A method for calculating three-dimensional rock mechanics parameters of a reservoir

Abstract

The present application provides a method for calculating three-dimensional reservoir rock mechanical parameters, including the following steps: conducting triaxial rock mechanical tests on reservoir cores of key wells to obtain static rock mechanical parameters at well points; extracting various seismic attribute data from the three-dimensional seismic data volume of the target interval in the work area and performing inversion on the seismic attribute data; conducting a correlation analysis on the static rock mechanical parameters at well points and the seismic attributes, and screening out sensitive seismic attributes with high correlation with the static rock mechanical parameters at well points; performing information fusion on the static rock mechanical parameters at well points and the sensitive seismic attributes to establish a prediction model for rock mechanical parameters; using the prediction model for rock mechanical parameters to predict the three-dimensional reservoir rock mechanical parameters in the work area. The present application can accurately predict the three-dimensional reservoir rock mechanical parameters, improve the calculation accuracy of the three-dimensional reservoir rock mechanical parameters, and the prediction results have high practical value for reservoir geomechanics heterogeneous modeling and stress field numerical simulation.

Description

Technical Field

[0001] This application belongs to the technical field of reservoir geomechanics. More specifically, it relates to a method for calculating three-dimensional rock mechanics parameters of a reservoir. Background Art

[0002] Rock mechanics parameters are the bridge connecting the geological sweet spots and engineering sweet spots of a reservoir, and are the key to reservoir stress field simulation, fracture genesis mechanism analysis, and engineering sweet spot evaluation. They are of great significance in aspects such as drilling design, oil and gas development, and well completion. Especially in reservoir stress field simulation, the accurate characterization of three-dimensional rock mechanics parameters of a reservoir is the key to the heterogeneous division of reservoir in-situ stress grids. At present, in research, the laboratory core measurement method and the geophysical logging data interpretation method are the most commonly used methods for obtaining rock mechanics parameters, but usually only the distribution of one-dimensional rock mechanics parameters along the wellbore can be obtained, and the cost is high. How to accurately characterize three-dimensional rock mechanics parameters is an actual problem faced by reservoir geomechanics research. Summary of the Invention

[0003] The purpose of this application is to provide a method for calculating three-dimensional rock mechanics parameters of a reservoir to solve the technical problem that the prior art cannot accurately characterize the three-dimensional rock mechanics parameters of a reservoir.

[0004] To achieve the above purpose, this application provides a method for calculating three-dimensional rock mechanics parameters of a reservoir, including the following steps:

[0005] S1: Conduct triaxial rock mechanics tests on reservoir cores of key wells to obtain static rock mechanics parameters at well points;

[0006] S2: Extract various seismic attribute data from the three-dimensional seismic data volume of the target interval in the work area, and invert the seismic attribute data;

[0007] S3: Conduct a correlation analysis on the static rock mechanics parameters at well points and the seismic attributes, and screen out sensitive seismic attributes with high correlation with the static rock mechanics parameters at well points;

[0008] S4: Conduct information fusion on the static rock mechanics parameters at well points and the sensitive seismic attributes to establish a rock mechanics parameter prediction model;

[0009] S5: Use the rock mechanics parameter prediction model to predict the three-dimensional rock mechanics parameters of the reservoir in the work area.

[0010] Further, the step S1 includes: according to the engineering rock mass test method standard, using a high-temperature and high-pressure rock physics test system to conduct triaxial rock mechanics experiments on rock samples. The rock samples are placed in a high-pressure chamber, different confining pressures are applied around them, the vertical stress of the rock is gradually increased to simulate the real three-dimensional stress environment underground, the strain values in the axial and radial directions of the rock samples are recorded, the corresponding rock stress-strain curves are obtained, and then the well point static rock mechanics parameters are obtained.

[0011] Further, the engineering rock mass test method standard is GB / T50266-99, and the high-temperature and high-pressure rock physics test system is the Autolab1500 high-temperature and high-pressure rock physics test system.

[0012] Further, the step S3 includes: performing correlation analysis on various well point seismic attributes and the well point static rock mechanics parameters through cross-plot analysis, and screening out the sensitive seismic attributes with high correlation with the well point static rock mechanics parameters according to the magnitude of the correlation coefficient and the degree of correlation.

[0013] Further, the step S4 includes: performing information fusion on the well point static rock mechanics parameters and the sensitive seismic attributes through multiple statistical regression method, calculating the regression coefficient through the least squares method operation, determining the weights of different sensitive seismic attributes, and establishing the rock mechanics parameter prediction model.

[0014] Further, the well point static rock mechanics parameters include Young's modulus and Poisson's ratio.

[0015] Further, the seismic attributes include instantaneous amplitude, instantaneous phase, phase shift, instantaneous frequency, instantaneous bandwidth, root mean square amplitude, amplitude square difference, amplitude cube difference, sampling point wave peak position, sampling point wave valley position, sampling point steepness, sampling point extreme value, dip curvature, strike curvature, coherence, similarity, variance, and wave impedance.

[0016] Further, the sensitive seismic attributes include variance, instantaneous amplitude, root mean square amplitude, wave impedance, and similarity.

[0017] Further, the rock mechanics parameter prediction model is:

[0018] E = 19.29 + 0.24 * variance + 0.15 * instantaneous amplitude + 0.20 * root mean square amplitude + 3.90 * wave impedance - 3.10 * similarity,

[0019] where E is Young's modulus, and the unit is GPa.

[0020] Further, the rock mechanics parameter prediction model is:

[0021] μ = 0.305 - 0.21 * variance - 0.11 * instantaneous amplitude + 0.32 * root mean square amplitude + 0.09 * wave impedance + 0.20 * similarity,

[0022] where μ is the Poisson's ratio, dimensionless.

[0023] Compared with the prior art, the present application has the following technical effects:

[0024] A method for calculating three-dimensional reservoir rock mechanics parameters of the present application can accurately predict three-dimensional reservoir rock mechanics parameters based on multiple seismic attributes, improve the calculation accuracy of three-dimensional reservoir rock mechanics parameters, and the prediction results have high practical value for reservoir geomechanics heterogeneous modeling and stress field numerical simulation. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a flowchart of a method for calculating three-dimensional reservoir rock mechanics parameters provided by an embodiment of the present application;

[0027] Figure 2 It is an interaction diagram of the correlation between well point static rock mechanics parameters and variance attributes provided by an embodiment of the present application;

[0028] Figure 3 It is an interaction diagram of the correlation between well point static rock mechanics parameters and instantaneous amplitude attributes provided by an embodiment of the present application;

[0029] Figure 4 It is an interaction diagram of the correlation between well point static rock mechanics parameters and root mean square amplitude attributes provided by an embodiment of the present application;

[0030] Figure 5 It is an interaction diagram of the correlation between well point static rock mechanics parameters and wave impedance attributes provided by an embodiment of the present application;

[0031] Figure 6 It is an interaction diagram of the correlation between well point static rock mechanics parameters and similarity attributes provided by an embodiment of the present application;

[0032] Figure 7 It is a three-dimensional distribution diagram of Young's modulus of the reservoir in the Jingbozi-Dabei area provided by an embodiment of the present application;

[0033] Figure 8This is the three-dimensional Poisson's ratio distribution map of the reservoirs in the Jingbozi-Dabei area provided by the embodiments of this application. Detailed implementation manners

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application clearer and more understandable, the following further details this application in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0035] The embodiments of this application provide a method for calculating three-dimensional rock mechanical parameters of reservoirs. The flow chart is as Figure 1 shown, and it includes the following steps:

[0036] S1: Conduct triaxial rock mechanical tests on the cores of the key wells in the reservoirs to obtain the static rock mechanical parameters of the well points;

[0037] S2: Extract various seismic attribute data of the three-dimensional seismic data volume of the target interval in the work area, and invert the seismic attribute data;

[0038] S3: Conduct a correlation analysis on the static rock mechanical parameters of the well points and the seismic attributes, and screen out the sensitive seismic attributes with high correlation with the static rock mechanical parameters of the well points;

[0039] S4: Conduct information fusion on the static rock mechanical parameters of the well points and the sensitive seismic attributes, and establish a prediction model for rock mechanical parameters;

[0040] S5: Use the prediction model for rock mechanical parameters to predict the three-dimensional rock mechanical parameters of the reservoirs in the work area.

[0041] Specifically, the above step S1 includes: According to the standard of test methods for engineering rock masses, use a high-temperature and high-pressure rock physics test system to conduct triaxial rock mechanical experiments on the rock samples. Put the rock samples into the high-pressure chamber, apply different confining pressures around, gradually increase the vertical stress of the rock, simulate the real three-dimensional stress environment underground, record the strain values of the rock samples in the axial and radial directions, obtain the corresponding rock stress-strain curve, and then obtain the static rock mechanical parameters of the well points. The static rock mechanical parameters of the well points include Young's modulus and Poisson's ratio, etc. The standard of test methods for engineering rock masses can refer to GB / T50266-99, and the high-temperature and high-pressure rock physics test system can be the Autolab1500 high-temperature and high-pressure rock physics test system.

[0042] Specifically, the above-mentioned step S3 includes: performing a correlation analysis on various seismic attributes of the well points and the static rock mechanical parameters of the well points through crossplot analysis, and screening out the sensitive seismic attributes with high correlation with the static rock mechanical parameters of the well points according to the magnitude of the correlation coefficient and the degree of correlation. The various seismic attributes include instantaneous amplitude, instantaneous phase, phase shift, instantaneous frequency, instantaneous bandwidth, root mean square amplitude, amplitude square difference, amplitude cube difference, peak position of the sampling point, trough position of the sampling point, steepness of the sampling point, extreme value of the sampling point, dip curvature, strike curvature, coherence, similarity, variance, and wave impedance, etc.

[0043] Specifically, the above-mentioned step S4 includes: performing information fusion on the static rock mechanical parameters of the well points and the sensitive seismic attributes through multiple statistical regression method, calculating the regression coefficients through least squares operation, determining the weights of different sensitive seismic attributes, and establishing a prediction model for rock mechanical parameters.

[0044] Taking the Bozii-Dabei block in the Kuqa Depression of the Tarim Basin, China as an example, the specific implementation process of the embodiments of the present application is described. The Bozii-Dabei block is located in the Kelasu structural belt of the Kuqa Depression in the Tarim Basin, and the 3D seismic data quality of the target Cretaceous Bashijiqike Formation is relatively good.

[0045] A method for calculating three-dimensional rock mechanical parameters of a reservoir based on detection of multiple seismic attributes according to an embodiment of the present application includes the following steps:

[0046] The first step: Conduct triaxial rock mechanical experiments on the cores of the reservoir in key wells to determine the static rock mechanical parameters of the well points: According to the test standard of "Standard for Test Methods of Engineering Rock Masses (GB / T 50266-99)", use the Autolab1500 high-temperature and high-pressure rock physics test system to conduct triaxial rock mechanical experiments on the rock samples. Place the rock samples in the high-pressure chamber, apply different confining pressures around, gradually increase the vertical stress of the rock, simulate the real three-dimensional stress environment underground, record the strain values in the axial and radial directions of the rock samples, obtain the corresponding rock stress-strain curves, and obtain the static rock mechanical parameters of the well points. The static rock mechanical parameters of the well points include Young's modulus and Poisson's ratio.

[0047] The second step: Extract the 3D seismic data of the target layer section in the work area from the 3D seismic data volume of the target layer section in the work area, and invert the extracted mutually independent multiple seismic attribute data. A total of eighteen seismic attributes including instantaneous amplitude, instantaneous phase, phase shift, instantaneous frequency, instantaneous bandwidth, root mean square amplitude, amplitude square difference, amplitude cube difference, peak position of the sampling point, trough position of the sampling point, steepness of the sampling point, extreme value of the sampling point, dip curvature, strike curvature, coherence, similarity, variance, and wave impedance are inverted;

[0048] Step 3: Use cross-plot analysis to analyze the correlation between various seismic attributes of the drilled wells and the determined well-point static rock mechanical parameters, check the correlation degree between various seismic attributes and static rock mechanical parameters, determine the magnitude of the correlation coefficient, and screen out five mutually independent sensitive seismic attributes of rock mechanical parameters, namely variance, instantaneous amplitude, root mean square amplitude, wave impedance, and similarity, as shown in Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 ;

[0049] Step 4: Use multivariate statistics to perform information fusion on the well-point static rock mechanical parameters and the screened sensitive seismic attributes. After least squares calculation, calculate the regression coefficients, determine the weights of different sensitive seismic attributes, and establish the following rock mechanical parameter prediction model:

[0050] E = 19.29 + 0.24 * variance + 0.15 * instantaneous amplitude + 0.20 * root mean square amplitude + 3.90 * wave impedance - 3.10 * similarity μ = 0.305 - 0.21 * variance - 0.11 * instantaneous amplitude + 0.32 * root mean square amplitude + 0.09 * wave impedance + 0.20 * similarity, where E is Young's modulus with the unit of GPa; μ is Poisson's ratio, dimensionless.

[0051] Step 5: Use the rock mechanical parameter prediction model constructed in Step 4 to predict the rock mechanical parameters of the reservoirs in the work area. The prediction results are shown in Figure 7 , Figure 8 ;

[0052] In the embodiment of the present application, by conducting triaxial rock mechanical tests on the cores of the key wells in the reservoir, the well-point static rock mechanical parameters are determined; by inverting the mutually independent seismic attribute data from the 3D seismic data volume and combining with the static rock mechanical parameters, the sensitive seismic attributes of rock mechanical parameters are screened; by fusing the sensitive seismic attributes and the well-point static rock mechanical parameters, a rock mechanical parameter prediction model is established to calculate the 3D rock mechanical parameters. The 3D rock mechanical parameter calculation method based on multiple seismic attribute detections provided by the embodiment of the present application has high practical value, improves the calculation accuracy of the 3D rock mechanical parameters of the reservoir, and the prediction results have practical significance for the heterogeneous modeling of reservoir geomechanics and the numerical simulation of the stress field.

[0053] The above embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for calculating three-dimensional rock mechanics parameters of a reservoir, characterized in that It includes the following steps: S1: Conduct triaxial rock mechanics tests on the cores of key wells to obtain the static rock mechanics parameters of the well points; S2: Extract various seismic attributes from the 3D seismic data volume of the target interval in the work area and invert the seismic attribute data; S3: Conduct a correlation analysis on the static rock mechanics parameters of the well points and the seismic attributes, and screen out the sensitive seismic attributes with high correlation with the static rock mechanics parameters of the well points; The sensitive seismic attributes include variance, instantaneous amplitude, root mean square amplitude, wave impedance, and similarity; S4: Conduct information fusion on the static rock mechanics parameters of the well points and the sensitive seismic attributes to establish a rock mechanics parameter prediction model; The rock mechanics parameter prediction model is: ， Among them, is the Young's modulus, with the unit of GPa; S5: Use the rock mechanics parameter prediction model to predict the 3D rock mechanics parameters of the reservoir in the work area.

2. The three-dimensional reservoir rock mechanics parameter calculation method according to claim 1, characterized in that, The step S1 includes: According to the engineering rock mass test method standard, use a high-temperature and high-pressure rock physics test system to conduct triaxial rock mechanics experiments on rock samples. Place the rock samples in the high-pressure chamber, apply different confining pressures around them, gradually increase the vertical stress of the rock, simulate the real underground three-dimensional stress environment, record the strain values in the axial and radial directions of the rock samples, obtain the corresponding rock stress-strain curve, and then obtain the static rock mechanics parameters of the well points.

3. The three-dimensional reservoir rock mechanical parameter calculation method according to claim 2, wherein, The engineering rock mass test method standard is GB / T50266-99, and the high-temperature and high-pressure rock physics test system is the Autolab1500 high-temperature and high-pressure rock physics test system.

4. A method for calculating three-dimensional rock mechanical parameters of a reservoir according to claim 1, characterized in that The step S3 includes: Conduct a correlation analysis on various seismic attributes of the well points and the static rock mechanics parameters of the well points through cross-plot analysis, and based on the magnitude of the correlation coefficient, screen out the sensitive seismic attributes with high correlation with the static rock mechanics parameters of the well points according to the degree of correlation.

5. The three-dimensional reservoir rock mechanics parameter calculation method according to claim 1, characterized in that The step S4 includes: Conduct information fusion on the static rock mechanics parameters of the well points and the sensitive seismic attributes through multiple statistical regression method, perform least squares method operation, calculate the regression coefficients, determine the weights of different sensitive seismic attributes, and establish the rock mechanics parameter prediction model.

6. The three-dimensional reservoir rock mechanical parameter calculation method according to claim 1, wherein The static rock mechanics parameters of the well points include Young's modulus and Poisson's ratio.

7. A method for calculating three-dimensional reservoir rock mechanical parameters according to claim 1, characterized in that, The seismic attributes include instantaneous amplitude, instantaneous phase, phase shift, instantaneous frequency, instantaneous bandwidth, root mean square amplitude, amplitude square difference, amplitude cube difference, wave peak position of sampling points, wave valley position of sampling points, steepness of sampling points, extreme values of sampling points, dip curvature, strike curvature, coherence, similarity, variance, and wave impedance.

8. The three-dimensional reservoir rock mechanics parameter calculation method according to claim 1, characterized in that The rock mechanics parameter prediction model is: ， Among them, is the Poisson's ratio, dimensionless.

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