A reservoir permeability determination method, system, device and readable storage medium

Abstract

This application discloses a method, system, device, and readable storage medium for determining reservoir permeability. The method comprises: obtaining formation pressure data from gas reservoir well tests at different time points; determining a logarithmic pressure curve and a logarithmic pressure derivative curve based on the formation pressure data; determining an intersection point between the logarithmic pressure curve and the logarithmic pressure derivative curve; and calculating the reservoir permeability of the gas reservoir well test based on the ordinate value of the intersection point. This method reduces the safety risks and testing costs of long-term testing and allows for simple and accurate calculation of reservoir permeability.

Description

Technical Field

[0001] The present application relates to the technical field of oil and natural gas extraction and analysis, and in particular to a reservoir permeability determination method, system, device, and readable storage medium. Background Art

[0002] This section is intended to provide a background or context to the embodiments of the present application that are recited in the claims. No admission is made that the description herein is prior art by virtue of its inclusion in this section.

[0003] Currently, well testing is an effective method for determining reservoir permeability. This method requires shutting in the well to test the time-varying pattern of wellbore pressure. A logarithmic plot of the pressure and pressure derivative with respect to time is then plotted, and the reservoir permeability is calculated based on the position of the horizontal line on the pressure derivative curve. However, for ultra-high-pressure, fractured tight sandstone gas reservoirs, where burial depths exceed 7,000 meters and formation pressures exceed 100 MPa, testing poses significant risks. Furthermore, the reservoir matrix is ​​dense, and the core permeability is less than 0.1 mD. Despite prolonged testing (over 400 hours), the derivative curve exhibits no horizontal segment, instead displaying a straight line with a slope of 0.5, characteristic of a fractured reservoir. Due to the absence of a horizontal line, accurate calculation of reservoir permeability is impossible. Summary of the Invention

[0004] The embodiments of the present application provide a reservoir permeability determination method, system, device and readable storage medium, which reduce testing risks, shorten testing time, obtain reliable reservoir permeability results, and reduce the uncertainty of permeability evaluation.

[0005] In a first aspect, an embodiment of the present application provides a method for determining reservoir permeability, comprising:

[0006] Obtain formation pressure data of gas reservoir well tests at different time points;

[0007] determining a pressure logarithmic curve and a pressure derivative logarithmic curve based on the formation pressure data;

[0008] determining an intersection point according to the logarithmic pressure curve and the logarithmic pressure derivative curve;

[0009] The reservoir permeability of the gas reservoir well test is calculated based on the vertical coordinate value of the intersection point.

[0010] Optionally, determining the intersection point according to the pressure logarithmic curve and the pressure derivative logarithmic curve includes:

[0011] Draw the pressure logarithmic curve and the extension line of the pressure derivative logarithmic curve;

[0012] An intersection point of the logarithmic pressure curve and an extension line of the logarithmic pressure derivative curve is determined.

[0013] Optionally, the calculating of the gas reservoir well test reservoir permeability according to the vertical coordinate value of the intersection point includes:

[0014] The reservoir permeability of the gas reservoir well test is calculated based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point.

[0015] Alternatively, the reservoir permeability of the gas reservoir well test is calculated according to the following formula based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point:

[0016]

[0017] Where K is the reservoir permeability, mD; q g is the gas well production, 10 4 m 3 / d; T is the gas reservoir temperature, K; h is the gas layer thickness, m; [Δm'] 交点 is the pressure derivative value at the intersection, MPa 2 / cP.

[0018] In a second aspect, an embodiment of the present application further provides a reservoir permeability determination system, comprising:

[0019] A data acquisition module is used to obtain formation pressure data of gas reservoir well tests at different time points;

[0020] a curve drawing module, configured to determine a pressure logarithmic curve and a pressure derivative logarithmic curve according to the formation pressure data;

[0021] an intersection point determination module, configured to determine an intersection point according to the pressure logarithmic curve and the pressure derivative logarithmic curve;

[0022] The reservoir permeability determination module is used to calculate the reservoir permeability of the gas reservoir well test based on the vertical coordinate value of the intersection point.

[0023] Optionally, the intersection determination module is specifically configured to:

[0024] Draw the pressure logarithmic curve and the extension line of the pressure derivative logarithmic curve;

[0025] An intersection point of the logarithmic pressure curve and an extension line of the logarithmic pressure derivative curve is determined.

[0026] Optionally, the reservoir permeability determination module is specifically configured to:

[0027] The reservoir permeability of the gas reservoir well test is calculated based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point.

[0028] Alternatively, the reservoir permeability of the gas reservoir well test is calculated according to the following formula based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point:

[0029]

[0030] Where K is the reservoir permeability, q g is the gas well production, T is the gas reservoir temperature, h is the gas layer thickness, [Δm'] 交点 is the pressure derivative value at the intersection point.

[0031] In a third aspect, an embodiment of the present application further provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, any of the methods described in the first aspect is implemented.

[0032] In a fourth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for executing any of the methods described in the first aspect.

[0033] In summary, this application discloses a method, system, device, and readable storage medium for determining reservoir permeability. These methods involve obtaining formation pressure data from gas reservoir well tests at different time points; determining a logarithmic pressure curve and a logarithmic pressure derivative curve based on the formation pressure data; determining an intersection point between the logarithmic pressure curve and the logarithmic pressure derivative curve; and calculating the reservoir permeability of the gas reservoir well test based on the ordinate value of the intersection point. This method reduces testing risk and test time, yields reliable reservoir permeability results, and reduces uncertainty in permeability evaluation. It also addresses the difficulty of calculating reservoir permeability when the pressure derivative does not exhibit a horizontal segment, and reduces the safety risks and testing costs of long-term testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0035] Figure 1 A schematic flow chart of a method for determining reservoir permeability provided in an embodiment of the present application;

[0036] Figure 2 This is a schematic diagram of an embodiment provided in the embodiments of this application;

[0037] Figure 3 This is a block diagram of a reservoir permeability determination system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. The embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0039] The principles and spirit of the present application are explained in detail below with reference to several representative implementations of the present application.

[0040] Although the present application provides method operation steps or device structures as shown in the following embodiments or drawings, more or fewer operation steps or module units may be included in the method or device based on routine or no creative labor. In the steps or structures where there is no necessary causal relationship logically, the execution order of these steps or the module structure of the device is not limited to the execution order or module structure shown in the embodiments or drawings of the present application. When the method or module structure is applied to an actual device or terminal product, it can be executed sequentially or in parallel according to the method or module structure shown in the embodiment or drawings.

[0041] Figure 1 A flow chart of a method for determining reservoir permeability is shown, the method comprising the following steps:

[0042] Step 101: Acquire formation pressure data of gas reservoir well tests at different time points;

[0043] Step 102: determining a pressure logarithmic curve and a pressure derivative logarithmic curve according to the formation pressure data;

[0044] Step 103: determining an intersection point according to the pressure logarithmic curve and the pressure derivative logarithmic curve;

[0045] Step 104: Calculate the reservoir permeability of the gas reservoir well test according to the vertical coordinate value of the intersection point.

[0046] Based on well test analysis theory, the pressure derivative curve always lies below the pressure curve, and the intersection of the two curves represents the limit of tight sandstone reservoirs. This method obtains formation pressure data from gas reservoir well tests at different time points; determines a logarithmic pressure curve and a logarithmic pressure derivative curve based on the formation pressure data; determines the intersection point based on the logarithmic pressure curve and the logarithmic pressure derivative curve; and calculates the reservoir permeability of the gas reservoir well test based on the ordinate value of the intersection point. This method reduces testing risk and test time, resulting in reliable reservoir permeability results and reduced uncertainty in permeability evaluation. It solves the problem of calculating reservoir permeability when the pressure derivative does not exhibit a horizontal section, and reduces the safety risks and testing costs of long-term testing.

[0047] In a possible implementation, in step 103 , an extension line of the logarithmic pressure curve and the logarithmic pressure derivative curve is drawn; and an intersection point of the logarithmic pressure curve and the extension line of the logarithmic pressure derivative curve is determined.

[0048] In one possible implementation, in step 104 , the reservoir permeability of the gas reservoir well test is calculated based on the gas well production, gas reservoir temperature, gas layer thickness, and the pressure derivative value at the intersection point.

[0049] Specifically, the reservoir permeability of the gas reservoir well test is calculated according to the following formula (1) based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection:

[0050]

[0051] Where K is the reservoir permeability, the unit is mD; q g is the gas well production, the unit is 10 4 m 3 / d; T is the gas reservoir temperature, unit is K; h is the gas layer thickness, unit is m; [Δm'] 交点 is the pressure derivative value at the intersection point, in MPa 2 / cP.

[0052] Figure 2 is a double logarithmic curve of pressure and pressure derivative over time. In this example, the gas well production is 30×10 4 m 3 / d; gas reservoir temperature is 419.5K; gas layer thickness is 62m; the vertical coordinate value at the intersection of pressure and pressure derivative [Δm'] 交点 2958MPa 2 / cP. Substituting the above values ​​into formula (1), we have

[0053]

[0054] It can be seen from the above embodiments that the reservoir permeability can be determined by the vertical coordinate value of the intersection of the extended lines of the double logarithmic curves of pressure and pressure derivative. This method solves the problem of calculating reservoir permeability when the pressure derivative does not have a horizontal section, and reduces the safety risks and testing costs of long-term testing.

[0055] In summary, this application discloses a method, system, device, and readable storage medium for determining reservoir permeability. These methods involve obtaining formation pressure data from gas reservoir well tests at different time points; determining a logarithmic pressure curve and a logarithmic pressure derivative curve based on the formation pressure data; determining an intersection point between the logarithmic pressure curve and the logarithmic pressure derivative curve; and calculating the reservoir permeability of the gas reservoir well test based on the ordinate value of the intersection point. This method reduces testing risk and test time, yields reliable reservoir permeability results, and reduces uncertainty in permeability evaluation. It also addresses the difficulty of calculating reservoir permeability when the pressure derivative does not exhibit a horizontal segment, and reduces the safety risks and testing costs of long-term testing.

[0056] Based on the same technical concept, the embodiment of the present application also provides a reservoir permeability determination system, such as Figure 3 Shown, including:

[0057] The data acquisition module 301 is used to acquire formation pressure data of gas reservoir well testing at different time points.

[0058] The curve drawing module 302 is used to determine a pressure logarithmic curve and a pressure derivative logarithmic curve according to the formation pressure data.

[0059] The intersection point determination module 303 is configured to determine an intersection point according to the pressure logarithmic curve and the pressure derivative logarithmic curve.

[0060] The reservoir permeability determination module 304 is used to calculate the reservoir permeability of the gas reservoir well test according to the vertical coordinate value of the intersection point.

[0061] Optionally, the intersection point determination module 303 is specifically configured to: draw an extension line of the pressure logarithmic curve and the pressure derivative logarithmic curve; and determine an intersection point of the extension line of the pressure logarithmic curve and the pressure derivative logarithmic curve.

[0062] Optionally, the reservoir permeability determination module 304 is specifically configured to calculate the reservoir permeability of the gas reservoir well test according to the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point.

[0063] Optionally, the reservoir permeability of the gas reservoir well test is calculated according to formula (1) based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point.

[0064] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0065] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0066] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0067] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0068] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for determining reservoir permeability, characterized in that: include: Obtain formation pressure data of gas reservoir well tests at different time points; determining a pressure logarithmic curve and a pressure derivative logarithmic curve based on the formation pressure data; determining an intersection point according to the logarithmic pressure curve and the logarithmic pressure derivative curve; Calculate the reservoir permeability of the gas reservoir well test according to the vertical coordinate value of the intersection point; Determining the intersection point according to the logarithmic pressure curve and the logarithmic pressure derivative curve includes: drawing an extension line of the logarithmic pressure curve and the logarithmic pressure derivative curve; An intersection point of the logarithmic pressure curve and an extension line of the logarithmic pressure derivative curve is determined.

2. The method according to claim 1, wherein Calculating the gas reservoir well test reservoir permeability according to the vertical coordinate value of the intersection point includes: The reservoir permeability of the gas reservoir well test is calculated based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point.

3. The method according to claim 2, wherein The reservoir permeability of the gas reservoir well test is calculated according to the following formula based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point: Where K is the reservoir permeability, mD; q g is the gas well production, 10 4 m 3 / d; T is the gas reservoir temperature, K; h is the gas layer thickness, m; [Dm'] 交点 is the pressure derivative value at the intersection, MPa 2 / cP.

4. A reservoir permeability determination system, characterized in that: include: A data acquisition module is used to obtain formation pressure data of gas reservoir well tests at different time points; a curve drawing module, configured to determine a pressure logarithmic curve and a pressure derivative logarithmic curve according to the formation pressure data; an intersection point determination module, configured to determine an intersection point according to the pressure logarithmic curve and the pressure derivative logarithmic curve; A reservoir permeability determination module is used to calculate the reservoir permeability of the gas reservoir well test based on the vertical coordinate value of the intersection point; The intersection determination module is specifically used to: draw the extension line of the pressure logarithmic curve and the pressure derivative logarithmic curve; and determine the intersection point of the extension line of the pressure logarithmic curve and the pressure derivative logarithmic curve.

5. The system according to claim 4, wherein: The reservoir permeability determination module is specifically used to: The reservoir permeability of the gas reservoir well test is calculated based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point.

6. The system according to claim 5, wherein: The reservoir permeability of the gas reservoir well test is calculated according to the following formula based on the gas well production, gas reservoir temperature, gas layer thickness and the pressure derivative value at the intersection point: Where K is the reservoir permeability, mD; q g is the gas well production, 10 4 m 3 / d; T is the gas reservoir temperature, K; h is the gas layer thickness, m; [Dm'] 交点 is the pressure derivative value at the intersection, MPa 2 / cP.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 3 is implemented.

8. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program for executing the method according to any one of claims 1 to 3.

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