Method and system for determining fracture network type of reservoir around well by using pressure recovery well testing data

Abstract

The invention discloses a method and system for determining the type of a reservoir fracture network around a well by using pressure recovery well testing data, and the method comprises the steps: obtaining the fracture development condition of the reservoir around a fractured tight sandstone gas reservoir gas well, and determining the fracture development density of a production well section and a reservoir transformation and production improvement scheme; on the basis of the fracture development density of the production well section and the reservoir transformation and production improvement scheme, pressure recovery well testing of the fractured tight sandstone gas reservoir gas well is carried out, and reservoir physical property parameters are obtained; and according to reservoir physical property parameters, the type of the reservoir fracture network around the well is determined by combining the relationship between the single well fracture development condition and the slope of the upwarp linear characteristic section in the later stage of the pressure recovery well testing curve pressure derivative. According to the method, the fracture development conditions of the reservoir around the well corresponding to different pressure recovery well test derivative curve characteristics can be determined, and fracture network development difference research can be carried out; and a basis is provided for carrying out crack research on a single well for obtaining the crack development condition of the reservoir around the well without developing methods such as imaging logging and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a method and a system for determining the type of reservoir fracture network around a well by using pressure recovery well test data. Background Art

[0002] Unsteady well testing is a well testing method widely used in the exploration and development of oil and gas fields. Its approach is to change the working system of oil, gas and water wells, such as opening a well from a shut-in state, or instantly shutting down a producing well, to cause pressure redistribution in the formation, and at the same time measure the change of bottom hole pressure over time. Based on this change, combined with the data such as the well production and oil and gas properties, the characteristic parameters of the test well and the test layer within the pressure influence range are studied. These parameters include the permeability K of the formation, the flow coefficient Kh / μ, the formation pressure P R , the skin coefficient S after completion, and the internal and external boundary characteristics, etc., mainly obtain the reservoir and boundary characteristics information. The research and analysis of the Kuche piedmont ultra-high pressure and high pressure fractured tight sandstone gas reservoirs show that the degree of reservoir fracture development is the most important factor affecting production capacity.

[0003] Most of the existing descriptions of common fracture development use the data obtained from imaging logging during the completion of a single well to interpret and divide the number of fractures developed in each section and the direction of the fractures, and use this to evaluate the fracture development density of a single well and whether it is conducive to reservoir transformation and production increase.

[0004] In addition, there are also gas wells that did not carry out imaging logging during drilling and completion. In order to analyze and judge the development of fractures around such single wells, innovative new methods are used to judge the development of fractures by studying the reservoir characteristics of the pressure recovery test performance of such wells. Summary of the invention

[0005] The present invention provides a method and system for determining the type of reservoir fracture network around a well using pressure recovery well test data. According to the well test characteristics of fractured tight gas reservoirs, the development of reservoir fractures around the well corresponding to different pressure recovery well test derivative curve characteristics are divided, which is used to solve the technical problem of analyzing and judging the development of fractures around the well of gas wells where imaging logging work has not been carried out during drilling and completion.

[0006] The present invention adopts the following technical solutions:

[0007] A method for determining the type of reservoir fracture network around a well using pressure recovery well test data comprises the following steps:

[0008] S1. Obtain the development of reservoir fractures around gas wells in fractured tight sandstone gas reservoirs, determine the density of fractures in the production well section and the reservoir transformation and production increase plan;

[0009] S2. Based on the fracture development density of the production well section and the reservoir transformation and production improvement plan determined in step S1, a pressure recovery test is carried out on a gas well in a fractured tight sandstone gas reservoir to obtain reservoir physical property parameters;

[0010] S3. Determine the type of reservoir fracture network around the well according to the reservoir physical property parameters obtained in step S2, combined with the fracture development of the single well and the slope relationship of the characteristic upward straight line segment of the pressure derivative of the pressure recovery test curve.

[0011] Specifically, step S1 is as follows:

[0012] S101, conducting single well electrical imaging logging during drilling and completion to obtain data to be tested;

[0013] S102, according to the measured data obtained in step S101, the resistivity and Standoff image of the formation around the well are obtained by processing and inversion, and the qualitative analysis and quantitative evaluation of the fractures and holes around the well are carried out to identify the number of fractures developed in different layers and the direction of the fractures;

[0014] S103. Evaluate the density of fracture development in the production well section and whether reservoir transformation is possible to increase production.

[0015] Furthermore, in step S101, the data to be measured is the impedance of each capacitor.

[0016] Specifically, step S2 is as follows:

[0017] S201. Prepare geological design and construction design for pressure recovery well testing;

[0018] S202, carry out the casting test, record the downhole temperature and pressure data according to the pressure recovery test design, and obtain the test data;

[0019] S203, performing pressure recovery well test analysis according to the test data obtained in step S202, drawing a double logarithmic curve graph of the pressure recovery well test, and obtaining reservoir physical property parameters.

[0020] Furthermore, in step S203, the double logarithmic curve diagram of the pressure recovery test includes a pressure difference curve and a pressure derivative curve.

[0021] Furthermore, the horizontal coordinate of the well test curve is:

[0022]

[0023] Among them, t D is dimensionless time, C D is the dimensionless well storage coefficient, K is the permeability, h is the effective thickness of the reservoir, Δt is the shut-in time, μ g is the viscosity of natural gas under formation conditions, and C is the well storage coefficient.

[0024] Furthermore, the vertical coordinate of the well test curve is:

[0025]

[0026]

[0027]

[0028] Among them, p D is the dimensionless pressure, q is the daily production of natural gas, B is the natural gas volume coefficient, Δp is the pressure recovery from well opening to time t, and p′ D is the dimensionless pressure derivative, and Δp′ is the pressure derivative.

[0029] Specifically, in step S3, the slope of the late upward straight line characteristic segment of the pressure derivative of the pressure recovery test curve is 1 / 2 to 1.

[0030] Furthermore, the gas wells with a slope of 1 have large fractures, high density and good continuity; the gas wells with a slope of 1 / 2 have long fractures, low density and poor continuity; and the gas wells with a slope of 1 / 2 to 1 have fractures, density and continuity that tend to improve.

[0031] In a second aspect, an embodiment of the present invention provides a system for determining the type of reservoir fracture network around a well using pressure recovery well test data, comprising:

[0032] Data module, to obtain the reservoir fracture development situation around the gas well in fractured tight sandstone gas reservoir, determine the fracture development density of the production well section and the reservoir transformation and production increase plan;

[0033] The test module conducts pressure recovery tests on gas wells in fractured tight sandstone gas reservoirs to obtain reservoir physical property parameters based on the fracture development density of the production well section and the reservoir transformation and production improvement plan determined by the data module;

[0034] The judgment module determines the type of reservoir fracture network around the well based on the reservoir physical property parameters obtained by the test module, combined with the fracture development of the single well and the slope relationship of the characteristic upward straight line segment of the pressure derivative of the pressure recovery test curve.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] A method for determining the type of reservoir fracture network around a well using pressure recovery test data, determining the development of reservoir fractures around the well corresponding to different pressure recovery test derivative curve characteristics, and providing a basis for conducting fracture research in a single well without using imaging logging and other methods to obtain the development of reservoir fractures around the well.

[0037] Furthermore, it is necessary to first conduct a study on the density of fracture development around a single well, and evaluate it based on the existing data or the data to be collected. At this time, the commonly used technology is to conduct single-well electrical imaging logging during drilling and completion.

[0038] Furthermore, in order to judge the fracture development by studying the reservoir characteristics of the pressure recovery test performance of this type of wells, it is necessary to obtain the pressure recovery data of this type of wells, conduct pressure recovery test analysis, draw a double logarithmic curve graph of the pressure recovery test, and obtain reservoir physical property parameters.

[0039] Furthermore, by combining the fracture development density around the single well in step S1 and the slope of the characteristic upward straight line segment of the pressure derivative of the pressure recovery test curve in step S3, the relationship or correlation between the two is obtained.

[0040] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0041] In summary, the present invention analyzes the development of reservoir fractures around the corresponding well according to the characteristics of the derivative curve of the pressure recovery test of the gas well, and conducts research on the difference in fracture network development based on this; and provides a basis for conducting fracture research on single wells that have not used imaging logging and other methods to obtain the development of reservoir fractures around the well.

[0042] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is the double logarithmic curve diagram of the pressure recovery test;

[0044] Figure 2 It is a schematic diagram of reservoir mode division;

[0045] Figure 3 It is a typical well test curve;

[0046] Figure 4 This is a schematic diagram of the east-west gas reservoir section of the M gas reservoir;

[0047] Figure 5 Fracture distribution diagram interpreted by imaging logging, where (a) is X2, (b) is X4, and (c) is X6;

[0048] Figure 6 The following are comparative analysis diagrams of the pressure recovery tests of the wells over the years, where (a) is X2, (b) is X4, and (c) is X6. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0051] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0052] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0053] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0054] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0055] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0056] The present invention provides a method for determining the type of reservoir fracture network around a well using pressure recovery test data, combining differential analysis of the characteristics of the pressure recovery test derivative curve and the actual fracture development of a single well, and judging the fracture development of the reservoir around the well according to the slope of the late upward straight line characteristic segment of the pressure derivative of the pressure recovery test curve.

[0057] The present invention provides a method for determining the type of reservoir fracture network around a well using pressure recovery well test data, comprising the following steps:

[0058] S1. Obtain the development of reservoir fractures around gas wells in fractured tight sandstone gas reservoirs;

[0059] S101. Conduct single well electrical imaging logging during drilling and completion, and record the required data, i.e. the impedance of each capacitor, as required;

[0060] S102. The impedance measured by the instrument is the comprehensive electrical response of the formation and drilling fluid. After processing and inversion, the resistivity of the formation around the well and the Standoff (gap between the electrode and the well wall) image are obtained, and the qualitative analysis and quantitative evaluation of the cracks and holes around the well are carried out to identify the number of cracks developed in different layers and the direction of the cracks;

[0061] S103. Evaluate the density of fracture development in the production well section and whether it is conducive to reservoir transformation and production increase.

[0062] S2. Conduct pressure recovery test of gas wells in fractured tight sandstone gas reservoirs;

[0063] S201. Prepare geological design and construction design for pressure recovery well testing;

[0064] S202, carry out the casting test, record the downhole temperature and pressure data according to the pressure recovery test design, and obtain the test data;

[0065] S203: Analyze the pressure recovery test, draw a double logarithmic curve of the pressure recovery test, and obtain reservoir physical property parameters.

[0066] See also Figure 1 The double logarithmic curve of the pressure recovery test includes two curves: the pressure difference curve and the pressure derivative curve.

[0067] It is particularly important to mention here that in well test analysis, the pressure derivative is defined as follows:

[0068] Pressure is differentiated with respect to time taking the logarithm. The characteristics of the pressure derivative are crucial for well test analysis.

[0069] Well test curve horizontal axis:

[0070]

[0071] Vertical coordinate of well test curve:

[0072]

[0073]

[0074]

[0075] Among them, t D is dimensionless time, C D is the dimensionless well storage coefficient, K is the permeability, h is the effective thickness of the reservoir, Δt is the shut-in time, μ g is the viscosity of natural gas under formation conditions, C is the well storage coefficient, p D is the dimensionless pressure, q is the daily production of natural gas, B is the natural gas volume coefficient, Δp is the pressure recovery from well opening to time t, and p′ D is the dimensionless pressure derivative, and Δp′ is the pressure derivative.

[0076] S3. Conduct research on the relationship between the development of fractures in a single well and the slope of the characteristic upward straight line segment of the pressure derivative of the pressure recovery test curve.

[0077] S301. Statistical analysis and summary of 62 ultra-high pressure and high pressure gas well pressure recovery tests. It is concluded that the slope of the characteristic segment of the upward straight line in the later stage of the pressure derivative of the pressure recovery test curve is between 1 / 2 and 1;

[0078] S302, gas wells with a slope close to 1, combined with imaging logging to interpret fracture development;

[0079] See also Figure 2 and Figure 3 The cracks are large in scale, high in density and good in continuity.

[0080] S303, gas wells with a slope of nearly 1 / 2, combined with imaging logging to interpret fracture development;

[0081] See also Figure 2 and Figure 3 , the cracks are long, the density is low and the continuity is poor.

[0082] S304, gas wells with slopes between 1 / 2 and 1, combined with imaging logging to interpret fracture development.

[0083] See also Figure 2 and Figure 3 The length, density, and continuity of the cracks are showing a trend of gradually improving.

[0084] The development of fractures in a single well affects the slope of the characteristic upward straight line segment in the later stage of the pressure derivative of the pressure recovery test curve.

[0085] In yet another embodiment of the present invention, a system for determining the type of reservoir fracture network around a well using pressure recovery well test data is provided. The system can be used to implement the above-mentioned method for determining the type of reservoir fracture network around a well using pressure recovery well test data. Specifically, the system for determining the type of reservoir fracture network around a well using pressure recovery well test data includes a data module, a test module and a judgment module.

[0086] The data module obtains the development of reservoir fractures around gas wells in fractured tight sandstone gas reservoirs, determines the density of fractures in the production well section and the reservoir transformation and production increase plan;

[0087] The test module conducts pressure recovery tests on gas wells in fractured tight sandstone gas reservoirs to obtain reservoir physical property parameters based on the fracture development density of the production well section and the reservoir transformation and production improvement plan determined by the data module;

[0088] The judgment module determines the type of reservoir fracture network around the well based on the reservoir physical property parameters obtained by the test module, combined with the fracture development of the single well and the slope relationship of the characteristic upward straight line segment of the pressure derivative of the pressure recovery test curve.

[0089] In another embodiment of the present invention, a terminal device is provided, the terminal device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the method for determining the type of reservoir fracture network around the well using pressure recovery well test data, including:

[0090] Obtain the reservoir fracture development situation around the gas wells in fractured tight sandstone gas reservoirs, determine the fracture development density of the production well section and the reservoir transformation and production improvement plan; based on the fracture development density of the production well section and the reservoir transformation and production improvement plan, carry out pressure recovery tests on gas wells in fractured tight sandstone gas reservoirs to obtain reservoir physical property parameters; according to the reservoir physical property parameters, combined with the fracture development situation of a single well and the slope relationship of the characteristic upward straight line segment of the pressure derivative in the later stage of the pressure recovery test curve, determine the reservoir fracture network type around the well.

[0091] In another embodiment of the present invention, the present invention further provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory, or a non-volatile memory (Non-Volatile Memory), such as at least one disk memory.

[0092] The processor may load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for determining the type of reservoir fracture network around a well using pressure recovery well test data in the above embodiment; the processor may load and execute the following steps of one or more instructions in the computer-readable storage medium:

[0093] Obtain the reservoir fracture development situation around the gas wells in fractured tight sandstone gas reservoirs, determine the fracture development density of the production well section and the reservoir transformation and production improvement plan; based on the fracture development density of the production well section and the reservoir transformation and production improvement plan, carry out pressure recovery tests on gas wells in fractured tight sandstone gas reservoirs to obtain reservoir physical property parameters; according to the reservoir physical property parameters, combined with the fracture development situation of a single well and the slope relationship of the characteristic upward straight line segment of the pressure derivative in the later stage of the pressure recovery test curve, determine the reservoir fracture network type around the well.

[0094] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0095] Example

[0096] See also Figure 4An ultra-deep, ultra-high-pressure, high-temperature fractured tight sandstone gas reservoir (hereinafter referred to as the M gas reservoir) in a basin in western China has an east-west short-axis anticline structure, and six wells have been put into production along the long axis of the structure.

[0097] Among them, the three wells X2, X4 and X6 located in the high, middle and low parts of the structure carried out shut-in pressure recovery tests on the entire gas reservoir for 2 to 3 consecutive years, and imaging logging was carried out to analyze the development of fractures around the wells.

[0098] Analysis steps:

[0099] (1) Summarize the fracture development of the perforated sections of the three wells X2, X4, and X6 (e.g. Figure 5 and Table 1).

[0100] Table 1 Statistics of fracture development in production well sections X2, X4 and X6

[0101] hashtag Production well section (m) Horizon Crack line density (line / m) Remark <![CDATA[X2]]> 5971.5～5985.5 <![CDATA[K1bs 3 ]]> 0.51 <![CDATA[X4]]> 5920～5958 <![CDATA[K1bx 2 ]]> 0.50 <![CDATA[X6]]> 6185.5～6197.5 <![CDATA[K1bx 2 ]]> 0.39

[0102] See also Figure 5 , from the interpretation results of imaging logging of each single well in the figure, the number of high-conductivity fractures / open fractures within the production well section is read, and the fracture line density within the production well section is calculated based on this.

[0103] (2) The pressure recovery tests of the three wells X2, X4 and X6 were analyzed. The results of the pressure recovery test curves are shown in Figure 6 .

[0104] See also Figure 6 , which is a comparison chart of the pressure recovery tests of the three wells X2, X4 and X6. From the figure, we can get the slope of the upward straight line characteristic segment of the pressure derivative in the double logarithmic curve of the single well pressure recovery test.

[0105] (3) Based on the analysis of the pressure recovery test curves of the three wells X2, X4 and X6, the details are as follows:

[0106] First, the well test curves of each well in the M gas reservoir are consistent with the well test characteristics of fractured tight gas reservoirs;

[0107] Secondly, wells X2 and X4 meet the characteristics of directional large fractures / fracture network development, and there are differences between wells X2 and X4 and X6. The fracture network development of X6 (slope of the pressure derivative straight line segment is 0.5) is relatively weaker than that of wells X2 and X4 in the high and middle parts of the structure, as shown in Table 2.

[0108] Table 2 Summary of fracture development and pressure derivative straight line slope in production well sections X2, X4, and X6

[0109] hashtag Production well section (m) Horizon Crack line density (line / m) Slope of pressure derivative line segment <![CDATA[X2]]> 5971.5～5985.5 <![CDATA[K1bs 3 ]]> 0.51 0.9 <![CDATA[X4]]> 5920～5958 <![CDATA[K1bx 2 ]]> 0.50 0.9 <![CDATA[X6]]> 6185.5～6197.5 <![CDATA[K1bx 2 ]]> 0.39 0.5

[0110] In summary, for fractured tight sandstone gas reservoirs, the strength of the fracture network of a single gas well will result in the slope of the pressure derivative straight line segment of the pressure recovery test curve being between 1 / 2 and 1, and the two are positively correlated; that is, the higher the fracture network development of a single gas well, the closer the slope of the pressure derivative straight line segment is to 1; the lower the fracture network development of a single gas well, the closer the slope of the pressure derivative straight line segment is to 1 / 2.

[0111] In summary, the present invention provides a method and system for determining the type of reservoir fracture network around a well using pressure recovery test data, and determines the development of reservoir fractures around the well corresponding to different pressure recovery test derivative curve characteristics, so as to carry out research on the difference in fracture network development; and provides a basis for conducting fracture research on a single well that has not carried out imaging logging and other methods to obtain the development of reservoir fractures around the well.

[0112] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0113] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0114] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0115] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0116] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0117] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0118] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0119] 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 generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. 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.

[0120] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0121] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0122] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for determining the type of reservoir fracture network around a well using pressure recovery test data, characterized in that: The following steps are involved: S1. Obtain the development of reservoir fractures around gas wells in fractured tight sandstone gas reservoirs, determine the density of fractures in the production well section and the reservoir transformation and production increase plan; S2. Based on the fracture development density of the production well section determined in step S1 and the reservoir transformation and production improvement plan, a pressure recovery test is carried out on a gas well in a fractured tight sandstone gas reservoir to obtain reservoir physical property parameters; S3. Determine the type of reservoir fracture network around the well according to the reservoir physical property parameters obtained in step S2, combined with the fracture development of the single well and the slope relationship of the characteristic upward straight line segment of the pressure derivative of the pressure recovery test curve.

2. The method for determining the type of reservoir fracture network around a well using pressure recovery well test data according to claim 1, characterized in that: Step S1 is specifically as follows: S101, conducting single well electrical imaging logging during drilling and completion to obtain data to be measured; S102, according to the measured data obtained in step S101, the resistivity and Standoff image of the formation around the well are obtained by processing and inversion, and the qualitative analysis and quantitative evaluation of the fractures and holes around the well are carried out to identify the number of fractures developed in different layers and the direction of the fractures; S103. Evaluate the density of fracture development in the production well section and whether reservoir transformation is possible to increase production.

3. The method for determining the type of reservoir fracture network around a well using pressure recovery test data according to claim 2, characterized in that: In step S101 , the data to be measured is the impedance of each capacitor.

4. The method for determining the type of reservoir fracture network around a well using pressure recovery well test data according to claim 1, characterized in that: Step S2 is specifically as follows: S201. Prepare geological design and construction design for pressure recovery well testing; S202, carry out the casting test, record the downhole temperature and pressure data according to the pressure recovery test design, and obtain the test data; S203, performing pressure recovery well test analysis according to the test data obtained in step S202, drawing a double logarithmic curve graph of the pressure recovery well test, and obtaining reservoir physical property parameters.

5. The method for determining the type of reservoir fracture network around a well using pressure recovery well test data according to claim 4, characterized in that: In step S203, the double logarithmic curve diagram of the pressure recovery test includes a pressure difference curve and a pressure derivative curve.

6. The method for determining the type of reservoir fracture network around a well using pressure recovery well test data according to claim 5, characterized in that: Well test curve horizontal axis: Among them, t D is dimensionless time, C D is the dimensionless well storage coefficient, K is the permeability, h is the effective thickness of the reservoir, Δt is the shut-in time, μ g is the viscosity of natural gas under formation conditions, and C is the well storage coefficient.

7. The method for determining the type of reservoir fracture network around a well using pressure recovery test data according to claim 5, characterized in that: Vertical coordinate of well test curve: Among them, p D is the dimensionless pressure, q is the daily production of natural gas, B is the natural gas volume coefficient, Δp is the pressure recovery from well opening to time t, and p′ D is the dimensionless pressure derivative, and Δp′ is the pressure derivative.

8. The method for determining the type of reservoir fracture network around a well using pressure recovery test data according to claim 1, characterized in that: In step S3, the slope of the late upward straight line characteristic segment of the pressure derivative of the pressure recovery test curve is 1 / 2 to 1.

9. The method for determining the type of reservoir fracture network around a well using pressure recovery well test data according to claim 8, characterized in that: For gas wells with a slope of 1, the fractures are large in scale, high in density and good in continuity; for gas wells with a slope of 1 / 2, the fractures are long, low in density and poor in continuity; for gas wells with a slope of 1 / 2 to 1, the fractures, density and continuity tend to improve.

10. A system for determining the type of reservoir fracture network around a well using pressure recovery test data, characterized in that: include: Data module, to obtain the reservoir fracture development situation around the gas well in fractured tight sandstone gas reservoir, determine the fracture development density of the production well section and the reservoir transformation and production increase plan; The test module conducts pressure recovery tests on gas wells in fractured tight sandstone gas reservoirs to obtain reservoir physical property parameters based on the fracture development density of the production well section and the reservoir transformation and production improvement plan determined by the data module; The judgment module determines the type of reservoir fracture network around the well based on the reservoir physical property parameters obtained by the test module, combined with the fracture development of the single well and the slope relationship of the characteristic upward straight line segment of the pressure derivative of the pressure recovery test curve.

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