Plane partitioning method for strike-slip fault zone

Abstract

The invention discloses a strike-slip fault zone plane partitioning method, and belongs to the technical field of strike-slip fault structure pattern research in petroleum and geological mine industries. According to the method, the strike-slip fault zone plane partitioning identification basis is improved, dynamic data information such as well drilling, well logging, coring and well logging is comprehensively utilized, dynamic data and static data are combined, the strike-slip fault zone plane structure pattern partitioning method is quantitatively indicated, and the strike-slip fault zone plane structure pattern partitioning reliability is quantitatively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of research on strike-slip fault structural styles in the petroleum and geological industries, and particularly relates to a method for planar zoning of a strike-slip fault zone. Background Art

[0002] Oil and gas reservoirs are mainly distributed on vertical fracture development zones, and such fracture development zones can extend to the surface. The distribution of other mineral deposits also tends to be along fracture development zones and fault zones, especially at the intersections of faults. Faults play a dual role in the process of oil and gas accumulation. On the one hand, faults play a role in storage and conduction for buried hill oil and gas accumulation, and on the other hand, they also play a sealing role in the process of oil and gas accumulation.

[0003] Due to the characteristics of lithologic-stratigraphic oil and gas reservoirs such as thin interbeds of sandstone and mudstone, complex fault systems, low-porosity and low-permeability reservoirs resulting in low oil layer resistivity and low productivity, especially in complex and diverse regions where tectonic activities are relatively intense, various types of structures such as folds, ductile shear zones, faults, thrust nappes, extensional detachment, strike-slip faults, joint fissures, and intrusive rock contact zones are well developed. The widely developed main faults have derived a large number of tensional and wrench-tensional secondary faults. As a high-yield oil and gas enrichment zone, the basement strike-slip fault zone in the oil and gas basin has broad prospects for oil and gas exploration and development. However, the complex fault characteristics bring difficulties to the subsequent geological research and production practice of oil and gas fields, and it is of great significance to identify the basement strike-slip faults and analyze their geometric and kinematic characteristics.

[0004] The doctoral thesis ("Mesozoic Strike-Slip Structures and Their Tectonic Evolution of the Hongche Fault Zone in the Northwestern Margin of the Junggar Basin", Yu Yangli) studied the tectonic geometric styles and deformation stages within the Hongche fault zone through the interpretation of high-precision two-dimensional and three-dimensional seismic data in the region, and discussed the kinematic mechanism of the Hongche area using three-dimensional tectonic plane restoration technology. Combining the previous studies on the Keluke-Baijiantan and Wuxia fault zones, the fault zone in the northwestern margin of the Junggar Basin developed dextral strike-slip activities during the Triassic-Jurassic period. At the same time, the Dalabute fault in western Junggar and the Irtysh fault on the northern margin of the Junggar Basin were also dextral strike-slip activities during this period.

[0005] The master's thesis ("Structural Characteristics of the Hanliu Fault Zone", Wang Xiaolei) is guided by the theories and methods of structural geometry, kinematics, and dynamics. Based on a deep understanding of the regional geological characteristics, starting from the analysis of seismic data, combined with well logging data and previous research results, typical depth profiles are selected, and the geometric characteristics, structural evolution, activity characteristics, and dynamic mechanisms of the Hanliu Fault Zone are explored using structural analysis methods. Combining previous research and comprehensive research results of geometric and kinematic characteristics, the following understandings are obtained regarding the main genetic causes of the fault zone: The Hanliu Fault is a reverse compensation fault caused by gravitational imbalance, which traces the rupture of the X shear plane in the region and forms a zigzag shape. The fault distribution pattern is controlled by the Zhenwu Fault and first develops at the turning point of the western strike of the Zhen Fault; since the Eocene, the direction of the regional tensile force has deflected northward, causing the fault to have a right-lateral strike-slip property and developing secondary faults mainly in the east-west direction; according to the development stages and associated relationships of the faults, the faults in the study area are divided into three development orders.

[0006] It can be seen that the existing methods for partitioning the planar structural patterns of strike-slip fault zones mainly combine the interpretation results of seismic data with the structural strike of the fault zone. This method classifies single wells based on the abnormal characteristics of the seismic reflection wave group interfaces of marker beds, and then conducts planar partitioning of the structural patterns by combining the angular differences in the structural strike. However, this method only uses static seismic data and structural strike data to determine the planar structural patterns of the fault zone through qualitative analysis.

[0007] Therefore, it is necessary to provide a method that comprehensively utilizes dynamic data information such as drilling, logging, coring, and well logging, combines dynamic and static data, and quantitatively indicates the partitioning method of the planar structural patterns of strike-slip fault zones. Summary of the Invention

[0008] In view of the problems existing in the prior art, the present invention provides a method for planar partitioning of a strike-slip fault zone, which improves the identification basis for planar partitioning of the strike-slip fault zone and uses multi-dimensional dynamic data such as drilling, logging, coring, and well logging to quantitatively improve the reliability of planar structural pattern partitioning of the strike-slip fault zone.

[0009] To achieve the above object, the present invention provides a method for planar partitioning of a strike-slip fault zone, including:

[0010] Step S101: Determine the position and number of fault planes: Determine the fault planes based on seismic fault data and drilling data;

[0011] Step S102: Parameter statistics: For each fault plane determined in Step S101, respectively sort out the dynamic data indicators related to the reservoir scale as parameters;

[0012] Step S103: Parameter correction, correct the parameters to the plane where the well trajectory is perpendicular to the fault zone;

[0013] Step S104: Analyze the relationship between the parameters and the position of the fracture surface to determine the key parameters;

[0014] Step S105: Analyze the relationship between the parameters and the position of the fracture surface to divide the planar structural style zones of the strike-slip fault zone.

[0015] In a preferred embodiment, in step S101, during the process of determining the fracture surface, taking the actually completed drilled wells as the research object, using the seismic profile fracture interpretation results, and combining with the drilling data, determine the position and quantity of the fracture surface.

[0016] In a preferred embodiment, the seismic fracture data is post-stack reverse-time migration 3D seismic data.

[0017] In a preferred embodiment, in step S101, the drilling data includes at least one of drilling washout, drilling loss, and logging interpretation reservoir results.

[0018] In a preferred embodiment, in step S102, the dynamic data indexes include at least one of the drilling washout length, mud loss volume, maximum loss rate, logging reservoir thickness, coring footage, and vertical thickness of the target layer reservoir body.

[0019] In a preferred embodiment, in step S103, according to the drilling trajectory inclination data and the included angle between the drilling trajectory and the strike of the fault zone, use trigonometric functions to correct the dynamic data indexes statistically obtained in step S102, and correct the dynamic data indexes to the parameters when the planar well trajectory is perpendicular to the fault zone and the well trajectory crosses the fault zone vertically at 90° longitudinally.

[0020] In a preferred embodiment, in step S103, the parameter correction formula is:

[0021] H = sinα * [sin(π * θ / 180) * L];

[0022] Wherein, H represents the corrected value of the drilling parameter value, α represents the included angle between the drilling trajectory and the strike of the fault zone, θ represents the drilling trajectory inclination angle value at the drilling parameter value-taking point, and L represents the drilling parameter inclination value along the drilling trajectory direction.

[0023] In a preferred embodiment, in step S103, each parameter needs to be corrected separately using the correction formula, each parameter corresponds to a different L, and after correction, it corresponds to a different H.

[0024] In a preferred embodiment, in step S104, according to the parameters statistically obtained in step S102 and the corrected dynamic data indexes in step S103, analyze the relationship between each parameter and the fracture surface.

[0025] In a preferred embodiment, in step S104, a statistical histogram or a statistical scatter plot is respectively made by combining a single drilling parameter index or a combined drilling parameter index with the drilling position, and the relationship between the parameter and the fracture surface is analyzed in combination with the known lateral connectivity between the fracture surfaces.

[0026] In a preferred embodiment, in step S104, according to the analysis results, three parameters, namely, mud loss volume, reservoir width, and maximum leakage rate, are related to the position of the fracture surface.

[0027] In a preferred embodiment, in step S105, based on the parameters related to the position of the fracture surface in step S104, a normal distribution characteristic map is drawn with the strike-slip fault zone as a unit; according to the correlation between the normal distribution range and the strike of the fault zone structure in the normal distribution characteristic map, the plane structural style zones of the strike-slip fault zone are quantitatively divided.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. The present invention provides a method for plane zoning of a strike-slip fault zone, which preliminarily interprets the positions and quantities of fracture surfaces developed in the completed wells based on post-stack reverse-time migration 3D seismic data; statistically screens drilling and logging dynamic parameters, and optimizes the parameters related to the fracture surface and the nearby reservoir. Through parameter analysis, the accuracy of the positions and quantities of the fracture surfaces in the completed wells is further improved; the drilling and logging data with inclined values are corrected by using a parameter correction formula; the corrected parameter values are plotted jointly with the positions of the completed wells, and the key parameters most sensitive to the positions of the fracture surfaces are gradually optimized, and the plane structural style zones of the strike-slip fault zone are quantitatively divided.

[0030] 2. By improving the identification basis for plane zoning of the strike-slip fault zone, the present invention uses multi-dimensional dynamic data such as drilling, logging, coring, and logging to quantitatively improve the reliability of plane structural style zoning of the strike-slip fault zone.

[0031] 3. The present invention has been widely applied in the research and zoning of the plane structural style of the carbonate ultra-deep strike-slip fault zone in the central region of the Shunbei Oil and Gas Field, guiding the research on the structural style of the strike-slip fault zone, and having a popularization and application prospect in the research of the plane zones of the same type of ultra-deep strike-slip fault structures in China. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic flow chart of the method for plane zoning of a strike-slip fault zone provided according to an embodiment of the present invention;

[0033] Figure 2 It is the determined positions and quantities of the fracture surfaces provided according to an embodiment of the present invention;

[0034] Figure 3 Schematic diagram of parameter correction provided according to an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of mud loss volume, reservoir width, maximum leakage rate and fracture plane position provided according to an embodiment of the present invention;

[0036] Figure 5 Schematic diagram of the plane partition result of the strike-slip fault zone after adopting the plane partition method of the strike-slip fault zone provided by the present application. Detailed implementation manners

[0037] The present invention relates to a method for plane partitioning of a strike-slip fault zone, a method for comprehensively using dynamic data information such as drilling, logging, coring and well logging, and a partitioning method for quantitatively indicating the plane structural pattern of the strike-slip fault zone by combining dynamic and static data.

[0038] Figure 1 The flow schematic diagram of the plane partition method of the strike-slip fault zone provided by the embodiment of the present invention is shown. As Figure 1 shown: In step S101: Determine the position and number of fracture planes

[0039] Based on seismic fracture data and drilling data, determine the fracture plane. During the determination of the fracture plane, taking the actually completed well as the research object, using the fracture interpretation results of the seismic profile, and combining data such as drilling blowout, leakage situation and logging interpretation of reservoir results, determine the position and number of the fracture plane, as shown in the appendix Figure 2 shown.

[0040] Next, go to step S102.

[0041] In step S102: Parameter statistics

[0042] For each fracture plane determined in step S101, respectively sort out the dynamic data indexes related to the reservoir scale as parameters. The dynamic data indexes include at least one of drilling blowout length, mud loss volume, maximum leakage rate, logging reservoir thickness, coring footage, and vertical thickness of the reservoir body in the target layer.

[0043] Next, go to step S103.

[0044] In step S103: Parameter correction, correct the parameters to the plane well trajectory perpendicular to the fault zone

[0045] According to the well trajectory inclination data of the drilling and the included angle between the well trajectory and the strike direction of the fault zone, use trigonometric functions to correct the dynamic data indexes statistically obtained in step S102, and correct the dynamic data indexes to the plane well trajectory perpendicular to the fault zone. The parameter value when the well trajectory crosses the fault zone vertically at 90° longitudinally is used as the corrected dynamic data index, as shown in the appendix Figure 3 shown.

[0046] Next, go to step S104.

[0047] In step S104: Analyze the relationship between the parameters and the position of the fracture surface to determine the key parameters

[0048] According to the parameters statistically obtained in step S102 and the corrected dynamic data indicators in step S103, analyze the relationship between each parameter and the fracture surface respectively, as shown in the appendix Figure 4 It can be seen that three parameters, namely the mud loss volume, the reservoir width, and the maximum leakage rate, are related to the position of the fracture surface.

[0049] Next, go to step S105.

[0050] In step S105: Analyze the relationship between the parameters and the position of the fracture surface to divide the plane tectonic style zones of the strike-slip fault zone

[0051] Based on the parameters related to the position of the fracture surface in step S104, draw a normal distribution characteristic diagram with the strike-slip fault zone as the unit; according to the correlation between the normal distribution range in the characteristic diagram and the difference in the strike of the fault zone structure, quantitatively divide the plane tectonic style zones of the strike-slip fault zone, as shown in the appendix Figure 5 described.

[0052] Next, in combination with Figure 2 , Figure 3 , Figure 4 and Figure 5 , further elaborate in detail the method for plane zoning of the strike-slip fault zone provided according to the embodiments of the present invention.

[0053] Appendix Figure 2 The seismic time section of the drilling trajectory direction on the strike-slip fault zone shows the position and quantity of the fracture surfaces determined in step S101. Seismic interpretation of fracture surfaces 1 and 2: refers to the display of the position and quantity results of the fracture surfaces determined by using post-stack reverse time migration 3D seismic data and combining with drilling data; the drilling leakage position, the drilling washout position, and the logging reservoir position: refer to the display of the corresponding depth positions on the drilling trajectory of the drilling leakage, drilling washout, and logging interpretation reservoir result data used when determining the fracture surface in step S101.

[0054] Appendix Figure 3 The schematic diagram of drilling parameter correction is to correct some drilling parameters related to the fracture surface according to the drilling trajectory inclination data and the angle between the drilling trajectory and the strike of the fault zone, mainly including the length of the drilled washout section, the drilling core penetration length near the fracture surface, the logging interpretation reservoir thickness, the vertical depth of the reservoir in the target interval, etc. These several main parameters all need to be corrected by the correction formula respectively, and each parameter corresponds to a different L, and after correction, it corresponds to a different H.

[0055] Parameter correction formula: H = sinα * [sin(π * θ / 180) * L]; where H represents the corrected value of the drilling parameter, α represents the angle between the drilling trajectory and the strike of the fault zone, θ represents the inclination angle value of the drilling trajectory at the drilling parameter value point, and L represents the inclination value of the drilling parameter along the drilling trajectory direction.

[0056] As shown in the appendix Figure 4 shown, taking all the completed drilling positions in the order of the strike of the fault zone as representatives of the fault plane positions, according to the parameters statistically obtained in step S102 and the corrected dynamic data indicators in step S103, using single drilling parameter indicators or combined drilling parameter indicators respectively, and jointly with the drilling positions for statistical histogram plotting or statistical scatter plotting. Using the statistical plotting results, combined with the known lateral connectivity degree between the fault planes, then analyze one by one the matching degree between the statistical laws presented by the statistical plotting results of single parameters or combined parameters jointly with the drilling positions and the lateral connectivity degree between the fault planes. During the process of statistical plotting comparison and analysis, compared with the formation of Figure 4 -B and Figure 4 -C shown, there is no obvious statistical law in the statistical plotting results of single parameter (vertical depth of the reservoir in the target interval) or combined parameter (length of the blowout interval + vertical depth of the reservoir in the target interval) jointly with the drilling positions. After comparison and optimization, it is found that the parameters with the highest sensitivity to the relationship with the fault plane position include: drilling mud loss volume, logged reservoir width, and maximum leakage rate, and a schematic diagram of the mud loss volume, reservoir width, and maximum leakage rate versus the fault plane position is formed ( Figure 4 -A).

[0057] As shown in the appendix Figure 5 shown, each longitudinal fault plane corresponds to a specific planar structural style type such as a stretching segment, a translational segment, or a squeezing segment on the plane. The previous static method for fault zone planar structural style zoning mainly divides the fault zone planar zone range according to the main types or lateral scales of the fault plane planar structural styles. According to the sensitive drilling parameter indicators with the highest correlation with the strike-slip fault plane position selected in step S104, combined with Figure 4 -A the normal distribution law and range, referring to the distribution characteristics of the fault plane structural styles on the plane, combining dynamic and static characterization indicators, considering both the combined distribution characteristics of the fault plane structural style types on the plane and referring to the dynamic parameter indicators such as drilling and logging and the information on the lateral connectivity degree between the fault planes, optimizing and improving the basis for fault zone planar zoning indicators, forming Figure 5 the schematic diagram showing the research results of the zoning range division of the planar structural styles of the strike-slip fault zone. The fault zone planar structural style zoning results guided by the solution of the present application have a better matching relationship with the lateral connectivity degree between the fault planes, and are more conducive to the zoning or unit development and utilization of the oil and gas resources in the fault zone.

[0058] The solution of the present invention is not limited to the technical means disclosed above, but also includes technical solutions composed of any combination of the above technical features. The above is the specific implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A method for planar zoning of strike-slip fault zones, characterized in that, Including: Step S101: Determine the position and quantity of the fracture surface: Determine the fracture surface based on seismic fracture data and drilling data; Step S102: Parameter statistics: For each fracture surface determined in Step S101, respectively sort out the dynamic data indexes related to the reservoir scale as parameters; Step S103: Parameter correction, correct the parameters to the vertical fracture zone of the plane well trajectory; Step S104: Analyze the relationship between the parameters and the position of the fracture surface to determine the key parameters; Step S105: Analyze the relationship between the parameters and the position of the fracture surface to divide the strike-slip fracture zone plane tectonic style zones.

2. The method according to claim 1, wherein In Step S101, during the process of determining the fracture surface, take the actually completed wells as the research object, and use the seismic profile fracture interpretation results and combine with the drilling data to determine the position and quantity of the fracture surface.

3. The method according to claim 1, characterized in that In Step S101, the drilling data includes at least one of drilling washout, drilling loss, and logging interpretation reservoir results.

4. The method according to claim 1, wherein In Step S102, the dynamic data indexes include at least one of the drilling washout length, mud loss volume, maximum loss rate, logging reservoir thickness, coring footage, and vertical thickness of the target layer reservoir body.

5. The method according to claim 1, wherein In Step S103, according to the well trajectory inclination data and the included angle between the well trajectory and the fracture zone strike, use trigonometric functions to correct the dynamic data indexes statistically obtained in Step S102, correct the dynamic data indexes to the vertical fracture zone of the plane well trajectory, and use the parameter value when the well trajectory vertically crosses the fracture zone at 90° longitudinally as the corrected dynamic data index.

6. The method according to claim 5, characterized in that, In Step S103, the parameter correction formula is: H = sinα * [sin(π * θ / 180) * L]; where, H represents the corrected value of the drilling parameter value, α represents the included angle between the well trajectory and the fracture zone strike, θ represents the well trajectory inclination angle value of the drilling parameter value point, and L represents the drilling parameter inclination value along the well trajectory direction; Each parameter needs to be corrected separately with the correction formula, each parameter corresponds to a different L, and after correction, it corresponds to a different H.

7. The method according to claim 6, wherein In Step S104, according to the parameters statistically obtained in Step S102 and the corrected dynamic data indexes in Step S103, analyze the relationship between each parameter and the fracture surface.

8. The method according to claim 1, wherein In Step S104, respectively use a single drilling parameter index or a combined drilling parameter index, and jointly conduct statistical histogram plotting or statistical scatter plotting with the drilling position, and combine the known lateral connectivity between the fracture surfaces to analyze the relationship between the parameters and the fracture surface.

9. The method according to claim 1, wherein, In Step S104, according to the analysis results, three parameters, namely the mud loss volume, reservoir width, and maximum loss rate, are related to the position of the fracture surface.

10. The method according to claim 1, characterized in that In Step S105, based on the parameters related to the position of the fracture surface in Step S104, draw a normal distribution characteristic diagram with the strike-slip fracture zone as the unit; according to the correlation between the normal distribution range in the normal distribution characteristic diagram and the difference in the fracture zone tectonic strike, quantitatively divide the strike-slip fracture zone plane tectonic style zones.

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