Method and device for determining water relative permeability curve of coal bed gas, medium and electronic equipment

Abstract

The invention discloses a coal bed gas water relative permeability curve determination method and device, a medium and electronic equipment. The method comprises the following steps: calculating a first average water saturation and a first average reservoir pressure corresponding to a target moment; determining a coal seam pressure field corresponding to the target moment according to a preset pressure distribution model and the first average reservoir pressure; determining a pressure and saturation relation curve corresponding to the target moment according to a preset initial coal bed gas water relative permeability curve; according to the coal seam pressure field and the pressure and saturation relation curve, a coal seam water saturation field corresponding to the target moment is determined, and the coal seam water saturation field is used for determining second average water saturation corresponding to the target moment; and based on the first average water saturation and the second average water saturation, determining a coal bed gas water relative permeability curve corresponding to the target moment. According to the method, the accuracy of calculating the gas-water relative permeability curve of the coal seam can be improved.

Description

Background Art

[0002] Currently, the commonly used method for obtaining the relative permeability curve of oil and gas reservoirs measures the cores sampled at the well site through laboratory experiments. The experimental methods include the steady-state method and the unsteady-state method. This assumption is applicable to oil and gas reservoirs with good homogeneity, such as sandstone gas reservoirs, shale gas reservoirs, etc. However, coal seams exhibit extremely strong heterogeneity, with well-developed face cleats, end cleats, and microfracture systems, and there are differences in the seepage capacities of face cleats, end cleats, and microfractures. The coal cores sampled at the well site show different seepage capacities in different directions.

[0003] Based on this, how to improve the accuracy of the gas-water relative permeability curve corresponding to the coal seam is a technical problem to be solved urgently. Summary of the Invention

[0004] The purpose of this application is to provide a method, device, medium, and electronic device for determining the gas-water relative permeability curve of coal seams. This application can improve the accuracy of calculating the gas-water relative permeability curve of coal seams.

[0005] Other characteristics and advantages of this application will become apparent through the following detailed description, or be learned in part through the practice of this application.

[0006] According to an aspect of the embodiments of this application, a method for determining the gas-water relative permeability curve of coal seams is provided. The method is characterized in that the method includes: calculating a first average water saturation and a first average reservoir pressure corresponding to a target moment, where the first average water saturation and the first average reservoir pressure are calculated through the basic parameters of the coal seam, the cumulative gas production, and the cumulative water production corresponding to the target moment; determining the coal seam pressure field corresponding to the target moment according to a preset pressure distribution model and the first average reservoir pressure; determining a pressure-saturation relationship curve corresponding to the target moment according to a preset initial gas-water relative permeability curve of the coal seam; determining the coal seam water saturation field corresponding to the target moment according to the coal seam pressure field and the pressure-saturation relationship curve, where the coal seam water saturation field is used to determine a second average water saturation corresponding to the target moment; and determining the gas-water relative permeability curve of the coal seam corresponding to the target moment based on the first average water saturation and the second average water saturation, where the gas-water relative permeability curve of the coal seam is used to characterize the gas-water seepage capacity of the coal seam corresponding to the target moment.

[0007] In an embodiment of the present application, based on the foregoing solution, determining the coal seam pressure field corresponding to the target moment according to the preset pressure distribution model and the first average reservoir pressure includes: calculating a target distance by obtaining the well control area of the coal seam, where the target distance is the distance between the boundary of the control area of the target well in the coal seam and the bottom hole of the target well; determining the coal seam pressure field corresponding to the target moment based on the target distance, the pressure distribution model, and the first average reservoir pressure.

[0008] In an embodiment of the present application, based on the foregoing solution, determining the pressure-saturation relationship curve corresponding to the target moment according to the preset initial coalbed methane-water relative permeability curve includes: obtaining the original coal seam pressure and the original water saturation of the coal seam; performing iteration on the original coal seam pressure based on a preset pressure difference and obtaining the number of iterations; determining the gas compressibility factor, the coalbed methane desorption compressibility factor, and the coal seam porosity according to the original coal seam pressure and the number of iterations, where the coal seam porosity is the coal seam porosity corresponding to the current coal seam pressure; determining the pressure-saturation relationship curve by combining the original coal seam pressure, the original water saturation of the coal seam, the initial coalbed methane-water relative permeability curve, the number of iterations, the gas compressibility factor, the coalbed methane desorption compressibility factor, and the coal seam porosity.

[0009] In an embodiment of the present application, based on the foregoing solution, determining the coalbed methane-water relative permeability curve corresponding to the target moment based on the first average water saturation and the second average water saturation includes: calculating the difference between the first average water saturation and the second average water saturation; determining the coalbed methane-water relative permeability curve corresponding to the target moment by judging the relationship between the difference and a preset difference interval.

[0010] In an embodiment of the present application, based on the foregoing solution, determining the coalbed methane-water relative permeability curve corresponding to the target moment by judging the relationship between the difference and a preset difference interval includes: if the difference belongs to the preset difference interval, determining the initial coalbed methane-water relative permeability curve as the coalbed methane-water relative permeability curve corresponding to the target moment.

[0011] In one embodiment of the present application, based on the foregoing solution, determining the coalbed methane water relative permeability curve corresponding to the target time by judging the relationship between the difference and a preset difference range includes: if the difference does not belong to the preset difference range, obtaining the gas relative permeability coefficient, water relative permeability coefficient and the first gas relative permeability of the initial coalbed methane water relative permeability curve, where the first gas relative permeability is the gas relative permeability at the time when the water saturation of the coal seam is equal to the irreducible water saturation of the coal seam; determining a new initial coalbed methane water relative permeability curve by adjusting the gas relative permeability coefficient and the water relative permeability coefficient; and according to the new initial coalbed methane water relative permeability curve, re-executing the step of determining the relationship curve between pressure and saturation corresponding to the target time according to the preset initial coalbed methane water relative permeability curve.

[0012] In one embodiment of the present application, based on the foregoing solution, the preset pressure distribution model is as follows:

[0013]

[0014] where r is the distance from any position of the coal seam to the bottom hole of the target well, in m; r w is the well diameter of the target well, in m; r b is the target distance, in m; P wf is the bottom hole pressure of the target well, in MPa; P b is the coal seam pressure at the boundary of the control area of the target well, in MPa; P is the coal seam pressure at the position r from the bottom hole, in MPa.

[0015] According to one aspect of the embodiments of the present application, there is provided a device for determining a coalbed methane water relative permeability curve, characterized in that the device includes: a calculation unit configured to calculate a first average water saturation and a first average reservoir pressure corresponding to a target time, where the first average water saturation and the first average reservoir pressure are calculated from the basic parameters of the coal seam, cumulative gas production and cumulative water production corresponding to the target time; a first determination unit configured to determine a coal seam pressure field corresponding to the target time according to a preset pressure distribution model and the first average reservoir pressure; a second determination unit configured to determine a relationship curve between pressure and saturation corresponding to the target time according to a preset initial coalbed methane water relative permeability curve; a third determination unit configured to determine a coal seam water saturation field corresponding to the target time according to the coal seam pressure field and the relationship curve between pressure and saturation, where the coal seam water saturation field is used to determine a second average water saturation corresponding to the target time; and a fourth determination unit configured to determine a coalbed methane water relative permeability curve corresponding to the target time based on the first average water saturation and the second average water saturation, where the coalbed methane water relative permeability curve is used to characterize the gas-water seepage capacity of the coal seam corresponding to the target time.

[0016] According to one aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. The computer program includes executable instructions. When the executable instructions are executed by a processor, the method described in the above embodiment is implemented.

[0017] According to one aspect of an embodiment of the present application, an electronic device is provided, comprising: one or more processors; and a memory for storing executable instructions of the processors, wherein when the executable instructions are executed by the one or more processors, the one or more processors implement the methods described in the above embodiments.

[0018] In this application, the basic parameters of the coal seam, the cumulative gas production and the cumulative water production corresponding to the coal seam are first obtained. Then, according to the basic parameters of the coal seam, the cumulative gas production and the cumulative water production, the first average water saturation and the first average reservoir pressure corresponding to the target time of the coal seam are calculated. Based on the pressure distribution model and the first average reservoir pressure, the coal seam pressure field is determined.

[0019] Secondly, according to the preset initial coalbed gas-water relative permeability curve, the pressure and saturation relationship curve corresponding to the coal seam is determined to convert the coal seam pressure field into a coal seam water saturation field. According to the coal seam water saturation field, the second average water saturation corresponding to the coal seam can be calculated.

[0020] Finally, by judging the difference between the first average water saturation and the second average water saturation, a coalbed methane-water relative permeability curve that can be used to characterize the corresponding coal seam is determined.

[0021] In addition, the present invention eliminates the influence of strong heterogeneity of coal seams on the acquisition of gas-water relative permeability curves, overcomes the limitation that the complete gas-water relative permeability can only be inverted at the end of gas well production, and can fully reflect the changing characteristics of gas-water relative permeability in different production stages of coalbed methane, and is advanced and scientific.

[0022] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0024] Figure 1 It is a flow chart of a method for determining a relative permeability curve of coalbed methane water according to an embodiment of the present application;

[0025] Figure 2 It is a block diagram of a device for determining the aqueous phase permeability curve of coalbed methane shown according to an embodiment of the present application;

[0026] Figure 3 It is a schematic diagram of the system structure of an electronic device shown according to an embodiment of the present application. Detailed implementation manners

[0027] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art.

[0028] In addition, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present application. However, those skilled in the art will realize that the technical solutions of the present application can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the present application.

[0029] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0030] The flowcharts shown in the accompanying drawings are only illustrative and not necessarily include all the content and operations / steps, nor are they necessarily executed in the described order. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to the actual situation.

[0031] It should be noted that: "a plurality of" mentioned herein refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0032] The implementation details of the technical solutions of the embodiments of the present application are elaborated in detail below:

[0033] According to one aspect of the present application, a method for determining the water relative permeability curve of coalbed methane is provided. Figure 1 FIG. Figure 1 is a flowchart of the method for determining the water relative permeability curve of coalbed methane shown according to an embodiment of the present application. This method for determining the water relative permeability curve of coalbed methane can be executed by a device with computing and processing capabilities. This method for determining the water relative permeability curve of coalbed methane at least includes steps 110 to 150, which are introduced in detail as follows:

[0034] In step 110, calculate the first average water saturation and the first average reservoir pressure corresponding to the target time. The first average water saturation and the first average reservoir pressure are calculated through the basic parameters of the coal seam, the cumulative gas production, and the cumulative water production corresponding to the target time.

[0035] In the present application, since the present application is to determine the gas-water relative permeability curve of the coal seam, and the coal seam has extremely strong heterogeneity. Therefore, the average water saturation corresponding to the coal seam can be calculated in different ways, so as to reflect the accuracy of the gas-water relative permeability curve of the coal seam according to the difference between different average water saturations.

[0036] Based on this, first, the first average water saturation and the first average reservoir pressure corresponding to the target time can be calculated through the principle of material conservation of coalbed methane. Among them, the first average water saturation and the first average reservoir pressure can be calculated through the basic parameters corresponding to the coal seam, the cumulative gas production, and the cumulative water production. The basic parameters may include the gas well control area, the coal seam thickness, the porosity, the original coal seam pressure, the original coal seam water saturation, the comprehensive compressibility coefficient of the coal seam, the pressure coefficient and volume coefficient of the Langmuir adsorption curve, the formation water volume coefficient, and the coal rock density.

[0037] Specifically, the first average reservoir pressure can be calculated through the following formula (1):

[0038]

[0039] Where G p is the cumulative gas production, m 3 ; W p is the cumulative water production, m 3 ; A is the well control area, m 2 ; h is the coal seam thickness, m; φ i is the porosity of the coal seam, dimensionless; S wi is the original water saturation of the coal seam, dimensionless; P i is the original pressure of the coal seam, MPa; C f is the compressibility coefficient of the coal rock, MPa -1 ; C w is the compressibility coefficient of the formation water, MPa -1 ; ρ is the coal rock density, Kg / m3 ; V L is the volume coefficient of the Langmuir adsorption curve of coal and rock, m 3 / t; P L is the pressure coefficient of the Langmuir adsorption curve of coal and rock, MPa; P d is the critical desorption pressure of the coal seam, MPa; P P is the average pressure of the coal seam corresponding to the target time, MPa; B w is the volume coefficient of formation water, which can be considered as 1; B gi and B g is the original pressure P of the coal seam i and the gas volume coefficient under the current average pressure of the coal seam.

[0040] The volume coefficient of the formation water and the gas volume coefficient can be calculated respectively through the following formulas (2)-(3):

[0041]

[0042]

[0043] where, P sc and T sc represent the atmospheric pressure and temperature under standard conditions, which are 0.101 MPa and 298 K respectively; Z sc is the compressibility factor under standard conditions, which can be considered as 1; Z is the gas compressibility factor under the average pressure of the coal seam at the current time, which can be obtained by looking up the table, dimensionless.

[0044] After calculating the first average reservoir pressure, in combination with the above formulas (1)-(3) and the following formula (4), calculate the first average water saturation.

[0045]

[0046] Continue to refer to Figure 1 , in step 120, according to the preset pressure distribution model and the first average reservoir pressure, determine the coal seam pressure field corresponding to the target time.

[0047] In this application, according to the pressure distribution model and the first average reservoir pressure, determine the coal seam pressure field corresponding to the target time. Among them, the pressure distribution model is as follows:[[]]

[0048]

[0049] where, r is the distance from any position of the coal seam to the bottom of the target well, m; r w is the well diameter of the target well, m; r b is the target distance, m; P wfis the bottom hole pressure of the target well, MPa; P b is the coal seam pressure at the boundary of the control area of the target well, MPa; P is the coal seam pressure at the position r from the bottom hole, MPa.

[0050] In an embodiment of the present application, determining the coal seam pressure field corresponding to the target moment according to the preset pressure distribution model and the first average reservoir pressure specifically includes steps 121 to 122:

[0051] Step 121, calculate the target distance by obtaining the well control area of the coal seam, where the target distance is the distance between the boundary of the control area of the target well in the coal seam and the bottom hole of the target well.

[0052] Step 122, determine the coal seam pressure field corresponding to the target moment based on the target distance, the pressure distribution model, and the first average reservoir pressure.

[0053] In this embodiment, during the process of determining the coal seam pressure field, first, the well control area of the coal seam can be obtained. Then, according to the following formula (6), the target distance is calculated. The target distance is the distance between the boundary of the control area of the target well in the coal seam and the bottom hole of the target well. Secondly, according to the target distance and the above formula (1), the following formula (7) can be obtained, and thus according to formula (7), the pressure corresponding to each position of the coal seam is calculated, that is, the coal seam pressure field is obtained.

[0054]

[0055]

[0056] It should be noted that in the process of determining the coal seam pressure in the present application, it can be set that the pressure of the coal seam is based on a target well and spreads outward in the form of a pressure wave. Among them, the pressure wave spreads outward in a circular form.

[0057] Continue to refer to Figure 1 , in step 130, determine the pressure - saturation relationship curve corresponding to the target moment according to the preset initial coal seam gas - water relative permeability curve.

[0058] In the present application, since the present application calculates the average water saturation corresponding to the coal seam in different ways, and thus reflects the accuracy of the gas - water relative permeability curve of the coal seam according to the difference between different average water saturations. Therefore, the pressure - saturation relationship curve corresponding to the target moment can be determined according to the preset initial coal seam gas - water relative permeability curve, so as to determine the average water saturation corresponding to the coal seam based on the pressure - saturation relationship curve.

[0059] In one embodiment of the present application, determining the pressure-saturation relationship curve corresponding to the target moment according to the preset initial coalbed methane-water relative permeability curve specifically includes steps 131 to 134:

[0060] Step 131, obtain the original coal seam pressure and the original water saturation of the coal seam.

[0061] Step 132, based on the preset pressure difference, iterate the original coal seam pressure and obtain the number of iterations.

[0062] Step 133, determine the gas-phase compressibility factor, the coalbed methane desorption compressibility factor, and the coal seam porosity according to the original coal seam pressure and the number of iterations, where the coal seam porosity is the coal seam porosity corresponding to the current coal seam pressure.

[0063] Step 134, combine the original coal seam pressure, the original water saturation of the coal seam, the initial coalbed methane-water relative permeability curve, the number of iterations, the gas-phase compressibility factor, the coalbed methane desorption compressibility factor, and the coal seam porosity to determine the pressure-saturation relationship curve.

[0064] In this embodiment, first, obtain the original coal seam pressure and the original water saturation of the coal seam corresponding to the coal seam. According to the preset pressure difference, iterate the original coal seam pressure to obtain the number of iterations.

[0065] During the iteration process, based on the original coal seam pressure and the number of iterations, multiple coal seam pressures with the same pressure difference can be obtained. According to each coal seam pressure, and in combination with the original water saturation of the coal seam, the initial coalbed methane-water relative permeability curve, and the number of iterations, the pressure-saturation relationship curve can be determined. For example, the preset pressure difference is 0.01 MPa. First, give the lowest pressure value of the coal seam, such as 0.1 MPa. According to the pressure difference and the lowest pressure value, gradually iterate the original coal seam pressure to calculate the number of iterations.

[0066] Then, determine the gas-phase compressibility factor, the coalbed methane desorption compressibility factor, and the coal seam porosity according to the original coal seam pressure and the number of iterations. Combine the original coal seam pressure, the original water saturation of the coal seam, the initial coalbed methane-water relative permeability curve, the number of iterations, the gas-phase compressibility factor, the coalbed methane desorption compressibility factor, and the coal seam porosity to determine the pressure-saturation relationship curve.

[0067] Specifically, the initial coalbed methane-water relative permeability curve can be determined by the following formulas (8)-(10).

[0068]

[0069]

[0070]

[0071] Among them, K rg is the gas-phase relative permeability, dimensionless; K rw is the water-phase relative permeability, dimensionless; S wc is the irreducible water saturation of the coal seam, which can be obtained from laboratory experiments, dimensionless.

[0072] Combining the above formulas (8)-(10) and the following formulas (11)-(15), determine the relationship curve between the pressure and the saturation.

[0073]

[0074] A1 = WGMR(C f + C g + C d ) (12)

[0075] B = WGMR(C f + C g ) + C f + C w (13)

[0076] C = WGMR + 1 (14)

[0077]

[0078] Among them, P n and P n+1 are the coal seam pressures calculated by the nth and (n + 1)th iterative steps, MPa; S w n and S w n+1 are the coal seam water saturations corresponding to P n and P n+1 , dimensionless; C g is the gas-phase compressibility, MPa -1 ; C d is the coalbed methane desorption compressibility, MPa -1 ; μ g and μ w are the gas-phase viscosity and the water-phase viscosity, which can be obtained by looking up the table at a given pressure and temperature, cp; φ is the coal seam porosity at the current pressure, dimensionless.

[0079] Furthermore, the gas-phase compressibility, the coalbed methane desorption compressibility and the coal seam porosity can be determined by combining the following formulas (16)-(18).

[0080]

[0081]

[0082] φ = φ i (1 - C f (P i - P)) (18)

[0083] where C g is the gas-phase compressibility factor, MPa -1 ; C d is the desorption compressibility factor of coalbed methane, MPa -1 ; φ is the coal seam porosity at the current pressure, dimensionless.

[0084] Continuing to refer to Figure 1 , in step 140, according to the coal seam pressure field and the pressure-saturation relationship curve, determine the coal seam water saturation field corresponding to the target time, and the coal seam water saturation field is used to determine the second average water saturation corresponding to the target time.

[0085] In this application, after obtaining the coal seam pressure field and the pressure-saturation relationship curve, determine the distribution characteristics of the coal seam pressure according to the coal seam pressure field, and in combination with the pressure-saturation relationship curve, determine the coal seam water saturation field corresponding to the target time. Based on the coal seam water saturation field, determine the second average water saturation corresponding to the coal seam.

[0086] Continuing to refer to Figure 1 , in step 150, based on the first average water saturation and the second average water saturation, determine the coal seam gas-water relative permeability curve corresponding to the target time, and the coal seam gas-water relative permeability curve is used to characterize the gas-water seepage capacity of the coal seam corresponding to the target time.

[0087] In this application, since this application calculates the average water saturation corresponding to the coal seam in different ways, the accuracy of the coal seam gas-water relative permeability curve is reflected according to the relationship between different average water saturations.

[0088] In an embodiment of this application, the determining the coal seam gas-water relative permeability curve corresponding to the target time based on the first average water saturation and the second average water saturation specifically includes steps 151 to 152:

[0089] Step 151, calculate the difference between the first average water saturation and the second average water saturation.

[0090] Step 152: Determine the coalbed methane water relative permeability curve corresponding to the target moment by judging the relationship between the difference value and a preset difference value range.

[0091] In this embodiment, by calculating the difference value between the first average water saturation and the second average water saturation, judge the relationship between the difference value and the preset difference value range, so as to determine the coalbed methane water relative permeability curve corresponding to the target moment. Among them, the preset difference value range can be [-0.5, 0.5].

[0092] Further, in an embodiment of the present application, if the difference value belongs to the preset difference value range, determine the initial coalbed methane water relative permeability curve as the coalbed methane water relative permeability curve corresponding to the target moment.

[0093] Further, in another embodiment of the present application, if the difference value does not belong to the preset difference value range, obtain the gas relative permeability curve coefficient, water relative permeability curve coefficient and the first gas relative permeability corresponding to the initial coalbed methane water relative permeability curve, where the first gas relative permeability is the gas relative permeability when the water saturation of the coal seam is equal to the irreducible water saturation of the coal seam; by adjusting the gas relative permeability curve coefficient and the water relative permeability curve coefficient, determine a new initial coalbed methane water relative permeability curve; according to the new initial coalbed methane water relative permeability curve, re-execute the step of determining the relationship curve between the pressure and saturation corresponding to the target moment according to the preset initial coalbed methane water relative permeability curve.

[0094] The device embodiments of the present application are introduced below, which can be used to execute the method for determining the coalbed methane water relative permeability curve in the above embodiments of the present application. For the details not disclosed in the device embodiments of the present application, please refer to the embodiments of the method for determining the coalbed methane water relative permeability curve in the above of the present application.

[0095] Figure 2 It is a block diagram of a device for determining a coalbed methane water relative permeability curve shown according to an embodiment of the present application.

[0096] Refer to Figure 2As shown, a device 200 for determining the aqueous relative permeability curve of coalbed methane according to an embodiment of the present application, the device 200 includes: a calculation unit 201, configured to calculate a first average water saturation and a first average reservoir pressure corresponding to a target time, the first average water saturation and the first average reservoir pressure being calculated through the basic parameters of the coal seam, the cumulative gas production, and the cumulative water production corresponding to the target time; a first determination unit 202, configured to determine the coal seam pressure field corresponding to the target time according to a preset pressure distribution model and the first average reservoir pressure; a second determination unit 203, configured to determine a pressure-saturation relationship curve corresponding to the target time according to a preset initial aqueous relative permeability curve of coalbed methane; a third determination unit 204, configured to determine the coal seam water saturation field corresponding to the target time according to the coal seam pressure field and the pressure-saturation relationship curve, the coal seam water saturation field being used to determine a second average water saturation corresponding to the target time; a fourth determination unit 205, configured to determine the aqueous relative permeability curve of coalbed methane corresponding to the target time based on the first average water saturation and the second average water saturation, the aqueous relative permeability curve of coalbed methane being used to characterize the gas-water seepage capacity of the coal seam corresponding to the target time.

[0097] As another aspect, the present application also provides a computer-readable storage medium, on which a program product capable of implementing the above method of the present specification is stored. In some possible implementation manners, each aspect of the present application can also be implemented in the form of a program product, which includes program code. When the program product runs on a terminal device, the program code is used to cause the terminal device to execute the steps according to various exemplary embodiments of the present application described in the above "Exemplary Method" section of the present specification.

[0098] A computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which readable program code is carried. Such a propagated data signal may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable signal medium may also be any readable medium other than the readable storage medium, and the readable medium may send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device.

[0099] The program code included on the readable medium can be transmitted by any appropriate medium, including but not limited to wireless, wired, optical fiber cable, RF, etc., or any suitable combination of the above.

[0100] The program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages such as Java, C++, etc., and also including conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, executed as a stand-alone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device can be connected to the user's computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., by connecting through the Internet using an Internet service provider).

[0101] As another aspect, this application also provides an electronic device capable of implementing the above method.

[0102] Those skilled in the art can understand that various aspects of this application can be implemented as a system, a method, or a program product. Therefore, various aspects of this application can be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects, which can be collectively referred to here as "circuits", "modules", or "systems".

[0103] Figure 3 For a schematic diagram of the system structure of the electronic device shown according to an embodiment of this application, refer to the following Figure 3 to describe the electronic device 300 according to this embodiment of this application. Figure 3 The electronic device 300 shown is merely an example and should not impose any limitations on the functions and usage scope of the embodiments of this application.

[0104] As shown in Figure 3 the electronic device 300 is presented in the form of a general-purpose computing device. The components of the electronic device 300 can include, but are not limited to: at least one of the above-mentioned processing units 310, at least one of the above-mentioned storage units 320, and a bus 330 connecting different system components (including the storage unit 320 and the processing unit 310).

[0105] Among them, the storage unit stores program code, and the program code can be executed by the processing unit 310, so that the processing unit 310 executes the steps according to various exemplary embodiments of this application described in the "Embodiment Method" section of this specification.

[0106] The storage unit 320 may include a readable medium in the form of a volatile storage unit, such as a random access memory (RAM) 321 and / or a cache storage unit 322, and may further include a read-only memory (ROM) 323.

[0107] The storage unit 320 may also include a program / utilities 324 having a set (at least one) of program modules 325. Such program modules 325 include, but are not limited to: an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include an implementation of a network environment.

[0108] The bus 330 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus structures.

[0109] The electronic device 300 may also communicate with one or more external devices 1200 (such as a keyboard, a pointing device, a Bluetooth device, etc.), and may also communicate with one or more devices that enable a user to interact with the electronic device 300, and / or communicate with any device that enables the electronic device 300 to communicate with one or more other computing devices (such as a router, a modem, etc.). Such communication may be carried out through an input / output (I / O) interface 350. Moreover, the electronic device 300 may also communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through a network adapter 360. As shown in the figure, the network adapter 360 communicates with other modules of the electronic device 300 through the bus 330. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 300, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0110] Through the description of the above embodiments, those skilled in the art can easily understand that the exemplary embodiments described herein can be implemented by software, or can be implemented by a combination of software and necessary hardware. Therefore, the technical solution according to the embodiments of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the embodiments of the present application.

[0111] In addition, the above-mentioned drawings are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, rather than for the purpose of limitation. It is easy to understand that the processes shown in the above-mentioned drawings do not indicate or limit the chronological order of these processes. Additionally, it is also easy to understand that these processes can be executed, for example, synchronously or asynchronously in multiple modules.

[0112] It should be understood that the present application is not limited to the exact structures that have been described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A method for determining the aqueous phase permeability curve of coalbed methane, characterized in that, The method includes: Calculating a first average water saturation and a first average reservoir pressure corresponding to a target time, where the first average water saturation and the first average reservoir pressure are calculated based on basic parameters of a coal seam, cumulative gas production, and cumulative water production corresponding to the target time; Determining a coal seam pressure field corresponding to the target time according to a preset pressure distribution model and the first average reservoir pressure; Determining a pressure-saturation relationship curve corresponding to the target time according to a preset initial coalbed methane-water relative permeability curve; Determining a coal seam water saturation field corresponding to the target time according to the coal seam pressure field and the pressure-saturation relationship curve, where the coal seam water saturation field is used to determine a second average water saturation corresponding to the target time; Determining a coalbed methane-water relative permeability curve corresponding to the target time based on the first average water saturation and the second average water saturation, where the coalbed methane-water relative permeability curve is used to characterize the gas-water seepage capacity of the coal seam corresponding to the target time.

2. The method according to claim 1, wherein The step of determining a coal seam pressure field corresponding to the target time according to a preset pressure distribution model and the first average reservoir pressure includes: Calculating a target distance by obtaining the well control area of the coal seam, where the target distance is the distance between the boundary of the control area of a target well in the coal seam and the bottom hole of the target well; Determining a coal seam pressure field corresponding to the target time based on the target distance, the pressure distribution model, and the first average reservoir pressure.

3. The method according to claim 1, characterized in that, The step of determining a pressure-saturation relationship curve corresponding to the target time according to a preset initial coalbed methane-water relative permeability curve includes: Obtaining the original coal seam pressure and the original coal seam water saturation; Iterating the original coal seam pressure based on a preset pressure difference and obtaining the number of iterations; Determining a gas-phase compressibility factor, a coalbed methane desorption compressibility factor, and a coal seam porosity according to the original coal seam pressure and the number of iterations, where the coal seam porosity is the coal seam porosity corresponding to the current coal seam pressure; Determining the pressure-saturation relationship curve by combining the original coal seam pressure, the original coal seam water saturation, the initial coalbed methane-water relative permeability curve, the number of iterations, the gas-phase compressibility factor, the coalbed methane desorption compressibility factor, and the coal seam porosity.

4. The method according to claim 1, characterized in that, The step of determining a coalbed methane-water relative permeability curve corresponding to the target time based on the first average water saturation and the second average water saturation includes: Calculating the difference between the first average water saturation and the second average water saturation; Determining a coalbed methane-water relative permeability curve corresponding to the target time by judging the relationship between the difference and a preset difference interval.

5. The method according to claim 4, characterized in that, The step of determining a coalbed methane-water relative permeability curve corresponding to the target time by judging the relationship between the difference and a preset difference interval includes: If the difference belongs to the preset difference interval, determining the initial coalbed methane-water relative permeability curve as the coalbed methane-water relative permeability curve corresponding to the target time.

6. The method according to claim 4, wherein The step of determining a coalbed methane-water relative permeability curve corresponding to the target time by judging the relationship between the difference and a preset difference interval includes: If the difference does not belong to the preset difference interval, obtain the gas-phase permeability curve coefficient, water-phase permeability curve coefficient, and the first gas-phase relative permeability corresponding to the initial coalbed methane water-phase permeability curve, where the first gas-phase relative permeability is the gas-phase relative permeability when the water saturation of the coal seam is equal to the irreducible water saturation of the coal seam; Determine a new initial coalbed methane water-phase permeability curve by adjusting the gas-phase permeability curve coefficient and the water-phase permeability curve coefficient; According to the new initial coalbed methane water-phase permeability curve, re-execute the step of determining the pressure-saturation relationship curve corresponding to the target time according to the preset initial coalbed methane water-phase permeability curve.

7. The method according to claim 1, wherein The preset pressure distribution model is as follows: Among them, r is the distance from any position in the coal seam to the bottom of the target well, in m; r w is the borehole diameter of the target well, in m; r b is the target distance, in m; P wf is the bottom hole pressure of the target well, in MPa; P b is the coal seam pressure at the boundary of the control area of the target well, in MPa; P is the coal seam pressure at the position r from the bottom of the well, in MPa.

8. A device for determining the aqueous phase permeability curve of coalbed methane, characterized in that, The device includes: A calculation unit configured to calculate a first average water saturation and a first average reservoir pressure corresponding to a target time, where the first average water saturation and the first average reservoir pressure are calculated based on the basic parameters of the coal seam, cumulative gas production, and cumulative water production corresponding to the target time; A first determination unit configured to determine the coal seam pressure field corresponding to the target time according to the preset pressure distribution model and the first average reservoir pressure; A second determination unit configured to determine the pressure-saturation relationship curve corresponding to the target time according to the preset initial coalbed methane water-phase permeability curve; A third determination unit configured to determine the coal seam water saturation field corresponding to the target time according to the coal seam pressure field and the pressure-saturation relationship curve, where the coal seam water saturation field is used to determine the second average water saturation corresponding to the target time; A fourth determination unit configured to determine the coalbed methane water-phase permeability curve corresponding to the target time based on the first average water saturation and the second average water saturation, where the coalbed methane water-phase permeability curve is used to characterize the gas-water seepage capacity of the coal seam corresponding to the target time.

9. A computer-readable storage medium, characterized in that, At least one program code is stored in the computer-readable storage medium, and the at least one program code is loaded and executed by a processor to implement the operations performed by the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that, The electronic device includes one or more processors and one or more memories, and at least one program code is stored in the one or more memories, and the at least one program code is loaded and executed by the one or more processors to implement the operations performed by the method according to any one of claims 1 to 7.

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