An oil and gas reservoir forming analysis method based on internal structure of fracture zone

Abstract

The application relates to an oil and gas reservoir forming analysis method based on the internal structure of a fracture zone, and solves the problem that the existing method cannot comprehensively analyze oil and gas reservoir forming because the influence of the fracture zone is not fully considered. The method comprises the following steps: S1, collecting basic data and identifying the main fracture zone in a selected research area; S2, dividing the internal structure of the fracture zone based on the identified main fracture zone in the research area; S3, collecting and analyzing samples to determine the source of oil and gas fluid; S4, analyzing and describing the migration track of the oil and gas fluid; S5, drawing an oil and gas reservoir forming mode diagram based on the analysis result of the migration track of the oil and gas fluid, and analyzing the oil and gas reservoir forming effect; and S6, summarizing the internal structure characteristics of the fracture zone and the influence law of the internal structure of the fracture zone on the oil and gas reservoir forming. The method can accurately provide favorable data support for oil and gas reservoirs and oil and gas migration, comprehensively analyze oil and gas reservoir forming, and accurately determine the target area of oil and gas exploration.

Description

Technical Field

[0001] This invention relates to the field of hydrocarbon accumulation technology, and in particular to a hydrocarbon accumulation analysis method based on the internal structure of fault zones. Background Technology

[0002] Hydrocarbon accumulation refers to the process by which oil and natural gas, through geological history, undergo formation, migration, accumulation, and ultimately storage under favorable geological conditions. This process involves multiple disciplines, including complex geodynamics, sedimentology, structural geology, rock physics, and geochemistry. The study of hydrocarbon accumulation aims to reveal the formation mechanisms, distribution patterns, and enrichment characteristics of oil and gas resources, providing a theoretical foundation and technical guidance for oil and gas exploration and development.

[0003] Fault zones play a crucial role in hydrocarbon accumulation. They are not only important channels for hydrocarbon migration but also key sites for hydrocarbon accumulation and preservation. By altering the continuity, permeability, and sealing properties of strata, they profoundly influence the generation, migration, accumulation, and preservation of hydrocarbons. Current hydrocarbon accumulation analysis employs traditional fault sealing assessment methods, which have significant limitations. First, these methods only consider a few factors and simplify to homogeneous bodies, relying on a single parameter for overall evaluation, failing to fully account for the influence of fault zones. This may lead to misjudgments of hydrocarbon migration paths and fault sealing properties (such as ignoring the role of faults as dominant channels). Second, traditional methods do not consider the internal structure of fault zones, such as their geometry, spatial distribution, and the correlation characteristics of fault activity history at different levels. This results in faults failing to provide accurate data support for hydrocarbon reservoirs and migration, thus preventing a comprehensive analysis of hydrocarbon accumulation. Therefore, in-depth research into the internal structure of fault zones and their mechanisms of action on hydrocarbon accumulation is of great significance for oil and gas exploration and development. Summary of the Invention

[0004] This invention addresses the problem that existing methods in the background art fail to fully consider the influence of fault zones, thus hindering comprehensive analysis of hydrocarbon accumulation. Instead, it provides a hydrocarbon accumulation analysis method based on the internal structure of fault zones. This method, through detailed analysis of the internal structure of fault zones, accurately provides valuable data support for hydrocarbon reservoirs and migration, enabling comprehensive analysis of hydrocarbon accumulation, accurate identification of target areas for hydrocarbon exploration, and a more accurate and reliable basis for hydrocarbon accumulation prediction, thus avoiding blind exploration and resource waste.

[0005] The present invention solves its problems through the following technical solution: This method for hydrocarbon accumulation analysis based on the internal structure of fault zones includes the following steps:

[0006] S1. Collect basic data and identify the main fault zones within the selected study area;

[0007] S2. Based on the identification of the main fault zones within the study area, the internal structure of the fault zones is divided.

[0008] S3. Collect and analyze samples to determine the source of oily gas.

[0009] S4. Characterize and analyze the migration trajectory of oil and gas fluids;

[0010] S5. Based on the analysis results of the hydrocarbon fluid migration trajectory characterization, draw hydrocarbon accumulation model diagrams and analyze hydrocarbon accumulation effects;

[0011] S6. Summarize and generalize the internal structural characteristics of fault zones and their influence on hydrocarbon accumulation.

[0012] Furthermore, the method for identifying the main fault zones within the selected study area in step S1 includes:

[0013] S11. Based on the collection of basic data on the study area, understand the geological background and fault zone development of the study area; based on the characteristics of fault zone geometry, spatial distribution, activity history and relationship with oil and gas reservoirs, select representative oil and gas exploration areas.

[0014] S12. Based on the selected representative oil and gas exploration areas, the main fault zones within the study area are identified through detailed geological surveys, seismic exploration, and drilling data analysis.

[0015] Furthermore, the basic data consists of geological data, including geological maps, structural maps, stratigraphic columns, and petrological data.

[0016] Furthermore, step S2, which involves dividing the internal structure of the fault zone, includes the following methods:

[0017] S21. Classify the fault zones into different levels. Select faults of different levels as research objects according to research needs. Conduct detailed field outcrop observations of the fault zones and record their macroscopic characteristics. Analyze the microstructure of rocks inside the fault zones through microscopic observation. Understand the degree of rock fragmentation and fracture development characteristics through the microstructure of rocks inside the fault zones.

[0018] The microstructure of the rocks within the fault zone includes the development of cracks and changes in mineral composition;

[0019] S22. Based on the degree of rock fragmentation and the characteristics of crack development, the fault zone is divided into two main structural units: the fracture zone and the crack zone. The fracture zone unit has severely fragmented rocks and densely developed cracks, while the crack zone unit is relatively intact and has sparsely distributed cracks.

[0020] Furthermore, the classification of the fault zones is based on the control of faults on tectonics and sedimentation, as well as the development history and scale of the faults. Faults can be classified into first-order faults, second-order faults, third-order faults, and even lower-order faults.

[0021] Furthermore, the method for collecting and analyzing samples in step S3 includes the following steps:

[0022] S31. Collect representative rock samples from the fracture zone and the crack zone respectively to ensure the integrity and representativeness of the samples; the representativeness of the collected samples means that they can represent the geological characteristics and hydrocarbon accumulation conditions of the study area.

[0023] S32. Conduct detailed field outcrop observations of the sampling area, record information on fracture development and hydrocarbon displays, and perform microscopic observations of the samples;

[0024] S33. Analyze the morphology, size and density of the fractures, perform homogenization temperature analysis, strontium isotope analysis and in-situ trace element analysis of inclusions, and determine the source, phase and evolution process of the oil and gas flow.

[0025] Furthermore, the method for characterizing and analyzing the migration trajectory of oil and gas fluids in step S4 includes:

[0026] The analysis of the migration trajectory of oil and gas fluids includes permeability analysis and fluid diagenetic evolution analysis;

[0027] S41. First, based on the relationship between the degree of fracture development and the permeability of oil and gas fluids, analyze the ease of oil and gas migration in different structural units, depict the migration trajectory of oil and gas fluids in the fracture zone, and clarify the main migration direction and accumulation area of ​​oil and gas.

[0028] S42. In conjunction with the diagenetic evolution process of fluids related to the fault zone, analyze the chemical changes and physical effects of oil and gas during migration and accumulation.

[0029] Furthermore, step S5, which involves drawing a hydrocarbon accumulation model diagram, should clearly show the internal structure of the fault zone, the hydrocarbon migration trajectory, the accumulation area, and the fluid source and stages.

[0030] Furthermore, step S5, which involves analyzing the hydrocarbon accumulation effect using a hydrocarbon accumulation model diagram, includes:

[0031] Assess the contribution of fault zones to hydrocarbon accumulation; analyze the role of different structural units in hydrocarbon accumulation; and identify the main controlling factors for hydrocarbon enrichment.

[0032] Furthermore, step S6 summarizes the influence of the internal structural characteristics of the fault zone on hydrocarbon accumulation as follows:

[0033] (1) The fault level controls the dominant channels for oil and gas migration. First-level faults dominate regional migration, while secondary faults affect local accumulation.

[0034] (2) The internal structural units determine the blocking and conduction capabilities. The fracture zone is mainly for conduction, while the crack zone also has the potential for blocking.

[0035] (3) The timing of fault activity determines the hydrocarbon accumulation efficiency; late-stage active faults are more likely to lead to hydrocarbon loss.

[0036] Compared with the above-mentioned background technology, the present invention has the following beneficial effects:

[0037] This hydrocarbon accumulation analysis method based on the internal structure of fault zones can generate hydrocarbon accumulation model diagrams by analyzing the internal structure of fault zones, the migration trajectory of hydrocarbon-bearing fluids, and the fluid sources and stages. These model diagrams can intuitively demonstrate the distribution patterns and enrichment characteristics of hydrocarbons within fault zones, providing a more accurate and reliable basis for hydrocarbon accumulation prediction.

[0038] This hydrocarbon accumulation analysis method based on the internal structure of fault zones is a novel approach and technical means for hydrocarbon exploration. The introduction and application of this method not only enriches the technical system of hydrocarbon exploration but also promotes the innovation and development of exploration technology. Through continuous practice and improvement, this method is expected to play an even more important role in future hydrocarbon exploration.

[0039] This hydrocarbon accumulation analysis method based on the internal structure of fault zones can more accurately determine the target areas for oil and gas exploration by finely analyzing the internal structure of fault zones, avoiding blind exploration and waste of resources. At the same time, this method can also improve exploration efficiency, shorten the exploration cycle, and reduce exploration costs. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present invention and, together with the specification, serve to explain the technical solutions of the present invention.

[0041] Figure 1 This is a flowchart of the hydrocarbon accumulation analysis method based on the internal structure of fault zones according to the present invention.

[0042] Figure 2 This is a plan view illustrating the fault zone identification and grading according to an embodiment of the present invention;

[0043] Figure 3 These are simulation diagrams of oil and gas migration and accumulation in an embodiment of the present invention; a is a cross-sectional view; b is a plan view;

[0044] Figure 4 This is a schematic diagram of a fractured oil and gas reservoir control model according to an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0046] Figure 1 This is a flowchart of a hydrocarbon accumulation analysis method based on the internal structure of fault zones. As shown in the diagram, this invention can identify the main fault zones within the study area. Fault zone identification should be based on their geometric morphology, spatial distribution, activity history, and relationship with hydrocarbon reservoirs. By deeply studying the internal structural characteristics and evolutionary history of fault zones, the migration paths, accumulation mechanisms, and preservation conditions of hydrocarbons within these zones can be revealed, providing new ideas and directions for hydrocarbon exploration and development. Secondly, the internal structure of fault zones can be classified according to their material composition, deformation characteristics, and relationship with hydrocarbon migration and accumulation. Based on their geometric morphology and internal structural characteristics, fault zones can be classified into different types. These detailed classifications contribute to a deeper understanding of the controlling role of fault zones in hydrocarbon accumulation. This study analyzes the hydrocarbon accumulation effect using hydrocarbon accumulation model diagrams, assesses the contribution of fault zones to hydrocarbon accumulation, analyzes the role of different structural units in the hydrocarbon accumulation process, and clarifies the main controlling factors for hydrocarbon enrichment. The purpose of drawing hydrocarbon accumulation model diagrams is to visually display key information such as the formation process, distribution characteristics, reservoir conditions, and hydrocarbon migration paths of hydrocarbon reservoirs, providing a scientific basis for oil and gas exploration and development. Finally, fault zones are important tectonic phenomena in oil and gas basins, composed of irregular rock masses divided by a series of complex fault planes, exhibiting high internal complexity and uneven deformation characteristics. Through laboratory simulation experiments and numerical simulations, this study investigates the role of fault zones in hydrocarbon accumulation, predicts hydrocarbon migration and accumulation patterns, and provides support for exploration decisions. The internal structural characteristics of fault zones have a significant impact on hydrocarbon accumulation. In oil and gas exploration, the development characteristics of fault zones and their mechanisms of action on hydrocarbon migration and accumulation should be fully considered, favorable exploration targets should be selected, and exploration methods should be optimized to improve the exploration success rate.

[0047] like Figure 1 As shown, a hydrocarbon accumulation analysis method based on the internal structure of fault zones includes the following steps:

[0048] S1. Collect basic data and identify the main fault zones within the selected study area;

[0049] The method for identifying major fault zones within a selected study area includes the following steps:

[0050] S11. Based on the collection of basic data on the study area, understand the geological background and fault zone development of the study area; based on its geometric morphology, spatial distribution, activity history and relationship with oil and gas reservoirs, select representative oil and gas exploration areas.

[0051] S12. Based on the selected representative oil and gas exploration areas, the main fault zones in the study area are identified through detailed geological surveys, seismic exploration, drilling data analysis, and other means.

[0052] The fundamental data refers to geological data. Geological data of the study area, including geological maps, structural maps, stratigraphic columns, and petrological data, are collected. This data forms the basis for understanding the geological background and fault zone development of the study area. Through detailed geological surveys, seismic exploration, and drilling data analysis, the main fault zones within the study area are identified. Fault zones, as important channels for oil and gas migration and key locations for oil and gas accumulation, have a significant impact on the oil and gas accumulation process due to their internal structure. In-depth research into the internal structural characteristics and evolutionary history of fault zones can reveal the migration paths, accumulation mechanisms, and preservation conditions of oil and gas within them, providing new ideas and directions for oil and gas exploration and development.

[0053] S2. Based on the identification of the main fault zones within the study area, the internal structure of the fault zones is divided.

[0054] The internal structure division of the fault zone includes selecting faults of different orders, observing internal structural features, and dividing into structural units; the criteria for internal structure division of the fault zone are as follows:

[0055] S21. Classify the fault zones into different levels. Select faults of different levels as research objects according to research needs. Conduct detailed field outcrop observations of the fault zones, record the macroscopic characteristics of the fault zones, and analyze the microstructure of the rocks inside the fault zones through microscopic observation, such as the development of cracks and changes in mineral composition. Through the microstructure of the rocks inside the fault zones, understand the degree of rock fragmentation and crack development characteristics.

[0056] S22. Based on the degree of rock fragmentation and the characteristics of fracture development, the fault zone is divided into two main structural units: the fracture zone and the fracture zone. The rocks in the fracture zone are severely fragmented and have densely developed fractures, while the fracture zone is relatively intact and has sparsely distributed fractures.

[0057] The classification of fault zones is mainly based on the control of faults on tectonics and sedimentation, as well as the development history and scale of the faults. Faults can be divided into first-order, second-order, third-order, and even lower-order faults. Different orders of faults play different roles in the process of hydrocarbon accumulation. By observing the exposure of fault zones in the field, we can intuitively understand the geometric shape, occurrence, displacement, and deformation characteristics of the strata on both sides of the fault zone. The internal structure of the fault zone can be classified according to its material composition, deformation characteristics, and relationship with hydrocarbon migration and accumulation. Based on the geometric shape and internal structural characteristics of the fault zone, it can be classified into different types. These detailed classifications help to understand the control of fault zones on hydrocarbon accumulation more deeply.

[0058] S3. Collect and analyze samples to determine the source of oily gas.

[0059] The sample collection and analysis includes: sample collection, field outcrop observation and laboratory analysis;

[0060] S31. Collect representative rock samples from the fracture zone and the crack zone respectively to ensure the integrity and representativeness of the samples;

[0061] S32. Conduct detailed field outcrop observations of the sampling area, record information on fracture development and hydrocarbon displays, and perform microscopic observations of the samples;

[0062] S33. Analyze the morphology, size, and density of fractures, perform homogenization temperature analysis, strontium isotope analysis, and in-situ trace element analysis of inclusions to determine the source, phase, and evolution process of the oil and gas flow.

[0063] The collected samples should be representative of the geological characteristics and hydrocarbon accumulation conditions of the study area, and their original state and structure should be preserved as much as possible. Damage or contamination should be avoided during collection. An appropriate amount of sample should be collected according to the analytical requirements to avoid wasting resources. Field outcrop observation is one of the important methods in geological research. By observing and studying the morphology, occurrence, and structural characteristics of surface or shallow geological bodies, a wealth of geological information can be obtained, providing important basis for subsequent sample collection and analysis. Laboratory analysis is the final step in sample collection and analysis, and a key step in obtaining accurate data and gaining a deeper understanding of geological processes. Sample collection and analysis is a systematic and complex process that requires scientific planning, meticulous operation, and strict management. Through this process, we can obtain a large amount of geological information and hydrocarbon accumulation condition data, providing strong support for geological exploration and oil and gas resource development.

[0064] S4. Characterization and analysis of the migration trajectory of oil and gas fluids;

[0065] The analysis of the migration trajectory of oil and gas fluids includes permeability analysis and fluid diagenetic evolution analysis;

[0066] S41. First, based on the relationship between the degree of fracture development and the permeability of oil and gas fluids, analyze the ease of oil and gas migration in different structural units, depict the migration trajectory of oil and gas fluids in the fracture zone, and clarify the main migration direction and accumulation area of ​​oil and gas.

[0067] S42. In conjunction with the diagenetic evolution process of fluids related to the fault zone, analyze the chemical changes and physical effects of oil and gas during migration and accumulation.

[0068] In petroleum geology research, accurately characterizing the migration trajectory of oil and gas-bearing gases is a crucial foundation for understanding hydrocarbon accumulation mechanisms, predicting hydrocarbon distribution, and assessing hydrocarbon resource potential. This process typically involves in-depth analysis of permeability and comprehensive consideration of fluid diagenetic evolution. Permeability is an important physical parameter describing the ability of rocks to allow fluids to pass through their pores or fractures, and it has a direct impact on hydrocarbon migration trajectories. By comprehensively applying these two analytical methods—permeability analysis and fluid diagenetic evolution analysis—we can gain a deeper understanding of the dynamic mechanisms, spatial distribution characteristics, and accumulation patterns of hydrocarbon migration.

[0069] S5. Based on the analysis results of the hydrocarbon fluid migration trajectory characterization, draw hydrocarbon accumulation model diagrams and analyze hydrocarbon accumulation effects;

[0070] Based on the analysis results of step S4, draw a hydrocarbon accumulation model diagram; the drawn hydrocarbon accumulation model diagram should clearly show the internal structure of the fault zone, the hydrocarbon migration trajectory, the accumulation area, and the fluid source and phase information;

[0071] Analysis of hydrocarbon accumulation effects using hydrocarbon accumulation model diagrams includes: assessing the contribution of fault zones to hydrocarbon accumulation, analyzing the role of different structural units in the hydrocarbon accumulation process, and identifying the main controlling factors for hydrocarbon enrichment.

[0072] The purpose of drawing hydrocarbon accumulation model diagrams is to intuitively show key information such as the formation process, distribution characteristics, reservoir conditions, and hydrocarbon migration paths of hydrocarbon reservoirs, so as to provide a scientific basis for hydrocarbon exploration and development. The hydrocarbon accumulation effect analysis mainly focuses on how various geological factors interact during the hydrocarbon accumulation process and jointly affect the formation, distribution, and scale of hydrocarbon reservoirs.

[0073] S6. Summarize the internal structural characteristics of fault zones and their influence on hydrocarbon accumulation.

[0074] The influence of the internal structural features of the fault zone on hydrocarbon accumulation is as follows:

[0075] Based on the empirical data obtained on fracture characteristics, fluid sources, and migration paths, the core laws governing the control of reservoirs by fracture zones are derived: (1) The fracture level controls the dominant channels for oil and gas migration, with first-level fractures dominating regional migration and second-level fractures affecting local accumulation; (2) Internal structural units determine the sealing-conduction capacity, with fracture zones mainly for conduction and fracture zones having sealing potential; (3) The phase of fracture activity determines the reservoir formation efficiency, with late-stage active fractures easily leading to oil and gas loss.

[0076] The internal structural characteristics of fault zones and their influence on hydrocarbon accumulation were summarized, and based on the research results, targeted oil and gas exploration suggestions were proposed, including the selection of exploration targets and the optimization of exploration methods.

[0077] Fault zones are important tectonic phenomena in hydrocarbon basins, consisting of irregular rock masses segmented by a series of complex fault planes. They exhibit high internal complexity and heterogeneous deformation characteristics. Laboratory simulations and numerical simulations are used to study the mechanisms by which fault zones play a role in hydrocarbon accumulation, predict hydrocarbon migration and accumulation patterns, and provide support for exploration decisions. The internal structural characteristics of fault zones have a significant impact on hydrocarbon accumulation. In hydrocarbon exploration, the development characteristics of fault zones and their mechanisms of action on hydrocarbon migration and accumulation should be fully considered to select favorable exploration targets and optimize exploration methods to improve the success rate of exploration.

[0078] Example 1

[0079] To make the objectives, technical solutions, and advantages of this invention clearer, the following description, using the exploration of a complex fault-block oil and gas reservoir in a basin as an example, will be further detailed with reference to the accompanying drawings.

[0080] This invention presents a hydrocarbon accumulation analysis method based on the internal structure of fault zones. By integrating techniques such as fine fault zone characterization, fluid migration dynamic simulation, and quantitative prediction of accumulation processes, it significantly improves the exploration accuracy and development efficiency of complex fault-block hydrocarbon reservoirs. This method demonstrates outstanding technical advantages in practical applications. The following section uses a typical complex fault-block hydrocarbon reservoir in a basin as an example to elaborate on its technical implementation path and application effects:

[0081] (1) Fine identification and classification of fault zones;

[0082] In the initial exploration phase of the target block, traditional seismic interpretation techniques identified only one main fault (F2), significantly limiting the exploration's understanding. However, through a re-integration and refined identification and subdivision of the internal structure of the fault zone, the faults in the study area were reclassified into one controlling fault (F2) and two secondary faults (F1 and F3). The study revealed that, for example... Figure 2 As shown, although fault F2 is relatively large (fault displacement of 150m), based on the characteristics of fault zone geometry, spatial distribution, fault activity history and relationship with oil and gas reservoirs, due to the complex internal structure of the fault zone, it actually acts as an advantageous channel for oil and gas migration; while fault F1, although smaller in scale (fault displacement of 80m), has excellent sealing capabilities due to the well-developed overall internal structure of the fault zone, and is therefore identified as a key exploration target area.

[0083] (2) Characterization and analysis of fluid source and transport path;

[0084] Based on the detailed identification and classification of fault zones in the previous stage, hydrocarbon migration simulations were conducted on the above faults to establish realistic geological models. These models fully considered the heterogeneous characteristics of the reservoirs, accurately set the spatial configuration relationship between sandstone and mudstone, and set the sand-to-soil ratio to 60%. Fluid migration simulations were performed on the slope to dynamically demonstrate the hydrocarbon migration process. Figure 3As shown, the simulation results reveal that the oil and gas migration paths exhibit different patterns depending on the proportion of effective sand bodies. In areas with good sand body continuity, oil and gas mainly migrate laterally along the sand body transport layer. As the proportion of effective sand bodies decreases, this area is more likely to form favorable oil and gas migration paths.

[0085] (3) The hydrocarbon accumulation model map guides exploration deployment;

[0086] Based on the above analysis of fluid sources and migration paths, a fault-controlled hydrocarbon reservoir model diagram is drawn, such as... Figure 4 As shown in the diagram, the vertical conduction capacity of faults is quantitatively evaluated through the fault-controlled hydrocarbon reservoir model. The vertical conduction and destructive capacity of faults are given priority. Through the analysis of fluid inclusion samples in the early stage, the ancient oil-water interface and the current oil-water interface are determined. Due to late-stage activation, the F2 fault has a significant destructive capacity. Early hydrocarbons migrated vertically along the F2 fault, but some hydrocarbons were lost because they were below the overflow point. The F1 and F3 faults have sealing capacity. The main hydrocarbons migrated laterally along the F1 and F3 faults to the shielded fault nose structure and accumulated efficiently, clearly showing that the current hydrocarbons are well preserved.

[0087] As seen in the above embodiments, the method of this invention, through a technical chain of "fracture structure classification—fluid migration characterization—quantitative prediction of hydrocarbon accumulation models," achieves precise exploration positioning, avoids blind drilling, breaks through the limitations of traditional understanding, and accurately identifies hidden oil and gas enrichment areas. For the first time, the dynamic analysis of the hydrocarbon accumulation process achieves precise matching between fracture activity periods and oil and gas charging processes. The technology of this invention has wide applicability, showing good application prospects in various types of oil and gas reservoirs, including complex fault blocks and lithological-structural composite reservoirs. Economic benefits are significantly improved by reducing exploration risks and increasing success rates, thereby greatly enhancing development efficiency. The successful application of this invention, combined with the preservation conditions for fracture activity history prediction, provides a completely new technical approach and methodological system for the exploration and development of complex oil and gas reservoirs, possessing significant theoretical and practical value.

[0088] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the implementation methods of the present invention, and should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of the present invention.

Claims

1. A method for analyzing hydrocarbon accumulation based on the internal structure of fault zones, characterized in that: Includes the following steps: S1. Collect basic data and identify the main fault zones within the selected study area; S2. Based on the identification of the main fault zones within the study area, the internal structure of the fault zones is divided. S3. Collect and analyze samples to determine the source of oily gas. S4. Characterization and analysis of the migration trajectory of oil and gas fluids; S5. Based on the analysis results of the hydrocarbon fluid migration trajectory characterization, draw hydrocarbon accumulation model diagrams and analyze hydrocarbon accumulation effects; S6. Summarize and generalize the internal structural characteristics of fault zones and their influence on hydrocarbon accumulation.

2. The hydrocarbon accumulation analysis method based on the internal structure of fault zones according to claim 1, characterized in that: The method for identifying the main fault zones within the selected study area in step S1 includes: S11. Based on the collection of basic data on the study area, understand the geological background and fault zone development of the study area; based on the characteristics of fault zone geometry, spatial distribution, activity history and relationship with oil and gas reservoirs, select representative oil and gas exploration areas. S12. Based on the selected representative oil and gas exploration areas, the main fault zones within the study area are identified through detailed geological surveys, seismic exploration, and drilling data analysis.

3. The hydrocarbon accumulation analysis method based on the internal structure of fault zones according to claim 1, characterized in that: The basic data is geological data, including geological maps, structural maps, stratigraphic columns, and petrological data.

4. The hydrocarbon accumulation analysis method based on the internal structure of fault zones according to claim 1, characterized in that: Step S2, the method for dividing the internal structure of the fault zone, includes: S21. Classify the fault zones into different levels. Select faults of different levels as research objects according to research needs. Conduct detailed field outcrop observations of fault zones of different levels and record the macroscopic characteristics of the fault zones. Analyze the microstructure of rocks inside the fault zones through microscopic observation. Understand the degree of rock fragmentation and crack development characteristics through the microstructure of rocks inside the fault zones. The microstructure of the rocks within the fault zone includes the development of cracks and changes in mineral composition; S22. Based on the degree of rock fragmentation and the characteristics of crack development, the fault zone is divided into two main structural units: the fracture zone and the crack zone. The fracture zone unit has severely fragmented rocks and densely developed cracks, while the crack zone unit is relatively intact and has sparsely distributed cracks.

5. The hydrocarbon accumulation analysis method based on the internal structure of fault zones according to claim 4, characterized in that: The classification of fault zones is based on the control of faults on tectonics and sedimentation, as well as the development history and scale of the faults. Faults can be classified into first-order faults, second-order faults, third-order faults, and even lower-order faults.

6. The hydrocarbon accumulation analysis method based on the internal structure of fault zones according to claim 1, characterized in that: The method for collecting and analyzing samples in step S3 includes the following steps: S31. Collect representative rock samples from the fracture zone and the crack zone respectively to ensure the integrity and representativeness of the samples; the representativeness of the collected samples means that they can represent the geological characteristics and hydrocarbon accumulation conditions of the study area. S32. Conduct detailed field outcrop observations of the sampling area, record information on fracture development and hydrocarbon displays, and perform microscopic observations of the samples; S33. Analyze the morphology, size and density of the fractures, perform homogenization temperature analysis, strontium isotope analysis and in-situ trace element analysis of inclusions, and determine the source, phase and evolution process of the oil and gas flow.

7. The hydrocarbon accumulation analysis method based on the internal structure of fault zones according to claim 1, characterized in that: The method for characterizing and analyzing the migration trajectory of oil and gas fluids in step S4 includes: The analysis of the migration trajectory of oil and gas fluids includes permeability analysis and fluid diagenetic evolution analysis; S41. First, based on the relationship between the degree of fracture development and the permeability of oil and gas fluids, analyze the ease of oil and gas migration in different structural units, depict the migration trajectory of oil and gas fluids in the fracture zone, and clarify the main migration direction and accumulation area of ​​oil and gas. S42. In conjunction with the diagenetic evolution process of fluids related to the fault zone, analyze the chemical changes and physical effects of oil and gas during migration and accumulation.

8. The hydrocarbon accumulation analysis method based on the internal structure of fault zones according to claim 1, characterized in that: The step S5, drawing a hydrocarbon accumulation model diagram, should clearly show the internal structure of the fault zone, the hydrocarbon migration trajectory, the accumulation area, and the fluid source and stages.

9. The hydrocarbon accumulation analysis method based on the internal structure of fault zones according to claim 8, characterized in that: Step S5, which analyzes the hydrocarbon accumulation effect using hydrocarbon accumulation model diagrams, includes: Assess the contribution of fault zones to hydrocarbon accumulation; analyze the role of different structural units in hydrocarbon accumulation; and identify the main controlling factors for hydrocarbon enrichment.

10. The method for hydrocarbon accumulation analysis based on the internal structure of fault zones according to claim 1, characterized in that: Step S6 summarizes the influence of the internal structural features of the fault zone on hydrocarbon accumulation as follows: (1) The fault level controls the dominant channels for oil and gas migration. First-level faults dominate regional migration, while secondary faults affect local accumulation. (2) The internal structural units determine the blocking and conduction capabilities. The fracture zone is mainly for conduction, while the crack zone also has the potential for blocking. (3) The timing of fault activity determines the hydrocarbon accumulation efficiency; late-stage active faults are more likely to cause hydrocarbon loss.

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