Micro-displacement small-fracture feature engraving method and system

Abstract

The invention belongs to the technical field of oil-gas exploration and development, and relates to a micro-displacement small fracture feature engraving method and system, and the method comprises the steps: obtaining a seismic data body and geosteering data of a target region; according to the geosteering data, position information of micro-displacement small fractures encountered by target well drilling is obtained; according to the seismic data volume, cutting a seismic section of the target well containing micro-displacement small fracture position information; taking the seismic section as a reference direction, and cutting a 360-degree rotation seismic section of the target well; carrying out micro-displacement small-fracture seismic response feature identification on the 360-degree rotation seismic section of the target well; and according to the seismic response feature recognition result, engraving the micro-displacement small fracture of the target well in drilling. The system comprises a first acquisition module, a second acquisition module, a first cutting module, a second cutting module, an identification module and an engraving module. According to the method, the micro-displacement small-fracture three-dimensional fine engraving capability is improved, the development characteristics of micro-displacement small fractures are defined, and finally the oil-gas exploration efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas exploration and development, and particularly relates to a micro-displacement small fracture feature engraving method and system. Background Art

[0002] In oil and gas exploration and development, it is often necessary to identify and determine the micro-displacement small faults in the target area and clarify their development characteristics. Micro-displacement small faults can be specifically understood as a fault structure (which can be called a micro-fault). This structure can serve as a storage space and / or seepage channel for low-porosity and low-permeability reservoirs, and plays an important role in oil and gas migration and accumulation. Usually, the above-mentioned micro-displacement small faults refer to faults with a fault distance of 7.5-20m in the target area. Specifically, there is often no obvious misalignment in the seismic reflection symmetric axis, which is manifested as local disturbances, folds, or energy changes such as sudden weakening of the amplitude.

[0003] Micro-displacement small faults are difficult to identify due to their small fault distance and short plane extension, and it is even more difficult to clearly define their morphological and structural characteristics. At present, the research on micro-displacement small faults is mainly focused on seismic technology, which improves the seismic resolution by increasing the frequency or improves the algorithm to obtain clearer imaging effects, and extracts attribute bodies based on various attributes such as the inclination and orientation of the fault. The attribute bodies are calculated based on the original seismic data body. Most of the existing methods identify and determine micro-displacement small faults based on the structural and shape characteristics reflected by the seismic data body. The structural characteristics of the micro-displacement small faults themselves cannot be finely portrayed or the portrayal accuracy is low. Summary of the invention

[0004] In view of the above problems, the technical solution adopted by the present invention is as follows: a method for engraving micro-displacement small fault features, the method comprising the following steps: obtaining seismic data volume and geological guidance data of the target area;

[0005] Obtain the location information of small micro-displacement fractures encountered in the target well according to the geological guidance data;

[0006] Cut the seismic section containing the location information of micro-displacement and small faults of the target well according to the seismic data volume;

[0007] Taking the seismic profile as the reference direction, cut the 360-degree rotating seismic profile of the target well;

[0008] Identify the seismic response characteristics of micro-displacement and small faults by rotating the 360-degree seismic profile of the target well;

[0009] According to the seismic response feature identification results, the micro-displacement small faults encountered in the target well are carved.

[0010] Further, the obtaining of the location information of the micro-displacement small fracture encountered in the target well according to the geological steering data includes:

[0011] According to the geological guidance data, horizontal wells, vertical wells or inclined wells that encounter small micro-displacement faults in the target area are selected to obtain the position information of the small micro-displacement faults encountered in the horizontal wells, vertical wells or inclined wells on the well trajectory.

[0012] Furthermore, the method of extracting a seismic profile containing micro-displacement and small fault location information of the target well according to the seismic data volume includes:

[0013] When the target well is a horizontal well that encounters a micro-displacement small fault, the starting point A of the horizontal section of the horizontal well is taken as the center point, point B is taken as the end point of the horizontal section, and the direction AB of the horizontal section well trajectory is taken as the seismic section direction. The seismic section containing the location information of the micro-displacement small fault is cut through the center point A.

[0014] When the target well is a vertical well or an inclined well that encounters a small micro-displacement fault, the wellhead of the vertical well or the inclined well is taken as the center point, the completion point of the vertical well or the inclined well is taken as the end point, and a seismic profile containing the location information of the small micro-displacement fault is cut through the wellhead and the completion point.

[0015] Furthermore, the method of cutting a 360-degree rotational seismic profile of the target well with the seismic profile as a reference direction includes: taking the cutting of the seismic profile along the well trajectory as a reference direction, taking the starting point A of the horizontal section of the horizontal well or the wellhead of the vertical well or the inclined well as the center point, and cutting the seismic profile at fixed angle intervals in a 360-degree azimuth to obtain a 360-degree rotational seismic profile of the horizontal well, the vertical well or the inclined well.

[0016] Furthermore, the identification of seismic response characteristics of micro-displacement and small faults on the 360-degree rotation seismic profile of the target well includes: identifying the seismic response characteristics of micro-displacement and small faults on the 360-degree rotation seismic profile of the horizontal well, vertical well or inclined well, and comparing the micro-displacement and small fault characteristics identified in each angle profile; and selecting the dominant azimuth seismic profile of the horizontal well, vertical well or inclined well that is orthogonal to the micro-displacement and small fault according to the micro-displacement and small fault characteristics identified in each angle profile.

[0017] Furthermore, carving the micro-displacement small faults encountered in the target well according to the seismic response characteristic identification results includes: performing three-dimensional fine carving of the micro-displacement small faults encountered in the horizontal well, vertical well or inclined well according to the dominant azimuth seismic profile orthogonal to the micro-displacement small faults, and determining the fracture elements and fracture types of the micro-displacement small faults.

[0018] Furthermore, the fault elements and fault types are: the fault elements include fault distance, dip, inclination and section length; the fault types are divided into low-angle shovel-type intralayer slip type and high-angle plate-type through-closure type.

[0019] Furthermore, the geological guidance data includes whether micro-displacement small faults are encountered and the location information of micro-displacement small faults; the seismic data body includes underground geological information and the style and type of micro-displacement small faults; the underground geological information includes stratum thickness, lithology and fractures.

[0020] In addition, the present invention also provides a micro-displacement small fracture feature engraving system, the system comprising: a first acquisition module, a second acquisition module, a first cutting module, a second cutting module, an identification module and an engraving module; the first acquisition module is used to acquire the seismic data body and geological guidance data of the target area; the second acquisition module is used to acquire the position information of the micro-displacement small fracture encountered in the target well according to the geological guidance data; the first cutting module is used to cut the seismic profile containing the micro-displacement small fracture position information of the target well according to the seismic data body; the second cutting module is used to cut the 360-degree rotation seismic profile of the target well with the seismic profile as the reference direction; the identification module is used to identify the seismic response characteristics of the micro-displacement small fracture of the 360-degree rotation seismic profile of the target well; the engraving module is used to engrave the micro-displacement small fracture encountered in the target well according to the seismic response characteristic identification result.

[0021] Furthermore, the identification module includes a comparison unit and a selection unit; the comparison unit is used to identify the seismic response characteristics of micro-displacement small faults in the 360-degree rotation seismic profile of the horizontal well, vertical well or inclined well, and compare the micro-displacement small fault characteristics identified in each angle profile; the selection unit is used to select the dominant azimuth seismic profile of the horizontal well, vertical well or inclined well that is orthogonal to the micro-displacement small fault based on the micro-displacement small fault characteristics identified in each angle profile.

[0022] The present invention designs a method and system for carving features of micro-displacement small faults. By combining the geological guidance data of horizontal wells, vertical wells or inclined wells, the method locates and identifies the micro-displacement small faults encountered during drilling. In view of the azimuthal anisotropy of the development of micro-displacement small faults, the method uses a 360-degree rotating section to finely carve the shape, style, dip, inclination and other elements of the micro-displacement small faults. By optimizing the direction of the seismic section that is orthogonal to the micro-displacement small fault, the three-dimensional fine carving capability of the micro-displacement small fault is improved, the development characteristics of the micro-displacement small fault are clarified, and the efficiency of oil and gas exploration is finally improved.

[0023] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 A schematic diagram of a micro-displacement small fracture feature engraving method in an embodiment of the present invention;

[0026] Figure 2 A geosteering model diagram in an embodiment of the present invention;

[0027] Figure 3 It is a schematic plan view of a 360-degree rotating seismic section in an embodiment of the present invention;

[0028] Figure 4 Schematic diagram of a micro-displacement small fracture feature engraving system in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] A micro-displacement small fracture feature engraving method, such as Figure 1 As shown, the method includes the following steps: S1, obtaining seismic data and geological guidance data of the target area; S2, obtaining the position information of the micro-displacement small fault encountered in the target well according to the geological guidance data; S3, cutting the seismic profile of the target well containing the position information of the micro-displacement small fault according to the seismic data body; S4, cutting the 360-degree rotation seismic profile of the target well with the seismic profile as the reference direction; S5, identifying the seismic response characteristics of the micro-displacement small fault of the 360-degree rotation seismic profile of the target well; S6, carving the micro-displacement small fault encountered in the target well according to the seismic response characteristic identification result.

[0031] In the embodiment of the present invention, the target area is the Luzhou block in southern Sichuan; specifically, in step S1, the seismic data body and geological guidance data of the Luzhou block in southern Sichuan are obtained, and the seismic data body is imported into seismic interpretation software such as petrel. The seismic profile is cut from the seismic data body to interpret the fault, and the seismic data body is imported into the seismic interpretation software, and the seismic data body is processed with the help of the seismic interpretation software, such as cutting seismic profiles, interpreting faults, and calculating attribute bodies. The geological guidance data can reflect whether small micro-displacement faults are encountered during the drilling process, and clarify the basic position information of small micro-displacement faults; such as Figure 2 The figure shows a geosteering model diagram drawn based on geosteering data. The model includes gamma, drilling time, total hydrocarbon and other logging curves; horizontal wellbore trajectory of horizontal well, depth of starting and ending points of horizontal section, formation depth and location of drilling faults. Through comparative analysis of multiple logging curves, high gamma values ​​at the numerical mutation point may indicate the development of faults. Combined with the wellbore trajectory, the location of drilling faults can be determined. The seismic data body can accurately reflect the geological information such as the thickness of the underground formation, lithology and fault development, and clarify the elements and types of micro-displacement small faults. Fault elements include fault distance, dip, dip angle and section length; fault types are divided into low-angle shovel-type intralayer slip type and high-angle plate-type through-closure type.

[0032] Specifically, in step S2, a horizontal well, a vertical well or an inclined well drilled with a micro-displacement small fault in the target area is selected according to the geological guidance data, and the position information of the micro-displacement small fault drilled by the horizontal well, the vertical well or the inclined well on the well trajectory is obtained.

[0033] In the embodiment of the present invention, a horizontal well drilled in the Luzhou block in southern Sichuan that encounters a micro-displacement small fault is selected through geological guidance data to obtain the location information of the drilled micro-displacement small fault on the well trajectory. The selected well can also be a vertical well or an inclined well, and the operation steps are not much different from those of a horizontal well, except that the selection of the center point is changed from the starting point of the horizontal well section to the wellhead.

[0034] Specifically, in step S3, when the target well is a horizontal well drilled with a small micro-displacement fault, the starting point A of the horizontal section of the horizontal well is taken as the center point, point B is taken as the end point of the horizontal section, and the direction AB of the horizontal section well trajectory is taken as the seismic section direction, and the seismic section containing the position information of the small micro-displacement fault is cut through the center point A. According to the position information of the small micro-displacement fault obtained in step S2, the small micro-displacement fault can be located on the cut seismic section, so as to obtain the basic element information of the small micro-displacement fault, and determine its type as a high-angle through-fault or a low-angle slip fault. When the target well is a vertical well or an inclined well drilled with a small micro-displacement fault, the wellhead of the vertical well or the inclined well is taken as the center point, and the completion point of the vertical well or the inclined well is taken as the end point, and the seismic section containing the position information of the small micro-displacement fault is cut through the wellhead and the completion point.

[0035] Specifically, in step S4, the seismic profile is taken as the reference direction, the horizontal segment starting point A or the wellhead is taken as the center point, and the seismic profile is cut at fixed angle intervals according to the 360-degree azimuth to obtain the 360-degree rotation seismic profile of the horizontal well, vertical well or inclined well. In the embodiment of the present invention, the horizontal well segment starting point A is taken as the center point, and a seismic profile is cut every 30 degrees according to the 360-degree azimuth to obtain the following: Figure 3 A 360-degree rotation seismic section of a horizontal well is shown. Figure 3 In the figure, the black circle indicates the well location and name (well 1 in the embodiment of the present invention), the starting point A of the horizontal segment is the center point, and point B is the end point of the horizontal segment; the AB line indicates the horizontal segment well trajectory, the green straight line indicates the 360-degree rotation profile line, and the red-brown curve indicates the micro-displacement small fault F1. Figure 3 In the figure, the starting point A is taken as the center point, and the seismic profile is cut at intervals of 30 degrees. It should be noted that the seismic profile can be cut at any angle interval with the starting point A as the center point. The smaller the cutting angle interval, the more detailed the subtle characteristic changes of micro-displacement and small faults in different directions can be reflected; but the smaller the interval, the better. Too small an interval will lead to unclear differences in the characteristics of micro-displacement and small faults in different directions. Generally speaking, it is best to set the cutting angle interval to 30 degrees.

[0036] Specifically, in step S5, the seismic response characteristics of micro-displacement small faults are identified for the 360-degree rotating seismic profile, and the characteristic information of micro-displacement small faults identified in each angle profile is compared to select the seismic profile that can better reflect the characteristics of micro-displacement small faults, and obtain the dominant azimuth seismic profile orthogonal to the horizontal well and the micro-displacement small fault; Figure 3 The seismic profile along the well trajectory AB direction is oblique to the micro-displacement small fault F1, so the micro-displacement small fault F1 may not have obvious seismic response characteristics in this profile, and it is impossible to carve the F1 micro-displacement small fault. Figure 3 The seismic profile in the 120-degree direction is nearly orthogonal to the F1 micro-displacement small fault, which can better reflect the seismic geological information of the micro-displacement small fault F1.

[0037] Specifically, in step S6, according to the 120-degree azimuth seismic profile selected in step S5, the micro-displacement small faults encountered by the horizontal wells in the Luzhou block in southern Sichuan are finely carved in three dimensions to clarify the information such as the fault elements and fault types. The 120-degree seismic profile only depicts the southern part of the fault, and it can also be translated northward along the profile direction to perform three-dimensional fine carving on the entire fault, such as Figure 3 CC shown ’ ,DD ′ Section. CC ’ ,DD ′ The wire represents the tracking of the micro-displacement small fracture F1, which is translated along the 120° direction in the 360° direction to carve the fracture spatial distribution and endpoints.

[0038] In addition, the present invention also designs a micro-displacement small fracture feature engraving system, such as Figure 4 As shown, the system includes: a first acquisition module, a second acquisition module, a first cutting module, a second cutting module, an identification module and a carving module; the first acquisition module is used to acquire the seismic data body and geological guidance data of the target area; the second acquisition module is used to acquire the position information of the micro-displacement small faults encountered in the target well according to the geological guidance data; the first cutting module is used to cut the seismic profile containing the micro-displacement small fault position information of the target well according to the seismic data body; the second cutting module is used to cut the 360-degree rotation seismic profile of the target well with the seismic profile as the reference direction; the identification module is used to identify the seismic response characteristics of the micro-displacement small faults of the 360-degree rotation seismic profile of the target well; the carving module is used to carve the micro-displacement small faults encountered in the target well according to the seismic response characteristic identification result.

[0039] Specifically, the identification module includes a comparison unit and a selection unit; the comparison unit is used to identify the seismic response characteristics of micro-displacement small faults in the 360-degree rotation seismic profile of the horizontal well, vertical well or inclined well, and compare the micro-displacement small fault characteristics identified in each angle profile; the selection unit is used to select the dominant azimuth seismic profile of the horizontal well, vertical well or inclined well that is orthogonal to the micro-displacement small fault based on the micro-displacement small fault characteristics identified in each angle profile.

[0040] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A micro-displacement small fracture feature engraving method, characterized in that: The method comprises the following steps: Obtain seismic data and geosteering information in the target area; Obtain the location information of small micro-displacement fractures encountered in the target well according to the geological guidance data; Cut the seismic section containing the location information of micro-displacement and small faults of the target well according to the seismic data volume; Taking the seismic profile as the reference direction, cut the 360-degree rotating seismic profile of the target well; Identify the seismic response characteristics of micro-displacement and small faults by rotating the 360-degree seismic profile of the target well; According to the seismic response feature identification results, the micro-displacement small faults encountered in the target well are carved.

2. The method according to claim 1, characterized in that The method of obtaining the location information of the micro-displacement and small fracture encountered in the target well according to the geological steering data includes: According to the geological guidance data, horizontal wells, vertical wells or inclined wells that encounter small micro-displacement faults in the target area are selected to obtain the position information of the small micro-displacement faults encountered in the horizontal wells, vertical wells or inclined wells on the well trajectory.

3. The method according to claim 2, characterized in that The method of cutting a seismic profile containing micro-displacement and small fault location information of a target well according to the seismic data volume comprises: When the target well is a horizontal well that encounters a micro-displacement small fault, the starting point A of the horizontal section of the horizontal well is taken as the center point, point B is taken as the end point of the horizontal section, and the direction AB of the horizontal section well trajectory is taken as the seismic section direction. The seismic section containing the location information of the micro-displacement small fault is cut through the center point A. When the target well is a vertical well or an inclined well that encounters a small micro-displacement fault, the wellhead of the vertical well or the inclined well is taken as the center point, the completion point of the vertical well or the inclined well is taken as the end point, and a seismic profile containing the location information of the small micro-displacement fault is cut through the wellhead and the completion point.

4. The method according to claim 3, characterized in that The method of taking the seismic profile as the reference direction and cutting the 360-degree rotating seismic profile of the target well comprises: Taking the seismic profile cut along the well trajectory as the reference direction, and the starting point A of the horizontal section of the horizontal well or the wellhead of the vertical well or inclined well as the center point, the seismic profile is cut at fixed angle intervals in 360-degree azimuth to obtain a 360-degree rotational seismic profile of the horizontal well, vertical well or inclined well.

5. The method according to claim 4, characterized in that The seismic response feature identification of micro-displacement small faults on the 360-degree rotation seismic profile of the target well includes: Identify the seismic response characteristics of micro-displacement and small faults on the 360-degree rotating seismic profiles of horizontal wells, vertical wells or inclined wells, and compare the micro-displacement and small fault characteristics identified at each angle profile; According to the characteristics of micro-displacement and small faults identified in each angle section, the dominant azimuth seismic sections orthogonal to the micro-displacement and small faults of the horizontal well, vertical well or inclined well are selected.

6. The method according to claim 5, characterized in that The method of carving the micro-displacement small fault encountered in the target well according to the seismic response feature identification result includes: According to the dominant azimuth seismic profile orthogonal to the micro-displacement small faults in the horizontal well, vertical well or inclined well, three-dimensional fine carving is performed on the micro-displacement small faults encountered in the horizontal well, vertical well or inclined well to determine the fault elements and fault types of the micro-displacement small faults.

7. The method according to claim 6, characterized in that The fault elements and fault types are: the fault elements include fault distance, dip, inclination and section length; the fault types are divided into low-angle shovel-type intralayer slip type and high-angle plate-type through-and-through closure type.

8. The method according to any one of claims 1 to 7, characterized in that: The geological guidance data includes whether the drilling encounters a small micro-displacement fault and the location information of the small micro-displacement fault; the seismic data body includes underground geological information and the style and type of the small micro-displacement fault; the underground geological information includes stratum thickness, lithology and fracture cracks.

9. A micro-displacement small fracture feature engraving system, characterized in that: The system comprises: a first acquisition module, a second acquisition module, a first cutting module, a second cutting module, a recognition module and a carving module; The first acquisition module is used to acquire seismic data volume and geological guidance data of the target area; The second acquisition module is used to obtain the location information of the micro-displacement small fracture encountered in the target well according to the geological guidance data; The first extraction module is used to extract the seismic profile containing micro-displacement and small fault location information of the target well according to the seismic data volume; The second cutting module is used to cut a 360-degree rotating seismic section of the target well with the seismic section as the reference direction; The identification module is used to identify the seismic response characteristics of micro-displacement and small faults in a 360-degree rotation seismic profile of the target well; The carving module is used to carve the micro-displacement small faults encountered in the target well according to the seismic response feature recognition result.

10. The system according to claim 9, characterized in that The recognition module includes a comparison unit and a selection unit; The comparison unit is used to identify the seismic response characteristics of micro-displacement and small faults in the 360-degree rotation seismic profile of the horizontal well, vertical well or inclined well, and compare the micro-displacement and small fault characteristics identified in each angle profile; The selection unit is used to select a dominant azimuth seismic profile orthogonal to a micro-displacement small fault in a horizontal well, a vertical well or a deviated well according to the micro-displacement small fault characteristics identified in each angle profile.

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