A method for determining the longitudinal cutting capacity of strike-slip fault zones

Abstract

The present application discloses a method for determining the longitudinal cutting ability of a strike-slip fault zone. By accurately reading the thickness of each layer involved in the rating of each sampling profile, the total thickness of the formation and the longitudinal cutting depth of the strike-slip fault zone, a strike-slip fault zone cutting ability index is constructed, an evaluation standard for the longitudinal cutting ability of the strike-slip fault zone on the formation is established, the spatial variation pattern of the longitudinal cutting ability of the strike-slip fault zone is clarified, and a mathematical method for accurately determining the longitudinal cutting ability of the strike-slip fault zone on the formation is used. The method can objectively and quantitatively evaluate the differences in the longitudinal cutting ability of different parts of the strike-slip fault zone, and can reasonably avoid the deficiency that the formation thickness in the same area is obviously different due to the differences in the original formation deposition degree or the differences in the later weathering and erosion degree in different parts of the same area and the same strike-slip fault zone, resulting in the inability to use a unified comparison standard to evaluate the longitudinal cutting ability of the strike-slip fault zone.

Description

Technical Field

[0001] The present application relates to the field of geological technology, and in particular to a method for determining the longitudinal cutting capacity of a strike-slip fault zone. Background Art

[0002] In recent years, numerous strike-slip faults have been discovered in China's Tarim Basin. Research on strike-slip fault zones has demonstrated their characteristic "reservoir control, reservoir control, and enrichment control" characteristics. Under the multi-stage transformation of strike-slip fault zones, deep and ultra-deep Ordovician carbonate reservoirs in the Tarim Basin have primarily developed along strike-slip fault zones, with hydrocarbon accumulation occurring within these zones. Based on this unique phenomenon, numerous researchers have established a fault-controlled hydrocarbon accumulation model within deep and ultra-deep strike-slip fault zones in the Tarim Basin. However, with increasing research on strike-slip faults, it has been gradually realized that while strike-slip faults exhibit high and steep strikes and penetrate directly into the basement, their penetration capacity varies significantly along their strike. This variation in characteristics significantly influences the coupling between strike-slip faults and source-kitchen systems, leading to varying hydrocarbon enrichment in carbonate reservoirs along the same strike-slip fault, further impacting the success rate of well placement.

[0003] With the continuous development of oil and gas resources, oil and gas exploration technology has advanced significantly worldwide. In oil and gas exploration, the study of fault zones is particularly important, especially strike-slip fault zones, which not only influence reservoir distribution but also directly impact the accumulation and flow of oil and gas. Due to their unique structural characteristics, strike-slip fault zones often serve as important pathways for oil and gas accumulation. In areas with typical strike-slip fault zones, such as the Tarim Basin, strike-slip fault zones play a significant role in controlling the formation and accumulation of oil and gas. Therefore, accurately assessing the vertical penetration capacity of strike-slip fault zones has become a pressing technical challenge in oil and gas exploration.

[0004] At present, research on strike-slip fault zones mainly focuses on the development characteristics of shallow reservoirs, especially on the lateral distribution and impact range of fault zones. However, there is still a large technical gap in the study of the vertical penetration capacity of strike-slip fault zones. Existing technologies mainly describe strike-slip fault zones through seismic reflection data or drilling data, but most studies lack quantitative analysis methods and often rely on empirical judgment, resulting in large differences in the assessment of the vertical penetration capacity of strike-slip fault zones in the same region by different researchers. In addition, when facing different strike-slip fault zones in the same area or different parts of the same strike-slip fault zone, existing technologies cannot effectively avoid the influence of factors such as sedimentation differences, weathering and erosion, and cannot provide a unified evaluation standard, which directly affects the accuracy of oil and gas exploration and the success rate of well deployment.

[0005] Therefore, in oil and gas exploration in strike-slip fault zones, the lack of quantitative standards for vertical penetration ability evaluation methods, the impact of formation thickness differences on assessment accuracy, and the difficulty of existing technologies in accurately depicting the spatial variation characteristics of strike-slip fault zones have become issues that need to be addressed urgently. Summary of the Invention

[0006] The present application provides a method for determining the longitudinal cutting capacity of a strike-slip fault zone, aiming to solve the problem that the existing technology is difficult to accurately characterize the spatial variation characteristics of a strike-slip fault zone.

[0007] A method for determining the longitudinal penetration capacity of a strike-slip fault zone, the method comprising:

[0008] S1: Based on actual seismic data, extract fault sensitivity attributes to clarify the dominant development locations of strike-slip fault zones on the plane and the degree of continuity on the profile;

[0009] S2: Determine the horizons involved in the evaluation of the longitudinal penetration capacity of strike-slip fault zones and determine the accuracy of the evaluation of the longitudinal penetration capacity of strike-slip fault zones;

[0010] S3: According to the target accuracy requirements, each sampling section is graded, involving the calculation of the thickness of each layer, the total thickness of the stratum, and the measurement of the longitudinal penetration depth of the strike-slip fault zone, and the longitudinal penetration capacity of the strike-slip fault in different sections is calculated;

[0011] S4: Construct a strike-slip fault zone penetration capacity index, establish an evaluation standard for the strike-slip fault zone's longitudinal penetration capacity of the strata, draw a curve of the strike-slip fault zone penetration capacity index change, and clarify the spatial variation pattern of the strike-slip fault zone's longitudinal penetration capacity.

[0012] In the above solution, optionally, step S1 includes:

[0013] S11: Based on actual seismic data, determine the location of strike-slip faults and analyze the scale of strike-slip faults;

[0014] S12: Extract sensitive attributes of strike-slip faults according to their scale;

[0015] S13: Based on seismic attributes, clarify the dominant development locations of strike-slip fault zones on the plane and the degree of continuity of strike-slip fault zones on the cross section;

[0016] In the above scheme, optionally, in step S11, the location of the strike-slip fault is determined by using the interruption, shift, or distortion of the seismic reflection event in the actual seismic data. The extension of the strike-slip fault on the seismic section is traced by the continuation of the interruption, shift, or distortion of the seismic reflection event in the longitudinal direction of the seismic section. The width of the interruption, shift, or distortion of the seismic reflection event in the lateral direction of the seismic section is combined to determine the scale of the strike-slip fault zone.

[0017] If the seismic reflection event is clearly observed to be interrupted or dislocated on the seismic profile, and the seismic reflection event has a large fault throw and a large width due to the interruption or dislocation, a fault throw of >20ms is considered a large fault throw, and a width of >40ms is considered a large width, and there is a preset impact on the stratigraphic and tectonic pattern, then the scale of the strike-slip fault is large;

[0018] If the seismic reflection event is clearly observed to be interrupted or dislocated on the seismic profile, and the seismic reflection event has a certain distance and width due to the interruption or dislocation, with a distance of 0 to 20 ms and a width of 10 to 40 ms, and the impact on the strata and structure is limited, then the scale of the strike-slip fault is moderate;

[0019] If distortion of seismic reflection events with a width less than 10 ms is observed on the seismic profile, it is considered that the scale of the strike-slip fault is small.

[0020] In the above scheme, optionally, in step S12, coherence volume or ant volume attributes are extracted from large-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones; ant volume or likelihood volume attributes are extracted from medium-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones; and likelihood volume or curvature volume attributes are extracted from small-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones.

[0021] If the same strike-slip fault zone has interruptions, slippage, or distortions in the seismic reflection phase axis on the seismic section, resulting in the strike-slip fault zone's fault throw and width varying frequently, and the strike-slip fault zone's size cannot be effectively distinguished, the method of fusing multiple seismic attributes can be used to combine the advantages of different attributes to jointly characterize the boundary and spatial distribution of the strike-slip fault zone.

[0022] In step S13, after extracting the seismic attributes, time slicing is performed to observe the differences in the planar distribution of the strike-slip fault zone at different time slices. Based on the changes in the planar continuity of the strike-slip fault zone at different time slices, the dominant development location of the strike-slip fault zone on the plane is determined. By cutting longitudinal sections, the longitudinal extension of the strike-slip fault zone at different sections is observed. Based on the changes in the continuity of the strike-slip fault zone at different sections, the continuity of the strike-slip fault zone on the section is determined.

[0023] On the time slice and profile, the higher the plane continuity of the strike-slip fault zone and the stronger its linear extension ability, the more developed the strike-slip fault zone is and it is the dominant development site; the lower the plane continuity and the more discontinuous the appearance, the weaker the development of the strike-slip fault zone.

[0024] In the above solution, optionally, step S2 includes:

[0025] S21: Based on the continuity of the strike-slip fault zone on the seismic attribute profile, determine the layers involved in the longitudinal penetration capacity rating of the strike-slip fault zone;

[0026] S22: Based on the dominant development locations of strike-slip fault zones on the seismic attribute plane, the accuracy of evaluating the longitudinal cutting capacity of strike-slip fault zones is determined.

[0027] In the above scheme, optionally, in step S21, when determining the horizons involved in the rating of the longitudinal penetration capability of the strike-slip fault zone, it is clarified that the degree of continuity of the strike-slip fault zone determined by the seismic attribute profile at this time is the minimum continuity degree and the maximum continuity degree of the entire strike-slip fault zone; the current minimum continuity degree of the entire strike-slip fault zone represents the minimum value of the horizons that can be penetrated in the longitudinal direction of the entire strike-slip fault zone, which is the weakest penetration capability value of the entire strike-slip fault zone, and the horizon closest to the deep part on the profile is recorded as the first penetration horizon C1; the current maximum continuity degree of the entire strike-slip fault zone represents the maximum value of the horizons that can be penetrated in the longitudinal direction of the entire strike-slip fault zone, which is the strongest penetration capability value of the entire strike-slip fault zone, and the horizon closest to the shallow part on the profile is recorded as the third penetration horizon C3; between the two horizons, the second penetration horizon C2 is selected based on actual exploration and development requirements and actual formation thickness;

[0028] In step S22, after clarifying the layers involved in the rating of the longitudinal cutting ability of the strike-slip fault zone, if there is a large stratum fluctuation, the dominant development position of the strike-slip fault zone in the target layer is accurately determined by extracting targeted seismic attributes along the layer; then, by counting the number of dominant development positions of the strike-slip fault zone on the plane, the width of each corresponding dominant development position of the strike-slip fault zone is measured, and the accuracy of the evaluation of the longitudinal cutting ability of the strike-slip fault zone is comprehensively determined.

[0029] The dominant development location of strike-slip fault zones in the plane is the location with high continuity and good linear extension on the plane attribute map. It is ensured that at least the two ends and the middle of any dominant development location of strike-slip fault zones in the plane are covered by sampling sections. The three sampling sections are used as the lower limit of the accuracy of the longitudinal cutting capacity evaluation of strike-slip fault zones.

[0030] In the above solution, optionally, step S3 includes:

[0031] S31: Based on the actual accuracy requirements, determine the sampling section locations and numbers Nn for measuring the thickness of each stratum involved in the rating, the total stratum thickness, and the longitudinal penetration depth of the strike-slip fault zone;

[0032] S32: Calculate the thickness of each stratum Hf and the total thickness of the stratum Hz involved in the rating on different sampling sections;

[0033] S33: Based on the actual strike-slip fault continuity degree of different sampling sections, the actual longitudinal penetration depth Sn of the strike-slip fault zone is measured;

[0034] S34: Based on the difference between the thickness of each layer Hf, the total thickness of the formation Hz and the actual longitudinal penetration depth Sn of the strike-slip fault zone involved in the rating of each profile, the longitudinal penetration capacity value Qn of the strike-slip fault of different profiles is calculated.

[0035] In the above solution, optionally, in step S31, when determining the sampling section location based on actual accuracy requirements, it is determined that all sampling sections must be arranged at equal distances; all sampling sections must be arranged perpendicular to the strike-slip fault zone;

[0036] In step S32, the stratigraphic thickness Hf of the rated horizons on different sections is the actual thickness of the corresponding sections of the actual horizons. When calculating the stratigraphic thickness Hf of the rated horizons on the sections, the minimum value of the horizons that can be cut through in the longitudinal direction of the entire strike-slip fault zone, represented by the current minimum continuity degree of the entire strike-slip fault zone, the maximum value of the horizons that can be cut through in the longitudinal direction of the entire strike-slip fault zone, represented by the current maximum continuity degree of the entire strike-slip fault zone, and the actual exploration and development requirements are combined to determine the calculation.

[0037] When calculating the total thickness Hz of the strata involved in the rating on the profile and the thickness of each stratum Hf, the calculation shall be carried out according to the degree of interpretation of the basic data of the actual exploration and development strata;

[0038] After the determination is completed, the depth values ​​Df1, Df2 and Df3 corresponding to the first cut-through layer C1, the second cut-through layer C2 and the third cut-through layer C3 are measured for each section respectively, and the stratum thickness Hf1 and Hf2 are calculated;

[0039] H f1 =D f1 -D f2 ;

[0040] H f2 =D f2 -D f3 ;

[0041] In step S32, the total thickness Hz of the strata involved in the rating on different sections is the thickness difference between the shallowest stratum depth Dq that can be cut through by the top of the strike-slip fault zone under the maximum continuity of the strike-slip fault zone in the current exploration and development and the depth Df2 corresponding to the second cut-through stratum C2;

[0042] H z =D q -D f2 ;

[0043] In step S33, during the actual interpretation of strike-slip faults, the degree of continuity of actual strike-slip faults in different sampling profiles varies greatly. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, if the strike-slip fault zone appears intermittently on the profile, and excluding the influence of the stratum being gypsum-salt rock, the intermittent interval exceeds 60-80 ms, then the intermittent strike-slip fault here is not a first-phase product. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, only the length of the strike-slip fault zone in the shallow layer can be used as the actual longitudinal penetration depth Sn of the strike-slip fault zone. If the strike-slip fault zone appears intermittently on the profile, the stratum is gypsum-salt rock, or the intermittent interval is less than 60 ms, then the intermittent strike-slip fault here is a first-phase product. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, the upper and lower segments are connected according to the trend and the two segments are used together as the actual longitudinal penetration depth Sn of the strike-slip fault zone.

[0044] In step S33, during the actual interpretation of strike-slip faults, strike-slip fault zones often continue a short distance into shallower strata after cutting through the interpreted strata in actual oil and gas exploration and development. When measuring the strike-slip fault zone longitudinal penetration depth Sn, this excess distance is ignored. The top of the actual strike-slip fault zone longitudinal penetration depth Sn is ensured to be the same as the shallowest stratum of the strata involved in the assessment.

[0045] In step S34, the total stratum thickness Hz and the actual longitudinal penetration depth Sn of the strike-slip fault zone of each profile rating are measured in sequence, and the difference between the two is used to obtain the longitudinal penetration capacity value Qn of the strike-slip fault of the corresponding profile;

[0046] Q n =S n -H z .

[0047] Step S4 includes: S41: Based on the positive or negative value of the strike-slip fault longitudinal cutting ability value Qn, correspondingly select the formation thickness Hf, thereby constructing the strike-slip fault zone "cutting ability index Zn".

[0048] S42: Divide the intervals according to the “cutting ability index Zn” value of the strike-slip fault zone and establish an evaluation standard for the longitudinal cutting ability of the strike-slip fault zone on the formation.

[0049] S43: For the strike-slip fault zone section number Nn, a curve of the strike-slip fault zone’s cutting ability index is drawn to clarify the spatial variation pattern of the strike-slip fault zone’s longitudinal cutting ability.

[0050] In the above scheme, optionally, in step S41, if the strike-slip fault longitudinal penetration capability value Qn is positive, it means that the strike-slip fault zone's actual longitudinal penetration depth Sn is greater than the total stratum thickness Hz of the layers involved in the profile rating, indicating that the strike-slip fault zone can actually longitudinally penetrate the second penetration layer C2. In this case, the stratum thickness Hf2 should be selected as the indicator for constructing the strike-slip fault zone's "penetration capability index Zn";

[0051] Z n =Q n / H f2 ;

[0052] If the strike-slip fault longitudinal penetration capacity value Qn is negative, it means that the strike-slip fault zone's actual longitudinal penetration depth Sn is less than the total stratum thickness Hz of the layers involved in the profile rating, indicating that the strike-slip fault zone cannot actually cut through the second penetration layer C2, but can only cut through the second penetration layer C1. In this case, the stratum thickness Hf1 should be selected as the indicator for constructing the strike-slip fault zone's "cutting capacity index Zn";

[0053] Z n =Q n / H f1 ;

[0054] In step S42, the intervals are divided according to the "cutting ability index Zn" value of the strike-slip fault zone, and an evaluation standard for the longitudinal cutting ability of the strike-slip fault zone to the stratum is established; when the cutting ability index Zn is positive and Zn>1, it indicates that the strike-slip fault can longitudinally cut through the second cutting layer C2 and can cut through the third cutting layer C3; when the cutting ability index Zn is positive and 0<Zn≤1, it indicates that the strike-slip fault can longitudinally cut through the second cutting layer C2 but cannot cut through the third cutting layer C3; when the cutting ability index Zn is negative and -1<Zn≤0, it indicates that the strike-slip fault can longitudinally cut through the first cutting layer C1 but cannot cut through the second cutting layer C2; when the cutting ability index Zn is negative and Zn≤-1, it indicates that the strike-slip fault cannot longitudinally cut through the first cutting layer C1;

[0055] In step S43, a rectangular coordinate system is established with the corresponding strike-slip fault zone section number Nn as the horizontal coordinate and the corresponding "cutting ability index Zn" of the strike-slip fault zone section as the vertical coordinate, and a curve chart of the change of the strike-slip fault zone cutting ability index is drawn. The spatial variation pattern of the longitudinal cutting ability of the strike-slip fault zone is clarified through the changes in the numerical values ​​of the "cutting ability index Zn" of different sections on the curve chart.

[0056] Compared with the prior art, this application has at least the following beneficial effects:

[0057] This application is based on further analysis and research of existing technical problems, and recognizes that it is difficult for existing technologies to accurately characterize the spatial variation characteristics of strike-slip fault zones. After accurately reading the thickness of each layer involved in the rating of each sampling profile, the total thickness of the stratum and the longitudinal penetration depth of the strike-slip fault zone, the longitudinal penetration capacity values ​​of the strike-slip fault of different profiles are obtained, a strike-slip fault zone penetration capacity index is constructed, an evaluation standard for the longitudinal penetration capacity of the strike-slip fault zone on the stratum is established, and the spatial variation pattern of the longitudinal penetration capacity of the strike-slip fault zone is clarified, thereby accurately determining the mathematical method for the longitudinal penetration capacity of the strike-slip fault zone on the stratum. This method can objectively and quantitatively evaluate the differences in the longitudinal penetration capacity of different parts of the strike-slip fault zone, and can reasonably avoid the deficiency of being unable to use a unified comparison standard to evaluate the longitudinal penetration capacity of the strike-slip fault zone when the stratum thickness in the same area is significantly different due to differences in the original stratum deposition degree or differences in the later weathering and erosion degree in the same area. It provides a practical solution for structural analysts who study strike-slip faults in oil and gas geological exploration and development. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 A schematic flow chart of a method for determining the longitudinal penetration capacity of a strike-slip fault zone provided in one embodiment of the present application;

[0059] Figure 2 A schematic diagram of a method for determining the longitudinal penetration capacity of a strike-slip fault zone provided in one embodiment of the present application;

[0060] Figure 3 A schematic diagram of a method for calculating the "cutting capability index Zn" of the 50th section of a sliding fault zone provided in one embodiment of the present application;

[0061] Figure 4 A schematic diagram of a method for calculating the "cutting capability index Zn" of the 84th section of a sliding fault zone provided in one embodiment of the present application;

[0062] Figure 5 A curve diagram of the change of the "cutting ability index" of a strike-slip fault zone provided in one embodiment of the present application. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0064] In one embodiment, Figure 1 As shown, a method for determining the longitudinal cutting capacity of a strike-slip fault zone is provided, comprising the following steps:

[0065] S1: Based on actual seismic data, extract fault sensitivity attributes to clarify the dominant development locations of strike-slip fault zones on the plane and the degree of continuity on the profile;

[0066] S2: Determine the horizons involved in the evaluation of the longitudinal penetration capacity of strike-slip fault zones and determine the accuracy of the evaluation of the longitudinal penetration capacity of strike-slip fault zones;

[0067] S3: According to the target accuracy requirements, each sampling section is graded, involving the calculation of the thickness of each layer, the total thickness of the stratum, and the measurement of the longitudinal penetration depth of the strike-slip fault zone, and the longitudinal penetration capacity of the strike-slip fault in different sections is calculated;

[0068] S4: Construct a strike-slip fault zone penetration capacity index, establish an evaluation standard for the strike-slip fault zone's longitudinal penetration capacity of the strata, draw a curve of the strike-slip fault zone penetration capacity index change, and clarify the spatial variation pattern of the strike-slip fault zone's longitudinal penetration capacity.

[0069] In this embodiment, step S1 includes:

[0070] S11: Based on actual seismic data, determine the location of strike-slip faults and analyze the scale of strike-slip faults;

[0071] S12: Extract sensitive attributes of strike-slip faults according to their scale;

[0072] S13: Based on seismic attributes, clarify the dominant development locations of strike-slip fault zones on the plane and the degree of continuity of strike-slip fault zones on the cross section;

[0073] In this embodiment, in step S11, the location of the strike-slip fault is determined by using the interruption, displacement, or distortion of the seismic reflection event in the actual seismic data. The extension of the strike-slip fault on the seismic section is traced by the continuation of the interruption, displacement, or distortion of the seismic reflection event in the longitudinal direction of the seismic section. The width of the interruption, displacement, or distortion of the seismic reflection event in the lateral direction of the seismic section is then combined to determine the scale of the strike-slip fault zone.

[0074] If the seismic reflection event is clearly observed to be interrupted or dislocated on the seismic profile, and the seismic reflection event has a large fault throw and a large width due to the interruption or dislocation, a fault throw of >20ms is considered a large fault throw, and a width of >40ms is considered a large width, and there is a preset impact on the stratigraphic and tectonic pattern, then the scale of the strike-slip fault is large;

[0075] If the seismic reflection event is clearly observed to be interrupted or dislocated on the seismic profile, and the seismic reflection event has a certain distance and width due to the interruption or dislocation, with a distance of 0 to 20 ms and a width of 10 to 40 ms, and the impact on the strata and structure is limited, then the scale of the strike-slip fault is moderate;

[0076] If distortion of seismic reflection events with a width less than 10 ms is observed on the seismic profile, it is considered that the scale of the strike-slip fault is small.

[0077] In this embodiment, in step S12, coherence volume or ant volume attributes are extracted from large-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones; ant volume or likelihood volume attributes are extracted from medium-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones; and likelihood volume or curvature volume attributes are extracted from small-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones.

[0078] If the same strike-slip fault zone has interruptions, slippage, or distortions in the seismic reflection phase axis on the seismic section, resulting in the strike-slip fault zone's fault throw and width varying frequently, and the strike-slip fault zone's size cannot be effectively distinguished, the method of fusing multiple seismic attributes can be used to combine the advantages of different attributes to jointly characterize the boundary and spatial distribution of the strike-slip fault zone.

[0079] In step S13, after extracting the seismic attributes, time slicing is performed to observe the differences in the planar distribution of the strike-slip fault zone at different time slices. Based on the changes in the planar continuity of the strike-slip fault zone at different time slices, the dominant development location of the strike-slip fault zone on the plane is determined. By cutting longitudinal sections, the longitudinal extension of the strike-slip fault zone at different sections is observed. Based on the changes in the continuity of the strike-slip fault zone at different sections, the continuity of the strike-slip fault zone on the section is determined.

[0080] On the time slice and profile, the higher the plane continuity of the strike-slip fault zone and the stronger its linear extension ability, the more developed the strike-slip fault zone is and it is the dominant development site; the lower the plane continuity and the more discontinuous the appearance, the weaker the development of the strike-slip fault zone.

[0081] In this embodiment, step S2 includes:

[0082] S21: Based on the continuity of the strike-slip fault zone on the seismic attribute profile, determine the layers involved in the longitudinal penetration capacity rating of the strike-slip fault zone;

[0083] S22: Based on the dominant development locations of strike-slip fault zones on the seismic attribute plane, the accuracy of evaluating the longitudinal cutting capacity of strike-slip fault zones is determined.

[0084] In this embodiment, in step S21, when determining the horizons involved in the longitudinal penetration rating of the strike-slip fault zone, it is clarified that the continuity degree of the strike-slip fault zone determined by the seismic attribute profile at this time is the minimum continuity degree and the maximum continuity degree of the entire strike-slip fault zone; the current minimum continuity degree of the entire strike-slip fault zone represents the minimum value of the horizons that can be penetrated in the longitudinal direction of the entire strike-slip fault zone, and is the weakest penetration value of the entire strike-slip fault zone. The horizon closest to the deep part on the profile is recorded as the first penetration horizon C1; the current maximum continuity degree of the entire strike-slip fault zone represents the maximum value of the horizons that can be penetrated in the longitudinal direction of the entire strike-slip fault zone, and is the strongest penetration value of the entire strike-slip fault zone. The horizon closest to the shallow part on the profile is recorded as the third penetration horizon C3; between the two horizons, the second penetration horizon C2 is selected based on actual exploration and development requirements and actual formation thickness;

[0085] In step S22, after clarifying the layers involved in the rating of the longitudinal cutting ability of the strike-slip fault zone, if there is a large stratum fluctuation, the dominant development position of the strike-slip fault zone in the target layer is accurately determined by extracting targeted seismic attributes along the layer; then, by counting the number of dominant development positions of the strike-slip fault zone on the plane, the width of each corresponding dominant development position of the strike-slip fault zone is measured, and the accuracy of the evaluation of the longitudinal cutting ability of the strike-slip fault zone is comprehensively determined.

[0086] The dominant development location of strike-slip fault zones in the plane is the location with high continuity and good linear extension on the plane attribute map. It is ensured that at least the two ends and the middle of any dominant development location of strike-slip fault zones in the plane are covered by sampling sections. The three sampling sections are used as the lower limit of the accuracy of the longitudinal cutting capacity evaluation of strike-slip fault zones.

[0087] In this embodiment, step S3 includes:

[0088] S31: Based on the actual accuracy requirements, determine the sampling section locations and numbers Nn for measuring the thickness of each stratum involved in the rating, the total stratum thickness, and the longitudinal penetration depth of the strike-slip fault zone;

[0089] S32: Calculate the thickness of each stratum Hf and the total thickness of the stratum Hz involved in the rating on different sampling sections;

[0090] S33: Based on the actual strike-slip fault continuity degree of different sampling sections, the actual longitudinal penetration depth Sn of the strike-slip fault zone is measured;

[0091] S34: Based on the difference between the thickness of each layer Hf, the total thickness of the formation Hz and the actual longitudinal penetration depth Sn of the strike-slip fault zone involved in the rating of each profile, the longitudinal penetration capacity value Qn of the strike-slip fault of different profiles is calculated.

[0092] In this embodiment, in step S31, when determining the sampling section locations based on actual accuracy requirements, it is determined that all sampling sections must be laid out at equal distances; all sampling sections must be laid out perpendicular to the strike-slip fault zone;

[0093] In step S32, the stratigraphic thickness Hf of the rated horizons on different sections is the actual thickness of the corresponding sections of the actual horizons. When calculating the stratigraphic thickness Hf of the rated horizons on the sections, the minimum value of the horizons that can be cut through in the longitudinal direction of the entire strike-slip fault zone, represented by the current minimum continuity degree of the entire strike-slip fault zone, the maximum value of the horizons that can be cut through in the longitudinal direction of the entire strike-slip fault zone, represented by the current maximum continuity degree of the entire strike-slip fault zone, and the actual exploration and development requirements are combined to determine the calculation.

[0094] When calculating the total thickness Hz of the strata involved in the rating on the profile and the thickness of each stratum Hf, the calculation shall be carried out according to the degree of interpretation of the basic data of the actual exploration and development strata;

[0095] After the determination is completed, the depth values ​​Df1, Df2 and Df3 corresponding to the first cut-through layer C1, the second cut-through layer C2 and the third cut-through layer C3 are measured for each section respectively, and the stratum thickness Hf1 and Hf2 are calculated;

[0096] H f1 =D f1 -D f2 ;

[0097] H f2 =D f2 -D f3 ;

[0098] In step S32, the total thickness Hz of the strata involved in the rating on different sections is the thickness difference between the shallowest stratum depth Dq that can be cut through by the top of the strike-slip fault zone under the maximum continuity of the strike-slip fault zone in the current exploration and development and the depth Df2 corresponding to the second cut-through stratum C2;

[0099] H z =D q -D f2 ;

[0100] In step S33, during the actual interpretation of strike-slip faults, the degree of continuity of actual strike-slip faults in different sampling profiles varies greatly. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, if the strike-slip fault zone appears intermittently on the profile, and excluding the influence of the stratum being gypsum-salt rock, the intermittent interval exceeds 60-80 ms, then the intermittent strike-slip fault here is not a first-phase product. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, only the length of the strike-slip fault zone in the shallow layer can be used as the actual longitudinal penetration depth Sn of the strike-slip fault zone. If the strike-slip fault zone appears intermittently on the profile, the stratum is gypsum-salt rock, or the intermittent interval is less than 60 ms, then the intermittent strike-slip fault here is a first-phase product. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, the upper and lower segments are connected according to the trend and the two segments are used together as the actual longitudinal penetration depth Sn of the strike-slip fault zone.

[0101] In step S33, during the actual interpretation of strike-slip faults, strike-slip fault zones often continue a short distance into shallower strata after cutting through the interpreted strata in actual oil and gas exploration and development. When measuring the strike-slip fault zone longitudinal penetration depth Sn, this excess distance is ignored. The top of the actual strike-slip fault zone longitudinal penetration depth Sn is ensured to be the same as the shallowest stratum of the strata involved in the assessment.

[0102] In step S34, the total stratum thickness Hz and the actual longitudinal penetration depth Sn of the strike-slip fault zone of each profile rating are measured in sequence, and the difference between the two is used to obtain the longitudinal penetration capacity value Qn of the strike-slip fault of the corresponding profile;

[0103] Q n =S n -H z .

[0104] In this embodiment, step S4 includes:

[0105] S41: Based on the positive or negative value of the longitudinal cutting ability value Qn of the strike-slip fault, the corresponding stratum thickness Hf is selected to construct the "cutting ability index Zn" of the strike-slip fault zone.

[0106] S42: Divide the intervals according to the “cutting ability index Zn” value of the strike-slip fault zone and establish an evaluation standard for the longitudinal cutting ability of the strike-slip fault zone on the formation.

[0107] S43: For the strike-slip fault zone section number Nn, a curve of the strike-slip fault zone’s cutting ability index is drawn to clarify the spatial variation pattern of the strike-slip fault zone’s longitudinal cutting ability.

[0108] In this embodiment, in step S41, if the strike-slip fault longitudinal penetration capability value Qn is positive, it means that the strike-slip fault zone's actual longitudinal penetration depth Sn is greater than the total stratum thickness Hz of the layers involved in the profile rating, indicating that the strike-slip fault zone can actually longitudinally penetrate the second penetration layer C2. In this case, the stratum thickness Hf2 should be selected as the indicator for constructing the strike-slip fault zone's "penetration capability index Zn";

[0109] Z n =Q n / H f2 ;

[0110] If the strike-slip fault longitudinal penetration capacity value Qn is negative, it means that the strike-slip fault zone's actual longitudinal penetration depth Sn is less than the total stratum thickness Hz of the layers involved in the profile rating, indicating that the strike-slip fault zone cannot actually cut through the second penetration layer C2, but can only cut through the second penetration layer C1. In this case, the stratum thickness Hf1 should be selected as the indicator for constructing the strike-slip fault zone's "cutting capacity index Zn";

[0111] Z n =Q n / H f1 ;

[0112] In step S42, the intervals are divided according to the "cutting ability index Zn" value of the strike-slip fault zone, and an evaluation standard for the longitudinal cutting ability of the strike-slip fault zone to the stratum is established; when the cutting ability index Zn is positive and Zn>1, it indicates that the strike-slip fault can longitudinally cut through the second cutting layer C2 and can cut through the third cutting layer C3; when the cutting ability index Zn is positive and 0<Zn≤1, it indicates that the strike-slip fault can longitudinally cut through the second cutting layer C2 but cannot cut through the third cutting layer C3; when the cutting ability index Zn is negative and -1<Zn≤0, it indicates that the strike-slip fault can longitudinally cut through the first cutting layer C1 but cannot cut through the second cutting layer C2; when the cutting ability index Zn is negative and Zn≤-1, it indicates that the strike-slip fault cannot longitudinally cut through the first cutting layer C1;

[0113] In step S43, a rectangular coordinate system is established with the corresponding strike-slip fault zone section number Nn as the horizontal coordinate and the corresponding "cutting ability index Zn" of the strike-slip fault zone section as the vertical coordinate, and a curve chart of the change of the strike-slip fault zone cutting ability index is drawn. The spatial variation pattern of the longitudinal cutting ability of the strike-slip fault zone is clarified through the changes in the numerical values ​​of the "cutting ability index Zn" of different sections on the curve chart.

[0114] This embodiment proposes a method for determining the longitudinal penetration capacity of strike-slip fault zones. To address the current problem of weak research on the longitudinal extension and penetration capacity of strike-slip fault zones in strike-slip fault zone studies, and the lack of an objective, quantitative, and standardized calculation method for the longitudinal penetration capacity of strike-slip fault zones that can eliminate discrepancies and uniformly compare different strike-slip fault zones within the same region and different parts of the same strike-slip fault zone, a method is provided. Based on actual accuracy requirements, after accurately reading the thickness of each layer involved in the rating of each sampling profile, the total thickness of the formation, and the longitudinal penetration depth of the strike-slip fault zone, the longitudinal penetration capacity values ​​of the strike-slip fault zone are calculated for different profiles. This method constructs a "penetration capacity index" for the strike-slip fault zone, establishes evaluation criteria for the longitudinal penetration capacity of the strike-slip fault zone, and clarifies the spatial variation pattern of the longitudinal penetration capacity of the strike-slip fault zone, thereby accurately determining the longitudinal penetration capacity of the strike-slip fault zone. This method provides a set of effective solutions for professionals studying the source connectivity, "reservoir control, reservoir control, and enrichment control" characteristics of strike-slip fault zones, and well site deployment.

[0115] In this embodiment, a method for determining the longitudinal penetration capacity of a strike-slip fault zone is provided, the method comprising:

[0116] S1: Based on actual seismic data, extract the fault sensitivity attributes and clarify the dominant development location of the strike-slip fault zone on the plane and the degree of continuity on the profile.

[0117] S2: Determine the layers involved in the evaluation of the longitudinal cutting capacity of the strike-slip fault zone and determine the accuracy of the evaluation of the longitudinal cutting capacity of the strike-slip fault zone.

[0118] S3: According to the actual accuracy requirements, each sampling profile is graded, involving the calculation of the thickness of each layer, the total thickness of the stratum, and the measurement of the longitudinal penetration depth of the strike-slip fault zone, and the longitudinal penetration capacity value of the strike-slip fault of different profiles is obtained.

[0119] S4: Construct a "cutting ability index" for strike-slip fault zones, establish an evaluation standard for the longitudinal cutting ability of strike-slip fault zones on strata, draw a curve of the change of the "cutting ability index" for strike-slip fault zones, and clarify the spatial variation pattern of the longitudinal cutting ability of strike-slip fault zones.

[0120] In this embodiment, step S1 includes:

[0121] S11: Based on actual seismic data, determine the location of strike-slip faults and analyze the scale of strike-slip faults.

[0122] S12: Targeted extraction of strike-slip fault sensitive attributes based on the strike-slip fault scale.

[0123] S13: Based on seismic attributes, clarify the dominant development locations of strike-slip fault zones in the plane and the degree of continuity of strike-slip fault zones in the profile.

[0124] In this embodiment, step S11 uses the presence of interruptions, shifts, or distortions in seismic reflection events in actual seismic data to determine the location of strike-slip faults. The extent of the strike-slip faults on the seismic profile is then traced by examining the continuity of the interruptions, shifts, or distortions along the longitudinal direction of the seismic profile. Combined with the width of the interruptions, shifts, or distortions along the lateral direction of the seismic profile, the scale of the strike-slip fault zone is roughly determined.

[0125] In this embodiment, if the seismic reflection events are clearly observed to be interrupted or dislocated on the seismic profile, and the interruption or dislocation causes the seismic reflection events to have a large fault throw (fault throw > 20 ms) and a large width (width > 40 ms), and has a certain impact on the strata and structural pattern, the strike-slip fault can be considered to be large in scale. If the seismic reflection events are clearly observed to be interrupted or dislocated on the seismic profile, and the interruption or dislocation causes the seismic reflection events to have a certain fault throw (fault throw 0-20 ms) and a certain width (width 10-40 ms), and has a limited impact on the strata and structure, the strike-slip fault can be considered to be moderate in scale. If only distortion of the seismic reflection events is observed on the seismic profile and the width is less than 10 ms, the strike-slip fault can be considered to be small in scale.

[0126] In this embodiment, in step S12, coherence body or ant body attributes can be extracted from large-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones; ant body or likelihood body attributes can be extracted from medium-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones; and likelihood body or curvature body attributes can be extracted from small-scale strike-slip fault zones to reflect the boundaries and spatial distribution of the strike-slip fault zones.

[0127] In this embodiment, if the same strike-slip fault zone has an interruption, displacement or distortion of the seismic reflection phase axis on the seismic profile, resulting in the strike-slip fault zone's fault throw and width varying frequently, making it difficult to effectively distinguish the size of the strike-slip fault zone, the method of fusing multiple seismic attributes can be used to combine the advantages of different attributes to jointly characterize the boundary and spatial distribution of the strike-slip fault zone.

[0128] In this embodiment, in step S13, after extracting the seismic attributes, time slicing can be performed to clearly observe the differences in the planar distribution of the strike-slip fault zone in different time slices. Based on the changes in the planar continuity of the strike-slip fault zone in different time slices, the dominant development location of the strike-slip fault zone in the plane can be determined. By cutting longitudinal sections, the longitudinal extension of the strike-slip fault zone in different sections can be clearly observed. Based on the changes in the continuity of the strike-slip fault zone in different sections, the continuity of the strike-slip fault zone in the section can be accurately determined.

[0129] In this embodiment, on the time slice and profile, the higher the planar continuity of the strike-slip fault zone and the stronger its linear extension ability, the more developed the strike-slip fault zone is and the more it is the dominant development site; the lower the planar continuity and the more discontinuous its appearance, the weaker the development of the strike-slip fault zone.

[0130] In this embodiment, step S2 includes: S21: determining the layers involved in the longitudinal cutting ability rating of the strike-slip fault zone based on the continuity degree of the strike-slip fault zone on the seismic attribute profile.

[0131] S22: Based on the dominant development locations of strike-slip fault zones on the seismic attribute plane, the accuracy of evaluating the longitudinal cutting capacity of strike-slip fault zones is determined.

[0132] In this embodiment, in step S21, when determining the horizons involved in the longitudinal penetration rating of the strike-slip fault zone, it is necessary to clarify that the continuity degree of the strike-slip fault zone determined by the seismic attribute profile should be the minimum and maximum continuity degrees of the entire strike-slip fault zone. The current minimum continuity degree of the entire strike-slip fault zone represents the minimum value of the horizons that can be penetrated in the longitudinal direction of the entire strike-slip fault zone, which is the weakest penetration value of the entire strike-slip fault zone. The horizon closest to the deep part on the profile is recorded as the first penetration horizon C1; the current maximum continuity degree of the entire strike-slip fault zone represents the maximum value of the horizons that can be penetrated in the longitudinal direction of the entire strike-slip fault zone, which is the strongest penetration value of the entire strike-slip fault zone. The horizon closest to the shallow part on the profile is recorded as the third penetration horizon C3; between the two horizons, the second penetration horizon C2 is selected based on actual exploration and development needs and actual formation thickness.

[0133] In this embodiment, in step S22, after determining the horizons involved in the strike-slip fault zone longitudinal penetration capacity assessment, if significant stratum fluctuations exist, targeted seismic attributes can be further extracted along the horizons to accurately determine the dominant strike-slip fault zone locations within the target horizons. The accuracy of the strike-slip fault zone longitudinal penetration capacity assessment can then be comprehensively determined by counting the number of dominant strike-slip fault zones on the plane and measuring the width of each corresponding dominant strike-slip fault zone location.

[0134] In this example, the dominant location for strike-slip fault zones is defined as the area with high continuity and good linear extension on the planar attribute map, and is typically located near overlapping strike-slip fault segments. It is important to ensure that sampling profiles cover at least both ends and the middle of any dominant location for strike-slip fault zones on the plane. Therefore, three sampling profiles are used as the lower limit for determining the accuracy of the longitudinal penetration capacity of strike-slip fault zones.

[0135] In this embodiment, step S3 includes: S31: based on actual accuracy requirements, determine the sampling section location and number Nn for measuring the thickness of each stratum involved in the rating, the total stratum thickness and the longitudinal penetration depth of the strike-slip fault zone.

[0136] S32: Calculate the individual stratum thickness Hf and the total stratum thickness Hz of the layers involved in the rating on different sampling sections.

[0137] S33: Based on the actual degree of continuity of strike-slip faults in different sampling sections, the actual longitudinal penetration depth Sn of the strike-slip fault zone is measured.

[0138] S34: Based on the difference between the thickness of each layer Hf, the total thickness of the formation Hz and the actual longitudinal penetration depth Sn of the strike-slip fault zone involved in the rating of each profile, the longitudinal penetration capacity value Qn of the strike-slip fault of different profiles is calculated.

[0139] In this embodiment, in step S31, when determining the sampling section locations based on actual accuracy requirements, it is first necessary to ensure that all sampling sections are equidistantly spaced. Second, all sampling sections must be arranged perpendicular to the strike-slip fault zone. This improves the analyzability of the sampling data and ensures that the sampling meets the actual structural analysis requirements.

[0140] In this embodiment, in step S32, the stratigraphic thickness Hf of the rated horizons on different profiles should be the actual thickness of the corresponding profile for the actual horizon. The stratigraphic thickness Hf of the rated horizons on the profile should be calculated based on the minimum value of the horizons that can be cut through in the longitudinal direction of the strike-slip fault zone, as represented by the current minimum continuity of the entire strike-slip fault zone, the maximum value of the horizons that can be cut through in the longitudinal direction of the entire strike-slip fault zone, as represented by the current maximum continuity of the entire strike-slip fault zone, and actual exploration and development requirements.

[0141] In this example, during actual oil and gas exploration and development, stratigraphic analysis is often performed only on key horizons, target horizons, and regional unconformities. Therefore, when calculating the total stratigraphic thickness Hz and the individual stratigraphic thickness Hf for the horizons involved in the cross-section rating, reasonable calculations should be performed based on the degree of interpretation of the basic data for the actual exploration and development horizons.

[0142] In this embodiment, in step S32, after the determination is completed, the depth values ​​Df1, Df2 and Df3 corresponding to the first cut-through layer C1, the second cut-through layer C2 and the third cut-through layer C3 are measured for each section respectively, and then the stratum thicknesses Hf1 and Hf2 are calculated.

[0143] H f1 =D f1 -D f2 ;H f2 =D f2 -D f3 ;

[0144] In this embodiment, in step S32, the total thickness Hz of the strata involved in the rating on different profiles should be the thickness difference between the shallowest stratum depth Dq that can be cut through by the top of the strike-slip fault zone under the maximum continuity of the strike-slip fault zone in the current exploration and development and the depth value Df2 corresponding to the second cut-through stratum C2.

[0145] H z =D q -D f2 ;

[0146] In this embodiment, during the interpretation of strike-slip faults in step S33, it is clearly observed that the degree of continuity of the actual strike-slip faults varies significantly across different sampling profiles. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, if the strike-slip fault zone appears intermittently on the profile, and, excluding the influence of gypsum-salt rock formations, the intermittent interval exceeds 60-80 ms, it can be assumed that the intermittent strike-slip fault is not a primary product. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, only the length of the strike-slip fault zone in the relatively shallow layer can be used as the actual longitudinal penetration depth Sn of the strike-slip fault zone. If the strike-slip fault zone appears intermittently on the profile, the formation is gypsum-salt rock, or the intermittent interval is less than 60 ms, it can be assumed that the intermittent strike-slip fault is a primary product. When measuring the actual longitudinal penetration depth Sn of the strike-slip fault zone, the upper and lower segments need to be connected according to the trend, and the combined result is the actual longitudinal penetration depth Sn of the strike-slip fault zone.

[0147] In this embodiment, during the actual interpretation of strike-slip faults in step S33, it is clearly discovered that strike-slip fault zones often extend a short distance into shallower strata after penetrating the interpreted horizons used in actual oil and gas exploration and development. This excess distance should be ignored when measuring the strike-slip fault zone's longitudinal penetration depth Sn. This ensures that the topmost point of the actual strike-slip fault zone's longitudinal penetration depth Sn is identical to the shallowest stratum in the horizon being assessed. This further ensures that the strength of a strike-slip fault zone's longitudinal penetration capability is entirely determined by the depth that its lowest portion can penetrate.

[0148] In this embodiment, in step S34, the total stratum thickness Hz of the layers involved in each profile rating and the actual longitudinal penetration depth Sn of the strike-slip fault zone are measured in sequence, and the difference between the two can be used to obtain the longitudinal penetration capacity value Qn of the strike-slip fault of the corresponding profile.

[0149] Q n =S n -H z ;

[0150] In this embodiment, step S4 includes:

[0151] S41: Based on the positive or negative value of the longitudinal cutting ability value Qn of the strike-slip fault, the corresponding stratum thickness Hf is selected to construct the "cutting ability index Zn" of the strike-slip fault zone.

[0152] S42: Divide the intervals according to the “cutting ability index Zn” value of the strike-slip fault zone and establish an evaluation standard for the longitudinal cutting ability of the strike-slip fault zone on the formation.

[0153] S43: Corresponding to the section number Nn of the strike-slip fault zone, a curve of the “cutting ability index” of the strike-slip fault zone is drawn to clarify the spatial variation pattern of the longitudinal cutting ability of the strike-slip fault zone.

[0154] In this embodiment, in step S41, if the strike-slip fault longitudinal cutting ability value Qn is positive (Qn>0), it means that the actual longitudinal cutting depth Sn of the strike-slip fault zone is greater than the total stratum thickness Hz of the layers involved in the profile rating, which means that the strike-slip fault zone can actually cut through the second cutting layer C2 in the longitudinal direction. At this time, the stratum thickness Hf2 should be selected as the indicator for constructing the "cutting ability index Zn" of the strike-slip fault zone.

[0155] Z n =Q n / H f2 ;

[0156] If the strike-slip fault longitudinal penetration ability value Qn is negative (Qn < 0), it means that the actual longitudinal penetration depth Sn of the strike-slip fault zone is less than the total stratum thickness Hz of the layers involved in the profile rating, which means that the strike-slip fault zone cannot actually cut through the second cutting layer C2 in the longitudinal direction and can only cut through the second cutting layer C1. At this time, the stratum thickness Hf1 should be selected as the indicator for constructing the "cutting ability index Zn" of the strike-slip fault zone.

[0157] Z n =Q n / H f1 ;

[0158] In this embodiment, in step S42, the strike-slip fault zone "penetration capability index Zn" is the ratio of the strike-slip fault's longitudinal penetration capability Qn to the formation thickness Hfn. Therefore, the strike-slip fault zone "penetration capability index Zn" can be used to divide the zone into intervals and establish an evaluation standard for the strike-slip fault zone's longitudinal penetration capability. When the cutting ability index Zn is positive and Zn>1, it means that the strike-slip fault can cut through the second cutting layer C2 longitudinally and can cut through the third cutting layer C3; when the cutting ability index Zn is positive and 0<Zn≤1, it means that the strike-slip fault can cut through the second cutting layer C2 longitudinally, but cannot cut through the third cutting layer C3; when the cutting ability index Zn is negative and -1<Zn≤0, it means that the strike-slip fault can cut through the first cutting layer C1 longitudinally, but cannot cut through the second cutting layer C2; when the cutting ability index Zn is negative and Zn≤-1, it means that the strike-slip fault cannot cut through the first cutting layer C1 longitudinally.

[0159] In this embodiment, in step S43, a rectangular coordinate system is established with the corresponding strike-slip fault zone section number Nn as the horizontal coordinate and the corresponding "cutting ability index Zn" of the strike-slip fault zone section as the vertical coordinate, and a curve chart of the change of the "cutting ability index" of the strike-slip fault zone is drawn. By the change of the numerical value of the "cutting ability index Zn" of different sections on the curve chart, the spatial variation pattern of the longitudinal cutting ability of the strike-slip fault zone can be clearly determined.

[0160] In a specific embodiment, the example uses the method for determining the longitudinal cutting capacity of a strike-slip fault zone to study the longitudinal cutting capacity of a strike-slip fault zone, such as Figure 2 shown.

[0161] First, based on three-dimensional seismic data from the Tahe region of the Tarim Basin, the location of strike-slip fault zones was determined by observing the occurrence of interruptions, slips, or distortions in seismic reflection events on seismic sections. Furthermore, the extent of strike-slip fault zones along the seismic sections was traced based on the continuity of these interruptions, slips, or distortions along the longitudinal direction of the seismic sections. Combined with the width of these interruptions, slips, or distortions along the lateral direction of the seismic sections, the extent of the strike-slip fault zones was roughly determined. The strike-slip fault zones in the Tahe region exhibit significant variations in throw along the strike, ranging from 0 to 38 milliseconds, and similarly large variations in width, ranging from 10 to 42 milliseconds. After refining the strike-slip fault zone based on throw size, strike-slip faults with throws greater than 20ms and widths greater than 40ms, which have a moderate impact on the stratigraphic and tectonic structure, are considered large-scale strike-slip faults; throws between 0 and 20ms and widths between 10 and 40ms, which have limited impact on the stratigraphic and tectonic structures, are considered moderate-scale strike-slip faults; and throws of 0ms and widths less than 10ms, where only slight distortions of seismic reflection events are observed, are considered small-scale strike-slip faults. For such cases with large throw variations and intermittent throws, this study uses a method that integrates three seismic attributes: coherence, ant volume, and curvature volume, to jointly characterize the boundaries and spatial distribution of strike-slip fault zones. After extracting seismic attributes, time slicing revealed that the strike-slip fault zone in the region develops at depths between -3850 and -5120 ms. Furthermore, the strike-slip fault zone exhibits strong planar continuity and linear extension in the intervals of -3800 to -3980 ms, -4190 to -4250 ms, -4480 to -4520 ms, and -4850 to -4900 ms. Predominantly developed strike-slip fault zones are clearly visible in these intervals. Cutting longitudinal sections revealed significant variations in the continuity of the strike-slip fault zone across different sections.

[0162] Based on the seismic attributes of the Tahe region, the continuity of the strike-slip fault zone observed on the cross-section reveals that the first cut-through horizon, C1, corresponding to the location with the lowest continuity along the entire strike-slip fault zone should be T80, and the third cut-through horizon, C3, corresponding to the location with the highest continuity along the entire strike-slip fault zone should be T90. Between these two horizons, the second cut-through horizon, C2, should be T81, based on actual exploration and development needs and the actual formation thickness. Because all three horizons in the Tahe region are characterized by high NE and low SW orientations, the time-slicing method for observing the dominant location of strike-slip faults is clearly inapplicable. It is necessary to extract seismic attributes along each of the three horizons and specifically observe the distribution of the dominant locations of strike-slip faults at different horizons to determine the accuracy of the longitudinal cut-through capacity assessment of the strike-slip fault zone. By extracting seismic attributes along the layers, it was found that the minimum range of the dominant development site of strike-slip faults among the three layers is 1352m. Therefore, in order to ensure that there should be at least three sampling sections in the dominant development site of any strike-slip fault zone on each plane, the lower limit of the accuracy of the longitudinal cutting ability evaluation of the strike-slip fault zone is set to 400m, and sampling is carried out every 400m.

[0163] After confirming the sampling accuracy, based on the accuracy requirements, the stratigraphic thickness Hf, total stratigraphic thickness Hz, strike-slip fault zone longitudinal penetration depth Sn and strike-slip fault longitudinal penetration capacity value Qn of each profile rating layer are measured and calculated in sequence with equal spacing and perpendicular to the strike-slip fault zone direction, such as Figure 2 For the Tahe area, taking the 50th section of a strike-slip fault zone as an example, the total thickness of the stratum is the thickness difference between the depth value Dq of the shallowest stratum (T74) in the current exploration and development and the depth value Df2 corresponding to the second cut-through layer C2: H z =D q -D f2 =-3750-(-4500ms)=750ms, the thickness of the two strata are: Hf1 is the thickness difference between the depth value Df2 of the second cut-through layer C2 (T81) and the depth value Df1 of the first cut-through layer C1 (T80): H f1 =D f1 -D f2 =-4225-(-4500)=275ms; Hf2 is the thickness difference between the depth value Df2 of the second cutting layer C2 (T81) and the depth value Df3 of the third cutting layer C3 (T90): H f1 =D f2 -D f3 =-4500-(-4888)=388ms; strike-slip fault longitudinal cutting capacity value Q n =S n -H z=1231-750=481ms, at this time, the longitudinal cutting ability value Qn of the strike-slip fault is positive (Qn>0), and the stratum thickness Hf2 should be selected as the indicator for constructing the "cutting ability index Zn" of the strike-slip fault zone. n =Q n / H f2 =481 / 388=1.24, such as Figure 3 Taking the 84th section of the strike-slip fault zone as an example, the total thickness of the stratum is the thickness difference between the depth value Dq of the shallowest stratum (T74) in the current exploration and development and the depth value Df2 corresponding to the second cutting layer C2: H z =D q -D f2 =-3768-(-4521ms)=753ms, the thickness of the two strata are: Hf1 is the thickness difference between the depth value Df2 of the second cut-through layer C2 (T81) and the depth value Df1 of the first cut-through layer C1 (T80): H f1 =D f1 -D f2 =-4245-(-4521)=276ms; Hf2 is the thickness difference between the depth value Df2 of the second cutting layer C2 (T81) and the depth value Df3 of the third cutting layer C3 (T90): H f1 =D f2 -D f3 =-4521-(-4913)=392ms; strike-slip fault longitudinal cutting capacity value Q n =S n -H z =634-753=-119ms, at this time the strike-slip fault longitudinal cutting ability value Qn is negative (Qn<0), the stratum thickness Hf1 should be selected as the indicator for constructing the strike-slip fault zone "cutting ability index Zn", Z n =Q n / H f2 =-119 / 276=-0.43, as Figure 4As shown. This method is used to obtain the "cutting ability index Zn" of each section of the entire fault zone, and then the strike-slip fault zone is divided into four intervals according to the "cutting ability index Zn" value, and an evaluation standard for the strike-slip fault zone's longitudinal cutting ability of the stratum is established. The study found that 54.8% of the fault zone has a positive cutting ability index Zn, and Zn>1, which proves that 54.8% of the strike-slip fault area can cut through the second cutting layer C2 (T81) and then continue to cut through the third cutting layer C3 (T90) in depth; 30.5% of the fault zone has a positive cutting ability index Zn, and 0<Zn≤1, which proves that the strike-slip fault area After the strike-slip fault cuts through the second cutting layer C2 (T81) in the longitudinal direction, it is unable to continue to cut through the third cutting layer C3 (T90) in depth; the cutting ability index Zn is negative in the 14.7% area of ​​the fault zone, and -1<Zn≤0, which proves that after the strike-slip fault cuts through the first cutting layer C1 (T80) in the longitudinal direction, it is unable to continue to cut through the third cutting layer C2 (T81) in depth; the strike-slip fault does not have a negative cutting ability index Zn, and Zn≤-1, which proves that even the weakest strike-slip fault zone can cut through the first cutting layer C1 (T80).

[0164] After the calculation of each profile data is completed, a rectangular coordinate system is established with the corresponding strike-slip fault zone profile number Nn as the horizontal coordinate and the corresponding strike-slip fault zone profile "cutting ability index Zn" as the vertical coordinate to draw a curve of the change of the strike-slip fault zone "cutting ability index". Through the change of the value of the "cutting ability index Zn" of different profiles on the curve, the spatial variation pattern of the longitudinal cutting ability of the strike-slip fault zone can be clearly seen, such as Figure 5 shown.

[0165] This embodiment provides a method for determining the vertical penetration capacity of strike-slip faults in oil and gas exploration and development. It provides a method for obtaining the vertical penetration capacity values ​​of strike-slip faults in different sections after accurately reading the thickness of each layer involved in the rating of each sampling profile, the total thickness of the formation, and the vertical penetration depth of the strike-slip fault zone according to actual accuracy requirements, constructing a "penetration capacity index" of the strike-slip fault zone, establishing an evaluation standard for the vertical penetration capacity of the strike-slip fault zone on the formation, clarifying the spatial variation pattern of the vertical penetration capacity of the strike-slip fault zone, and thus accurately determining the vertical penetration capacity of the strike-slip fault zone on the formation. This patent solves the shortcomings of subjective research methods and methods in the process of studying the longitudinal extension and penetration capacity of strike-slip fault zones, and solves the problem of lack of a method to avoid differences and unified comparison when evaluating the vertical penetration capacity of different strike-slip fault zones in the same area and different parts of the same strike-slip fault zone in the same area.

[0166] This embodiment primarily provides a mathematical method for studying the vertical penetration capacity of strike-slip faults, based on the actual accuracy requirements of oil and gas exploration and development. After accurately reading the thickness of each layer involved in the rating of each sampling profile, the total thickness of the formation, and the vertical penetration depth of the strike-slip fault zone, the vertical penetration capacity values ​​of the strike-slip faults in different profiles are calculated, a "penetration capacity index" of the strike-slip fault zone is constructed, an evaluation standard for the vertical penetration capacity of the strike-slip fault zone on the formation is established, and the spatial variation pattern of the vertical penetration capacity of the strike-slip fault zone is clarified, thereby accurately determining the vertical penetration capacity of the strike-slip fault zone on the formation. This method can objectively and quantitatively evaluate the differences in the vertical penetration capacity of different parts of the strike-slip fault zone, and can reasonably avoid the deficiency of not being able to use a unified comparison standard to evaluate the vertical penetration capacity of the strike-slip fault zone when the formation thickness in the same region is significantly different between different strike-slip fault zones or different parts of the same region or the same strike-slip fault zone due to differences in the original sedimentation degree or the degree of later weathering and erosion. It provides a practical solution for structural analysts who study strike-slip faults in oil and gas geological exploration and development.

[0167] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for determining the longitudinal cutting capacity of a strike-slip fault zone, characterized in that: The method comprises the following steps: S1: Based on actual seismic data, extract fault sensitivity attributes to clarify the dominant development locations of strike-slip fault zones on the plane and the degree of continuity on the profile; S2: Determine the horizons involved in the evaluation of the longitudinal penetration capacity of strike-slip fault zones and determine the accuracy of the evaluation of the longitudinal penetration capacity of strike-slip fault zones; S3: According to the target accuracy requirements, each sampling section is graded, involving the calculation of the thickness of each layer, the total thickness of the stratum, and the measurement of the longitudinal penetration depth of the strike-slip fault zone, and the longitudinal penetration capacity of the strike-slip fault in different sections is calculated; S4: Construct a strike-slip fault zone penetration capacity index, establish an evaluation standard for the strike-slip fault zone's vertical penetration capacity of the stratum, draw a curve of the strike-slip fault zone penetration capacity index change, and clarify the spatial variation pattern of the strike-slip fault zone's vertical penetration capacity; Wherein, step S4 includes: S41: Based on the longitudinal cutting capacity value Q of the strike-slip fault n The positive or negative value corresponds to the selected stratum thickness H f , thus constructing the "cutting ability index Z" of the strike-slip fault zone n ”; S42: According to the strike-slip fault zone "cutting ability index Z n " value, divide the interval, and establish the evaluation standard of the strike-slip fault zone's ability to cut through the stratum vertically; S43: corresponding strike-slip fault zone section number N n , draw a curve of the change of the cutting ability index of the strike-slip fault zone, and clarify the spatial change pattern of the longitudinal cutting ability of the strike-slip fault zone.

2. The method according to claim 1, characterized in that Step S1 includes: S11: Based on actual seismic data, determine the location of strike-slip faults and analyze the scale of strike-slip faults; S12: Targeted extraction of strike-slip fault sensitive attributes based on strike-slip fault scale; S13: Based on seismic attributes, clarify the dominant development locations of strike-slip fault zones in the plane and the degree of continuity of strike-slip fault zones in the profile.

3. The method according to claim 2, characterized in that In step S11, the location of the strike-slip fault is determined by using the interruption, displacement, or distortion of the seismic reflection event in the actual seismic data. The extension of the strike-slip fault on the seismic section is traced by the continuation of the interruption, displacement, or distortion of the seismic reflection event in the longitudinal direction of the seismic section. The width of the interruption, displacement, or distortion of the seismic reflection event in the lateral direction of the seismic section is then combined to determine the scale of the strike-slip fault zone. If the seismic reflection event is clearly observed to be interrupted or dislocated on the seismic profile, and the seismic reflection event has a large fault throw and a large width due to the interruption or dislocation, a fault throw of >20ms is considered a large fault throw, and a width of >40ms is considered a large width, and there is a preset impact on the stratigraphic and tectonic pattern, then the scale of the strike-slip fault is large; If the seismic reflection event is clearly observed to be interrupted or dislocated on the seismic profile, and the seismic reflection event has a certain distance and width due to the interruption or dislocation, with a distance of 0 to 20 ms and a width of 10 to 40 ms, and the impact on the strata and structure is limited, then the scale of the strike-slip fault is moderate; If distortion of seismic reflection events is observed on the seismic profile and their width is less than 10 ms, the strike-slip fault is considered to be small in scale.

4. The method according to claim 2, characterized in that In step S12, coherence volume or ant volume attributes are extracted from large-scale strike-slip fault zones to reflect the boundaries and spatial distribution of strike-slip fault zones; ant volume or likelihood volume attributes are extracted from medium-scale strike-slip fault zones to reflect the boundaries and spatial distribution of strike-slip fault zones; likelihood volume or curvature volume attributes are extracted from small-scale strike-slip fault zones to reflect the boundaries and spatial distribution of strike-slip fault zones; If the same strike-slip fault zone has interruptions, slippage, or distortions in the seismic reflection phase axis on the seismic section, resulting in the strike-slip fault zone's fault throw and width varying frequently, and the strike-slip fault zone's size cannot be effectively distinguished, the method of fusing multiple seismic attributes can be used to combine the advantages of different attributes to jointly characterize the boundary and spatial distribution of the strike-slip fault zone. In step S13, after extracting the seismic attributes, time slicing is performed to observe the differences in the planar distribution of the strike-slip fault zone at different time slices. Based on the changes in the planar continuity of the strike-slip fault zone at different time slices, the dominant development location of the strike-slip fault zone on the plane is determined. By cutting longitudinal sections, the longitudinal extension of the strike-slip fault zone at different sections is observed. Based on the changes in the continuity of the strike-slip fault zone at different sections, the continuity of the strike-slip fault zone on the section is determined. On the time slice and profile, the higher the plane continuity of the strike-slip fault zone and the stronger its linear extension ability, the more developed the strike-slip fault zone is and it is the dominant development site; the lower the plane continuity and the more discontinuous the appearance, the weaker the development of the strike-slip fault zone.

5. The method according to claim 1, wherein Step S2 includes: S21: Based on the continuity of the strike-slip fault zone on the seismic attribute profile, determine the layers involved in the longitudinal penetration capacity rating of the strike-slip fault zone; S22: Based on the dominant development locations of strike-slip fault zones on the seismic attribute plane, the accuracy of evaluating the longitudinal cutting capacity of strike-slip fault zones is determined.

6. The method according to claim 5, characterized in that In step S21, when determining the horizons involved in the longitudinal penetration rating of the strike-slip fault zone, it is clarified that the continuity degree of the strike-slip fault zone determined by the seismic attribute profile at this time is the minimum continuity degree and the maximum continuity degree of the entire strike-slip fault zone; the current minimum continuity degree of the entire strike-slip fault zone represents the minimum value of the horizons that can be penetrated in the longitudinal direction of the entire strike-slip fault zone, and is the weakest penetration value of the entire strike-slip fault zone, and the horizon closest to the deep part on the profile is recorded as the first penetration horizon C1; the current maximum continuity degree of the entire strike-slip fault zone represents the maximum value of the horizons that can be penetrated in the longitudinal direction of the entire strike-slip fault zone, and is the strongest penetration value of the entire strike-slip fault zone, and the horizon closest to the shallow part on the profile is recorded as the third penetration horizon C3; Between the two layers, the second cutting layer C2 is selected based on the actual exploration and development requirements and the actual formation thickness; In step S22, after the horizons involved in the strike-slip fault zone longitudinal penetration capacity evaluation are determined, if there is a large stratum fluctuation, targeted seismic attributes are extracted along the horizon to accurately determine the dominant development location of the strike-slip fault zone in the target horizon. Then, the number of dominant development locations of the strike-slip fault zone on the plane is counted, and the width of each corresponding dominant development location of the strike-slip fault zone is measured to comprehensively determine the accuracy of the strike-slip fault zone longitudinal penetration capacity evaluation. The dominant development site of the strike-slip fault zone in the plane is the site with high continuity and good linear extension on the plane attribute map. It is ensured that at least the two ends and the middle of any dominant development site of the strike-slip fault zone in the plane are covered by sampling sections. The three sampling sections are used as the lower limit of the accuracy of the evaluation of the longitudinal cutting ability of the strike-slip fault zone.

7. The method according to claim 1, characterized in that Step S3 includes: S31: Based on the actual accuracy requirements, determine the sampling section location and number N for measuring the thickness of each layer involved in the rating, the total thickness of the formation, and the longitudinal penetration depth of the strike-slip fault zone. n ; S32: Calculate the thickness H of each layer involved in the rating on different sampling sections f and the total thickness of the formation H z ; S33: According to the actual continuity of strike-slip faults in different sampling sections, the actual longitudinal penetration depth S of the strike-slip fault zone is measured. n ; S34: Combined with the thickness of each layer involved in the rating of each profile, H f , total stratum thickness H z and the actual longitudinal penetration depth S of the strike-slip fault zone n By subtraction, we can obtain the longitudinal cutting capacity Q of strike-slip faults in different sections. n .

8. The method according to claim 7, characterized in that In step S31, when determining the sampling section locations based on actual accuracy requirements, it is determined that all sampling sections must be laid out at equal distances; all sampling sections must be laid out perpendicular to the strike-slip fault zone; In step S32, the stratum thickness H of the layers involved in the rating on different sections is f , is the actual thickness value of the corresponding section of the actual layer; the stratum thickness H of the layer involved in the rating on the section f The calculation is determined by combining the minimum value of the strata that can be cut through in the longitudinal direction of the strike-slip fault zone represented by the current minimum continuity of the entire strike-slip fault zone, the maximum value of the strata that can be cut through in the longitudinal direction of the strike-slip fault zone represented by the current maximum continuity of the entire strike-slip fault zone, and the actual exploration and development needs; The total thickness H of the strata involved in the rating on the cross section z 、Thickness of each layer H f When making calculations, the degree of interpretation of basic data based on actual exploration and development horizons should be used; After the determination is completed, the depth values ​​D corresponding to the first cutting layer C1, the second cutting layer C2 and the third cutting layer C3 are measured for each section respectively. f1 、D f2 and D f3 , calculate the stratum thickness H f1 and H f2 ; H f1 =D f1 -D f2 ; H f2 =D f2 -D f3 ; In step S32, the total thickness H of the strata involved in the rating on different sections z , is the top depth of the shallowest stratum in the current exploration and development that can be cut through by the top of the strike-slip fault zone under the maximum continuity of the strike-slip fault zone. q The depth value D corresponding to the second cutting layer C2 f2 Thickness difference; H z =D q -D f2 ; In step S33, in the actual interpretation process of strike-slip faults, the continuity of strike-slip faults in different sampling sections varies greatly. n If the strike-slip fault zone appears intermittently on the profile, and the influence of the stratum being gypsum-salt rock is excluded, and the intermittent interval exceeds 60-80ms, then the intermittent strike-slip fault here is not a product of the first phase, and the actual longitudinal penetration depth S of the strike-slip fault zone is measured. n When the strike-slip fault zone length in the shallow layer can be taken as the actual longitudinal penetration depth S of the strike-slip fault zone, n If the strike-slip fault zone appears intermittently on the profile, and the stratum is gypsum salt rock or the intermittent interval is less than 60ms, then the intermittent strike-slip fault here is the product of the first phase, and the actual longitudinal penetration depth S of the strike-slip fault zone is measured. n When the upper and lower sections are connected according to the trend, they are taken together as the actual longitudinal penetration depth S of the strike-slip fault zone. n ; In step S33, in the actual interpretation process of strike-slip faults, the strike-slip fault zone often cuts through the interpreted layer in actual oil and gas exploration and development, and then continues to the shallow strata for a short distance. n When measuring, ignore the distance beyond this part; ensure that the actual longitudinal penetration depth S of the strike-slip fault zone is n The topmost layer is the same as the shallowest layer of the horizon involved in the rating; In step S34, the total thickness H of the strata involved in each profile rating is measured in sequence. z and the actual longitudinal penetration depth S of the strike-slip fault zone n The difference between the two can be used to obtain the longitudinal cutting capacity value Q of the strike-slip fault of the corresponding section. n ; Q n =S n -H z 。 9. The method according to claim 1, characterized in that In step S41, if the strike-slip fault longitudinal cutting ability value Q n If it is positive, it means the actual longitudinal penetration depth S of the strike-slip fault zone n Greater than the total thickness H of the strata involved in the profile rating z , which means that the strike-slip fault zone can actually cut through the second cutting layer C2 in the longitudinal direction. At this time, the stratum thickness H should be selected. f2 As a method to construct the "cutting ability index Z" of strike-slip fault zone n ” indicator; Z n =Q n / H f2 ; If the longitudinal cutting capacity of the strike-slip fault is Q n If it is negative, it means the actual longitudinal penetration depth S of the strike-slip fault zone n Less than the total thickness H of the strata involved in the profile rating z , which means that the strike-slip fault zone cannot actually cut through the second cutting layer C2 in the longitudinal direction, and can only cut through the second cutting layer C1. In this case, the stratigraphic thickness H should be selected. f1 As a method to construct the "cutting ability index Z" of strike-slip fault zone n ” indicator; Z n =Q n / H f1 ; In step S42, according to the strike-slip fault zone "cutting ability index Z n "The value is divided into intervals, and the evaluation standard of the strike-slip fault zone's ability to cut through the formation vertically is established; when the cutting ability index Z n is positive, and Z n When the cutting ability index Z is greater than 1, it indicates that the strike-slip fault can cut through the second cutting layer C2 and the third cutting layer C3 in the longitudinal direction. n is positive, and 0<Z n When ≤1, it means that the strike-slip fault can cut through the second cutting layer C2 in the longitudinal direction, but cannot cut through the third cutting layer C3; when the cutting ability index Z n is negative, and -1<Z n When ≤0, it means that the strike-slip fault can cut through the first cutting layer C1 in the longitudinal direction, but cannot cut through the second cutting layer C2; when the cutting ability index Z n is negative, and Z n When ≤-1, it means that the strike-slip fault cannot cut through the first cutting layer C1 longitudinally; In step S43, the section number N corresponding to the strike-slip fault zone is used. n is the horizontal axis, corresponding to the "cutting ability index Z" of the strike-slip fault zone section n " is the vertical coordinate, a rectangular coordinate system is established, and a curve of the cutting ability index of the strike-slip fault zone is drawn. The "cutting ability index Z" of different sections on the curve is n "The change in the value clearly defines the spatial variation pattern of the longitudinal cutting ability of the strike-slip fault zone.

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