Method for improving reverse fault modeling precision, storage medium and electronic equipment

Abstract

The invention belongs to the technical field of three-dimensional geological modeling in oilfield development, and discloses a method for improving reverse fault modeling precision, a storage medium and electronic equipment. The method comprises the following steps: establishing a spatial position of a fault by using fault data, and depicting a fault track layer by layer according to an interpretation parameter of the fault so as to obtain a fault model; for an original well W penetrating through the fault, the position where a breakpoint is located serves as an original point, and two virtual wells, namely a W1 well and a W2 well, of the original well W are arranged on the hanging wall and the footwall of the fault correspondingly; the altitude position of a ground breakpoint is determined in combination with seismic data, well point data of an original well W is cut off at the breakpoint, and values are assigned to a well W1 and a well W2 respectively; and utilizing the data of the W1 well and the W2 well to obtain an attribute model through attribute interpolation calculation. According to the method, the virtual well is arranged, the upper wall and the lower wall of the reverse fault are assigned respectively, and the well point data can be utilized to the maximum degree to improve the geological modeling precision of the reverse fault.

Description

Technical Field

[0001] The invention belongs to the technical field of three-dimensional geological modeling in oil field development, and specifically relates to a method for improving reverse fault modeling accuracy, a storage medium and an electronic device. Background Art

[0002] Three-dimensional geological modeling is to describe and characterize the reservoir based on a multidisciplinary database. The richness and accuracy of the data largely determine the accuracy of the model. High-precision geological models can accurately characterize reservoir characteristics and better predict reservoirs and deploy new wells. In the oil field development area, logging is the only method that can provide continuous information on the physical response of reservoir rock in the entire well section. Therefore, the integrity of logging data is particularly important.

[0003] In the process of modeling complex fault blocks, it is generally difficult to characterize reverse faults. Reverse faults are faults in which the upper plate slides upward along the fault plane. They are mainly manifested by the relative rise of the upper plate and the relative decline of the lower plate. Therefore, wells that penetrate reverse faults will have repeated layers, and the logging interpretation of the top depth, oil layer thickness, porosity, permeability and other attributes of the same layer will have two or more values. At present, when the conventional interpolation calculation method is used for reverse fault modeling, only one value can be used for a certain attribute of the same grid. For wells that penetrate reverse faults, if there is one value for each of the upper and lower plates of the same layer, the original well point data of the other plate must be discarded, which makes the utilization rate of this well point data less than 100%, which will cause the loss of control points of the reservoir attribute model. The grid attribute interpolation near the fault and at the well point is obtained by extrapolation of other well point data, which greatly reduces the accuracy of modeling.

[0004] In the prior art, there are methods to improve the model accuracy by splicing the repeated layers on both sides of the upper and lower plates of the reverse fault, and there are also methods to deal with reverse faults by first deleting the duplicate data and then manually assigning values. In practical applications, the above methods will not only waste some valuable logging data and reduce the accuracy of interpolation operations, but also require multiple manual adjustments, which are inefficient and time-consuming.

[0005] Chinese patent CN108254779A discloses a three-dimensional structural modeling method, which uses the fault data in the depth domain of seismic interpretation as basic data and the drilling breakpoint data as correction data to construct a fault model so that the drilling breakpoint passes through the fault plane in the fault model; the fault plane is projected onto the well, and the fault blocks are divided and compared into small layers to generate accurate drilling small layer division and comparison data; the drilling small layer division and comparison data is used as basic data and the seismic interpretation depth domain stratigraphic data is used as a trend surface to construct a small layer level of a small layer with corresponding seismic interpretation depth domain fault data, and establish a three-dimensional framework model; according to the drilling small layer division and comparison data, the drilling small layer division and comparison data are divided into small layers and compared into small layers, and ... The data is used to generate the isopach map of the small layers using the top and bottom layer data of the small layers, and to construct a three-dimensional small layer model; the units are further subdivided vertically to construct a three-dimensional structural model; the structural modeling method of this patent can quickly and accurately establish a three-dimensional structural model, but this method focuses on constructing fault models and small layer models based on the depth domain fault data, drilling breakpoint data, small layer comparison data and depth domain stratigraphic data of seismic interpretation, and does not involve the problem of how to establish attribute models such as top structure, effective thickness, porosity, and permeability when crossing a reverse fault and causing multiple data to appear at the same well point and the same stratigraphic position.

[0006] Chinese patent CN103514630A discloses a method for three-dimensional modeling of fault structures. First, the fault data is integrated into a three-dimensional visualization system, and the fault control points are extracted and interpreted to form fault lines; then, connection analysis of various situations and revision of fault lines and fault attributes are performed, the relationship between faults is calculated, and a fault network reflecting its topological structure is established; then, the fault plane is intersected with the constructed initial stratum model to obtain the initial intersection line of the stratum and the fault, and the fault distance is calculated for each breakpoint on the initial intersection line, and a 3D fault line containing the upper and lower plates is obtained; then, by setting weights for the various types of fault data generated above, the fault plane is fitted to form a fault plane network, and a stratum model is constructed. The method of this patent can effectively perform data detection and ensure the accuracy of the fault model. However, the method of this patent is a modeling method for establishing fault planes and fault models based on fault data of boreholes, 2D / 3D profiles, structural geological maps, and fault attributes. It also does not involve the issue of how to establish attribute models such as top structure, effective thickness, porosity, and permeability when crossing a reverse fault and causing multiple data to appear at the same well point and the same layer. Summary of the invention

[0007] The present invention aims to address the problems existing in the prior art and provide a method, storage medium and electronic device for improving the accuracy of reverse fault modeling. By setting virtual wells and assigning values ​​to the upper and lower plates of the reverse fault respectively, the accuracy of reverse fault geological modeling can be improved by maximizing the use of well point data.

[0008] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0009] A method for improving the accuracy of reverse fault geological modeling, the method comprising the following steps:

[0010] Step S1: depicting fault trajectory;

[0011] The spatial position of the fault is established using the fault data, and the fault trajectory is depicted layer by layer according to the interpretation parameters of the fault, so as to obtain the fault model;

[0012] Step S2: setting a virtual well;

[0013] For the original well W that crosses the fault, take the location of the fault point as the origin, and set two virtual wells of the original well W in the upper and lower walls of the fault: Well W1 and Well W2;

[0014] Step S3: virtual well assignment;

[0015] Combined with the seismic data, the elevation position of the breakpoint on the well is determined, and the well point data of the original well W is truncated at the breakpoint, and values ​​are assigned to wells W1 and W2 respectively, and the upper plate data of the original well W is assigned to well W1 located in the upper plate, and the lower plate data is assigned to well W2 located in the lower plate;

[0016] Step S4: model interpolation calculation;

[0017] Using the data from Well W1 and Well W2, the attribute model was obtained through attribute interpolation calculation to complete the reverse fault geological modeling.

[0018] Furthermore, in step S1, the interpretation parameters of the fault include fault throw, strike, dip and inclination.

[0019] Furthermore, in step S2, well W1 is located at the upper wall of the fault where the original well W is located, and well W2 is located at the lower wall of the fault that is closest to well W1 in a straight-line distance.

[0020] Further, in step S4, the attribute model includes at least the following attribute parameters: top structure, reservoir thickness, effective thickness, porosity and permeability.

[0021] Furthermore, in step S4, the attribute interpolation adopts triangular interpolation method, Kriging interpolation method or equal probability random simulation method.

[0022] At the same time, the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a computer, the computer executes any of the methods described above.

[0023] In addition, the present invention also provides an electronic device, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor, and when the processor executes the program, the method described in any one of the above items is implemented.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] The present invention solves the problem that well point data cannot be fully used in the case of reverse faults, greatly improves the accuracy of reverse fault modeling, reduces the time consumed by manual adjustment, and can increase the constraint points of the original data in the reservoir attribute simulation calculation, thereby better reflecting the vertical and horizontal heterogeneity of the reservoir, improving the accuracy of reservoir simulation, and having high practical value.

[0026] At the same time, compared with the method of the existing patent, the method of the present invention is based on the construction of the fault. For wells drilled through the reverse fault, if there are two or more data at the same well point and the same layer, the original well is virtualized into two wells, representing the data of the same layer of the upper and lower plates respectively, and the grid position is moved to fall into different grids within the minimum error range. The known grid control data is added for attribute interpolation, thereby improving the modeling accuracy of the attribute model of the top structure, effective thickness, porosity, permeability and other attribute parameters of the reverse fault oil and gas reservoir.

[0027] The method of the present invention is used to deploy well locations, which plays an important role in the three-dimensional geological modeling and numerical simulation application of a certain oil field. The method of the present invention is used to perform fine characterization of the reverse faults of the reservoir, and the utilization rate of the well data that penetrates the fault is increased to 100%, the accuracy of three-dimensional geological modeling is increased from 80% to 90%, and the conformity rate of discarded well point data is increased from 85% to 95%, which has a high practical application value; at the same time, 25 new wells are drilled near the reverse faults of the construction oil field, with a drilling success rate of 96% and a new production capacity of 16,000 tons, which further verifies that the model built by the method of the present invention is accurate and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a method for improving the accuracy of reverse fault geological modeling in Example 1 of the present invention;

[0029] Figure 2 It is a schematic diagram of setting a virtual well in Example 1 of the present invention;

[0030] Figure 3 It is a 3D schematic diagram of a certain layer of the actual reservoir three-dimensional geological elevation model in Example 1 of the present invention;

[0031] Figure 4Schematic diagrams comparing reservoir thickness plane diagrams obtained by interpolation using two methods in Example 1 of the present invention; wherein, Figure (a) is an isovalue diagram without considering the effective thickness of virtual well points, and Figure (b) is an isovalue diagram considering the effective thickness of virtual well points;

[0032] Figure 5 A schematic diagram of a fault model for fault F1 constructed in Example 2 of the present invention;

[0033] Figure 6 It is a schematic diagram of reservoir thickness data of the slice and truncation of the altitude model in Example 2 of the present invention;

[0034] Figure 7 Schematic diagram of the comparison of the plane diagrams of the porosity model obtained by interpolation using two methods in Example 2 of the present invention; wherein, Figure (a) is a contour map without considering the effective porosity of virtual well points, and Figure (b) is a contour map considering the effective porosity of virtual well points. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] Combination Figure 1 As shown, an embodiment of the present invention provides a method for improving the accuracy of reverse fault geological modeling, the method comprising the following steps:

[0038] Step S1: depicting fault trajectory;

[0039] The spatial position of the fault is established using the fault data, and the fault trajectory is depicted layer by layer according to the interpretation parameters of the fault, so as to obtain the fault model;

[0040] Among them, the interpretation parameters of the fault include fault distance, strike, dip and inclination.

[0041] Step S2: setting a virtual well;

[0042] For the original well W that crosses the fault, take the location of the fault point as the origin, and set two virtual wells of the original well W in the upper and lower plates of the fault: Well W1 and Well W2; among them, Well W1 is located in the upper plate of the fault where the original well W is located, and Well W2 is located in the lower plate of the fault with the shortest straight-line distance to Well W1.

[0043] like Figure 2 To set up a virtual well schematic, specifically, Figure 2(a) is a schematic diagram of the original formation, the oblique line T1 represents the reverse fault, S1 and S2 represent the disconnected formations, and the arrow line W represents the original well W that penetrates the reverse fault; Figure 2 (b) is a schematic diagram of a three-dimensional geological model, in which the broken line T2 represents a fault in the grid, the arrow line W1 represents a virtual well W1 located at the original well W, and the arrow line W2 represents a virtual well W2 located at the foot of the fault.

[0044] Figure 3 It is a 3D schematic diagram of a layer of the actual reservoir three-dimensional geological elevation model, where W1 represents the virtual well W1 located at the original well W, and W2 is the virtual well W2 located at the foot of the fault.

[0045] Step S3: virtual well assignment;

[0046] Combined with the seismic data, the altitude position of the breakpoint on the well is determined, and the well point data of the original well W is truncated at the breakpoint. The wells W1 and W2 are assigned values ​​respectively. The upper plate data of the original well W is assigned to the well W1 located in the upper plate, and the lower plate data is assigned to the well W2 located in the lower plate.

[0047] Step S4: model interpolation calculation;

[0048] Using the data from two virtual wells, W1 and W2, the attribute model was obtained through attribute interpolation calculation to complete the reverse fault geological modeling.

[0049] Attribute interpolation is a method that must be used in existing geological modeling technology. Generally, modeling software will provide different interpolation methods (such as triangular interpolation, Kriging interpolation, equal probability random simulation method, etc.). Geological modeling requires the simulation target to be gridded. The grid is the smallest unit of the geometric space after the geological model is discretized. Each grid requires the assignment of relevant attributes, such as the top structure, effective thickness, porosity, permeability and other attributes of a certain layer of the model. Taking effective thickness as an example, for a well with known data (such as the effective thickness interpreted by well logging) that falls on a certain grid, the grid has the corresponding effective thickness value, but the grid without actual well points between the two wells has no value. The value of each grid must be obtained through mathematical interpolation calculation. This process is attribute interpolation.

[0050] In the two embodiments of the present invention, the attribute model includes attribute parameters such as top structure, reservoir thickness, effective thickness, porosity and permeability. If the study requires an attribute model including other attribute parameters, such as fracture thickness, fracture porosity, fracture permeability, fracture saturation, fracture density and other attribute parameters, they can also be obtained using the same method mentioned above.

[0051] Figure 4Figure 2 is a schematic diagram comparing the reservoir thickness plane maps obtained by the two methods, where Figure (a) is the contour map without considering the effective thickness of the virtual well point, and Figure (b) is the contour map with considering the effective thickness of the virtual well point.

[0052] In Figure (b), W1 represents the virtual well W1 located at the original well W, and W2 is the virtual well W2 set at the bottom of the fault. The reservoir thickness of the original well point data here is 21.7 meters, and the traditional method of interpolation calculation is 19.2 meters, with an error of 11.52%. Since the model algorithm cannot use values ​​of different depths for interpolation calculation at the same point, the data of the bottom of the fault is lost; the embodiment of the present invention sets a virtual well and then interpolates, and the reservoir thickness here is 22.1 meters, and the error is 1.84%. Compared with the traditional method, the embodiment of the present invention considers the error of the reservoir thickness calculated by the virtual well from 11.52% to 1.84%.

[0053] The embodiment of the present invention uses a method of setting virtual wells to achieve the maximum use of well point data for fine characterization of the fault. Although conventional methods can also use interpolation to obtain data of the bottom wall of the fault, their accuracy cannot be guaranteed. The method of the present invention uses a method of setting virtual wells at the bottom wall of the fault before the prior art performs interpolation calculations to assign values ​​to the upper and lower walls of the reverse fault, maximize the use of existing well point data, achieve a more detailed characterization of the fault, and greatly improve the accuracy of reverse fault modeling.

[0054] Example 2

[0055] The embodiment of the present invention adopts the method of embodiment 1, and applies the technology of improving the accuracy of three-dimensional geological modeling by setting virtual wells in the three-dimensional geological modeling of a certain construction oil field. The specific implementation steps are as follows:

[0056] Step S1: depicting fault trajectory;

[0057] According to the fault elements interpreted from the earthquake, the spatial position of the reverse fault F1 is established in space, and a fault model is established, such as Figure 5 As shown;

[0058] Step S2: setting a virtual well;

[0059] Well W in the study area penetrates the reverse fault F1. The characteristics of repeated layers can be clearly seen on the well logging curve. Combined with the seismic profile, it is determined that the fault passes through Well W at an altitude of -953.5m. At the breakpoint, the well logging curve, reservoir thickness and interpretation result data (porosity, permeability, saturation) are truncated at -953.5m.

[0060] Step S3: virtual well assignment;

[0061] See also Figure 6As shown, a virtual well W1 is set on the upper plate of the fault, the well point coordinates of the W well are assigned to the W1 well, and the well point data above the breakpoint is copied to the W1 well; a virtual well W2 is set at the foot plate of the fault closest to the W well in a straight line, and the data below -953.5 m above sea level are assigned to the W2 well. This method makes the utilization rate of the well point data reach 100%;

[0062] Step S4: model interpolation calculation;

[0063] Combining the structural plane and fault model of seismic interpretation, the structural planes of each layer were established, and a three-dimensional grid model was built; after the data of well W1 and well W2 were gridded, the reservoir, porosity and permeability models were established through interpolation calculations.

[0064] Taking the porosity model as an example, see Figure 7 As shown, Figure (a) is the contour map without considering the effective porosity of the virtual well point, and Figure (b) is the contour map considering the effective porosity of the virtual well point. The porosity in the well point data of the original well W is 33.4%, and the porosity at the bottom of the fault obtained by interpolation of the W well data is 31.5%. After considering the setting of the virtual well, the interpolation result of the data is 33.8%, and the error is reduced from 5.96% to 1.2%, and the data accuracy is significantly improved.

[0065] Example 3

[0066] An embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a computer, the computer executes the method described in Embodiment 1.

[0067] The storage medium may include: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0068] Example 4

[0069] An embodiment of the present invention provides an electronic device, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the method described in Embodiment 1 is implemented.

[0070] The above description is only an embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the application scope of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for improving the accuracy of reverse fault geological modeling, characterized in that: The method comprises the following steps: Step S1: depicting fault trajectory; The spatial position of the fault is established using the fault data, and the fault trajectory is depicted layer by layer according to the interpretation parameters of the fault, so as to obtain the fault model; Step S2: setting a virtual well; For the original well W that crosses the fault, take the location of the fault point as the origin, and set two virtual wells of the original well W in the upper and lower walls of the fault: Well W1 and Well W2; Step S3: virtual well assignment; Combined with the seismic data, the elevation position of the breakpoint on the well is determined, and the well point data of the original well W is truncated at the breakpoint, and values ​​are assigned to wells W1 and W2 respectively, and the upper plate data of the original well W is assigned to well W1 located in the upper plate, and the lower plate data is assigned to well W2 located in the lower plate; Step S4: model interpolation calculation; Using the data from Well W1 and Well W2, the attribute model was obtained through attribute interpolation calculation to complete the reverse fault geological modeling.

2. The method according to claim 1, characterized in that: In step S1, the interpretation parameters of the fault include fault throw, strike, dip and inclination.

3. The method according to claim 1, characterized in that In step S2, well W1 is located at the upper wall of the fault where the original well W is located, and well W2 is located at the lower wall of the fault that is closest to well W1 in a straight line distance.

4. The method according to claim 1, characterized in that: In step S4, the attribute model includes at least the following attribute parameters: top structure, reservoir thickness, effective thickness, porosity and permeability.

5. The method according to claim 1 or 4, characterized in that: In step S4, the attribute interpolation adopts triangular interpolation method, Kriging interpolation method or equal probability random simulation method.

6. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a computer, the computer executes the method according to any one of claims 1 to 5.

7. An electronic device comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method according to any one of claims 1 to 5 is implemented.

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