S gi / B gi , obtain the free gas geological reserves of the nth type of reservoir in the target gas well, where G yn A represents the free gas geological reserves of the nth type of reservoir in the target gas well, gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, h represents the effective thickness of the nth type of reservoir in the target gas well, φ represents the effective porosity of the nth type of reservoir in the target gas well, S gi represents the original gas saturation of the nth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the nth type of reservoir in the target gas well; Adding the adsorbed gas geological reserves of the n-th type of reservoir in the target gas well to the free gas geological reserves of the n-th type of reservoir in the target gas well to obtain the well-controlled reserves of the n-th type of reservoir in the target gas well; According to formula A gn =2*L b *F n *L far , and obtain the gas-bearing area of ​​the nth type of reservoir in the target gas well, where A gn represents the gas-bearing area of ​​the nth type of reservoir in the target gas well, L b represents the actual horizontal length of the nth type of reservoir in the target gas well, L far represents the horizontal control half-length of the nth type of reservoir in the target gas well, F n It represents the drilling rate of the nth type of reservoir in the target gas well.

4. The method according to claim 1, characterized in that When the first target stage is the fracturing stage, the step of obtaining the well-controlled reserves of the target gas well in the first target stage includes: According to formula G xm =0.01*A gm* h*ρ y *C x , to obtain the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, where G xm represents the adsorbed gas geological reserves of the mth type of reservoir in the target gas well, A gm represents the gas-bearing area of ​​the mth type reservoir in the target gas well, h represents the effective thickness of the mth type reservoir in the target gas well, and ρ y represents the shale mass density of the mth type of reservoir in the target gas well, C x represents the shale adsorbed gas content of the mth type of reservoir in the target gas well; According to formula G ym =0.01*A gm *h*φ*S gi / B gi , and obtain the free gas geological reserves of the mth type of reservoir in the target gas well, where G ym represents the free gas geological reserves of the mth type of reservoir in the target gas well, A gm represents the gas-bearing area of ​​the mth type of reservoir in the target gas well, h represents the effective thickness of the mth type of reservoir in the target gas well, φ represents the effective porosity of the mth type of reservoir in the target gas well, S gi represents the original gas saturation of the mth type of reservoir in the target gas well, B gi represents the original shale gas volume coefficient of the mth type of reservoir in the target gas well; Adding the adsorbed gas geological reserves of the mth type of reservoir in the target gas well to the free gas geological reserves of the mth type of reservoir in the target gas well to obtain the well-controlled reserves of the nth type of reservoir in the target gas well; According to formula A gm =2*L c *R m *L far， Get the gas-bearing area of ​​the mth type of reservoir in the target gas well, where A gn represents the gas-bearing area of ​​the mth type reservoir in the target gas well, L represents the horizontal length of the mth type reservoir in the target gas well after drilling, and L far represents the controlled half length of the m-th type of reservoir in the target gas well in the horizontal direction, R m It represents the fracturing rate of the mth type of reservoir in the target gas well.

5. The method according to claim 1, characterized in that The method also includes a second target phase; The method further comprises: When the second target stage is the drainage stage, the EUR of the target gas well in the drainage stage is determined based on a pre-stored regression formula, as well as the test production of the target gas well, the average wellhead pressure, the pressure drop from the opening to the wellhead of the test device, and the maximum constant return rate.

6. The method according to claim 1, characterized in that The method also includes a second target phase; The method further comprises: When the second target stage is a fast decline stage or a slow decline stage, the EUR of the target gas well in the fast decline stage or the slow decline stage is determined based on the hyperbolic decline curve.

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