Numerical Well Testing Method and Device for Fracture Interference in Horizontal Wells of Shale Oil Hydraulic Fracturing

Abstract

The present application provides a numerical well testing method and device for fracture interference in shale oil and gas fracturing horizontal wells. The method includes: establishing a physical model of a shale oil and gas reservoir; establishing a numerical model of fracture interference in a shale oil and gas reservoir based on the physical model; inputting basic parameter data into the numerical model, changing the values of interference parameters, and obtaining multiple double logarithm curves under different values of the interference parameters. The interference parameters include one or more of a fracture interference coefficient, a well horizontal section length, and a hydraulic fracture angle. The fracture interference coefficient is the ratio of the number of actual connected fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well to the number of connectable fractures; comparing the multiple double logarithm curves to explain the influence degree of the interference parameters on the pressure of the test well. The method of the present application introduces the concept of a fracture interference coefficient and includes hydraulic fractures in the physical model, so as to be able to explore the influence of hydraulic fractures on the pressure and production of the test well.

Description

Technical Field

[0001] The present application relates to the technical field of gas reservoir development, and particularly to a numerical well testing method and device for fracture interference in shale oil fracturing horizontal wells. Background Art

[0002] With the exploitation of global energy, oil and gas resources are facing severe challenges of low single-well productivity and low recovery rate. Fracturing and horizontal wells are currently commonly used technologies to alleviate the above challenges. A horizontal well is a well with a wellbore drilled horizontally for a certain length, aiming to increase the exposed area of the oil and gas reservoir. Fracturing refers to a method of forming fractures in an oil or gas reservoir by using hydraulic action during the process of oil or gas production. Both fracturing and horizontal well technologies can improve single-well productivity.

[0003] At home and abroad, in order to improve the recovery rate of shale oil and gas, the wellbore spacing of fracturing horizontal wells has been continuously reduced, resulting in continuous occurrence of fracture interference phenomena between fracturing wells. The interference phenomenon refers to the phenomenon that when multiple wells in the same oil and gas layer produce simultaneously, the change in the working system of any one well causes changes in the bottom-hole pressure and production of other wells. In order to explore the well interference phenomenon, currently, a well interference curve model is usually established, that is, a physical model of the stimulation well and the test well is first established, then a mathematical model is established based on the above physical model, and then the data model is solved to obtain the curves of the bottom-hole pressure and pressure derivative of the test well changing with time, so as to evaluate the influence of various influencing factors on the bottom-hole pressure of the test well.

[0004] Currently, in oil exploitation, fracturing technology is used to make horizontal wells generate more hydraulic fractures. However, the existing methods for characterizing well interference are difficult to evaluate the influence of hydraulic fractures on the bottom-hole pressure of the test well. Summary of the Invention

[0005] The present disclosure provides a numerical well testing method and device for fracture interference in shale oil fracturing horizontal wells to explore the influence degree of hydraulic fractures on the bottom-hole pressure and production of the test well.

[0006] In a first aspect, the present application provides a numerical well testing method for fracture interference in shale oil fracturing horizontal wells, including:

[0007] Based on the fracturing effect of the test well, establish a physical model of the shale oil and gas reservoir;

[0008] According to the physical model, establish a numerical model of the shale oil and gas reservoir;

[0009] Input the basic parameter data into the numerical model, and change the values of the interference parameters to obtain multiple double-logarithmic curves under different values of the interference parameters. Among them, the double-logarithmic curves are used to represent the corresponding relationship between the pressure and time of the test well. The interference parameters include one or more of a fracture interference coefficient, a well horizontal section length, and a hydraulic fracture angle. The fracture interference coefficient is the ratio of the actual number of connected fractures between the hydraulic fractures of the test well and the hydraulic fractures of the stimulation well to the number of connectable fractures between the hydraulic fractures of the test well and the hydraulic fractures of the stimulation well;

[0010] Compare the multiple double-logarithmic curves to explain the influence degree of the interference parameters on the pressure of the test well.

[0011] In a second aspect, the present application provides a numerical well testing device for fracture interference in shale oil fracturing horizontal wells, including:

[0012] A first establishment module for establishing a physical model of a shale oil and gas reservoir based on the fracturing effect of a test well;

[0013] A second establishment module for establishing a numerical model of the shale oil and gas reservoir according to the physical model;

[0014] An input module for inputting basic parameter data into the numerical model and changing the values of interference parameters to obtain multiple double-logarithmic curves under different values of the interference parameters. Among them, the double-logarithmic curves are used to represent the corresponding relationship between the pressure and time of the test well. The multiple interference parameters include one or more of a fracture interference coefficient, a well horizontal section length, and a hydraulic fracture angle. The fracture interference coefficient is the ratio of the actual number of connected fractures between the hydraulic fractures of the test well and the hydraulic fractures of the stimulation well to the number of connectable fractures between the hydraulic fractures of the test well and the hydraulic fractures of the stimulation well;

[0015] A comparison module for comparing the multiple double-logarithmic curves to explain the influence degree of the interference parameters on the shale oil and gas reservoir.

[0016] In a third aspect, the present application provides an electronic device, including:

[0017] At least one processor and a memory;

[0018] The memory stores computer execution instructions;

[0019] The at least one processor executes the computer execution instructions stored in the memory, so that the at least one processor executes the numerical well testing method for fracture interference in shale oil fracturing horizontal wells as described in the first aspect above.

[0020] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the shale oil fracturing horizontal well fracture interference numerical well test method as described in the first aspect above.

[0021] This application provides a shale oil fracturing horizontal well fracture interference numerical well test method and device. First, a physical model is established, and a numerical model is established based on the physical model. Then, the numerical model is solved to obtain a double logarithm curve. The physical model includes a hydraulic fracture. By changing the values of the interference parameters related to the hydraulic fracture, the double logarithm curve changes. And under different values of the interference parameters, the numerical model is solved to obtain multiple double logarithm curves. By analyzing the multiple double logarithm curves, the influence degree of the interference parameters related to the hydraulic fracture on the bottom hole pressure of the test well can be explored. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application and used together with the specification to explain the principles of the present application.

[0023] Figure 1 It is a schematic diagram of the application scenario of the shale oil fracturing horizontal well fracture interference numerical well test method provided by the embodiment of the present application;

[0024] Figure 2 It is a schematic flow chart of the shale oil fracturing horizontal well fracture interference numerical well test method provided by the embodiment of the present application Figure 1 ;

[0025] Figure 3 It is a schematic diagram of the connectivity degree of the inter-well hydraulic fracture provided by the embodiment of the present application;

[0026] Figure 4 It is a schematic diagram of the comparison of the horizontal section lengths of different wells provided by the embodiment of the present application;

[0027] Figure 5 It is a schematic diagram of the model under different hydraulic fracture angles provided by the embodiment of the present application;

[0028] Figure 6 It is a schematic flow chart of the shale oil fracturing horizontal well fracture interference numerical well test method provided by the embodiment of the present application Figure 2 ;

[0029] Figure 7 It is a schematic diagram of the physical model provided by the embodiment of the present application Figure 1 ;

[0030] Figure 8 It is a schematic diagram of the physical model provided by the embodiment of the present application Figure 2 ;

[0031] Figure 9 Schematic diagram of the global coordinates and local coordinates of hydraulic fractures provided by the embodiments of the present application;

[0032] Figure 10 Schematic diagram of the physical model under different fracture interference coefficients provided by the embodiments of the present application;

[0033] Figure 11 Schematic diagram of four different connection methods provided by the embodiments of the present application;

[0034] Figure 12 Schematic diagram of the double logarithmic curve under different fracture interference coefficients provided by the embodiments of the present application;

[0035] Figure 13 Schematic diagram of the double logarithmic curve with and without natural fractures provided by the embodiments of the present application;

[0036] Figure 14 Schematic diagram of the double logarithmic curve before and after the fitting process provided by the embodiments of the present application;

[0037] Figure 15 Schematic diagram of the structure of the numerical well test device for fracture interference in shale oil fracturing horizontal wells provided by the embodiments of the present application;

[0038] Figure 16 Hardware structure diagram of the electronic device provided by the embodiments of the present application.

[0039] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0040] To make the objectives, 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 with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] Figure 1 Schematic diagram of the application scenario of the numerical well test method for fracture interference in shale oil fracturing horizontal wells provided by the embodiments of the present application. As Figure 1As shown, 101 is an oil and gas reservoir, which can be any type of oil and gas reservoir, such as a shale oil and gas reservoir, etc. In order to improve the extraction efficiency of oil and gas resources in the oil and gas reservoir, a plurality of horizontal wells are usually deployed in the oil and gas reservoir 101. A horizontal well is a well with a well inclination angle of 90 degrees or close to 90 degrees. Figure 1 Wells 102 and 103 are both horizontal wells.

[0042] In order to further improve the recovery rate of the oil and gas reservoir 101, the wellbore spacing of the horizontal wells is usually reduced, but this is accompanied by the generation of well interference. In order to explore the well interference phenomenon, a horizontal well in the oil and gas reservoir 101 is usually selected as a test well 102, and another horizontal well is selected as an excitation well 103. The change in the production mechanism of the excitation well 103 usually leads to changes in the pressure and production of the test well 102, that is, the well interference phenomenon occurs.

[0043] In order to explore the phenomenon of well interference, the numerical well test method is usually used at present, that is, first establish the physical model of the oil and gas reservoir 101, the exciting well 103, and the test well 102, and then establish the mathematical model based on the physical model, and finally solve the mathematical model to obtain the double logarithmic curve of the pressure change of the test well over time, and change the parameters related to the interference factors to make the double logarithmic curve change. The change of the double logarithmic curve can be used to explore the change of the pressure and production of the test well 102 caused by the interference factors.

[0044] However, for shale oil and gas reservoirs, fracturing technology is usually required in the process of oil and gas resource extraction. Fracturing refers to a method of using hydraulic force to form cracks in oil and gas layers during oil or gas production, which can also be called hydraulic fracturing. The use of fracturing technology causes more hydraulic fractures 104 in shale oil and gas reservoirs, making the well-to-well interference phenomenon more significant. The current numerical well testing method is difficult to explore the impact of hydraulic fractures on the bottom hole pressure and production of the test well.

[0045] The hydraulic fracture 104 is a fracture generated by the fracturing technology when exploiting oil and gas resources in a horizontal well of shale oil. In order to explore the influence of the hydraulic fracture 104 on the bottom hole pressure of the test well, it is necessary to set the hydraulic fracture 104 in the physical model during the numerical well test. However, how to set the hydraulic fracture 104 in the physical model and then explore the influence of the hydraulic fracture 104 on the bottom hole pressure and production of the test well 102 is an important problem to be solved urgently.

[0046] During the actual production process, hydraulic fractures 104 will be generated in both the stimulation well and the test well after fracturing technology. If we want to explore the influence of hydraulic fractures 104 on the well interference phenomenon, we need to consider the influence of the hydraulic fractures 104 of the stimulation well 103 and the hydraulic fractures 104 of the test well 102 on the bottom-hole pressure and production of the test well 102. It is known that the better the connectivity between the stimulation well 103 and the test well 102, the more significant the influence of the stimulation well 103 on the test well 102. Therefore, it is necessary to explore the influence of the connectivity between the hydraulic fractures 104 of the stimulation well 103 and the hydraulic fractures 104 of the test well 102 on the bottom-hole pressure of the test well 102.

[0047] In view of the above problems, the present application proposes a numerical well test method and device for fracture interference in shale oil fracturing horizontal wells, which is applied to the field of gas reservoir development technology. This method introduces the concept of fracture interference coefficient, which is the ratio of the actual number of connected fractures between the hydraulic fractures of the test well and the hydraulic fractures of the stimulation well to the number of connectable fractures between the hydraulic fractures of the test well and the hydraulic fractures of the stimulation well. By changing the fracture interference coefficient, double-logarithmic curves in various scenarios are obtained. Through the comparison between the above-mentioned multiple double-logarithmic curves, the influence of hydraulic fractures on the bottom-hole pressure of the test well can be reflected, and the well interference phenomenon can be better reflected.

[0048] Next, the technical solutions shown in the present application will be described in detail through specific embodiments. It should be noted that the following several specific embodiments can be combined with each other, and the same or similar content will not be repeated in different embodiments.

[0049] The method of the embodiment of the present application can be executed by a data processing device, such as a computer, a server, etc., and a software application program, such as a commercial mathematical software (MATLAB) program, etc., can be installed on the data processing device.

[0050] Figure 2 is a schematic flow chart of the numerical well test method for fracture interference in shale oil fracturing horizontal wells provided by the embodiment of the present application Figure 1 As Figure 2 shown, the method includes:

[0051] S201. Based on the fracturing effect of the test well, establish a physical model of the shale oil and gas reservoir.

[0052] The test well is the well whose bottom-hole pressure is to be explored as it changes with time, and it can be a horizontal well. The physical model can be a model drawn through a software program.

[0053] S202. According to the physical model, establish a numerical model of the shale oil and gas reservoir.

[0054] The numerical model is a seepage mathematical model established based on the above physical model. The numerical model will be introduced in detail in the subsequent examples.

[0055] S203. Input the basic parameter data into the numerical model, and change the values of the interference parameters to obtain multiple double-logarithmic curves under different values of the interference parameters. The double-logarithmic curves are used to represent the corresponding relationship between the pressure and time of the test well. The interference parameters include one or more of the fracture interference coefficient, the horizontal section length of the well, and the hydraulic fracture angle. The fracture interference coefficient is the ratio of the actual number of connected fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well to the number of connectable fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well.

[0056] The basic parameter data are data related to the shale oil and gas reservoir and the properties of the test well, which will be introduced in detail in the subsequent examples. The interference parameters are data related to the hydraulic fracture, and it can be one or more of the fracture interference coefficient, the horizontal section length of the well, and the hydraulic fracture angle. The fracture interference coefficient can be defined by the formula: δ = n / N; where δ is the fracture interference coefficient, which is a value less than or equal to 1 and greater than or equal to 0; n is the actual number of connected fractures between the hydraulic fracture of the stimulation well and the hydraulic fracture of the test well; N is the number of connectable fractures between the hydraulic fracture of the stimulation well and the hydraulic fracture of the test well.

[0057] Figure 3 It is a schematic diagram of the connectivity of the inter-well hydraulic fractures provided by the embodiments of the present application. As Figure 3 shown, the stimulation well 301 and the test well 302 each contain a hydraulic fracture. The number of hydraulic fractures 303 of the stimulation well is 6, and the number of hydraulic fractures 304 of the test well is 6. In Figure 3 , the angle between the hydraulic fracture and the stimulation well / test well is 90 degrees. In practice, the angle between the two can be changed arbitrarily. Figure 3 In the scenario shown, the actual number of connected fractures between the hydraulic fracture of the stimulation well and the hydraulic fracture of the test well is 4, that is, n is 4; the number of connectable fractures between the hydraulic fracture of the stimulation well and the hydraulic fracture of the test well is 6, that is, only considering the connection between the hydraulic fracture of the stimulation well and the hydraulic fracture of the test well closest to it, without considering other connection situations. Therefore, at this time, the number of connectable fractures between the hydraulic fracture of the stimulation well and the hydraulic fracture of the test well is 6. Then the fracture interference coefficient δ = 4 / 6 = 0.67.

[0058] The horizontal section length of the well refers to the horizontal section length of the stimulation well or the test well. When exploring the influence of the horizontal section length of the well on the bottom hole pressure change of the test well, the horizontal section lengths of the test well and the stimulation well can be set to be the same, and by increasing or decreasing the horizontal section lengths of the test well and the stimulation well simultaneously, double-logarithmic curves in different scenarios can be obtained. Figure 4Schematic diagram for comparing horizontal section lengths of different wells provided by the embodiments of the present application. As Figure 4 shown, Figure 4 (a), the horizontal section lengths of the test well and the stimulation well are less than Figure 4 (b), the horizontal section lengths of the stimulation well and the test well.

[0059] The hydraulic fracture angle refers to the angle between the hydraulic fracture of the stimulation well and the horizontal section of the stimulation well, or the angle between the hydraulic fracture of the test well and the horizontal section of the test well. Figure 5 Schematic diagram of the model under different hydraulic fracture angles provided by the embodiments of the present application. As Figure 5 shown, the hydraulic fracture angle between the hydraulic fracture of the stimulation well 501 and the horizontal section of the stimulation well 501 is 60 degrees; the hydraulic fracture angle between the hydraulic fracture of the test well 502 and the horizontal section of the test well 502 is 90 degrees. Changing the hydraulic fracture angle generally refers to changing the hydraulic fracture angle of the stimulation well.

[0060] Changing the value of the interference parameter means changing the value of the fracture interference coefficient or the well horizontal section length or the hydraulic fracture angle. For example, when exploring the influence of the fracture interference coefficient on the bottom hole pressure of the test well, multiple double-logarithmic curves are obtained by changing the value of the fracture interference coefficient; when exploring the influence of the well horizontal section length on the bottom hole pressure of the test well, multiple double-logarithmic curves are obtained by changing the value of the well horizontal section length.

[0061] S204. Compare multiple double-logarithmic curves to explain the influence degree of the interference parameter on the pressure of the test well.

[0062] After changing the value of the interference parameter, the double-logarithmic curve will change accordingly. If the interference parameter has a greater influence on the pressure of the test well, the corresponding change in the double-logarithmic curve is greater; if the interference parameter has a smaller influence on the pressure of the test well, the corresponding change in the double-logarithmic curve is smaller; if the interference parameter has no influence on the bottom hole pressure of the test well, the corresponding double-logarithmic curve does not change.

[0063] The shale oil fracturing horizontal well fracture interference numerical well testing method provided by the embodiments of the present application establishes a physical model according to the fracturing effect of the test well. The physical model includes hydraulic fractures, and by changing the interference parameters related to the hydraulic fractures, the final double-logarithmic curve changes, so that the influence degree of the interference parameter on the bottom hole pressure of the test well can be explained according to the changes between multiple double-logarithmic curves. The numerical well testing method of the present application helps to better explain the well interference phenomenon.

[0064] Figure 6 Flow schematic of the shale oil fracturing horizontal well fracture interference numerical well testing method provided by the embodiments of the present application Figure 2 . As Figure 6 shown, the method includes:

[0065] S601. Use Monte Carlo random simulation for programming calculations to randomly generate multiple natural fractures in shale oil and gas reservoirs.

[0066] Monte Carlo is a calculation method that can randomly generate multiple natural fractures. And the number of natural fractures can be set. Natural fractures refer to the fractures naturally formed in shale oil and gas reservoirs. In shale oil and gas reservoirs, natural fractures are randomly distributed. Therefore, natural fractures are randomly generated by Monte Carlo. In addition, the coordinates of natural fractures are randomly generated by Monte Carlo. By establishing natural fractures, the actual situation of shale oil and gas reservoirs can be more accurately simulated, which helps to improve the reliability of the numerical well test method for fracture interference in horizontal wells of shale oil fracturing.

[0067] S602. Based on the fracturing effect of the test well, establish a physical model of the shale oil and gas reservoir.

[0068] In a possible implementation, the physical model includes a test well, an exciting well, hydraulic fractures, natural fractures, and multiple regions;

[0069] The multiple regions include a fracture network region, an affected region, and an original reservoir. The fracture network region is the region affected by fracturing with a permeability greater than or equal to the first preset threshold. The affected region is the region affected by fracturing with a permeability less than the first preset threshold and greater than or equal to the second preset threshold. The original reservoir is the unmodified region not affected by fracturing;

[0070] Among them, the first preset threshold is greater than the second preset threshold.

[0071] The hydraulic fractures include the hydraulic fractures generated after the test well is pressured, that is, the hydraulic fractures of the test well, and also include the hydraulic fractures generated after the test well is fractured, that is, the hydraulic fractures of the test well. Natural fractures are the fractures naturally existing in shale oil and gas reservoirs. In the embodiments of the present application, the number of natural fractures and the number of hydraulic fractures are not specifically limited.

[0072] Figure 7 Schematic diagram of the physical model provided by the embodiments of the present application Figure 1 . As Figure 7 shown, the physical model includes multiple randomly generated natural fractures 701, and the shale oil and gas reservoir is divided into multiple regions. Among them, the fracture network region 702 is the most significantly affected by natural fractures and hydraulic fractures. Secondly, the affected region 703 is the region less affected by natural fractures and hydraulic fractures. The original reservoir 704 is the region not affected by natural fractures and hydraulic fractures.

[0073] By dividing the physical model into multiple regions according to the degree of influence of natural fractures and hydraulic fractures, the physical model is made closer to the actual production process of a fractured horizontal well in a shale oil and gas reservoir, which helps to improve the reliability of the numerical well test method for fracture interference in a shale oil fractured horizontal well.

[0074] In another possible implementation, the basic parameter data includes one or more of the following parameters:

[0075] The permeability of the fracture network area, the permeability of the affected area, and the permeability of the original reservoir;

[0076] The porosity of the fracture network area, the porosity of the affected area, and the porosity of the original reservoir;

[0077] The coordinates of the natural fractures, the coordinates of the connection points of the test well and the stimulation well, the wellbore radius of the test well, the compressibility coefficient, the viscosity and thickness of the shale oil and gas reservoir, the volume coefficient of the test well, and the wellbore storage coefficient of the test well.

[0078] The coordinates of the connection point of the test well refer to the coordinates of the point where the hydraulic fracture of the test well intersects with the test well when the hydraulic fractures of the test well and the stimulation well are connected; the coordinates of the connection point of the stimulation well refer to the coordinates of the point where the hydraulic fracture of the stimulation well intersects with the stimulation well when the hydraulic fractures of the stimulation well and the test well are connected.

[0079] S603. Establish a numerical model of the shale oil and gas reservoir according to the physical model.

[0080] It should be understood that the implementation of S603 is similar to Figure 2 the implementation of S202 in, and will not be elaborated here.

[0081] S604. Input the basic parameter data into the numerical model and change the values of the interference parameters to obtain multiple double-logarithmic curves under different values of the interference parameters, where the double-logarithmic curve is used to represent the corresponding relationship between the pressure of the test well and time, and the interference parameters include one or more of the fracture interference coefficient, the horizontal section length of the well, and the hydraulic fracture angle. The fracture interference coefficient is the ratio of the actual number of connected fractures between the hydraulic fractures of the test well and the stimulation well to the number of connectable fractures between the hydraulic fractures of the test well and the stimulation well.

[0082] It should be understood that the implementation of S604 is similar to Figure 2 the implementation of S203 in, and will not be elaborated here.

[0083] S605. Compare the multiple double-logarithmic curves to explain the degree of influence of the interference parameters on the pressure of the test well.

[0084] It should be understood that the implementation of S605 is similar toFigure 2 The implementation of S204 is similar and will not be elaborated here.

[0085] The following describes in detail the numerical well test method for fracture interference in shale oil and gas fracturing horizontal wells in combination with the specific process.

[0086] First, Monte Carlo random simulation is used for programming calculation. 50 natural fractures are randomly generated in the shale oil and gas reservoir, and the coordinates of some natural fractures are shown in Table 1.

[0087] Table 1 Coordinates of Some Natural Fractures

[0088]

[0089]

[0090] Then, a physical model is established, as Figure 8 shown. The physical model includes an active well 801, a test well 802, hydraulic fractures, natural fractures, and multiple regions. The multiple regions include a fracture network region 803, an affected region 804, and a virgin reservoir 805.

[0091] Next, a numerical model is established based on the above physical model, and this numerical model is the mathematical model. For different regions in the physical model, their corresponding matrix flow equations are as follows:

[0092]

[0093]

[0094]

[0095]

[0096] Among them, Equation (1) is the matrix flow equation of the fracture network region; Equation (2) is the matrix flow equation of the affected region; Equation (3) is the matrix flow equation of the virgin reservoir; Equation (4) is the matrix flow equation of the hydraulic fracture of the test well.

[0097] Km, K1, K2, and Kf are the permeabilities of the fracture network region, affected region, virgin reservoir, and hydraulic fracture, respectively, in mD; Фm, Ф1, Ф2, and Фf are the porosities of the fracture network region, affected region, virgin reservoir, and hydraulic fracture, respectively, dimensionless; pm, p1, p2, and pf are the pressures of the fracture network region, affected region, virgin reservoir, and hydraulic fracture, respectively, in atm; x and y are the coordinate systems; ξ is the local coordinate system of the fracture. Figure 9 It is a schematic diagram of the global coordinates and the local coordinates of the hydraulic fracture provided by the embodiment of the present application.

[0098] Next, input the basic parameter data into the numerical model and input the fracture interference coefficients with different values. The values of the fracture interference coefficients are 0, 0.33, 0.67, and 1 respectively, and multiple double-logarithmic curves are obtained.

[0099] Table 2 shows some of the basic parameter data as follows:

[0100] Table 2 Basic Parameter Data Table Required for the Reservoir

[0101]

[0102]

[0103] The coordinates of the connectable points of the test well and the stimulation well are shown in Table 3. By changing the coordinates of the connectable points between the test well and the stimulation well, the number of connections between the hydraulic fractures of the stimulation well and the hydraulic fractures of the test well can be adjusted, thereby changing the fracture interference coefficient.

[0104] Figure 10 It is a schematic diagram of the physical model under different fracture interference coefficients provided by the embodiment of the present application. As Figure 10 shown, the physical models with the fracture interference coefficient values of 0, 0.33, 0.67, and 1 are successively as Figure 10 (a), Figure 10 (b), Figure 10 (c), Figure 10 (d) shown.

[0105] Table 3 Connectable Point Coordinates of the Test Well and the Stimulation Well

[0106]

[0107] In the established numerical model, the physical threshold grid is made adjacent through non-adjacent connections, and the definition of the conductivity of non-adjacent parts in the calculation domain is calculated. Figure 11 It is a schematic diagram of four different connection methods provided by the embodiment of the present application. As Figure 11 shown, there are a total of four connection methods, which are successively: fracture 1102 and fracture 1102, fracture 1102 and matrix 1101, matrix 1101 and matrix 1101, fracture 1102 and well grid 1103. The above-mentioned fracture 1102 refers to the hydraulic fracture of the test well.

[0108] For the three connection methods of fracture 1102 and fracture 1102, fracture 1102 and matrix 1101, and matrix 1101 and matrix 1101, the conductivity between the grids is:

[0109]

[0110] Among them, k NNC is the permeability of the connection unit, mD; ANNC is the contact area between connection units; d NNC is the distance between connection units, m.

[0111] When the connection method is different, the above connection units are different. For example, when the connection method is between fracture 1102 and fracture 1102, the connection unit is fracture to fracture, and the corresponding k NNC is the permeability between fractures; A NNC is the contact area between fractures; d NNC is the distance between fractures.

[0112] For the connection method between fracture 1102 and well grid 1103, according to the equivalent radius concept of the well model based on steady-state flow (Peaceman well model), considering well storage and skin, the calculation formula is as follows:

[0113]

[0114]

[0115]

[0116] where, w f is the fracture aperture, m; L is the fracture unit length, m; W- is the fracture unit height, m; p e is the pressure of the grid where the well is located, MPa; p wf is the bottom-hole pressure, MPa; S is the skin factor, dimensionless; C is the wellbore storage coefficient of the test well, m 3 / MPa; WI f is the well index of the fracture, dimensionless; r w is the wellbore radius, m; r e is the equivalent radius of the well, m.

[0117] Solving the above numerical model is based on the principle of automatic differentiation, and the finite element method is used to solve formulas (1)-(4). To simplify the solution process, first, the divergence operator (div) and gradient operator (grad) programs are written through the MATLAB program, and then the fully implicit discrete forms of equations (1) to equation (4) and equation (8) are obtained:

[0118]

[0119]

[0120]

[0121]

[0122]

[0123] Then, based on the automatic differentiation technique and the Newton iteration principle, the discrete equations for each grid are obtained by combining Equation (9) to Equation (13).

[0124] The discrete method between grids can be obtained based on the conductivity equation (5), and different k values are adopted under different connection methods NNC 、A NNC 、d NNC . By synthesizing the discrete equations of each grid and between grids and programming with MATLAB, the numerical solution of the mathematical model can be obtained.

[0125] Finally, the above solution results are dimensionless processed using Formulas (14) and (15) to obtain the double logarithmic curves with different fracture interference coefficients.

[0126]

[0127]

[0128] Among them, K is the permeability of the shale oil and gas reservoir, μm 2 ; h is the thickness of the shale oil and gas reservoir, m; Φ is the porosity, in decimals; q is the surface flow rate, m 3 / d; μ is the viscosity of the crude oil, cp; B is the formation volume factor of the crude oil, m 3 / m 3 ; C t is the comprehensive formation compressibility, MPa -1 ; Δt is the production time, h; Δp is the production pressure difference of the test well, MPa.

[0129] Figure 12 This is the schematic diagram of the double logarithmic curves under different fracture interference coefficients provided by the embodiments of the present application. As Figure 12 shown, under different fracture interference coefficients, the double logarithmic curves deviate, indicating that the fracture interference coefficient has a certain influence on the production of the bottom hole pressure of the test well.

[0130] In addition, natural fractures are not introduced in the existing numerical well testing methods. Therefore, the double logarithmic curve with a fracture interference coefficient of 0 is selected, and then the natural fractures are removed to explore the influence of natural fractures on the bottom hole pressure of the test well. Figure 13 This is the schematic diagram of the double logarithmic curves with and without natural fractures provided by the embodiments of the present application. As Figure 13 shown, after removing the natural fractures, the double logarithmic curve changes greatly, indicating that the influence of natural fractures on the bottom hole pressure of the test well is relatively significant.

[0131] To explore the influence of the horizontal section length of the well and the hydraulic fracture angle on the bottom-hole pressure of the test well, the horizontal section length of the well can also be changed. For example, Figure 4 as shown, shorten or extend the horizontal length of the well, and correspondingly adopt the above physical model and numerical model establishment process to obtain multiple double-logarithmic curves. Through the changes in the double-logarithmic curves, explore the influence of the horizontal section length of the well on the bottom-hole pressure of the test well. The value of the hydraulic fracture angle can also be changed. For example, Figure 5 as shown, change the angle between the hydraulic fracture of the stimulation well and the horizontal section of the stimulation well to obtain multiple double-logarithmic curves. Through the changes in the double-logarithmic curves, explore the influence of the hydraulic fracture angle on the bottom-hole pressure of the test well. During the process of exploring the influence of the horizontal section length of the well on the bottom-hole pressure of the test well and exploring the influence of the hydraulic fracture angle on the bottom-hole pressure of the test well, the acquisition methods of multiple double-logarithmic curves are similar to the process of exploring the influence of the fracture interference coefficient on the bottom-hole pressure of the test well described above, and will not be elaborated here.

[0132] In a possible implementation manner, based on the numerical model, calculate the pressure data of the test well.

[0133] Take the pressure data as the actual well test data, and change the target parameters for the fitting of the double-logarithmic curve. The target parameters include one or more of the well storage coefficient, permeability, fracture half-length, and fracture interference coefficient.

[0134] Calculating the pressure data of the test well is the pressure data obtained after solving the above numerical model. Through this pressure data and the determined known target parameters, an initial double-logarithmic curve can be obtained. Then, using this pressure data again, change the value of the target parameter, and the double-logarithmic curve will change continuously. Continuously change the value of the target parameter until the double-logarithmic curve almost coincides with the initial double-logarithmic curve, and the fitting process ends.

[0135] Compare the target parameters corresponding to the double-logarithmic curve finally fitted with the initial double-logarithmic curve with the determined known target parameters corresponding to the initial double-logarithmic curve. Table 4 shows the comparison of the target parameters before and after the fitting process.

[0136] Table 4 Comparison of target parameters before and after the fitting process

[0137] Parameter Actual Value Fitted Value <![CDATA[Well storage coefficient C (m 3 / MPa)]]> 0.230592 0.338809 Permeability K (mD) 0.1 0.0620904 <![CDATA[Fracture half-length X f (m)]]> 100 156.311 Fracture Interference Coefficient δ (Decimal) 0.33 0.33

[0138] Figure 14 This is a schematic diagram of the double-logarithmic curve before and after the fitting process provided by the embodiment of the present application. As Figure 14 shown, before and after the fitting, the double-logarithmic curves basically coincide. At the same time, it can be seen from Table 4 that the difference in the values of the target parameters before and after the fitting is small, indicating that the shale oil fracturing horizontal well fracture interference numerical well test method provided by the embodiment of the present application has high reliability.

[0139] Figure 15 This is a schematic structural diagram of the shale oil and gas fracturing horizontal well fracture interference numerical well test device 150 provided by the embodiments of the present application. As Figure 15 shown, the device 150 includes: a first establishment module 1501, a second establishment module 1502, an input module 1503, and a comparison module 1504.

[0140] The first establishment module 1501 is configured to establish a physical model of the shale oil and gas reservoir based on the fracturing effect of the test well;

[0141] The second establishment module 1502 is configured to establish a numerical model of the shale oil and gas reservoir according to the physical model;

[0142] The input module 1503 is configured to input basic parameter data into the numerical model and change the values of the interference parameters to obtain multiple double-logarithmic curves under different values of the interference parameters, where the double-logarithmic curve is used to represent the correspondence between the pressure and time of the test well, and the multiple interference parameters include one or more of a fracture interference coefficient, a well horizontal section length, and a hydraulic fracture angle. The fracture interference coefficient is the ratio of the actual number of connected fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well to the number of connectable fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well;

[0143] The comparison module 1504 is configured to compare the multiple double-logarithmic curves to explain the influence degree of the interference parameters on the shale oil and gas reservoir.

[0144] Optionally, the above device 150 further includes:

[0145] A programming calculation module, configured to perform programming calculations using Monte Carlo stochastic simulation to randomly generate multiple natural fractures in the shale oil and gas reservoir.

[0146] Optionally, the physical model includes a test well, a stimulation well, a hydraulic fracture, a natural fracture, and multiple regions;

[0147] The multiple regions include a fracture network region, an affected region, and an original reservoir. The fracture network region is a region affected by fracturing with a permeability greater than or equal to a first preset threshold. The affected region is a region affected by fracturing with a permeability less than the first preset threshold and greater than or equal to a second preset threshold. The original reservoir is an untransformed region not affected by fracturing;

[0148] Wherein, the first preset threshold is greater than the second preset threshold.

[0149] Optionally, the basic parameter data includes one or more of the following parameters:

[0150] The permeability of the fracture network region, the permeability of the affected region, and the permeability of the original reservoir;

[0151] The porosity of the fracture network area, the porosity of the affected area, and the porosity of the original reservoir;

[0152] The coordinates of natural fractures, the coordinates of the connection points of the test well and the stimulation well, the wellbore radius of the test well, the compressibility, the viscosity and thickness of the shale oil and gas reservoir, the volume factor of the test well, and the wellbore storage coefficient of the test well.

[0153] Optionally, the above device 150 further includes:

[0154] A calculation module for calculating the pressure data of the test well based on the numerical model;

[0155] Taking the pressure data as actual well test data, changing target parameters for fitting of the double logarithmic curve, where the target parameters include one or more of the well storage coefficient, permeability, fracture half-length, and fracture interference coefficient.

[0156] The shale oil fracturing horizontal well fracture interference numerical well test device provided by the embodiments of the present application is applicable to the above method embodiments and will not be elaborated herein.

[0157] An electronic device is provided in an embodiment of the present application, as Figure 16 shown, Figure 16 The electronic device 160 shown includes: a processor 1601 and a memory 1602. Among them, the processor 1601 and the memory 1602 are connected, such as connected through a bus 1603. Optionally, the electronic device 160 may further include a transceiver 1604. It should be noted that in practical applications, the transceiver 1604 is not limited to one, and the structure of this electronic device does not constitute a limitation to the embodiments of the present application.

[0158] The processor 1601 may be a CPU (Central Processing Unit, central processor 1601), a general-purpose processor 1601, a DSP (Digital Signal Processor, data signal processor 1601), an ASIC (Application Specific Integrated Circuit, application-specific integrated circuit), an FPGA (Field Programmable Gate Array, field programmable gate array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute various exemplary logical blocks, modules, and circuits described in combination with the disclosed content of the present application. The processor 1601 may also be a combination for implementing computing functions, such as a combination including one or more microprocessors 1601, a combination of a DSP and a microprocessor 1601, etc.

[0159] The bus 1603 may include a path for transmitting information among the above components. The bus 1603 can be a PCI (Peripheral Component Interconnect) bus 1603 or an EISA (Extended Industry Standard Architecture) bus 1603, etc. The bus 1603 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 16 only a thick line is used in Figure 16 , but it does not mean that there is only one bus 1603 or one type of bus 1603.

[0160] The memory 1602 can be a ROM (Read Only Memory) or other types of static storage devices that can store static information and instructions, a RAM (Random Access Memory) or other types of dynamic storage devices that can store information and instructions, or it can also be an EEPROM (Electrically Erasable Programmable Read Only Memory), a CD-ROM (Compact Disc Read Only Memory), or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto.

[0161] The memory 1602 is used to store the application program code for implementing the solution of this application, and is controlled by the processor 1601 for execution. The processor 1601 is used to execute the application program code stored in the memory 1602 to implement the content shown in the foregoing method embodiments.

[0162] Among them, the electronic device includes but is not limited to: mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Tablet Computers), PMPs (Portable Multimedia Players), in-vehicle terminals (such as in-vehicle navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. It can also be a server, etc. Figure 16 The electronic device shown is only an example and should not impose any limitations on the functions and usage scope of the embodiments of the present disclosure.

[0163] An embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program runs on a computer, the computer can execute the corresponding content in the foregoing method embodiment.

[0164] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include well-known common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of the present application are pointed out by the claims.

[0165] It should be understood that the present application is not limited to the exact structures already described 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 numerical well testing method and device for fracture interference in shale oil fracturing horizontal wells, characterized in that, comprising: Based on the fracturing effect of the test well, establish a physical model of the shale oil and gas reservoir; According to the physical model, establish a numerical model of the shale oil and gas reservoir; Input the basic parameter data into the numerical model, and change the value of the interference parameter to obtain multiple double logarithmic curves under different values of the interference parameter. Among them, the double logarithmic curve is used to represent the corresponding relationship between the pressure and time of the test well. The interference parameter includes one or more of the fracture interference coefficient, the length of the horizontal section of the well, and the hydraulic fracture angle. The fracture interference coefficient is the ratio of the actual number of connected fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well to the number of connectable fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well; Compare the multiple double logarithmic curves to explain the influence degree of the interference parameter on the pressure of the test well.

2. The method according to claim 1, characterized in that, Before establishing the physical model of the shale oil and gas reservoir based on the fracturing effect of the test well, the method further includes: Use Monte Carlo random simulation for programming calculation to randomly generate multiple natural fractures in the shale oil and gas reservoir.

3. The method according to claim 2, characterized in that, The physical model includes the test well, the stimulation well, hydraulic fractures, natural fractures and multiple regions; The multiple regions include a fracture network region, an affected region and an original reservoir. The fracture network region is a region affected by fracturing with a permeability greater than or equal to a first preset threshold. The affected region is a region affected by fracturing with a permeability less than the first preset threshold and greater than or equal to a second preset threshold. The original reservoir is an untransformed region not affected by fracturing; Wherein, the first preset threshold is greater than the second preset threshold.

4. The method according to claim 3, characterized in that, The basic parameter data includes one or more of the following parameters: The permeability of the fracture network region, the permeability of the affected region and the permeability of the original reservoir; The porosity of the fracture network region, the porosity of the affected region and the porosity of the original reservoir; The coordinates of the natural fractures, the connection point coordinates of the test well and the stimulation well, the wellbore radius of the test well, the compressibility, the viscosity and thickness of the shale oil and gas reservoir, the volume coefficient of the test well and the wellbore storage coefficient of the test well.

5. The method according to any one of claims 1 to 4, characterized in that, The method further includes: Based on the numerical model, calculate the pressure data of the test well; Use the pressure data as the actual well test data, and change the target parameter to fit the double logarithmic curve. The target parameter includes one or more of the well storage coefficient, permeability, fracture half-length and fracture interference coefficient.

6. A numerical well testing device for fracture interference in shale oil fracturing horizontal wells, comprising: A first establishment module for establishing a physical model of the shale oil and gas reservoir based on the fracturing effect of the test well; A second establishment module, configured to establish a numerical model of the shale oil and gas reservoir according to the physical model; An input module, configured to input basic parameter data into the numerical model and change the values of interference parameters, so as to obtain multiple double-logarithmic curves under different values of the interference parameters, where the double-logarithmic curves are used to represent the correspondence between the pressure and time of the test well, and the multiple interference parameters include one or more of a fracture interference coefficient, a horizontal section length of the well, and a hydraulic fracture angle, and the fracture interference coefficient is the ratio of the actual number of connected fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well to the number of connectable fractures between the hydraulic fracture of the test well and the hydraulic fracture of the stimulation well; A comparison module, configured to compare the multiple double-logarithmic curves to explain the influence degree of the interference parameters on the shale oil and gas reservoir.

7. The device according to claim 6, wherein, the device further includes: A programming calculation module, configured to perform programming calculations using Monte Carlo random simulation to randomly generate multiple natural fractures in the shale oil and gas reservoir.

8. The device according to claim 7, wherein, the physical model includes the test well, the stimulation well, hydraulic fractures, natural fractures, and multiple regions; the multiple regions include a fracture network region, an affected region, and an original reservoir. The fracture network region is a region affected by fracturing with a permeability greater than or equal to a first preset threshold. The affected region is a region affected by fracturing with a permeability less than the first preset threshold and greater than or equal to a second preset threshold. The original reservoir is an unmodified region not affected by fracturing; wherein, the first preset threshold is greater than the second preset threshold.

9. An electronic device, wherein, it includes: at least one processor and a memory; the memory stores computer-executable instructions; the at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor executes the shale oil fracturing horizontal well fracture d interference numerical well test method according to any one of claims 1-5.

10. A computer-readable storage medium, wherein, the computer-readable storage medium stores computer-executable instructions, and when the computer-executable instructions are executed by a processor, they are used to implement the shale oil fracturing horizontal well fracture interference numerical well test method according to any one of claims 1-5.

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