Evaluation method of vertical oil and gas transport capacity based on the combination pattern of compression-torsion faults

Abstract

The present invention provides a method for evaluating the vertical conductivity of oil and gas based on compression-torsion fault combination patterns, comprising: step 1: selecting a block with discovered reserves at a high level of exploration; step 2: dividing oil and gas vertical migration and accumulation units under the joint control of the fault combination pattern and regional caprock; step 3: statistically analyzing the fault combination pattern, the thickness of the corresponding regional caprock, and the scale of discovered reserves; step 4: calculating the vertical conductivity index of oil and gas for the fault combination pattern corresponding to the vertical migration and accumulation unit; and step 5: fitting vertical conductivity index curves of faults with different combination patterns to multiple block sample points to form a quantitative evaluation chart. This method for evaluating the vertical conductivity of oil and gas based on compression-torsion fault combination patterns solves the problem of evaluating the vertical conductivity of oil and gas in complex compression-torsion fault zones in clastic basins. It is more consistent with the development characteristics of compression-torsion faults and petroleum geological conditions in compression-torsion superimposed basins dominated by clastic rock filling, effectively guiding oil and gas exploration practices, and has good prospects for application and promotion.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration and development in compression-torsion oil and gas basins, and in particular to a method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults. Background Art

[0002] Faults are the vertical links connecting layered elements such as source rocks, reservoirs, and caprocks within petroliferous basins. They are also crucial for studying the migration and accumulation of oil and gas. Modern petroleum geology has conducted extensive research on the zoning structure of individual faults, clarifying that a single fault is not a surface but a single entity, divided into fracture zones and fracture zones from the two sides of the fault toward the center. Modern petroleum geology evaluates the oil and gas conductivity of faults primarily based on fault zoning. Various evaluation methods have been developed based on factors influencing fault opening and closing, such as fault strike, the lithologic relationship between the two sides, and mudstone smearing in the fracture zone. Extensive analysis of compression-torsion faults within the clastic rock series of the Junggar Basin reveals widespread development of large compression-torsion fault zones, but not single, large faults. Compression-torsion fault zones are composed of multiple sets of faults, making it difficult to characterize which faults conduct oil and gas and which block it using current analytical techniques. For compression-torsion basins mainly filled with clastic rocks, the vertical migration and accumulation of oil and gas are mainly controlled by the "aggregate" of compression-torsion faults rather than by a single fault. Evaluating the vertical conductivity of a single fault has lost its clear petroleum geological significance.

[0003] Geometric patterns such as en echelon, feather, and reticular are used to describe the planar development and composition of transpressional faults, encompassing key aspects of the vertical migration of oil and gas along fault zones, such as shear fracture strength, fault density, and occurrence. According to simple shear theory, with increasing transpressional deformation and the superposition of multiple tectonic phases, the number and density of fault formations increase, leading to the emergence of transpressional fault "aggregates" with varying compositional patterns, such as "steps," "flowers," and "braids," on cross-section. Compressional-torsional fault zone composition is a morphological representation of the extent of tectonic damage to rock formations (especially regional caprocks). Theoretically, the vertical transportability of oil and gas is closely related to fault zone composition. Given the petroleum geology of transpressional superimposed basins dominated by clastic rock infill, where complex fault zones develop and single major faults are absent, a novel and operational method for evaluating vertical transportability of oil and gas with clear petroleum geological significance is needed to provide technical support for the study of oil and gas migration and accumulation patterns in large transpressional superimposed basins.

[0004] The exploration levels of different tectonic units in petroliferous basins in western China vary greatly. The knowledge and technical achievements obtained in some highly explored units can be applied to areas with low exploration levels and other similar petroliferous basins.

[0005] In the Chinese patent application with application number: CN201811456445.5, a method for evaluating the vertical conductivity of an active section is disclosed, which is characterized in that it includes the following steps: Step A, determining the effective activity time at different positions of the section, selecting different positions of the section, calculating the distance between the breakpoints of the two reservoir plates of the section, and dividing it by the thickness of the reservoir, the effective activity time of the section for the reservoir can be obtained: T storage = (h storage - h storage') / H storage; wherein h storage and h storage' are the breakpoint depths of the rising plate and the descending plate of the reservoir, respectively, in m; H storage is the thickness of the reservoir, in m; Step B, determining the dynamic intensity of the reservoir formation between the source and the reservoir of the section, characterizing the dynamic intensity of the reservoir formation between the source and the reservoir according to the ratio of the difference in static pressure between the source rock layer and the reservoir to the difference in hydrostatic pressure. Pressure difference: f = (Psource - Preservoir) / (ρwaterghsource - ρwaterghreservoir), wherein Psource and Preservoir are the static pressures of the source rock layer and the reservoir, respectively, in MPa; ρwater is the density of water, in 1.0 g / cm3; g is the acceleration of gravity, in 9.8 m / s2; hsource and hreservoir are the burial depths of the source rock layer and the reservoir, in m; Step C, determining the vertical conductivity of the section at different positions, calculating the vertical conductivity S of the section to the reservoir according to the connection between the section and the reservoir at different positions: Sreservoir = Treservoir × freservoir = (hreservoir - hreservoir') / Hreservoir × (Psource - Preservoir) / (ρwaterghsource - ρwaterghreservoira); Step D, evaluating the vertical conductivity of the reservoir according to the value of S calculated through the above steps.

[0006] In the Chinese patent application with application number: CN201710566937.9, a method for evaluating the vertical conductivity of reverse fault units in the volcanic rock area of the piedmont thrust belt is involved. The steps include: establishing a fault zone structural geological model, establishing a permeability and effective stress relationship model of the fault zone structural layer, establishing a geometric relationship model of the fault zone structural layer, a component fault zone permeability evaluation model, constructing a mathematical model of the fault zone permeability correction factor, optimizing the fault conductivity evaluation profile, establishing a vertical conductivity quantitative evaluation model for the fault unit, and determining the threshold value of the fault conductivity quantitative evaluation index.

[0007] The Chinese patent application, application number CN201711417931.1, involves a quantitative evaluation method for the unconformity conductivity of clastic rocks. First, a conceptual model of the unconformity conductivity pattern is constructed; then, a mathematical model of the unconformity fluid migration rate is constructed; this mathematical model is improved to obtain an improved mathematical model of the unconformity fluid migration rate; and based on the improved mathematical model of the unconformity fluid migration rate, a mathematical model of the unconformity conductivity rate is constructed to quantitatively evaluate the unconformity conductivity of clastic rocks.

[0008] The above existing technologies are significantly different from the present invention and fail to solve the technical problem we want to solve. Therefore, we have invented a new method for evaluating the vertical oil and gas conductivity based on the combination pattern of compression-torsion faults. Summary of the Invention

[0009] The purpose of the present invention is to provide a method for evaluating the vertical conductivity of oil and gas based on the combination pattern of compression-torsion faults, which is suitable for evaluating the vertical conductivity of oil and gas in fault zones of compression-torsion superimposed basins and analyzing the lateral diversion of oil and gas resources.

[0010] The object of the present invention can be achieved by the following technical measures: a method for evaluating the vertical conductivity of oil and gas based on the combination pattern of compression-torsion faults, the method for evaluating the vertical conductivity of oil and gas based on the combination pattern of compression-torsion faults comprising:

[0011] Step 1: Select blocks with high exploration degree and discovered reserves;

[0012] Step 2: Divide the vertical hydrocarbon migration and accumulation units under the joint control of fault combination patterns and regional caprocks;

[0013] Step 3: Conduct statistics on fault combination patterns, caprock thickness in corresponding fault-penetrating areas, and discovered reserve scale;

[0014] Step 4: Calculate the vertical oil and gas conductivity index of the combined fault pattern corresponding to the vertical migration and accumulation unit;

[0015] Step 5: Fit vertical conductivity index curves of faults with different combination styles at multiple block sample points to form a quantitative evaluation chart.

[0016] The purpose of the present invention can also be achieved by the following technical measures:

[0017] In step 1, select the areas with 3D seismic coverage and a well density higher than 0.5 wells / km in the compression-torsion superimposed basin. 2 The number of blocks selected shall not be less than 5.

[0018] In step 1, the oil and gas in the selected block originate from a set of main source rock layers, migrate mainly vertically, and accumulate in multiple layers along the compression-torsion fault zone, with low loss.

[0019] In step 2, well and seismic data are used to analyze the development characteristics of the target stratum compression-torsion faults, identify and mark the braid, flower and step section combination styles; draw the fault combination style, regional cap rock and discovered reserves configuration framework profile; divide the oil and gas vertical migration and accumulation units according to the fault combination style and the regional cap rock element configuration relationship, and mark the serial number n from shallow to deep.

[0020] In step 2, the combination styles of compression-torsion faults are intuitively characterized as braid, flower, and step styles, corresponding to the decreasing degree of compression-torsion rupture, fault development group, and fault density.

[0021] In step 3, statistics on fault combination patterns, cap rock thickness in corresponding fault-penetrating areas, and discovered reserves are carried out, and a statistical table of fault combination patterns, cap rock thickness, and discovered converted proved reserves for each migration and accumulation unit is established.

[0022] In step 3, the scale of discovered and proved reserves R of different vertical migration and accumulation units is calculated. The scale of discovered and proved, probable and predicted reserves is required to be converted according to the ratio coefficient of 1.0:0.45:0.15:

[0023] R=0.15R pos +0.45R con +R pro (1)

[0024] In formula (1), R is the scale of proven reserves found in the vertical migration and accumulation unit, R pos R is the predicted size of discovered reserves; con is the scale of discovered controlled reserves; R pro The scale of discovered and proven reserves.

[0025] In step 4, the oil and gas vertical conductivity index Iv of the fault combination patterns corresponding to different oil and gas migration and accumulation units is calculated:

[0026]

[0027] In formula (2), Lv is the vertical conductivity index of oil and gas in the combined fault calculated by the present invention, which has a value between 0 and 1 and is dimensionless. A larger Lv value indicates a stronger vertical conductivity of oil and gas. n is the vertical migration and accumulation unit number, which is marked from shallow to deep.

[0028] In step 4, the calculated oil and gas vertical conductivity index is entered into the statistical table of fault combination patterns, cap rock thickness and discovered converted proved reserves established in step 3.

[0029] In step 5, the vertical oil and gas conductivity index of multiple blocks is calculated according to the above steps 2, 3 and 4, and the fault combination pattern, cap rock thickness and the scale of discovered converted proved reserves are entered into the statistical table.

[0030] In step 5, a scatter plot of the vertical conductivity index distribution of different fault combination styles is drawn with the regional cover thickness as the linear abscissa and the vertical conductivity index calculated in step 4 as the probability ordinate.

[0031] In step 5, mathematical statistics methods are used to fit the oil and gas vertical conductivity index curves of different combination styles of faults respectively; thus forming a quantitative evaluation chart of the oil and gas vertical conductivity index under the joint control of different combination styles of faults and regional caprocks.

[0032] In step 5, the oil and gas vertical conductivity index quantitative evaluation chart uses a linear abscissa corresponding to the change in regional cap rock thickness and a probability ordinate corresponding to the oil and gas vertical conductivity index of different combination faults. The value range of the conductivity index is 0.01-1.

[0033] The method for evaluating the vertical conductivity of oil and gas based on the combination pattern of compression-torsion faults in the present invention has been formed through detailed dissection of discovered oil and gas reservoirs in areas with a higher degree of exploration, in order to serve the oil and gas exploration practices in large compression-torsion superimposed basins in western China. The present invention is an evaluation method based on the development characteristics of compression-torsion faults in the Junggar Basin and the practice of oil and gas exploration. It has been applied to multiple tectonic units such as the sag zone and the piedmont thrust-slip zone in the Junggar Basin, solving the problem of the method for evaluating the vertical conductivity of oil and gas in complex compression-torsion fault zones in clastic rock basins. Compared with the oil and gas conductivity evaluation method based on a single fault, the present invention is more in line with the development characteristics of compression-torsion faults and petroleum geological conditions in compression-torsion superimposed basins with clastic rock filling as the main component.

[0034] Compared to methods based on single-fault-based assessments of oil and gas conductivity, this method better reflects the fault development characteristics and petroleum geology of compressional-torsional basins dominated by clastic rock infill. It effectively guides practical oil and gas exploration activities and has promising prospects for widespread application. Although the accuracy of this method's assessment is limited by the number of selectable high-exploration-level blocks, the results demonstrate strong predictive power, with an accuracy rate exceeding 87% for oil and gas intervals. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of a method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults in a specific embodiment of the present invention;

[0036] Figure 2 A schematic diagram of the fault combination pattern, regional cover rock, and proven reserve configuration grid section of the Xiazijie block and its vertical migration and accumulation unit division in a specific embodiment of the present invention;

[0037] Figure 3 This is a quantitative evaluation chart of the vertical oil and gas conductivity index under the joint control of different combinations of compressional-torsional faults and regional caprocks in the Junggar Basin in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0038] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

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

[0040] The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults of the present invention includes the following steps:

[0041] Step 1: Select blocks with high exploration degree and discovered reserves;

[0042] Select the 3D seismic coverage in the compression-torsion superimposed basin and the drilling density is higher than 0.5 wells / km 2 The number of blocks selected should be no less than 5 (increasing the number of samples will improve the evaluation accuracy of the present invention). The oil and gas in the selected blocks mainly migrate vertically, are accumulated in multiple layers, and have low loss, so as to meet the effective sample requirements of the statistical analysis of the present invention.

[0043] Step 2: Divide the vertical hydrocarbon migration and accumulation units under the joint control of fault patterns and regional caprocks;

[0044] Use well and seismic data to analyze the development characteristics of target strata compression-torsion faults, identify and mark the "braid", "flower" and "step" section combination patterns; draw the fault combination pattern, regional cap rock and discovered reserves configuration framework profile; divide the vertical oil and gas migration and accumulation units according to the fault combination pattern and regional cap rock element configuration relationship, and mark the sequence number n from shallow to deep, such as Figure 2 As shown, three vertical oil and gas migration and accumulation units are divided.

[0045] The compression-torsion fault combination patterns are intuitively characterized as "braid", "flower" and "step" patterns, and the corresponding compression-torsion rupture degree, fault development group and fault density decrease in sequence.

[0046] Step 3: Conduct statistics on fault combination patterns, caprock thickness in corresponding fault-penetrating areas, and discovered reserve scale;

[0047] The scale of discovered and proved reserves R of different vertical migration and accumulation units is calculated. The scale of discovered and proved reserves, probable and predicted reserves is required to be converted according to the ratio coefficient of 1.0:0.45:0.15:

[0048] R=0.15R pos +0.45R con +R pro (1)

[0049] In formula (1), R is the scale of proven reserves found in the vertical migration and accumulation unit, Rpos R is the predicted size of discovered reserves; con is the scale of discovered controlled reserves; R pro The scale of discovered and proven reserves.

[0050] Establish a statistical table of fault combination patterns, cap rock thickness and scale of discovered and proven reserves for each migration and accumulation unit.

[0051] Step 4: Calculate the vertical oil and gas conductivity index of the combined fault pattern corresponding to the vertical migration and accumulation unit;

[0052] Calculate the oil and gas vertical conductivity index Iv of the fault combination patterns corresponding to different oil and gas migration and accumulation units:

[0053]

[0054] In formula (2), Lv is the vertical oil and gas conductivity index of the combined fault calculated by the present invention, which is dimensionless and ranges from 0 to 1. A larger Lv value indicates a stronger vertical oil and gas conductivity. n is the serial number of the vertical migration and accumulation unit divided and marked in step 2, marked as 1, 2, and 3 from shallow to deep.

[0055] The calculated oil and gas vertical conductivity index is entered into the statistical table of fault combination patterns, cap rock thickness, and discovered converted proved reserves established in step 3, as shown in Table 1.

[0056] Step 5: Fit vertical conductivity index curves of faults with different combination styles at multiple block sample points to form a quantitative evaluation chart.

[0057] According to the above steps 2, 3 and 4, calculate the vertical conductivity index of oil and gas in multiple blocks, and enter the statistical table of fault combination style, cap rock thickness and the scale of discovered converted proved reserves; use the regional cap rock thickness as the linear abscissa and the vertical conductivity index calculated in step 4 as the probability ordinate to draw a scatter plot of the vertical conductivity index distribution of different fault combination styles; use mathematical statistics methods to fit the oil and gas vertical conductivity index curves of different combination styles of faults respectively; Figure 3 As shown in the figure, a quantitative evaluation chart of the vertical conductivity index of oil and gas under the joint control of different combination styles of faults and regional cap rocks is formed to serve the evaluation of the vertical conductivity capacity of oil and gas in the less explored areas of compressional-torsional superimposed basins.

[0058] The quantitative evaluation chart uses a linear abscissa corresponding to the change in regional cap rock thickness, and a probability ordinate corresponding to the vertical oil and gas conductivity index of different combination faults, with the value range of the conductivity index being 0.01 to 1.

[0059] In a specific embodiment 1 of the present invention, Figure 1 As shown, Figure 1This is a flow chart of the method for evaluating the vertical transport capacity of oil and gas in the Junggar Basin based on the combination pattern of compressional-torsion faults. The method includes the following steps:

[0060] In step 101, 11 areas with 3D seismic coverage and a drilling density of more than 0.5 wells / km in the Junggar Basin, including Xiazijie, Baikouquan, Yongjin, Jimusar, Beisantai and Shazhang, were selected. 2 Discovered reserve blocks. Selected blocks must demonstrate vertical oil and gas migration, multi-layered accumulation, and low loss, meeting the statistical analysis requirements of the present invention and serving as the data basis for the present invention's method. The process proceeds to step 102.

[0061] In step 102, the oilfield geological anatomy and oil and gas vertical migration and accumulation unit division are carried out on the Xiazijie block selected in step 101: seismic structural analysis technology is used to carry out fault interpretation from shallow to deep layers to clarify the fault development characteristics of different strata. In the example of the present invention, three types of compression-torsion fault combination patterns, namely "braid", "flower" and "step" are divided and labeled; drilling and logging data and existing geological data of the block are used to determine the development layer and thickness of the regional cap rock; combined with the discovered oil and gas reservoirs and the third-level reserve reporting data, the fault combination pattern, regional cap rock and the discovered oil and gas reservoir configuration framework profile are drawn; such as Figure 2 As shown, three vertical oil and gas migration and accumulation units are divided based on the combination pattern of compression-squeezal faults and the configuration relationship of regional caprock elements, and are numbered n=1, 2, and 3 from shallow to deep. The process enters step 103.

[0062] In step 103, the scale of proven, controlled and predicted reserves of different migration and accumulation units is counted. The scale of proven, controlled and predicted reserves is required to be converted according to the ratio of 1.0:0.45:0.15, that is, formula (1) R = 0.15R pos +0.45R con +R pro Calculate the scale of discovered and proved reserves R for different vertical migration and accumulation units. In the present invention, the scale of discovered and proved reserves R1 for migration and accumulation unit 1 in the Xiazijie block is 10.46 million tons, the scale of discovered and proved reserves R2 for migration and accumulation unit 2 is 20.59 million tons, and the scale of discovered and proved reserves R3 for migration and accumulation unit 3 is 16.62 million tons. A statistical table of fault combination patterns, caprock thickness, and discovered and proved reserves for each vertical migration and accumulation unit in the Xiazijie block is established, as shown in Table 1:

[0063] Table 1 Statistics of fault combination patterns, caprock thickness and the scale of discovered and proven reserves

[0064]

[0065] The process enters step 104.

[0066] In step 104, the oil and gas vertical conductivity index Lv of the faults of different combination styles in the Moxizhuang area is calculated based on the quantitative evaluation chart in the specific embodiment 1 of the present invention.

[0067] Formula (2) Calculate the vertical conductivity index of the combined faults corresponding to different oil and gas migration and accumulation units. Migration and accumulation unit 1 is mainly a flower-shaped fault that breaks through the top of migration and accumulation unit 2. The vertical conductivity index of oil and gas migration and lateral diversion of the cap rock is corresponding to the flower-shaped fault. The petroleum geology meaning is that 33% of the oil and gas resources migrate vertically along the flower-shaped fault zone to the migration and accumulation unit 1, while 67% of the oil and gas resources are laterally diverted and accumulated in the migration and accumulation unit 2. The migration and accumulation unit 2 is mainly the braided fault that penetrates the top cap rock of the migration and accumulation unit 3, which conducts the vertical oil and gas migration and accumulation of migration and accumulation units 2 and 1. The corresponding braided fault vertical conductivity index is Petroleum geology suggests that 65% of oil and gas resources migrate vertically along the braided fault zone to form accumulation units 1 and 2, while 35% of oil and gas resources divert laterally to form accumulation units 3. The calculated vertical oil and gas accumulation index for the Xiazijie block is entered into Table 1, which contains statistics on fault patterns, caprock thickness, and discovered and proven reserves, established in Step 3. The process then proceeds to Step 105.

[0068] In step 105, the oil and gas vertical conductivity index of the selected blocks such as Baikouquan block, Ji7 well area and Yong6 well area is calculated according to steps 2, 3 and 4 respectively, and the corresponding data are entered into the statistical table of fault combination pattern, cap rock thickness and discovered converted proved reserves scale; this example uses EXCELL software to draw a scatter plot of the vertical conductivity index distribution of faults with different combination patterns, with the regional cap rock thickness as the linear abscissa and the vertical conductivity index calculated in step 4 as the probability ordinate; as shown in FIG. Figure 3 As shown in the figure, the oil and gas vertical conductivity index curves of the "braid", "flower" and "step" combination faults in the Junggar Basin are fitted; a quantitative evaluation chart of the oil and gas vertical conductivity index of the compression-torsion faults with different combination styles in the Junggar Basin is formed to serve the evaluation of the oil and gas vertical conductivity capacity and the analysis of the lateral diversion of oil and gas resources in the complex compression-torsion fault zone in the Junggar Basin.

[0069] In a second specific embodiment of the present invention, a method for evaluating the vertical oil and gas transport capacity of the Moxizhuang compressional-torsion fault zone based on the combination pattern of compressional-torsion faults in the shallow, highly explored, and deep, less explored areas of the Junggar Basin depression is provided. The method includes the following steps:

[0070] In step 101, the Moxizhuang Oilfield is selected. This field has a high degree of exploration in shallow and medium layers, with discovered oil and gas reservoirs primarily derived from the Permian P2w main source rock system, primarily characterized by vertical migration and low loss, and has deep exploration potential yet to be evaluated. The process then proceeds to step 102.

[0071] In step 102, deep drilling data from adjacent areas and 3D seismic data are combined to map the fault pattern, regional caprock, and discovered reservoir configuration framework of the Moxizhuang area. Four vertical hydrocarbon migration and accumulation units, K1h-K1q, J1s-J1b, T2k-T1b, and P3w-P2w, are identified from shallow to deep layers and numbered n = 1, 2, 3, and 4, respectively. The process then proceeds to step 103.

[0072] In step 103, the proven, controlled and predicted reserves of the high-exploration migration and accumulation units are calculated. The proven, controlled and predicted reserves are converted according to the ratio of 1.0:0.45:0.15, that is, R = 0.15R in formula (1). pos +0.45R con +R pro Calculate the scale of discovered and proved reserves R for different vertical migration and accumulation units. In the Moxizhuang Oilfield, only migration and accumulation unit 2 has discovered a scale of proved reserves R1 = 20.59 million tons. In migration and accumulation unit 1, there are a large number of oil and gas shows but no reserves reported. In migration and accumulation units 3 and 4, no wells have been drilled yet. A statistical table of fault combination patterns, caprock thickness, and discovered and proved reserves scale for each vertical migration and accumulation unit in the Moxizhuang Oilfield was established, as shown in Table 2:

[0073] Table 2 Statistics of fault combination patterns, caprock thickness and reserve scale predicted by the method of the present invention

[0074]

[0075] The process enters step 104.

[0076] In step 104, the vertical conductivity index Lv of the combined faults of different combinations of compression and torsional faults and regional caprocks in the Junggar Basin is calculated based on the quantitative evaluation chart of the oil and gas vertical conductivity index under the joint control of different combination styles of compression and torsional faults and regional caprocks in specific embodiment 1, or based on the oil and gas vertical conductivity index curve fitting formula of the "braid", "flower" and "step" combined faults in the Junggar Basin in embodiment 1. The vertical conductivity index Lv of the combined faults of different oil and gas migration and accumulation units is calculated based on the oil and gas vertical conductivity curve fitting formula of the "braid", "flower" and "step" combined faults in the Junggar Basin in embodiment 1. The vertical conductivity index of the migration and accumulation unit 1 is mainly the step fault that breaks through the top regional caprock of the migration and accumulation unit 2, and the corresponding step fault vertical conductivity index Lv = 0.056ln(56) + 0.2879 = 0.06. The petroleum geology meaning is that 6% of the oil and gas resources migrate vertically along the step fault zone to the migration and accumulation unit 1 to form a reservoir, while 94% of the oil and gas resources are laterally diverted and accumulated in the migration and accumulation unit 2. Migration and accumulation unit 2 is mainly caused by the vertical transport of oil and gas through the cap rock at the top of migration and accumulation unit 3, and the corresponding vertical transport index of the flower-shaped fault is Lv = 0.076ln(478) + 0.6257 = 0.15. In petroleum geology, 15% of the oil and gas resources migrate vertically along the flower-shaped fault zone and accumulate in migration and accumulation units 2 and 1, while 75% of the oil and gas resources are laterally diverted and accumulated in migration and accumulation unit 3. Migration and accumulation unit 3 is mainly caused by the vertical transport of oil and gas through the cap rock at the top of migration and accumulation unit 4, and the corresponding vertical transport index of the braided fault is Lv = -0.122ln(185) + 1.2426 = 0.61. Petroleum geology suggests that 61% of oil and gas resources migrate vertically along braided fault zones to form accumulation units 3, 2, and 1, while 49% of oil and gas resources divert laterally to form accumulation units 4 or within source rock formations. The vertical oil and gas accumulation index for the Moxizhuang area, calculated using the method of the present invention, is entered into Table 2, a statistical table of fault patterns, caprock thickness, and discovered and proven reserves, established in step 103. The process then proceeds to step 105.

[0077] In step 105, according to formula (2) Predict the proven reserves R corresponding to different oil and gas migration and accumulation units. In migration and accumulation unit 2, it has been discovered that their reserves R2 = 20.56 million tons, the vertical conductivity index of the step-like combined fault Lv = 0.06, according to the formula The reserve scale of migration and accumulation unit 1 is calculated as R1 = 1.16 million tons. In migration and accumulation unit 2, the vertical conductivity index of the flower-shaped fault is Lv = 0.15. According to the formula The reserve scale of migration and accumulation unit 3 is calculated as R3 = 123.08 million tons. In migration and accumulation unit 3, the vertical conductivity index of braided faults is Lv = 0.61. According to the formula The reserve scale of migration and accumulation unit 4 is calculated as R4 = 92.58 million tons. The reserve scales of each migration and accumulation unit in the Moxizhuang area calculated using the method of the present invention are entered into the statistical table 2 of fault combination patterns, caprock thickness, and discovered and proved reserves scale established in step 103 .

[0078] In the second specific embodiment of the present invention, the oil and gas generated in the Lower Urho Formation (P2w) of the Permian System in the Moxizhuang area migrated and accumulated in multiple vertical systems along the compression-torsion fault zone. The deep exploration potential and expected reserve scale were predicted based on the reserve discovery scale of the high-exploration migration and accumulation units in the middle and shallow layers.

[0079] In a specific embodiment 3 of the present invention, a method for evaluating the vertical oil and gas transport capacity of the Ke-Bai fault zone based on the combination pattern of compressional and torsional faults in the high exploration and development area of the Junggar Basin's piedmont zone is provided. The method comprises the following steps:

[0080] In step 101, the Karamay Oilfield's Blocks 1, 7, 5, and 8, which have high exploration and development levels, primarily derive their oil and gas from the Permian Fengcheng Formation source rocks (P1f), primarily migrate vertically, form multi-layered reservoirs, and have low dissipation rates, are selected as analysis samples. The process then proceeds to step 102.

[0081] In step 102, a cross-section of the fault pattern, regional caprock, and discovered reservoir configuration framework is drawn. From shallow to deep, four vertical hydrocarbon migration and accumulation units are identified: J3q, J2x-J1b, T2k-P3w, and P2w-C. These units are numbered n = 1, 2, 3, and 4, respectively. The process then proceeds to step 103.

[0082] In step 103, the reported proved petroleum reserves for migration and accumulation unit 1 in this example are calculated as R1 = 9.5573 million tons, the reported proved petroleum reserves for migration and accumulation unit 2 as R2 = 74.0174 million tons, and the reported proved petroleum reserves for migration and accumulation unit 3 as R3 = 234.6950 million tons. Furthermore, the reported proved petroleum reserves for migration and accumulation unit 4 in the adjacent source rock formations as R4 = 220.6061 million tons are calculated. The process then proceeds to step 104.

[0083] In step 104, according to formula (2) Calculate the vertical conductivity index Lv of the combined faults corresponding to different oil and gas migration and accumulation units. Migration and accumulation unit 1 is mainly a step fault that breaks through the cap rock in the top area of migration and accumulation unit 2. The vertical conductivity index of the step fault is The petroleum geology meaning is that 12% of the oil and gas resources migrate vertically along the step fault zone to the migration and accumulation unit 1, while 88% of the oil and gas resources are laterally diverted to the migration and accumulation unit 2. The migration and accumulation unit 2 is mainly the flower-shaped fault that breaks through the cap rock in the top area of the migration and accumulation unit 3, which conducts vertical oil and gas migration and lateral diversion to form accumulation. The corresponding vertical conductivity index of the flower-shaped fault is The petroleum geology means that 26% of the oil and gas resources migrate vertically along the flower-shaped fault zone and accumulate in migration and accumulation units 2 and 1, while 74% of the oil and gas resources are laterally diverted and accumulated in migration and accumulation unit 3. Migration and accumulation unit 3 is mainly due to the vertical migration and lateral diversion of oil and gas by the braided fault that penetrates the cap rock at the top of migration and accumulation unit 4. The corresponding braided fault vertical conductivity index is Petroleum geology means that 59% of the oil and gas resources migrate vertically along the braided fault zone to form accumulation units 3, 2, and 1, while 41% of the oil and gas resources are laterally diverted to form accumulation units 4. The process proceeds to step 105.

[0084] In step 105, a statistical table of fault combination patterns, caprock thickness, discovered and proved reserves, and calculated vertical oil and gas conductivity index for each vertical migration and accumulation unit in Example 3 is established. As shown in Table 3:

[0085] Table 3 Statistics of Ke-Bai fault combination patterns, caprock thickness and the scale of discovered and converted proven reserves

[0086]

[0087] Example 3 forms a reference system for evaluating the vertical transport capacity of oil and gas for the "aggregates" of faults of different combinations in the Ke-Bai fault zone in the piedmont zone of the Junggar Basin. It only serves the evaluation of the vertical migration capacity of oil and gas, the lateral diversion of oil and gas resources, and the analysis of the interlayer distribution of oil and gas resources in the Ke-Bai fault zone and the surrounding areas with relatively low exploration levels.

[0088] The present invention's method for evaluating the vertical transportability of oil and gas based on the combination of compression-torsion fault patterns has been applied in areas of varying exploration depth in the Junggar Basin, solving the problem of evaluating and predicting the vertical migration and accumulation patterns of oil and gas in complex compression-torsion fault zones. Compared to methods based on the evaluation of oil and gas transportability based on single faults, the present invention is more consistent with the fault development characteristics and petroleum geological conditions of compression-torsion superimposed basins dominated by clastic rock filling, effectively guiding practical oil and gas exploration activities. It has excellent application and promotion prospects, especially in areas where existing analytical techniques cannot fully describe the complex development characteristics of compression-torsion faults.

[0089] Although the evaluation accuracy of the present invention is restricted by the number of selectable high-exploration blocks, the evaluation results have a strong predictive effect, with the oil and gas layer segment display consistency rate exceeding 87%.

[0090] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0091] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. A method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults, characterized by: The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults includes: Step 1: Select blocks with high exploration degree and discovered reserves; Step 2: Divide the vertical hydrocarbon migration and accumulation units under the joint control of fault combination patterns and regional caprocks; Step 3: Conduct statistics on fault combination patterns, caprock thickness in corresponding fault-penetrating areas, and discovered reserve scale; Step 4: Calculate the vertical oil and gas conductivity index of the combined fault pattern corresponding to the vertical migration and accumulation unit; Step 5: Fit vertical conductivity index curves of faults with different combination patterns at multiple block sample points to form a quantitative evaluation chart; In step 3, statistics on fault combination patterns, cap rock thickness in corresponding fault-penetrating areas, and discovered reserves are collected, and a statistical table of fault combination patterns, cap rock thickness, and discovered converted proved reserves for each migration and accumulation unit is established; In step 3, the scale of discovered and proved reserves R of different vertical migration and accumulation units is calculated. The scale of discovered and proved reserves, probable and predicted reserves is required to be converted according to the ratio coefficient of 1.0:0.45:0.15: R=0.15RR pos +0.45R con +R pro (1) In formula (1), R is the scale of proven reserves found in the vertical migration and accumulation unit, R pos R is the predicted size of discovered reserves; con is the scale of discovered controlled reserves; R pro The scale of discovered and proven reserves; In step 4, the vertical oil and gas conductivity index Lv of the fault combination patterns corresponding to different oil and gas migration and accumulation units is calculated: In formula (2), Lv is the vertical conductivity index of oil and gas in the calculated combined fault pattern, which is dimensionless and ranges from 0 to 1. The larger the Lv value, the stronger the vertical conductivity of oil and gas. n is the vertical migration and accumulation unit number, which is marked from shallow to deep. In step 4, the calculated oil and gas vertical conductivity index is entered into the statistical table of fault combination patterns, cap rock thickness and discovered converted proved reserves established in step 3.

2. The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults according to claim 1 is characterized in that: In step 1, select the areas with 3D seismic coverage and a well density higher than 0.5 wells / km in the compression-torsion superimposed basin. 2 The number of blocks selected shall not be less than 5.

3. The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-twist faults according to claim 2, characterized in that: In step 1, the oil and gas in the selected block originate from a set of main source rock layers, migrate mainly vertically, and accumulate in multiple layers along the compression-torsion fault zone, with low loss.

4. The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults according to claim 1, characterized in that: In step 2, well and seismic data are used to analyze the development characteristics of the target stratum compression-torsion faults, identify and mark the braid, flower and step section combination styles; draw the fault combination style, regional cap rock and discovered reserves configuration framework profile; divide the oil and gas vertical migration and accumulation units according to the fault combination style and the regional cap rock element configuration relationship, and mark the serial number n from shallow to deep.

5. The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults according to claim 4 is characterized in that: In step 2, the combination styles of compression-torsion faults are intuitively characterized as braid, flower, and step styles, corresponding to the decreasing degree of compression-torsion rupture, fault development group, and fault density.

6. The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults according to claim 1, characterized in that: In step 5, the vertical oil and gas conductivity index of multiple blocks is calculated according to the above steps 2, 3 and 4, and the fault combination pattern, cap rock thickness and the scale of discovered converted proved reserves are entered into the statistical table.

7. The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults according to claim 6, characterized in that: In step 5, a scatter plot of the vertical conductivity index distribution of different fault combination styles is drawn with the regional cover thickness as the linear abscissa and the vertical conductivity index calculated in step 4 as the probability ordinate.

8. The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults according to claim 7 is characterized in that: In step 5, mathematical statistics methods are used to fit the oil and gas vertical conductivity index curves of different combination styles of faults respectively; thus forming a quantitative evaluation chart of the oil and gas vertical conductivity index under the joint control of different combination styles of faults and regional caprocks.

9. The method for evaluating the vertical transport capacity of oil and gas based on the combination pattern of compression-torsion faults according to claim 8, characterized in that: In step 5, the oil and gas vertical conductivity index quantitative evaluation chart uses a linear abscissa corresponding to the change in regional cap rock thickness and a probability ordinate corresponding to the oil and gas vertical conductivity index of different combination faults. The value range of the conductivity index is 0.01-1.

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