Three-dimensional cross-section plugging prediction method based on pseudo-acoustic wave constrained inversion

Abstract

The present invention provides a three-dimensional section sealing prediction method based on pseudo-acoustic constrained inversion. The three-dimensional section sealing prediction method based on pseudo-acoustic constrained inversion includes: Step 1, combining the high-frequency information of the shale content curve, reconstructing the acoustic wave data, and obtaining pseudo-wave impedance data based on three-dimensional geological modeling; Step 2, performing lithology identification on the pseudo-wave impedance data to convert it into lithology information, and obtaining lithology impedance data; Step 3, respectively extracting the lithology impedance along the upper and lower plates of the fault plane in three-dimensional space; Step 4, performing energy correlation on both sides of the fault to obtain the three-dimensional section sealing prediction result; Step 5, quantitatively analyzing through known development well data to evaluate the section sealing prediction result. The three-dimensional section sealing prediction method based on pseudo-acoustic constrained inversion has a high reliability in predicting the section sealing under the condition of less well data, has better operability, is innovative and practical, and is conducive to popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of fault sealing prediction in oil exploration and development, and particularly to a three-dimensional section sealing prediction method based on pseudo-acoustic constrained inversion. Background Art

[0002] In order to meet the demand for natural gas in the economic development of the eastern region and implement the natural gas development strategy of Sinopec Corporation, a research project on the evaluation and design technology for converting aquifers into underground gas storage reservoirs has been carried out.

[0003] Currently, the main research methods for fault sealing mainly use the shale smear factor (SSF) and the fault gouge ratio method (SGR). Most of them conduct sealing research on the fault plane, and rarely study the three-dimensional sealing of the section from the three-dimensional space. In the traditional section sealing research method, a large amount of drilling and logging data and test data are added during the research process. When the well data in the study area is insufficient, the section sealing prediction result is unreliable.

[0004] In the Chinese patent application with the application number: CN201710456485.9, a fault block trap evaluation method based on quantitative prediction of oil-bearing height is involved. It includes the following steps: 1) Evaluation of the activity of the main controlling fault of the fault block trap to be evaluated; 2) Establishing a quantitative prediction model for the oil-bearing height of the fault block trap; Dissecting the reservoir-forming conditions of the existing reservoir-forming fault block traps in the study area, using SPSS software to conduct partial correlation analysis, finding out the main controlling factors of the oil-bearing height of the fault block trap, establishing a multiple regression expression between the oil-bearing height and these main controlling factors, and finally establishing a quantitative prediction model for the oil-bearing height of the fault block traps in the study area; 3) Using the above-established prediction model to calculate the oil-bearing height of the trap to be evaluated, guiding the exploration deployment of the fault block trap, and improving the success rate of trap drilling.

[0005] In the Chinese patent application with the application number: CN201610183490.2, a quantitative evaluation method for the three-dimensional sealing of faults based on in-situ stress simulation is involved. It includes the following steps: Step 1, testing the mechanical parameters of rock strength; Step 2, testing the magnitude and direction of the current in-situ stress; Step 3, establishing a fault tectonic mechanical model; Step 4, calculating the sealing evaluation parameters; Step 5, optimizing the fault sealing index; Step 6, evaluating the three-dimensional sealing of the fault.

[0006] In the Chinese patent application with the application number: CN202010906824.0, a method for predicting the opening and closing of faults in an oil and gas bearing basin is involved. The method includes: based on the opening and closing states of each of a plurality of specific section points in the explored faults that can identify their opening and closing properties using the drilling data of the hanging wall and footwall of the faults, and a plurality of related sensitive geological parameters, constructing a fault opening and closing prediction model through a machine learning classification algorithm; based on the position parameters and a plurality of sensitive geological parameters of each target position of the section of the fault to be predicted, establishing a data set of the section of the fault to be predicted; and using the plurality of sensitive geological parameters in the data set of the section of the fault to be predicted as input items, obtaining the fault opening and closing results of each target position of the section of the fault to be predicted in the form of output items through the fault opening and closing prediction model.

[0007] The above prior arts are all quite different from the present invention and cannot solve the technical problems we want to solve. Therefore, we have invented a new three-dimensional section sealing prediction method based on pseudo-acoustic wave constrained inversion. Summary of the Invention

[0008] The object of the present invention is to provide a three-dimensional section sealing prediction method based on pseudo-acoustic wave constrained inversion with a high reliability for predicting section sealing in the case of less well data.

[0009] The object of the present invention can be achieved by the following technical measures: A three-dimensional section sealing prediction method based on pseudo-acoustic wave constrained inversion, and this three-dimensional section sealing prediction method based on pseudo-acoustic wave constrained inversion includes:

[0010] Step 1, combining the high-frequency information of the shale content curve, reconstructing the acoustic wave data, and obtaining pseudo-wave impedance data based on three-dimensional geological modeling;

[0011] Step 2, performing lithology identification on the pseudo-wave impedance data to convert it into lithology information and obtaining lithology impedance data;

[0012] Step 3, respectively extracting the lithology impedance along the hanging wall and footwall of the fault plane in three-dimensional space;

[0013] Step 4, performing energy correlation on both sides of the fault to obtain the three-dimensional section sealing prediction result;

[0014] Step 5, quantitatively analyzing through the known development well data to evaluate the three-dimensional section sealing prediction result.

[0015] The object of the present invention can also be achieved by the following technical measures:

[0016] In step 1, the shale content curve is standardized, the high-frequency information of the shale content curve is retained through a high-pass filtering method, and the high-frequency components of the shale content are fused and reconstructed with the acoustic wave curve in the frequency domain.

[0017] In Step 1, a geological model is built in three-dimensional space by using the fine interpreted sequence interface and cross-section, and impedance data is obtained through constrained inversion using the reconstructed acoustic wave curve.

[0018] In Step 2, the pseudo acoustic impedance threshold value R of sandstone and mudstone is statistically analyzed. thed Using the formula map the mudstone impedance information below the threshold value to the range of [0, 1], and use the formula map the sandstone impedance information above the threshold value to the range of [1, 2]. Remove the dimension of the pseudo impedance, and convert the impedance information into lithology information through actual well data. Among them: R represents the pseudo acoustic impedance data, R min is the minimum value of the impedance, and R max is the maximum value of the impedance.

[0019] In Step 3, in three-dimensional space, the average energy is obtained by opening a time window upward along the fault plane for the lithology impedance data, and project the lithology information of the hanging wall of the fault onto the fault plane F up = F up (x, y, t); Similarly, open a time window downward along the fault plane for the lithology impedance data to obtain the average energy, and project the lithology information of the footwall of the fault onto the fault plane F dw = F dw (x, y, t). Among them: F dw represents the hanging wall of the fault, F dw is the lithology data of the footwall, and x, y, t represent the three-dimensional spatial positions of the lithology data, which are the horizontal and vertical coordinates and time respectively.

[0020] In Step 4, after obtaining the lithology information on both sides of the fault respectively, calculate the energy correlation between the upper and lower plates at the same position on the fault plane, and get the following:

[0021]

[0022] Among them, N is the window size, taking 5 - 7.

[0023] In Step 4, the larger the B f value, the stronger the docking of sandstone to sandstone on both sides of the fault plane. The smaller the value, the higher the proportion of mudstone, indicating that mudstone is docked with mudstone on both sides of the fault plane, and the sealing property is good.

[0024] In Step 5, through quantitative analysis of the known development well data, it is considered that the fault with a B f value less than 0.4 has good sealing property. When B f is between 0.4 - 0.7, it belongs to semi-open and semi-closed. When the B f value is greater than 0.7, the fault has poor sealing property.

[0025] The three-dimensional section plugging prediction method based on pseudo-acoustic wave constrained inversion in the present invention combines well and seismic data, uses pseudo-acoustic wave inversion to expand the single-point well lithology information into space, and considers the plugging property of the section in three-dimensional space. Compared with previous methods, it has a high reliability in predicting the plugging property of the section with less well data, has better operability, is innovative and practical, and is conducive to popularization. This method has achieved remarkable application effects in the construction of the Yong 21 gas storage reservoir in the Shengli Oilfield. The predicted results of the section plugging property are highly consistent with the actual water body distribution and the reservoir pressure system, providing a reliable basis for the construction of the gas storage reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flowchart of a specific embodiment of the three-dimensional section plugging prediction method based on pseudo-acoustic wave constrained inversion of the present invention;

[0027] Figure 2 It is a schematic diagram of acoustic wave reconstruction in a specific embodiment of the present invention;

[0028] Figure 3 It is a three-dimensional acoustic wave reconstruction wave impedance inversion diagram in a specific embodiment of the present invention;

[0029] Figure 4 It is a projection section diagram of the upper wall lithology information of the fault in a specific embodiment of the present invention;

[0030] Figure 5 It is a projection section diagram of the lower wall lithology information of the fault in a specific embodiment of the present invention;

[0031] Figure 6 It is a schematic diagram of quantitatively studying fault plugging based on actual development wells in a specific embodiment of the present invention;

[0032] Figure 7 It is a projection section diagram of the upper wall lithology information of the fault in a specific embodiment of the present invention;

[0033] Figure 8 It is a projection section diagram of the lower wall lithology information of the fault in a specific embodiment of the present invention;

[0034] Figure 9 It is a schematic diagram of quantitatively studying fault plugging based on actual development wells in a specific embodiment of the present invention.

[0035] Figure 10 It is a projection section diagram of the upper wall lithology information of the fault in a specific embodiment of the present invention;

[0036] Figure 11 It is a projection section diagram of the lower wall lithology information of the fault in a specific embodiment of the present invention;

[0037] Figure 12Schematic diagram for quantitatively studying fault sealing based on actual development wells in a specific embodiment of the present invention. Detailed implementation manners

[0038] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0039] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, and / or combinations thereof.

[0040] The three-dimensional section sealing prediction method based on pseudo-acoustic wave constrained inversion of the present invention includes the following steps:

[0041] Step 1: Combine the high-frequency information of the shale content curve to reconstruct the acoustic wave data, and obtain the wave impedance data on the basis of three-dimensional geological modeling.

[0042] Standardize the shale content curve, retain the high-frequency information of the shale content curve through a high-pass filtering method, and fuse and reconstruct the high-frequency components of the shale content with the acoustic wave curve in the frequency domain.

[0043] Utilize the fine-interpreted sequence interface and section plane to build a geological model in three-dimensional space, and perform constrained inversion through the reconstructed acoustic wave curve to obtain the wave impedance data.

[0044] Step 2: Perform lithology identification on the wave impedance data to convert it into lithology information, and obtain the lithology impedance data.

[0045] Statistically analyze the pseudo-acoustic wave impedance threshold value R of sandstone and shale thed , and use the formula Map the shale wave impedance information below the threshold value to the range of [0, 1], and use the formula Map the sandstone wave impedance information above the threshold value to the range of [1, 2]. In this way, the dimension of the pseudo-wave impedance can be removed, and the wave impedance information can be converted into lithology information through actual well data. In addition, the present invention specifically projects the shale wave impedance data to the range of [0, 1] in order to highlight the shale information when calculating the energy correlation in the next step.

[0046] Step 3: Extract the lithology impedance along the upper and lower plates of the fault plane in three-dimensional space respectively.

[0047] In three-dimensional space, a time window is opened upward along the fault plane to obtain the average energy of the lithology impedance data, and the lithology information of the fault hanging wall is projected onto the cross section F. up =F up (x, y, t); Similarly, the time window of the lithology impedance data is opened downward along the fault plane to obtain the average energy, and the lithology information of the fault footwall is projected onto the section F dw =F dw (x, y, t).

[0048] Step 4: perform energy correlation to obtain the three-dimensional cross-section plugging prediction result. The larger the value, the better the performance. The smaller the value, the better the performance.

[0049] After obtaining the lithology information of the two sides of the fault, the energy correlation between the upper and lower sides is calculated at the same position of the section, and the following is obtained:

[0050]

[0051] Where N is the window size, which is usually 5-7. f The larger the value, the stronger the connection between the two sandstones in the cross section. The smaller the value, the higher the proportion of mudstone. The two mudstones in the cross section are connected to mudstone, and the sealing property is good.

[0052] Step 5: Through quantitative analysis of known development well data, evaluate the prediction results of cross-section plugging performance. Through quantitative analysis of known development well data, it is believed that B f The faults with a value less than 0.4 have good sealing properties. f Between 0.4 and 0.7, it is half open and half closed. f Faults with values ​​greater than 0.7 have poor sealing properties.

[0053] In the specific embodiment 1 of the present invention, Figure 1 As shown, Figure 1 The present invention is a flow chart of a three-dimensional cross-section plugging prediction method based on pseudo-acoustic wave constrained inversion.

[0054] In step 101, the shale content curve is standardized, the high-frequency information of the shale content curve is retained by a high-pass filtering method, and the high-frequency components of the shale content are fused and reconstructed with the acoustic wave curve in the frequency domain ( Figure 2 ); Conduct fine closure interpretation of the target layer sequence interface and section in the study area, minimize the interpretation density, eliminate closure errors as much as possible, and avoid affecting the accuracy of later 3D modeling; use fine interpretation of sequence interface and section to build a geological model in 3D space, and then perform constrained inversion through the reconstructed acoustic wave curve to obtain wave impedance data ( Figure 3 ).

[0055] In step 102, the pseudo-acoustic impedance threshold value R of the sandstone and mudstone in the study area is statistically analyzed. thed , using the formula The mudstone wave impedance information below the threshold is mapped to the range of [0,1], using the formula The wave impedance information of sandstones above the threshold value is mapped to the range of [1, 2], so that the dimension of the pseudo-wave impedance can be removed and the wave impedance information can be converted into lithology information through actual well data. In addition, the present invention deliberately projects the wave impedance data representing mudstone to the range of [0, 1] in order to highlight the mudstone information when obtaining energy correlation in the next step.

[0056] In step 103, in three-dimensional space, the average energy of the lithology impedance data is calculated in a 5 ms time window along the fault plane, and the lithology information of the upper wall of the fault is projected onto the cross section F. up =F up (x, y, t)( Figure 4 ); Similarly, the average energy of the lithology impedance data in the 5ms time window along the fault plane is calculated, and the lithology information of the fault footwall is projected onto the section F dw =F dw (x, y, t)( Figure 5 ).

[0057] In step 104, after obtaining the lithology information of the two sides of the fault, the energy correlation between the upper and lower sides is calculated at the same position of the section, and the following is obtained:

[0058]

[0059] Where N is the window size, which is usually 5-7. In this example, the window value is 5. f The larger the value, the stronger the connection between the two sandstones in the cross section. The smaller the value, the higher the proportion of mudstone. The two mudstones in the cross section are connected to mudstones, and the plugging performance is good. Figure 6 ).

[0060] In step 105, through quantitative analysis of known development well data, it is considered that B f The faults with a value less than 0.4 have good sealing properties. f Between 0.4 and 0.7, it is half open and half closed. f Faults with values ​​greater than 0.7 have poor sealing properties.

[0061] In the specific embodiment 2 of the present invention, three-dimensional sealing prediction is performed on other faults in the study area. Figure 1 The present invention is a flow chart of a three-dimensional cross-section plugging prediction method based on pseudo-acoustic wave constrained inversion.

[0062] In step 101, the shale content curve is standardized, and the high-frequency information of the shale content curve is retained by a high-pass filtering method. The high-frequency components of the shale content are fused and reconstructed with the acoustic wave curve in the frequency domain, and then the wave impedance data ( Figure 3 ).

[0063] In step 102, the pseudo-acoustic impedance threshold value R of the sandstone and mudstone in the study area is statistically analyzed. thed , using the formula The mudstone wave impedance information below the threshold is mapped to the range of [0,1], using the formula The wave impedance information of sandstones above the threshold value is mapped to the range of [1, 2], so that the dimension of the pseudo-wave impedance can be removed and the wave impedance information can be converted into lithology information through actual well data. In addition, the present invention deliberately projects the wave impedance data representing mudstone to the range of [0, 1] in order to highlight the mudstone information when obtaining energy correlation in the next step.

[0064] In step 103, in three-dimensional space, the average energy of the lithology impedance data is calculated in a 15 ms time window along the fault plane, and the lithology information of the upper wall of the fault is projected onto the cross section F. up =F up (x, y, t)( Figure 7 ); Similarly, the average energy of the lithology impedance data in the 15ms time window along the fault plane is calculated, and the lithology information of the fault footwall is projected onto the section F dw =F dw (x, y, t)( Figure 8 ).

[0065] In step 104, after obtaining the lithology information of the two sides of the fault, the energy correlation between the upper and lower sides is calculated at the same position of the section, and the following is obtained:

[0066]

[0067] Where N is the window size, which is usually 5-7. In this example, the window value is 7. f The larger the value, the stronger the connection between the two sandstones in the cross section. The smaller the value, the higher the proportion of mudstone. The two mudstones in the cross section are connected to mudstones, and the plugging performance is good. Figure 9 ).

[0068] In step 105, through quantitative analysis of the known development well data near the fracture in this example, it is considered that B f The faults with a value less than 0.5 have good sealing properties. f Between 0.5 and 0.7, it is half open and half closed. f The faults with a value greater than 0.7 have poor sealing properties. The prediction results show that the overall sealing properties of the faults in this example are good, but the sealing properties of the faults in the middle are poor.

[0069] In specific embodiment 3 of the present invention, three-dimensional sealing prediction is performed on other faults in the study area. Figure 1 The present invention is a flow chart of a three-dimensional cross-section plugging prediction method based on pseudo-acoustic wave constrained inversion.

[0070] In step 101, the shale content curve is standardized, and the high-frequency information of the shale content curve is retained by a high-pass filtering method. The high-frequency components of the shale content are fused and reconstructed with the acoustic wave curve in the frequency domain, and then the wave impedance data ( Figure 3 ).

[0071] In step 102, the pseudo-acoustic impedance threshold value R of the sandstone and mudstone in the study area is statistically analyzed. thed , using the formula The mudstone wave impedance information below the threshold is mapped to the range of [0,1], using the formula The wave impedance information of sandstones above the threshold value is mapped to the range of [1, 2], so that the dimension of the pseudo-wave impedance can be removed and the wave impedance information can be converted into lithology information through actual well data. In addition, the present invention deliberately projects the wave impedance data representing mudstone to the range of [0, 1] in order to highlight the mudstone information when obtaining energy correlation in the next step.

[0072] In step 103, in three-dimensional space, the average energy of the lithology impedance data is calculated in a 10 ms time window along the fault plane, and the lithology information of the upper wall of the fault is projected onto the cross section F. up =F up (x, y, t)( Figure 10 ); Similarly, the average energy of the lithology impedance data in the 10ms time window along the fault plane is calculated, and the lithology information of the fault footwall is projected onto the section F dw =F dw (x, y, t)( Figure 11 ).

[0073] In step 104, after obtaining the lithology information of the two sides of the fault, the energy correlation between the upper and lower sides is calculated at the same position of the section, and the following is obtained:

[0074]

[0075] Where N is the window size, which is usually 5-7. In this example, the window value is 5. f The larger the value, the stronger the connection between the two sandstones in the cross section. The smaller the value, the higher the proportion of mudstone. The two mudstones in the cross section are connected to mudstones, and the plugging performance is good. Figure 12 ).

[0076] In step 105, through quantitative analysis of the known development well data near the fracture in this example, it is considered that B f The faults with a value less than 0.5 have good sealing properties. f Between 0.5 and 0.7, it is half open and half closed. f The faults with a value greater than 0.7 have poor sealing properties. The prediction results show that the overall sealing properties of the faults in this example are good, but the sealing properties of the faults in the middle are poor.

[0077] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0078] Except for the technical features described in the specification, they are all well-known technologies to those skilled in the art.

Claims

1. A three-dimensional cross-section plugging prediction method based on pseudo-acoustic wave constrained inversion, characterized in that The three-dimensional section sealing prediction method based on pseudo-acoustic wave constrained inversion includes: Step 1: Combine the high-frequency information of the shale content curve, reconstruct the acoustic wave data, and obtain pseudo-wave impedance data based on three-dimensional geological modeling. Step 2: Perform lithology identification on the pseudo-wave impedance data to convert it into lithology information and obtain lithology impedance data. Step 3: Extract lithology impedance along the upper and lower plates of the fault plane in three-dimensional space respectively. Step 4: Perform energy correlation on both sides of the fault to obtain the three-dimensional section sealing prediction result. Step 5: Evaluate the section sealing prediction result through quantitative analysis of known development well data. In step 2, statistically analyze the pseudo-acoustic impedance threshold value R of sandstone and mudstone thed , and use the formula to map the mudstone wave impedance information below the threshold value to the range [0, 1], and use the formula to map the sandstone wave impedance information above the threshold value to the range [1, 2], where: R represents the pseudo-acoustic impedance data, R min is the minimum value of wave impedance, and R max is the maximum value of wave impedance; finally, remove the dimension of the pseudo-wave impedance, and convert the wave impedance information into lithology information through actual well data.

2. The three-dimensional cross-section plugging prediction method based on pseudo-acoustic wave constrained inversion according to claim 1, wherein In Step 1, standardize the shale content curve, retain the high-frequency information of the shale content curve through high-pass filtering, and fuse and reconstruct the high-frequency components of the shale content and the acoustic wave curve in the frequency domain.

3. The three-dimensional section plugging prediction method based on pseudo-acoustic wave constrained inversion according to claim 1, characterized in that In Step 1, utilize the fine-interpreted sequence interface and fault plane to build a geological model in three-dimensional space, and obtain wave impedance data through constrained inversion with the reconstructed acoustic wave curve.

4. The three-dimensional cross-section plugging prediction method based on pseudo-acoustic wave constrained inversion according to claim 1, characterized in that In step 3, in the three-dimensional space, an average energy is obtained by opening a time window upward along the fault plane for the lithologic impedance data, and the lithologic information of the hanging wall of the fault is projected onto the fault plane F up = F up (x, y, t); similarly, an average energy is obtained by opening a time window downward along the fault plane for the lithologic impedance data, and the lithologic information of the footwall of the fault is projected onto the fault plane F dw = F dw (x, y, t); where: F dw represents the hanging wall of the fault, F dw is the lithologic data of the footwall, and x, y, t represent the three-dimensional spatial positions of the lithologic data, which are the horizontal and vertical coordinates and time respectively.

5. The three-dimensional section plugging prediction method based on pseudo-acoustic wave constrained inversion according to claim 4, characterized in that In Step 4, after obtaining the lithology information on both sides of the fault respectively, calculate the energy correlation of the upper and lower plates at the same position on the fault plane. The formula is as follows: where N is the window size, taking 5 - 7.

6. The three-dimensional section plugging prediction method based on pseudo-acoustic wave constrained inversion according to claim 5, wherein In step 4, B f The larger the value, the stronger the docking of sandstones on both sides of the fault surface. The smaller the value, the higher the proportion of mudstone. Mudstones on both sides of the fault surface are docked with mudstones, showing good sealing performance.

7. The three-dimensional cross-section plugging prediction method based on pseudo-acoustic wave constrained inversion according to claim 6, characterized in that In step 5, through quantitative analysis of known development well data, it is considered that the fault with a B f value less than 0.4 has good fault sealing, and the B f value between 0.4 and 0.7 belongs to semi-open and semi-closed, and the B f fault with a value greater than 0.7 has poor fault sealing.

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