Probe coefficient acquisition method and device in pressure pretest, equipment and medium

Abstract

The invention discloses a method, a device, equipment and a medium for acquiring a probe coefficient in pressure pretest, and the method comprises the steps: determining the incidence relation between the probe coefficient and a target pressure related parameter according to the incidence relation between the fluidity of a pressure drop method and the steady-state flow pressure of a probe; based on an analytical solution of a pressure equation of the probe or a numerical solution of an oil reservoir simulation probe pretest process, extrapolating time to infinity for calculation to obtain target pressure related parameters; and determining the probe coefficient according to the incidence relation between the probe coefficient and the target pressure related parameter and the target pressure related parameter. According to the invention, accurate determination of the probe coefficients is realized, the application range is wide, and the probe coefficients of various types of probes can be determined by using the scheme.

Description

Technical Field

[0001] The invention relates to the field of oil well exploration, and in particular to a method, a device, equipment and a medium for obtaining a probe coefficient in a pressure pre-test. Background Art

[0002] In the field of oil well exploration, it is necessary to conduct pre-testing during the formation testing phase. The main objectives of the pre-testing are: (1) to obtain the pressure gradient by measuring the true formation pressure; (2) to calculate the near-wellbore fluidity. When calculating the near-wellbore fluidity, it is necessary to pre-test the probe shape factor coefficient (Probe Shape Factor), referred to as the probe coefficient. In the prior art, the commonly used method for obtaining the probe coefficient is to estimate it by referring to literature data. However, in actual applications, the geometric shapes and sizes of the probes vary. It is difficult to obtain an accurate probe coefficient using the existing probe coefficient acquisition method, which in turn affects the accuracy of the fluidity calculation. Summary of the invention

[0003] In view of the above problems, the present invention is proposed to provide a method, device, equipment and medium for obtaining probe coefficients in pressure pre-testing that overcome the above problems or at least partially solve the above problems.

[0004] According to one aspect of an embodiment of the present application, a method for obtaining a probe coefficient in a pressure pretest is provided, the method comprising: According to the correlation between the flow rate of the pressure drop method and the steady-state flow pressure of the probe, the correlation between the probe coefficient and the target pressure-related parameters is determined; Based on the analytical solution of the pressure equation of the probe or the numerical solution of the pre-test process of the reservoir simulation probe, the time is extrapolated to infinity for calculation to obtain the target pressure related parameters; The probe coefficient is determined according to the correlation between the probe coefficient and the target pressure related parameters and the target pressure related parameters.

[0005] Furthermore, the correlation between the mobility of the pressure drop method and the steady-state flow pressure of the probe is expressed as:

[0006] Where m represents mobility; k represents formation permeability; μ represents fluid viscosity; h represents reservoir thickness; p ssD represents the dimensionless pressure of steady-state flow; q represents the pump flow rate; Δp dd Indicates the pre-test pressure difference; C pf Represents the probe coefficient.

[0007] Furthermore, when the target pressure-related parameter is the dimensionless pressure of the steady-state flow, the correlation between the probe coefficient and the target pressure-related parameter is expressed as:

[0008] Among them, C pf represents the probe coefficient; h represents the reservoir thickness; p ssD Represents the dimensionless pressure for steady-state flow.

[0009] Furthermore, based on the analytical solution of the pressure equation of the probe or the numerical solution of the reservoir simulation probe pre-test process, the time is extrapolated to infinity for calculation, and the target pressure related parameters are further obtained, including: Based on the analytical solution of the pressure equation of the probe, the time in the analytical solution is extrapolated to infinity for calculation to obtain the dimensionless pressure of steady flow; Among them, the analytical solution of the pressure equation of the probe is obtained by solving the pressure diffusion equation and boundary conditions.

[0010] Furthermore, when the target pressure-related parameter is the pre-tested pressure difference, the correlation relationship between the probe coefficient and the target pressure-related parameter is expressed as:

[0011] Among them, C pf represents the probe coefficient; m represents the fluidity; Δp dd represents the pre-test pressure difference; q represents the pump flow rate; k represents the formation permeability; μ represents the fluid viscosity.

[0012] Furthermore, based on the analytical solution of the pressure equation of the probe or the numerical solution of the reservoir simulation probe pre-test process, the time is extrapolated to infinity for calculation, and the target pressure related parameters are further obtained, including: Based on the numerical solution of the reservoir simulation probe pre-test process, the spherical flow pressure difference in the numerical solution is extrapolated to time infinity for calculation to obtain the pre-test pressure difference; Among them, the numerical solution of the reservoir simulation probe pre-test process is the correlation between time and spherical flow pressure difference determined by numerical simulation of different probe types within different parameter ranges.

[0013] According to another aspect of an embodiment of the present application, a probe coefficient acquisition device in a pressure pre-test is provided, the device comprising: A first determination module is adapted to determine a correlation between a probe coefficient and a target pressure-related parameter based on a correlation between the fluidity of a pressure drop method and a probe steady-state flow pressure; A calculation module, suitable for the analytical solution of the pressure equation based on the probe or the numerical solution of the reservoir simulation probe pre-test process, extrapolating the time to infinity for calculation to obtain the target pressure related parameters; The second determination module is adapted to determine the probe coefficient according to the correlation relationship between the probe coefficient and the target pressure related parameter and the target pressure related parameter.

[0014] According to another aspect of the embodiment of the present application, there is provided a computing device, including: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the probe coefficient acquisition method in the above-mentioned pressure pre-test.

[0015] According to another aspect of the embodiment of the present application, a computer storage medium is provided, in which at least one executable instruction is stored, and the executable instruction enables a processor to perform operations corresponding to the probe coefficient acquisition method in the above-mentioned stress pre-test.

[0016] According to another aspect of an embodiment of the present application, a computer program product is provided, comprising at least one executable instruction, wherein the executable instruction enables a processor to perform operations corresponding to the probe coefficient acquisition method in the above-mentioned stress pre-test.

[0017] According to the technical solution provided by the present invention, based on the correlation between the fluidity of the pressure drop method and the steady-state flow pressure of the probe, the correlation between the probe coefficient and the target pressure-related parameters can be accurately determined; based on the analytical solution of the pressure equation of the probe or the numerical solution of the reservoir simulation probe pre-test process, the target pressure-related parameters can be conveniently obtained by extrapolating time to infinity for calculation, and then the probe coefficient can be determined according to the correlation between the probe coefficient and the target pressure-related parameters and the target pressure-related parameters, thereby achieving accurate determination of the probe coefficient. The solution has a wide range of applications, and various types of probes can use the solution to determine their probe coefficients. The determined probe coefficient can be used in the fluidity calculation of the pre-test process, which helps to improve the accuracy and reliability of the fluidity calculation, and thus obtain accurate formation permeability.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1 A schematic diagram of a flow chart of a method for acquiring probe coefficients in a pressure pre-test according to an embodiment of the present application is shown; Figure 2 A schematic diagram showing the relationship between pressure response and time during the pre-testing process of the cable and the formation tester while drilling is shown; Figure 3 A schematic diagram of an oil well / reservoir system is shown; Figure 4 A schematic diagram of a standard circular probe is shown; Figure 5 The results of the analytical solution of the pre-test under the condition of 1000mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 1 ; Figure 6 The results of the analytical solution of the pre-test under the condition of 100mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 1 ; Figure 7 The results of the analytical solution of the pre-test under the condition of 10mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 1 ; Figure 8 The results of the analytical solution of the pre-test under the condition of 1mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 1 ; Fig. 9 A schematic diagram of a large suction port elliptical probe is shown; Fig.10 The results of the analytical solution of the pre-test under the condition of 1000mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 2 ; Fig.11 The results of the analytical solution of the pre-test under the condition of 100mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 2 ; Fig.12 The results of the analytical solution of the pre-test under the condition of 10mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 2 ; Fig.13 The results of the analytical solution of the pre-test under the condition of 1mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 2 ; Fig.14 A schematic diagram of an extra-large suction port elliptical probe is shown; Fig.15The results of the analytical solution of the pre-test under the condition of 1000mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 3 ; Fig.16 The results of the analytical solution of the pre-test under the condition of 100mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 3 ; Fig.17 The results of the analytical solution of the pre-test under the condition of 10mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 3 ; Fig.18 The results of the analytical solution of the pre-test under the condition of 1mD formation permeability and the numerical solution of the reservoir simulation probe pre-test process are shown. Figure 3 ; Fig.19 A structural block diagram of a probe coefficient acquisition device in a pressure pre-test according to an embodiment of the present application is shown; Fig. 20 A schematic diagram of the structure of a computing device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0020] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0021] Figure 1 FIG. 1 is a flow chart showing a method for obtaining probe coefficients in a pressure pre-test according to an embodiment of the present application. Figure 1 As shown, the method comprises the following steps: Step S101, determining the correlation between the probe coefficient and target pressure related parameters according to the correlation between the flow rate of the pressure drop method and the steady-state flow pressure of the probe.

[0022] In order to facilitate the analysis of the relationship between the fluidity and the probe coefficient of the pressure drop method, the pre-test process of the cable and the formation tester while drilling is introduced below. Figure 2 The schematic diagram of the relationship between pressure response and time during the pre-test of the cable and the formation tester while drilling is shown. Figure 2 As shown, the pre-test process of the cable and the formation tester while drilling can be divided into five stages, which are the instrument placement stage, the sealing stage, the pressure drop stage, the pressure recovery stage and the pressure measurement stop stage.

[0023] 1) Instrument placement stage: Place the formation tester to the measuring depth point in the well. The pressure measured at this time is the mud column pressure before measurement.

[0024] 2) Sealing stage: Push the probe against the well wall to form a seal with the well wall.

[0025] 3) Pressure drop stage: At a constant rate, the piston in the formation tester is moved to increase the volume of the pipeline, thereby reducing the pipeline pressure. Figure 2 At time t1 in the figure, the reservoir fluid cannot flow into the pipeline because the pressure is greater than the reservoir pressure. The corresponding expansion volume V1 is not the reservoir fluid (usually V1 is less than 1cm 3 ), this process is called flowline decompression. When the pressure is lower than the reservoir pressure (corresponding to Figure 2 At time t2 in the flow chart, the reservoir fluid begins to flow in, and the pipeline pressure drop will approach the steady state exponentially. In the late stage of pressure drop, spherical steady flow is achieved under long time and low rate. The effective test volume of formation fluid is V2, which is not equal to the total volume V=V1+V2.

[0026] 4) Pressure recovery phase: Stop moving the piston (corresponding to Figure 2 The pressure is restored to the reservoir pressure exponentially at time t3. The early stage of pressure recovery depends on pipeline storage (Flowline Storage) and measurement tools (such as pressure measuring instruments), and the later stage forms spherical and / or radial flow (corresponding to Figure 2 time t4).

[0027] 5) Stop pressure measurement stage: The pressure measured at this time is the mud column pressure after measurement.

[0028] Goode and Thambynayagam et al. proposed a correlation between the flow rate of the pressure drop method and the steady-state flow pressure of the probe in 1992. The correlation is expressed as:

[0029] Where m represents mobility; k represents formation permeability; μ represents fluid viscosity; h represents reservoir thickness; p ssD represents the dimensionless pressure of steady-state flow; q represents the pump flow rate; Δp dd Indicates the pre-test pressure difference; C pf Represents the probe coefficient.

[0030] In the embodiment of the present application, the target pressure-related parameter may be a dimensionless pressure of a steady-state flow or a pre-tested pressure difference.

[0031] Specifically, when the target pressure-related parameter is the dimensionless pressure of steady-state flow, the correlation between the probe coefficient and the dimensionless pressure of steady-state flow can be determined based on the correlation between the mobility of the pressure drop method and the steady-state flow pressure of the probe. The correlation is expressed as:

[0032] Among them, C pf represents the probe coefficient; h represents the reservoir thickness; p ssD Represents the dimensionless pressure for steady-state flow.

[0033] When the unit of h is in (inch), the unit of k is mD, the unit of μ is cP, and the unit of q is cm 3 / s, we can get:

[0034] According to the correlation between the probe coefficient and the dimensionless pressure of steady-state flow, if the analytical solution of the dimensionless pressure of steady-state flow can be obtained, the probe coefficient can be obtained.

[0035] When the target pressure-related parameter is the pre-test pressure difference, the correlation between the probe coefficient and the pre-test pressure difference can be determined based on the correlation between the flow rate of the pressure drop method and the steady-state flow pressure of the probe. The correlation is expressed as:

[0036] Among them, C pf represents the probe coefficient; m represents the fluidity; Δp dd represents the pre-test pressure difference; q represents the pump flow rate; k represents the formation permeability; μ represents the fluid viscosity.

[0037] Step S102, based on the analytical solution of the pressure equation of the probe or the numerical solution of the reservoir simulation probe pre-test process, the time is extrapolated to infinity for calculation to obtain the target pressure related parameters.

[0038] Step S103, determining the probe coefficient according to the correlation relationship between the probe coefficient and the target pressure related parameter and the target pressure related parameter.

[0039] When the target pressure-related parameter is the dimensionless pressure of steady-state flow, the time in the analytical solution can be extrapolated to infinity for calculation based on the analytical solution of the pressure equation of the probe to obtain the dimensionless pressure of steady-state flow, and then the probe coefficient is determined by combining the correlation between the probe coefficient determined in step S101 and the dimensionless pressure of steady-state flow; when the target pressure-related parameter is the pre-test pressure difference, the spherical flow pressure difference in the numerical solution can be extrapolated to infinity for calculation based on the numerical solution of the pre-test process of the reservoir simulation probe to obtain the pre-test pressure difference, and then the probe coefficient is determined by combining the correlation between the probe coefficient determined in step S101 and the pre-test pressure difference.

[0040] The following is a detailed introduction to the method of obtaining the probe coefficient based on the analytical solution of the pressure equation of the probe and the method of obtaining the probe coefficient based on the numerical solution of the reservoir simulation probe pre-test process.

[0041] (1) The method of obtaining the probe coefficient based on the analytical solution of the pressure equation of the probe: The analytical solution of the pressure equation of the probe is obtained by solving the pressure diffusion equation and boundary conditions. Specifically, the boundary conditions include upper and lower boundary conditions and constant pressure boundary conditions. The time in the analytical solution of the pressure equation of the probe is extrapolated to infinity for calculation to obtain the dimensionless pressure of the steady-state flow.

[0042] Figure 3 A schematic diagram of an oil well / reservoir system is shown, such as Figure 3 As shown, the vertical height of the inclined well from the bottom of the reservoir is D b , in inches; the perforation length of the well is L w , in inches; the angle of inclination is θ. The upper and lower boundary conditions can be no flow or constant pressure. The reservoir thickness is h, in inches; the vertical permeability of the formation is k v , unit is mD; the horizontal permeability of the formation is k h , in mD. In the embodiment of the present application, the pressure diffusion of the formation test can be regarded as the liquid flowing into the wellbore in a plane radial direction in the infinite formation, and propagating to the reservoir in a hemispherical manner in space. The medium flowing in the pores is a single-phase slightly compressible liquid. Taking the cylindrical coordinate system, since the shape of the source can be regarded as a point source relative to the infinite formation, the pressure diffusion equation is obtained:

[0043] Where p is the pressure at the probe, in psi; r is the radial distance in the cylindrical coordinate system, in in; θ is the azimuth angle in the cylindrical coordinate system, dimensionless; z is the height in the cylindrical coordinate system, in in; represents the formation porosity, the unit is %; μ represents the fluid viscosity, the unit is cP; c tIndicates the fluid compressibility coefficient in psi -1 ;k v Indicates the vertical permeability of the formation, in mD; k h represents the horizontal permeability of the formation in mD; t represents time. In SI (International System of Units) units, the constant 0.0002637 needs to be converted to 1.

[0044] The pressure diffusion equation describes the radial flow of a slightly compressible liquid with a constant compressibility coefficient in a porous medium, or in this case, the pressure distribution in the reservoir p=p(r,θ,z,t) is the pressure (in psi) at a distance from the well (r,θ,z) at time t (in seconds). For the upper and lower boundaries of the formation, when the pressure caused by the flow of the fluid propagates in the formation and encounters an impermeable formation, that is, z=0 and z=h, the pressure is constant or there is no flow, that is, the upper and lower boundary conditions, expressed as:

[0045] p(r,θ,z,t)| z=0 =p i p(r,θ,z,t)| z=h =p i Among them, p i Indicates formation pressure in psi.

[0046] For an infinite formation, the liquid flows radially toward the wellbore in a plane. It is assumed that the pressure in the formation is balanced and equal to the original formation pressure, that is, the pressure in the definition domain is p i , so the initial condition is obtained, expressed as: p(r,θ,z,t)| t=0 =p i For the relative infinity, the pressure remains unchanged, that is, the constant pressure boundary condition is expressed as:

[0047] The production (pumping) conditions are expressed as:

[0048] Among them, q w Indicates the pump flow rate in cm 3 / s;L w The integral term represents the fluid pumping rate per unit well length. In SI units, the constant 0.001127 needs to be converted to 1.

[0049] By solving the above pressure diffusion equation, the analytical solution of the pressure equation of the probe can be obtained. Goode and Thambynayagam proposed in 1992 that for unbounded homogeneous reservoirs, under the condition of no flow in the wellbore, the dimensionless analytical solution of the point source pressure equation is:

[0050] In the formula, , , ,

[0051] G(θ,β) can be obtained by numerical integration:

[0052] Among them, p D represents dimensionless pressure; t D represents dimensionless time; θ represents the azimuth angle of the cylindrical coordinate system; z D represents dimensionless distance; h D represents the dimensionless reservoir thickness; α and β represent dummy variables; k represents the formation permeability, in mD; r w Indicates the well diameter, in inches; Δp indicates the difference between the formation pressure and the pressure at the probe, in psi; q indicates the pump flow rate, in cm 3 / s; μ represents fluid viscosity, in cP; t represents time, in s; Indicates the formation porosity, unit is %; c t Indicates the fluid compressibility coefficient in psi -1 ; z represents the height of the cylindrical coordinate system, in inches; k h Indicates the horizontal permeability of the formation, in mD; k v represents the vertical permeability of the formation, in mD; h represents the reservoir thickness, in in; G (θ, β) is a wellbore response function defined; represents the nth-order derivative of the Bessel function of the first kind; represents the nth-order derivative of the Bessel function of the second kind.

[0053] Then according to the above formulas, the dimensionless pressure p of the steady flow can be obtained ssD for:

[0054] After the steady-state flow dimensionless pressure is obtained by the analytical solution of the pressure equation based on the probe, the steady-state flow dimensionless pressure is substituted into the correlation between the probe coefficient determined in step S101 and the steady-state flow dimensionless pressure to calculate the probe coefficient.

[0055] For a radius of r p The effective probe radius is r e= r p / 1.414. In the model based on analytical solution, the effective probe radius is used. The determination of the effective probe radius needs to consider the influence of wellbore, probe shape, etc. on the descending flow. According to the correlation between the probe coefficient and the dimensionless pressure of steady flow, the probe coefficient of the circular probe can be calculated.

[0056] For elliptical probes, the dimensionless analytical solution of the line source pressure equation can be used to obtain the dimensionless pressure of steady flow, and then the probe coefficient of the elliptical probe can be determined based on the correlation between the probe coefficient and the dimensionless pressure of steady flow and the dimensionless pressure of steady flow. Among them, the dimensionless analytical solution of the line source pressure equation has one more integral than the dimensionless analytical solution of the point source pressure equation.

[0057] (2) Method for obtaining probe coefficients based on the numerical solution of the reservoir simulation probe pre-test process: Among them, the numerical solution of the reservoir simulation probe pre-test process is the correlation between time and spherical flow pressure difference determined by numerical simulation of different probe types within different parameter ranges. Probe types can be divided according to the geometric shape and size of the probe. Using reservoir simulation software, a large number of numerical simulations are performed for different probe types within different parameter ranges; based on a large amount of simulation data, the maximum pressure of the spherical flow is determined (that is, the pressure of the spherical flow is extrapolated to time infinity); then the probe coefficient is determined based on the flow calculation method of steady-state flow.

[0058] Specifically, a large number of pre-test simulation cases were conducted under constant pumping flow conditions over a wide range of parameters using reservoir simulation software for different probe types. The correlation between time t and spherical flow pressure difference Δp was determined from the simulation case results, and then t was extrapolated to infinity to obtain the pre-test pressure difference Δp dd Since the pre-tested pressure difference Δp is known dd , fluidity m and pumping flow rate q, then the probe coefficient can be determined according to the correlation between the probe coefficient determined in step S101 and the pre-tested pressure difference.

[0059] Taking several probe types as examples, the following compares the results of the probe coefficient acquisition method based on the analytical solution of the pressure equation of the probe and the probe coefficient acquisition method based on the numerical solution of the reservoir simulation probe pre-test process.

[0060] For a standard circular probe, the schematic diagram of a standard circular probe can be as follows: Figure 4As shown. The probe coefficient obtained by the analytical solution of the pressure equation based on the probe is 2424. In order to verify the difference between the analytical solution and the numerical solution of the reservoir simulation probe pre-test process, the pre-test numerical simulation was carried out under the conditions of formation permeabilities of 1000mD, 100mD, 10mD and 1mD respectively, with the pumping flow rate being a constant value. The log-log plot of the pressure difference and its derivative versus time during the pressure drop process is shown as follows: Figures 5 to 8 As shown, Figures 5 to 8 The solid line in is the result of analytical solution, and the dots and diamonds are the results of numerical solution of reservoir simulation. Specifically, PTA_dP represents the pressure obtained based on analytical solution; PTA_dP' represents the derivative of pressure obtained based on analytical solution; ECL_dP represents the pressure obtained based on numerical solution; ECL_dP' represents the derivative of pressure obtained based on numerical solution. Figures 5 to 8 It can be seen that there are some differences between the analytical solution and the numerical solution in the initial short time; when the spherical flow is reached (the pressure difference derivative is -0.5), the difference between the two is very small.

[0061] The probe coefficient of the standard circular probe was tested using analytical and numerical solutions, and the results are shown in Table 1. Assuming that the probe coefficient of the standard circular probe is 2424, the fluidity and formation permeability can be calculated using the correlation between the fluidity of the pressure drop method and the steady-state flow pressure of the probe. Then, the calculated fluidity and the actual fluidity are compared, and the error between the two is calculated. According to Table 1, the average error of the fluidity calculated using the analytical solution is less than 0.2%; the average error of the fluidity calculated using the numerical solution is less than 3.8%. The results are satisfactory.

[0062] Table 1 Test results of the probe coefficient of the standard circular probe using analytical and numerical solutions

[0063] For the large suction port elliptical probe, the schematic diagram of the large suction port elliptical probe can be as follows: Fig. 9 As shown. The probe coefficient obtained by the analytical solution of the pressure equation based on the probe is 741. In order to verify the difference between the analytical solution and the numerical solution of the reservoir simulation probe pre-test process, the pre-test numerical simulation was carried out under the conditions of formation permeabilities of 1000mD, 100mD, 10mD and 1mD respectively, with the pumping flow rate being a constant value. The log-log plot of the pressure difference and its derivative versus time during the pressure drop process is shown in Figures 10 to 13 As shown, Figures 10 to 13The solid line in is the result of analytical solution, and the dots and diamonds are the results of numerical solution of reservoir simulation. Specifically, PTA_dP represents the pressure obtained based on analytical solution; PTA_dP' represents the derivative of pressure obtained based on analytical solution; ECL_dP represents the pressure obtained based on numerical solution; ECL_dP' represents the derivative of pressure obtained based on numerical solution. Figures 10 to 13 It can be seen that there are some differences between the analytical solution and the numerical solution in the initial short time; when the spherical flow is reached (the pressure difference derivative is -0.5), the difference between the two is very small.

[0064] The probe coefficient of the large suction elliptical probe was tested using analytical and numerical solutions, and the results are shown in Table 2. Assuming that the probe coefficient 741 of the probe is true, the fluidity and formation permeability can be calculated using the correlation between the fluidity of the pressure drop method and the steady-state flow pressure of the probe, and then the calculated fluidity and the actual fluidity are compared, and the error between the two is calculated. According to Table 2, the average error of the fluidity calculated using the analytical solution is less than 0.6%; the average error of the fluidity calculated using the numerical solution is less than 5.1%. The results are satisfactory.

[0065] Table 2 Test results of the probe coefficient of the large suction port elliptical probe using analytical and numerical solutions

[0066] For the extra-large suction oval probe, the schematic diagram of the extra-large suction oval probe can be as follows Fig.14 As shown. The probe coefficient obtained by the analytical solution of the pressure equation based on the probe is 570. In order to verify the difference between the analytical solution and the numerical solution of the reservoir simulation probe pre-test process, the pre-test numerical simulation was carried out under the conditions of formation permeabilities of 1000mD, 100mD, 10mD and 1mD respectively, with the pumping flow rate being a constant value. The log-log plot of the pressure difference and its derivative versus time during the pressure drop process is shown in Figures 15 to 18 As shown, Figures 15 to 18 The solid line in is the result of analytical solution, and the dots and diamonds are the results of numerical solution of reservoir simulation. Specifically, PTA_dP represents the pressure obtained based on analytical solution; PTA_dP' represents the derivative of pressure obtained based on analytical solution; ECL_dP represents the pressure obtained based on numerical solution; ECL_dP' represents the derivative of pressure obtained based on numerical solution. Figures 15 to 18 It can be seen that there are some differences between the analytical solution and the numerical solution in the initial short time; when the spherical flow is reached (the pressure difference derivative is -0.5), the difference between the two is very small.

[0067] The probe coefficient of the super-large suction elliptical probe was tested using analytical solutions and numerical solutions, and the results are shown in Table 3. Assuming that the probe coefficient of the super-large suction elliptical probe is 570, the fluidity and formation permeability can be calculated using the correlation between the fluidity of the pressure drop method and the steady-state flow pressure of the probe, and then the calculated fluidity and the actual fluidity are compared, and the error between the two is calculated. According to Table 3, the average error of the fluidity calculated using the analytical solution is less than 0.8%; the average error of the fluidity calculated using the numerical solution is less than 0.6%. The results are satisfactory.

[0068] Table 3 Test results of the probe coefficient of the super-large suction port elliptical probe using analytical and numerical solutions

[0069] For other types of probes, their probe coefficients can also be calculated in the above manner, which will not be described in detail here.

[0070] According to the method for obtaining the probe coefficient in the pressure pretest provided in the embodiment of the present application, based on the correlation between the fluidity of the pressure drop method and the steady-state flow pressure of the probe, the correlation between the probe coefficient and the target pressure-related parameters can be accurately determined; based on the analytical solution of the pressure equation of the probe or the numerical solution of the reservoir simulation probe pretest process, the target pressure-related parameters can be conveniently obtained by extrapolating time to infinity for calculation, and then the probe coefficient can be determined based on the correlation between the probe coefficient and the target pressure-related parameters and the target pressure-related parameters, thereby achieving accurate determination of the probe coefficient. This scheme has a wide range of applications, and various types of probes can use this scheme to determine their probe coefficients. The determined probe coefficient can be used in the fluidity calculation of the pretest process, which helps to improve the accuracy and reliability of the fluidity calculation, and thus obtain accurate formation permeability.

[0071] Fig.19 FIG. 4 shows a structural block diagram of a probe coefficient acquisition device in a pressure pre-test according to an embodiment of the present application. Fig.19 As shown, the device includes: a first determination module 1910 , a calculation module 1920 and a second determination module 1930 .

[0072] The first determination module 1910 is adapted to determine the correlation between the probe coefficient and the target pressure-related parameters according to the correlation between the fluidity of the pressure drop method and the steady-state flow pressure of the probe.

[0073] The calculation module 1920 is suitable for: extrapolating the time to infinity for calculation based on the analytical solution of the pressure equation of the probe or the numerical solution of the reservoir simulation probe pre-test process to obtain the target pressure related parameters.

[0074] The second determination module 1930 is adapted to determine the probe coefficient according to the correlation relationship between the probe coefficient and the target pressure related parameter and the target pressure related parameter.

[0075] Optionally, the correlation between the mobility of the pressure drop method and the steady-state flow pressure of the probe is expressed as:

[0076] Where m represents mobility; k represents formation permeability; μ represents fluid viscosity; h represents reservoir thickness; p ssD represents the dimensionless pressure of steady-state flow; q represents the pump flow rate; Δp dd Indicates the pre-test pressure difference; C pf Represents the probe coefficient.

[0077] Optionally, when the target pressure-related parameter is a dimensionless pressure of a steady-state flow, the correlation between the probe coefficient and the target pressure-related parameter is expressed as:

[0078] Among them, C pf represents the probe coefficient; h represents the reservoir thickness; p ssD Represents the dimensionless pressure for steady-state flow.

[0079] Optionally, the calculation module 1920 is further suitable for: based on the analytical solution of the pressure equation of the probe, extrapolating the time in the analytical solution to infinity for calculation to obtain the dimensionless pressure of the steady-state flow; wherein, the analytical solution of the pressure equation of the probe is obtained by solving the pressure diffusion equation and boundary conditions.

[0080] Optionally, when the target pressure-related parameter is a pre-tested pressure difference, the correlation relationship between the probe coefficient and the target pressure-related parameter is expressed as:

[0081] Among them, C pf represents the probe coefficient; m represents the fluidity; Δp dd represents the pre-test pressure difference; q represents the pump flow rate; k represents the formation permeability; μ represents the fluid viscosity.

[0082] Optionally, the calculation module 1920 is further suitable for: based on the numerical solution of the reservoir simulation probe pre-test process, extrapolating the spherical flow pressure difference in the numerical solution to time infinity for calculation to obtain a pre-test pressure difference; wherein the numerical solution of the reservoir simulation probe pre-test process is a correlation relationship between time and spherical flow pressure difference determined by numerically simulating different probe types within different parameter ranges.

[0083] According to the probe coefficient acquisition device in the pressure pretest provided in the embodiment of the present application, the correlation between the probe coefficient and the target pressure-related parameters can be accurately determined based on the correlation between the fluidity of the pressure drop method and the steady-state flow pressure of the probe; based on the analytical solution of the pressure equation of the probe or the numerical solution of the reservoir simulation probe pretest process, the target pressure-related parameters can be conveniently obtained by extrapolating time to infinity for calculation, and then the probe coefficient can be determined based on the correlation between the probe coefficient and the target pressure-related parameters and the target pressure-related parameters, thereby achieving accurate determination of the probe coefficient. This scheme has a wide range of applications, and various types of probes can use this scheme to determine their probe coefficients. The determined probe coefficient can be used in the fluidity calculation of the pretest process, which helps to improve the accuracy and reliability of the fluidity calculation, and thus obtain accurate formation permeability.

[0084] The present invention also provides a non-volatile computer storage medium, which stores at least one executable instruction, and the executable instruction can execute the probe coefficient acquisition method in the pressure pre-test in any of the above method embodiments.

[0085] An embodiment of the present invention provides a computer program product, which includes at least one executable instruction or computer program, which can enable a processor to perform operations corresponding to the probe coefficient acquisition method in the stress pretest in any of the above method embodiments.

[0086] Fig. 20 A schematic diagram of the structure of a computing device according to an embodiment of the present application is shown. The specific embodiment of the present application does not limit the specific implementation of the computing device.

[0087] like Fig. 20 As shown, the computing device may include: a processor 2002 , a communication interface 2004 , a memory 2006 , and a communication bus 2008 .

[0088] The processor 2002, the communication interface 2004, and the memory 2006 communicate with each other via the communication bus 2008. The communication interface 2004 is used to communicate with other devices such as a client or other server network elements. The processor 2002 is used to execute the program 210, which can specifically execute the relevant steps in the embodiment of the probe coefficient acquisition method for the pressure pre-test of the computing device.

[0089] Specifically, the program 2010 may include program codes, which include computer operation instructions.

[0090] The processor 2002 may be a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application. The one or more processors included in the computing device may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0091] The memory 2006 is used to store the program 2010. The memory 2006 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0092] Program 2010 can be specifically used to enable processor 2002 to execute the probe coefficient acquisition method in the pressure pretest in any of the above-mentioned method embodiments. The specific implementation of each step in program 2010 can refer to the corresponding descriptions in the corresponding steps and units in the above-mentioned probe coefficient acquisition embodiment in the pressure pretest, which will not be repeated here. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process of the above-described equipment and modules can refer to the corresponding process description in the above-mentioned method embodiment, which will not be repeated here.

[0093] The algorithm and display provided herein are not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the teachings based on this. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the present invention is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to realize the content of the present invention described herein, and the description of the above specific languages ​​is for disclosing the best mode of the present invention.

[0094] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0095] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in less than all of the features of the individual embodiments previously disclosed. Therefore, the claims that follow the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present invention.

[0096] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and further may be divided into a plurality of submodules or subunits or subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device so disclosed may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0097] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0098] The various component embodiments of the present invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It should be understood by those skilled in the art that a microprocessor or a digital signal processor (DSP) may be used in practice to implement some or all of the functions of some or all of the components in the embodiments of the present invention. The present invention may also be implemented as a device or apparatus program (e.g., a computer program and a computer program product) for executing part or all of the methods described herein. Such a program implementing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such a signal may be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0099] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.

Claims

1. A method for obtaining probe coefficients in a pressure pre-test, characterized in that: The method comprises: According to the correlation between the flow rate of the pressure drop method and the steady-state flow pressure of the probe, the correlation between the probe coefficient and the target pressure-related parameters is determined; Based on the analytical solution of the pressure equation of the probe or the numerical solution of the pre-test process of the reservoir simulation probe, the time is extrapolated to infinity for calculation to obtain the target pressure related parameters; The probe coefficient is determined according to the correlation between the probe coefficient and the target pressure related parameter and the target pressure related parameter.

2. The method for obtaining probe coefficients in pressure pre-testing according to claim 1, characterized in that: The correlation between the mobility of the pressure drop method and the steady-state flow pressure of the probe is expressed as: Where m represents mobility; k represents formation permeability; μ represents fluid viscosity; h represents reservoir thickness; p ssD represents the dimensionless pressure of steady-state flow; q represents the pump flow rate; Δp dd Indicates the pre-test pressure difference; C pf Represents the probe coefficient.

3. The method for obtaining probe coefficients in pressure pre-testing according to claim 2, characterized in that: When the target pressure-related parameter is the dimensionless pressure of steady-state flow, the correlation relationship between the probe coefficient and the target pressure-related parameter is expressed as: Among them, C pf represents the probe coefficient; h represents the reservoir thickness; p ssD Represents the dimensionless pressure for steady-state flow.

4. The method for obtaining probe coefficients in pressure pre-testing according to claim 3, characterized in that: The analytical solution of the pressure equation based on the probe or the numerical solution of the reservoir simulation probe pre-test process, extrapolating the time to infinity for calculation, and obtaining the target pressure related parameters further include: Based on the analytical solution of the pressure equation of the probe, the time in the analytical solution is extrapolated to infinity for calculation to obtain the dimensionless pressure of the steady-state flow; The analytical solution of the pressure equation of the probe is obtained by solving the pressure diffusion equation and boundary conditions.

5. The method for obtaining probe coefficients in pressure pre-testing according to claim 2, characterized in that: When the target pressure-related parameter is the pre-tested pressure difference, the correlation relationship between the probe coefficient and the target pressure-related parameter is expressed as: Among them, C pf represents the probe coefficient; m represents the fluidity; Δp dd represents the pre-test pressure difference; q represents the pump flow rate; k represents the formation permeability; μ represents the fluid viscosity.

6. The method for obtaining probe coefficients in pressure pre-testing according to claim 5, characterized in that: The analytical solution of the pressure equation based on the probe or the numerical solution of the reservoir simulation probe pre-test process, extrapolating the time to infinity for calculation, and obtaining the target pressure related parameters further include: Based on the numerical solution of the reservoir simulation probe pre-test process, the spherical flow pressure difference in the numerical solution is extrapolated to time infinity for calculation to obtain the pre-test pressure difference; The numerical solution of the reservoir simulation probe pre-test process is the correlation between time and spherical flow pressure difference determined by numerical simulation of different probe types within different parameter ranges.

7. A probe coefficient acquisition device in a pressure pre-test, characterized in that: The device comprises: A first determination module is adapted to determine a correlation between a probe coefficient and a target pressure-related parameter based on a correlation between the fluidity of a pressure drop method and a probe steady-state flow pressure; A calculation module, adapted to calculate based on an analytical solution of a pressure equation of a probe or a numerical solution of a pre-test process of a reservoir simulation probe, extrapolating time to infinity to obtain the target pressure related parameters; The second determination module is adapted to determine the probe coefficient according to the association relationship between the probe coefficient and the target pressure related parameter and the target pressure related parameter.

8. A computing device, characterized in that include: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the probe coefficient acquisition method in the pressure pre-test according to any one of claims 1-6.

9. A computer storage medium, characterized in that: The computer storage medium stores at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the probe coefficient acquisition method in the pressure pre-test according to any one of claims 1-6.

10. A computer program product, characterized in that It includes at least one executable instruction, and the executable instruction enables the processor to execute the operation corresponding to the probe coefficient acquisition method in the pressure pre-test according to any one of claims 1-6.

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