Post-stack inversion method, system and device for heterogeneous reservoir of carbonate rock

Abstract

The invention relates to the technical field of oil exploration, in particular to a carbonatite heterogeneous reservoir post-stack inversion method, system and device. Comprising the following steps: S1, acquiring basic data of a research area; s2, acquiring an initial inversion low-frequency trend model; s3, carbonate rock heterogeneous reservoirs and wave impedance threshold values of non-reservoir waves in the research area are obtained, the carbonate rock heterogeneous reservoirs comprise various types of reservoirs, and the wave impedance threshold values of different reservoirs are different; s4, obtaining seismic attributes sensitive to different types of reservoir bodies; s5, the inversion low-frequency trend model obtained in the step S2, the wave impedance threshold value obtained in the step S3 and the seismic attributes obtained in the step S4 are processed, and a low-frequency model under lithofacies control is obtained; s6, performing inversion on the low-frequency model under lithofacies control obtained in the step S5 to obtain an inversion result under lithofacies control; and the precision of the post-lamination inversion of the heterogeneous reservoir of the carbonate rock is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum exploration, and in particular to a post-stack inversion method, system and device for carbonate rock heterogeneous reservoirs. Background Art

[0002] Carbonate vuggy reservoirs are formed by hydrothermal dissolution along faults or unconformities, resulting in highly heterogeneous reservoirs. Their reflection characteristics appear as "beaded" reflections on seismic profiles. The prediction of carbonate vuggy reservoirs remains a hot topic and a challenge.

[0003] The most important method for reservoir identification is seismic inversion. This method uses seismic data, constrained by drilling and logging data, to determine the structure and physical properties of subsurface rock formations. Inversion methods can be divided into two categories based on the seismic data used: pre-stack inversion and post-stack inversion. This method involves post-stack inversion. Post-stack inversion has evolved over the years into a variety of techniques, with constrained sparse pulse inversion and geostatistical inversion being the most widely used.

[0004] Constrained sparse pulse inversion generally uses the fast constrained trend algorithm, which establishes a low-frequency trend model of wave impedance based on well logging, seismic, and geological structure data. However, the fast constrained trend algorithm has limitations and may not be suitable for all situations. This method is based on the theory of laterally continuous sedimentary reservoir media and is not suitable for heterogeneous reservoirs such as fault-controlled fracture-vuggy carbonate reservoirs.

[0005] Therefore, there is an urgent need to provide a post-stack inversion method, system and device for carbonate heterogeneous reservoirs to improve the prediction accuracy of such reservoirs. Summary of the Invention

[0006] The present invention solves the technical problems existing in the prior art and provides a post-stack inversion method, system and device for carbonate rock heterogeneous reservoirs.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] The post-stack inversion method for carbonate heterogeneous reservoirs includes the following steps:

[0009] S1. Obtain basic data of the study area;

[0010] S2, based on the basic data obtained in step S1, obtaining an initial inversion low-frequency trend model;

[0011] S3. Obtain the wave impedance threshold values ​​of carbonate rock heterogeneous reservoirs and non-reservoir waves in the study area. Carbonate rock heterogeneous reservoirs include various types of reservoirs, and the wave impedance threshold values ​​of different reservoirs are different.

[0012] S4. Obtain seismic attributes that are sensitive to different reservoir types;

[0013] S5, processing the inverted low-frequency trend model obtained in step S2, the wave impedance threshold value obtained in step S3, and the seismic attributes obtained in step S4 to obtain a low-frequency model controlled by lithofacies;

[0014] S6. Invert the low-frequency model under the control of lithofacies obtained in step S5 to obtain an inversion result under the control of lithofacies.

[0015] Furthermore, the specific method of step S2 is: performing constrained sparse pulse inversion on the basic data obtained in step S1 to obtain the initial inversion low-frequency trend model of the study area.

[0016] Furthermore, the specific method of constrained sparse pulse inversion is:

[0017] S201, preprocessing basic data;

[0018] S202, extracting low-frequency components from basic data;

[0019] S203, using the low-frequency components extracted in step S202, establishing a low-frequency trend change model describing the study area;

[0020] S204: Verify the feasibility of the low-frequency trend change model established in S203. When the feasibility conditions are met, it is output as the initial inversion low-frequency trend model. When the feasibility conditions are not met, repeat steps S201-S203 until the feasibility conditions are met and output the inversion low-frequency trend model.

[0021] Furthermore, the preprocessing in step S201 includes removing noise, and performing time domain and frequency domain filtering.

[0022] Furthermore, in step S202, low-frequency components are extracted by filtering and wavelet transform methods.

[0023] Furthermore, the verification method in step S204 is: applying the low-frequency trend change model obtained in step S203 to seismic data interpretation and analysis, and comparing the application results with production data.

[0024] Furthermore, the feasible condition in step S204 is that the comparison result between the application result and the production data is within a set threshold range.

[0025] Furthermore, the carbonate rock heterogeneous reservoir in step S3 includes cave reservoirs, pore reservoirs and fracture reservoirs.

[0026] Furthermore, S3 specifically includes the following steps:

[0027] S301, respectively determining the seismic response characteristics of cave reservoirs, pore reservoirs, and fracture reservoirs;

[0028] S302, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the cave reservoir determined in step S301, and calculating a wave impedance threshold value of the cave reservoir;

[0029] S303, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the porous reservoir determined in step S301, and calculating a wave impedance threshold value of the porous reservoir;

[0030] S304, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the fractured reservoir determined in step S301, and calculating a wave impedance threshold value of the fractured reservoir;

[0031] S305 , determining a wave impedance threshold value for non-reservoir waves based on the wave impedance threshold value of the cave reservoir, the wave impedance threshold value of the pore reservoir, and the wave impedance threshold value of the fracture reservoir.

[0032] Furthermore, the seismic attributes obtained in step S4 include seismic attributes of cave reservoirs, seismic attributes of pore reservoirs, and seismic attributes of fracture reservoirs.

[0033] Furthermore, S5 includes the following steps:

[0034] S501. For the study area, combining the wave impedance threshold value obtained in step S3 and the seismic attributes obtained in step S4, perform lithofacies interpretation, and identify and divide areas of different lithofacies through seismic data interpretation and geological knowledge;

[0035] S502, extracting low-frequency features from the seismic data of the low-frequency trend model inverted in step S2 in different lithofacies regions, including low-frequency amplitude and low-frequency phase;

[0036] S503, establishing lithofacies relationships, based on the low-frequency characteristics of different lithofacies regions, establishing relationships between lithofacies changes and low-frequency characteristics in seismic data through regression analysis or lithofacies statistical methods;

[0037] S504: Using the lithofacies relationship established in step S503, a low-frequency model under lithofacies control is established.

[0038] Furthermore, S5 also includes step S505: applying the low-frequency model under lithofacies control established in S504 to seismic data interpretation and analysis for identifying lithofacies interfaces, reservoir distribution and prediction.

[0039] Furthermore, in step S6, the low-frequency model under the control of lithofacies obtained in step S5 is inverted by using the same constrained sparse pulse inversion method as that in step S2.

[0040] Furthermore, the post-stack inversion method also includes step S7, which is specifically: combining drilling and logging information to verify the inversion results of the low-frequency model under lithofacies control, and continuously optimizing the low-frequency model under lithofacies control by continuously and iteratively optimizing the wave impedance threshold value and seismic attributes.

[0041] A system using any of the above-mentioned post-stack inversion methods for carbonate heterogeneous reservoirs includes a first module, a second module, a third module, a fourth module, a fifth module, a sixth module and a seventh module connected in sequence, wherein the first module is used to execute the content of step S1, the second module is used to execute the content of step S2, the third module is used to execute the content of step S3, the fourth module is used to execute the content of step S4, the fifth module is used to execute the content of step S5, the sixth module is used to execute the content of step S6, and the seventh module is used to execute the content of step S7.

[0042] A carbonate rock heterogeneous reservoir post-stack inversion device comprises a storage medium and a processor, wherein the storage medium stores a computer program, and the processor is used to implement a carbonate rock heterogeneous reservoir post-stack inversion method when executing the computer program.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention obtains an inversion low-frequency trend model through the basic data of the study area, and then obtains a low-frequency model under lithofacies control based on the inversion low-frequency trend model, the wave impedance threshold value of different reservoirs in the study area, and the seismic attributes of different reservoirs in the study area. The low-frequency model under lithofacies control is then used as input for constrained sparse pulse inversion to obtain an inversion result under lithofacies control, thereby achieving an improvement in the accuracy of post-stack inversion of heterogeneous carbonate reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0047] like Figure 1As shown, the present invention provides a post-stack inversion method for carbonate heterogeneous reservoirs, comprising the following steps:

[0048] S1. Obtain basic data, which includes seismic data, well logging data, and stratigraphic data of the study area.

[0049] S2. Obtaining an initial inverted low-frequency trend model. The specific method is: performing constrained sparse pulse inversion on the basic data obtained in step S1 to obtain the pulse inversion result of the study area, that is, the initial inverted low-frequency trend model.

[0050] The specific method of constrained sparse pulse inversion is:

[0051] S201, data preprocessing, preprocessing the basic data, the preprocessing method includes removing noise, and performing time domain and frequency domain filtering;

[0052] S202, low-frequency component extraction, extracting low-frequency components from basic data through filtering and wavelet transform methods;

[0053] S203, low-frequency trend modeling, using the low-frequency components extracted in step S202, to establish a low-frequency trend change model describing the study area, in the form of fitting curves or interpolation;

[0054] S204. Verify the feasibility of the low-frequency trend change model established in S203. When the feasibility conditions are met, it is output as the initial inversion low-frequency trend model. If the feasibility conditions are not met, repeat steps S201-S203 until the feasibility conditions are met, and output the inversion low-frequency trend model. The verification method is: apply the low-frequency trend change model obtained in step S203 to seismic data interpretation and analysis, and compare the application results with actual drilling emptying, leakage and other production data. The feasibility condition is that the comparison result between the application result and the production data is within the set threshold range.

[0055] S3. Obtain the wave impedance threshold values ​​of carbonate rock heterogeneous reservoirs and non-reservoir waves in the study area. Carbonate rock heterogeneous reservoirs include cave reservoirs, pore reservoirs, and fracture reservoirs. The specific steps include:

[0056] S301, respectively determining the seismic response characteristics of cave reservoirs, pore reservoirs, and fracture reservoirs;

[0057] S302, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the cave reservoir determined in step S301, and calculating a wave impedance threshold value of the cave reservoir;

[0058] S303, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the porous reservoir determined in step S301, and calculating a wave impedance threshold value of the porous reservoir;

[0059] S304, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the fractured reservoir determined in step S301, and calculating a wave impedance threshold value of the fractured reservoir;

[0060] S305 , determining a wave impedance threshold value for non-reservoir waves based on the wave impedance threshold value of the cave reservoir, the wave impedance threshold value of the pore reservoir, and the wave impedance threshold value of the fracture reservoir.

[0061] S4. Extract seismic attributes that are sensitive to different reservoir types. Seismic attributes that are sensitive to different reservoir types refer to seismic attributes that can significantly distinguish different types of reservoirs and are used to highlight the vertical characteristics of different reservoirs such as caves, pores, and fractures.

[0062] S5, obtaining a low-frequency model under lithofacies control, specifically comprising the following steps:

[0063] S501. For the study area, perform lithofacies interpretation based on the heterogeneous reservoir obtained in step S3, the wave impedance threshold value of the non-reservoir wave, and the seismic attributes obtained in step S4. Identify and demarcate areas of different lithofacies through seismic data interpretation and geological knowledge. Lithofacies refers to the distribution and changes of different rock types or lithologic units, which reflects the lithologic differences within the formation.

[0064] S502, extracting low-frequency features from the initial inversion low-frequency trend model obtained in step S2, and extracting low-frequency features in the seismic data in different lithofacies regions, including low-frequency amplitude and low-frequency phase;

[0065] S503, establishing lithofacies relationships, based on the low-frequency characteristics of different lithofacies regions, establishing relationships between lithofacies changes and low-frequency characteristics in seismic data through regression analysis or lithofacies statistical methods;

[0066] S504, using the lithofacies relationship established in step S503, establish a low-frequency model describing lithofacies control;

[0067] S505. Apply the low-frequency model under lithofacies control established in S504 to seismic data interpretation and analysis to help identify lithofacies interfaces, reservoir distribution, and prediction.

[0068] S6. Using the low-frequency model under lithofacies control obtained in step S5 as input, constrained sparse pulse inversion is performed to obtain an inversion result under lithofacies control. The constrained sparse pulse inversion in this step is the same as the constrained sparse pulse inversion method in step S2.

[0069] S7. Verify the inversion results of the low-frequency model under lithofacies control by combining drilling and logging information. The specific verification method is to compare the inversion results with actual drilling and production information to verify the feasibility of the method; at the same time, continuously optimize the low-frequency model under lithofacies control by repeatedly iteratively optimizing the wave impedance threshold value and seismic attributes, thereby improving the reservoir inversion accuracy and completing the wave impedance inversion.

[0070] The present invention also provides a post-stack inversion system for carbonate heterogeneous reservoirs, comprising a first module, a second module, a third module, a fourth module, a fifth module, a sixth module and a seventh module. The first module, the second module, the third module, the fourth module, the fifth module, the sixth module and the seventh module are connected in sequence. The first module is used to execute the content of step S1, the second module is used to execute the content of step S2, the third module is used to execute the content of step S3, the fourth module is used to execute the content of step S4, the fifth module is used to execute the content of step S5, the sixth module is used to execute the content of step S6, and the seventh module is used to execute the content of step S7.

[0071] The present invention also provides a post-stack inversion device for carbonate rock heterogeneous reservoirs, comprising a storage medium and a processor. The storage medium stores a computer program, and the processor is used to implement a post-stack inversion method for carbonate rock heterogeneous reservoirs when executing the computer program.

[0072] The present invention realizes the post-stack inversion of carbonate rock fault-controlled fracture-cavity reservoirs with strong heterogeneity, and improves the accuracy of post-stack inversion of carbonate rock heterogeneous reservoirs.

[0073] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A post-stack inversion method for carbonate heterogeneous reservoirs, characterized in that: The following steps are involved: S1. Obtain basic data of the study area; S2, based on the basic data obtained in step S1, obtaining an initial inversion low-frequency trend model; S3. Obtain the wave impedance threshold values ​​of carbonate rock heterogeneous reservoirs and non-reservoir waves in the study area. Carbonate rock heterogeneous reservoirs include various types of reservoirs, and the wave impedance threshold values ​​of different reservoirs are different. S4. Obtain seismic attributes that are sensitive to different reservoir types; S5, processing the inverted low-frequency trend model obtained in step S2, the wave impedance threshold value obtained in step S3, and the seismic attributes obtained in step S4 to obtain a low-frequency model controlled by lithofacies; S6. Invert the low-frequency model under the control of lithofacies obtained in step S5 to obtain an inversion result under the control of lithofacies.

2. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 1 is characterized in that: The specific method of step S2 is: perform constrained sparse pulse inversion on the basic data obtained in step S1 to obtain the initial inversion low-frequency trend model of the study area.

3. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 2, characterized in that: The specific method of constrained sparse pulse inversion is: S201, preprocessing basic data; S202, extracting low-frequency components from basic data; S203, using the low-frequency components extracted in step S202, establishing a low-frequency trend change model describing the study area; S204: Verify the feasibility of the low-frequency trend change model established in S203. When the feasibility conditions are met, it is output as the initial inversion low-frequency trend model. When the feasibility conditions are not met, repeat steps S201-S203 until the feasibility conditions are met and output the inversion low-frequency trend model.

4. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 3, characterized in that: The preprocessing in step S201 includes removing noise and performing time domain and frequency domain filtering.

5. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 3, characterized in that: In step S202, low-frequency components are extracted by filtering and wavelet transform methods.

6. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 3, characterized in that: The verification method in step S204 is: applying the low-frequency trend change model obtained in step S203 to seismic data interpretation and analysis, and comparing the application results with production data.

7. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 6, characterized in that: The feasibility condition in step S204 is that the comparison result between the application result and the production data is within the set threshold range.

8. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 1, characterized in that: The carbonate rock heterogeneous reservoirs in step S3 include cave reservoirs, pore reservoirs and fracture reservoirs.

9. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 8, characterized in that: S3 specifically includes the following steps: S301, respectively determining the seismic response characteristics of cave reservoirs, pore reservoirs, and fracture reservoirs; S302, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the cave reservoir determined in step S301, and calculating a wave impedance threshold value of the cave reservoir; S303, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the porous reservoir determined in step S301, and calculating a wave impedance threshold value of the porous reservoir; S304, performing seismic inversion or seismic interpretation based on the seismic response characteristics of the fractured reservoir determined in step S301, and calculating a wave impedance threshold value of the fractured reservoir; S305 , determining a wave impedance threshold value for non-reservoir waves based on the wave impedance threshold value of the cave reservoir, the wave impedance threshold value of the pore reservoir, and the wave impedance threshold value of the fracture reservoir.

10. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 8, characterized in that: The seismic attributes obtained in step S4 include the seismic attributes of cave reservoirs, the seismic attributes of pore reservoirs, and the seismic attributes of fracture reservoirs.

11. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 1, characterized in that: S5 includes the following steps: S501. For the study area, combining the wave impedance threshold value obtained in step S3 and the seismic attributes obtained in step S4, perform lithofacies interpretation, and identify and divide areas of different lithofacies through seismic data interpretation and geological knowledge; S502, extracting low-frequency features from the seismic data of the low-frequency trend model inverted in step S2 in different lithofacies regions, including low-frequency amplitude and low-frequency phase; S503, establishing lithofacies relationships, based on the low-frequency characteristics of different lithofacies regions, establishing relationships between lithofacies changes and low-frequency characteristics in seismic data through regression analysis or lithofacies statistical methods; S504: Using the lithofacies relationship established in step S503, a low-frequency model under lithofacies control is established.

12. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 11, characterized in that: S5 also includes step S505: applying the low-frequency model under lithofacies control established in S504 to seismic data interpretation and analysis for identifying lithofacies interfaces, reservoir distribution, and prediction.

13. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 1, characterized in that: In step S6, the low-frequency model under the control of lithofacies obtained in step S5 is inverted using the same constrained sparse pulse inversion method as in step S2.

14. The post-stack inversion method for carbonate heterogeneous reservoirs according to claim 1, characterized in that: The post-stack inversion method further includes step S7, which specifically comprises: verifying the inversion results of the low-frequency model under lithofacies control obtained by combining drilling and logging information, and continuously optimizing the low-frequency model under lithofacies control by repeatedly iteratively optimizing the wave impedance threshold value and seismic attributes.

15. A system using the carbonate rock heterogeneous reservoir post-stack inversion method according to any one of claims 1 to 14, characterized in that: It includes a first module, a second module, a third module, a fourth module, a fifth module, a sixth module and a seventh module connected in sequence, wherein the first module is used to execute the content of step S1, the second module is used to execute the content of step S2, the third module is used to execute the content of step S3, the fourth module is used to execute the content of step S4, the fifth module is used to execute the content of step S5, the sixth module is used to execute the content of step S6, and the seventh module is used to execute the content of step S7.

16. A post-stack inversion device for carbonate heterogeneous reservoirs, characterized in that: The invention comprises a storage medium and a processor, wherein the storage medium stores a computer program, and the processor is used for implementing a post-stack inversion method for carbonate rock heterogeneous reservoirs when executing the computer program.

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