Oil and gas detection method and system for deep and large strike-slip fault-controlled reservoirs

Abstract

The application discloses a kind of oil and gas detection method and system for deep large strike-slip fault controlled reservoir, comprising: according to oil and gas reservoir depth, fault zone width and oil and gas leakage source and its associated components, the area to be explored of underlying deep large strike-slip fault controlled reservoir is measured line deployment, and near-surface sample is collected according to the measured line deployed;Select the geochemical index sensitive to fault and oil and gas, and determine the experimental method of each index, and then according to the determined experimental method, the collected sample is tested one by one for each geochemical index, and the measured results containing geochemical anomaly characteristic information are obtained;According to the seismic feature map and geochemical measured results of the area to be explored, the relationship between the seismic characteristics and the geochemical anomaly characteristics is analyzed to identify the oil and gas content and distribution characteristics of the area to be explored.The present application provides a theoretical and practical basis for geochemical exploration of deep large strike-slip fault controlled fracture-cave type oil and gas reservoir, and improves the exploration effect.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration technology, and in particular to a method and system for detecting the oil and gas content of deep strike-slip fault-controlled reservoirs. Background Technology

[0002] Fracture-vuggy oil and gas reservoirs controlled by deep strike-slip fault zones (also known as fault-dissolved oil and gas reservoirs) are formed by using deep strike-slip faults as the main channels for oil and gas migration and accumulation, guiding oil and gas to the fractured zone of the strike-slip fault and the nearby carbonate fracture-vuggy reservoir space. In recent years, this type of oil and gas accumulation has become a hot topic in carbonate reservoir oil and gas exploration. Currently, the exploration of deep strike-slip fault-controlled fracture-vuggy oil and gas reservoirs is mainly based on seismic methods. However, because these reservoirs are generally buried at great depths, seismic methods are affected by surface conditions (such as thick sand layers) and reservoir heterogeneity, leading to significant uncertainties in seismic detection of hydrocarbon potential. In addition, seismic methods are extremely costly, affecting exploration decisions and progress. In recent years, deep strike-slip fault-controlled fracture-vuggy (fault-dissolved) oil and gas reservoirs discovered in the Tarim Basin have developed strike-slip faults with near-vertical dips, and oil and gas are mainly transported vertically. Geochemical exploration technology based on the theory of vertical micro-permeability of oil and gas can detect the oil and gas content of fault zones on the surface above nearly vertical fault zones. It is direct and economical, and when combined with seismic data, it can improve the success rate of identifying oil and gas-bearing fault zones.

[0003] Existing research largely focuses on measuring geochemical effects above normal or reverse faults, or inferring fault distribution by detecting geochemical effects above faults, particularly gas geochemical effects. It does not address geochemical detection techniques for hydrocarbon-bearing properties in fracture-vuggy (fault-dissolved) reservoirs controlled by deep strike-slip faults. While some literature reports on surface hydrocarbon microbial exploration of fault-dissolved reservoirs, these primarily involve single-method indicators of hydrocarbon microorganisms, offering no fundamental difference from conventional trap geochemical exploration approaches. They fail to theoretically and practically study the hydrocarbon-bearing potential of fracture-vuggy (fault-dissolved) reservoirs controlled by deep strike-slip faults. Summary of the Invention

[0004] The purpose of this invention is to provide a theoretical and practical solution for conducting effective geochemical detection techniques on fracture-vuggy (fracture-dissolved) reservoirs controlled by deep strike-slip faults.

[0005] To address the aforementioned technical problems, this invention provides a method for detecting the hydrocarbon potential of deep strike-slip fault-controlled reservoirs. The method includes: deploying survey lines in the exploration area of ​​the underlying deep strike-slip fault-controlled reservoir based on reservoir depth, fault width, hydrocarbon leakage sources, and associated components; collecting near-surface samples according to the deployed survey lines; selecting geochemical indicators sensitive to faults and hydrocarbons and determining experimental methods for each indicator; then testing each geochemical indicator on the collected near-surface samples according to the determined experimental methods to obtain measured results containing geochemical anomaly information; and identifying the hydrocarbon potential and distribution characteristics of the exploration area by analyzing the relationship between seismic features and geochemical anomalies based on the seismic feature map and the geochemical measured results.

[0006] Preferably, the geochemical indicators include: a first type of indicator reflecting micro-leaking of active light hydrocarbons, a second type of indicator reflecting the characteristics of associated gas and light hydrocarbons in reservoirs controlled by deep strike-slip faults, a third type of indicator reflecting micro-leaking of semi-active light hydrocarbons, and a fourth type of indicator reflecting the genesis and properties of hydrocarbons.

[0007] Preferably, the experimental methods used to determine the first type of indicators include: free hydrocarbon determination, headspace light hydrocarbon determination, and oil and gas microbial determination; the experimental methods used to determine the second type of indicators include: determination of free gas He, Ne, and H2, and determination of headspace gas He, Ne, and H2; the experimental methods used to determine the third type of indicators include: determination of pyrolytic hydrocarbons; and the experimental methods used to determine the fourth type of indicators include: determination of stable carbon isotopes of methane, and determination of three-dimensional fluorescence spectroscopy.

[0008] Preferably, the deployment of survey lines includes: geochemical exploration survey lines are deployed perpendicular to the strike-slip fault and along the strike-slip fault, wherein the survey lines perpendicular to the fault strike are centered on the strike-slip fault, and the length of the lateral lines to both sides is not less than 2.5km-3.0km; the length of the survey lines along the strike-slip fault is determined according to the exploration requirements, wherein the spacing between survey line points perpendicular to the strike-slip fault is 0.1km-0.5km, and the spacing between survey line points along the strike-slip fault is 0.25km-2.0km.

[0009] Preferably, the spacing of the survey lines is determined according to the exploration objective. Specifically, if a favorable oil and gas-bearing area is preferred, the spacing of the survey lines perpendicular to the strike-slip fault is 0.25km-0.5km, and the spacing of the survey lines along the strike-slip fault is 0.5km-2km. If a target oil and gas-bearing area is preferred, the spacing of the survey lines perpendicular to the strike-slip fault is 0.1km-0.25km, and the spacing of the survey lines along the strike-slip fault is 0.25km-0.5km.

[0010] Preferably, the seismic feature map includes a seismic coherence map and a seismic amplitude map. The step of identifying the hydrocarbon potential and distribution characteristics of the area to be explored by analyzing the relationship between seismic features and geochemical anomaly features based on the seismic feature map of the area to be explored and the geochemical measurement results includes: separating geochemical anomalies from the background in the area to be explored based on the geochemical measurement results to identify the morphology and intensity characteristics of regional geochemical anomalies; and, based on the morphology and intensity characteristics of the geochemical anomalies, analyzing the relationship between the distribution of faults, fracture-vuggy reservoirs, and comprehensive geochemical anomalies according to the seismic coherence map and the seismic amplitude map, thereby obtaining an evaluation result of the hydrocarbon potential and distribution range of the area to be explored.

[0011] Preferably, the hydrocarbon prediction method further includes: constructing a basic neural network model; based on the basic neural network model, constructing an identification and prediction model by training the basic neural network model according to a dataset of known geochemical anomalies above deep strike-slip fault-controlled fracture-vuggy hydrocarbon reservoirs and a dataset of geochemical background samples in blank areas; and using the identification and prediction model based on the geochemical measurement results to predict the hydrocarbon content and hydrocarbon distribution of deep strike-slip fault-controlled fracture-vuggy reservoirs in the current exploration area.

[0012] On the other hand, the present invention also provides an hydrocarbon detection system for reservoirs controlled by deep strike-slip faults, comprising: a survey line deployment module, which is used to deploy survey lines in the exploration area of ​​the reservoir controlled by the underlying deep strike-slip fault according to the reservoir burial depth, fault zone width, and hydrocarbon leakage sources and their associated components, and to collect near-surface samples according to the deployed survey lines; an index selection and testing module, which is used to select geochemical indices sensitive to faults and hydrocarbons and determine the experimental method for each index, and then test each geochemical index on the collected near-surface samples one by one according to the determined experimental method to obtain measured results containing geochemical anomaly information; and a measured result analysis module, which is used to identify the hydrocarbon potential and distribution characteristics of the exploration area by analyzing the relationship between the seismic characteristics and the geochemical anomaly characteristics based on the seismic feature map and the geochemical measured results of the exploration area.

[0013] Preferably, in the survey line deployment module, the geochemical exploration survey lines are deployed perpendicular to the strike-slip fault and along the strike-slip fault. The survey lines perpendicular to the fault strike are centered on the strike-slip fault, and the length of the lateral lines to both sides is not less than 2.5km-3.0km. The length of the survey lines along the strike-slip fault is determined according to the exploration requirements. The spacing between survey line points perpendicular to the strike-slip fault is 0.1km-0.5km, and the spacing between survey line points along the strike-slip fault is 0.25km-2.0km.

[0014] Preferably, the hydrocarbon detection system further includes: a prediction model construction module, which is used to construct a basic neural network model, and then, based on the basic neural network model, according to the known geochemical anomaly sample dataset above the deep strike-slip fault-controlled fracture-vuggy hydrocarbon reservoir and the geochemical background sample dataset of the blank area, to construct an identification and prediction model by training the basic neural network model. Finally, based on the geochemical measurement results, the identification and prediction model is used to predict the hydrocarbon content and hydrocarbon distribution of the deep strike-slip fault-controlled fracture-vuggy reservoir in the current exploration area.

[0015] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0016] This invention proposes a method and system for detecting hydrocarbon potential in deep, large strike-slip fault-controlled reservoirs. This method and system belong to the field of oil and gas exploration. Addressing the lack of low-cost, specific geochemical techniques in existing hydrocarbon detection methods for deep, large strike-slip fault-controlled fracture-vuggy (fault-dissolved) reservoirs, this invention establishes a geochemical technique for detecting hydrocarbon potential in deep, large strike-slip fault-controlled fracture-vuggy reservoirs. This technique integrates grid deployment, index selection, experimental method selection, and anomaly evaluation. This invention provides theoretical and practical basis for geochemical exploration of deep, large strike-slip fault-controlled fracture-vuggy oil and gas reservoirs, improving exploration results.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 This is a step diagram illustrating the method for detecting the oil and gas content of the Shenzhen-Dalian strike-slip fault-controlled reservoir according to an embodiment of this application.

[0020] Figure 2 This is a flowchart illustrating the method for detecting the oil and gas content of the Shenzhen-Dalian strike-slip fault-controlled reservoir, as described in this application.

[0021] Figure 3 This is a schematic diagram of the structure of the oil and gas content detection system for the Shenzhen-Dalian strike-slip fault-controlled reservoir according to an embodiment of this application. Detailed Implementation

[0022] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0023] Furthermore, the steps illustrated in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than that shown here.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0025] Fracture-vuggy oil and gas reservoirs controlled by deep strike-slip fault zones (also known as fault-dissolved oil and gas reservoirs) are formed by using deep strike-slip faults as the main channels for oil and gas migration and accumulation, guiding oil and gas to the fractured zone of the strike-slip fault and the nearby carbonate fracture-vuggy reservoir space. In recent years, this type of oil and gas accumulation has become a hot topic in carbonate reservoir oil and gas exploration. Currently, the exploration of deep strike-slip fault-controlled fracture-vuggy oil and gas reservoirs is mainly based on seismic methods. However, because these reservoirs are generally buried at great depths, seismic methods are affected by surface conditions (such as thick sand layers) and reservoir heterogeneity, leading to significant uncertainties in seismic detection of hydrocarbon potential. In addition, seismic methods are extremely costly, affecting exploration decisions and progress. In recent years, deep strike-slip fault-controlled fracture-vuggy (fault-dissolved) oil and gas reservoirs discovered in the Tarim Basin have developed strike-slip faults with near-vertical dips, and oil and gas are mainly transported vertically. Geochemical exploration technology based on the theory of vertical micro-permeability of oil and gas can detect the oil and gas content of fault zones on the surface above nearly vertical fault zones. It is direct and economical, and when combined with seismic data, it can improve the success rate of identifying oil and gas-bearing fault zones.

[0026] Existing research largely focuses on measuring geochemical effects above normal or reverse faults, or inferring fault distribution by detecting geochemical effects above faults, particularly gas geochemical effects. It does not address geochemical detection techniques for hydrocarbon-bearing properties in fracture-vuggy (fault-dissolved) reservoirs controlled by deep strike-slip faults. While some literature reports on surface hydrocarbon microbial exploration of fault-dissolved reservoirs, these primarily involve single-method indicators of hydrocarbon microorganisms, offering no fundamental difference from conventional trap geochemical exploration approaches. They fail to theoretically and practically study the hydrocarbon-bearing potential of fracture-vuggy (fault-dissolved) reservoirs controlled by deep strike-slip faults.

[0027] To address the aforementioned technical problems, this application proposes a method and system for detecting the hydrocarbon potential of deep strike-slip fault reservoirs. This method and system can, both theoretically and practically, effectively deploy survey networks for fracture-vuggy (fault-dissolved) reservoirs controlled by deep strike-slip faults, reflect hydrocarbon information within deep fault zones, and provide specific geochemical detection techniques for anomaly evaluation. This invention improves the success rate of hydrocarbon exploration in deep strike-slip fault-controlled fracture-vuggy (fault-dissolved) reservoirs, reduces exploration costs, and establishes an effective geochemical detection technique for hydrocarbon potential in these reservoirs, enabling future applications in integrated geological, geophysical, and geochemical exploration.

[0028] Guided by the theory of vertical hydrocarbon diffusion and seepage in oil and gas reservoirs, the geochemical anomaly pattern above a deep, large strike-slip fault-controlled fracture-vuggy reservoir is generally characterized by banded patterns. Based on the reservoir's burial depth and fault zone width, oil and gas seepage sources and their associated components, and surface conditions, an effective and targeted survey network is deployed. Indicators reflecting modern compensatory active micro-seepage and sensitive to oil and gas in deep, large strike-slip fault zones are selected. Multi-indicator pattern identification is employed for anomaly evaluation, establishing a geochemical detection technology for the hydrocarbon content of deep, large strike-slip fault-controlled fracture-vuggy reservoirs.

[0029] Figure 1 This is a step diagram illustrating the method for detecting the hydrocarbon content of the Shenzhen-Dalian strike-slip fault-controlled reservoir, as described in an embodiment of this application. Figure 1As shown, the hydrocarbon detection method described in this embodiment of the invention is implemented according to the following steps: Step S110, based on the burial depth of the hydrocarbon reservoir, the width of the fault zone, and the hydrocarbon leakage source and its associated components, a survey line is deployed in the exploration area of ​​the reservoir controlled by the underlying deep strike-slip fault, and near-surface samples are collected according to the deployed survey line; Step S120, geochemical indicators sensitive to faults and hydrocarbons are selected and the experimental methods for each indicator are determined. Then, each geochemical indicator is tested on the collected near-surface samples one by one according to the determined experimental methods to obtain the measured results containing geochemical anomaly information; Step S130, based on the seismic feature map of the exploration area and the measured results obtained in Step S120, the hydrocarbon content and distribution characteristics of the exploration area are identified by analyzing the relationship between seismic features and geochemical anomaly features.

[0030] Figure 2 This is a flowchart illustrating the method for detecting the hydrocarbon content of the Shenzhen-Dalian strike-slip fault-controlled reservoir, as described in this application. The following is a summary of the method. Figure 1 and Figure 2 The specific process of the oil and gas content detection method described in the embodiments of the present invention will be explained.

[0031] Unlike conventional trap-type oil and gas reservoirs, deep strike-slip fault-controlled fracture-vuggy oil and gas reservoirs are reservoirs and rich areas controlled by strike-slip fault zones. The oil-bearing area is generally strip-shaped in the plane, and the width of the fault zone plus karst body is generally 200-1000 meters. The burial depth of the oil and gas reservoir is generally 7000-8000 meters.

[0032] Based on hydrocarbon diffusion theory and the results of grid tests conducted above deep strike-slip fault-controlled fracture-cavity (fault-dissolved) oil and gas reservoirs, step S110 will deploy survey lines in the exploration area containing deep strike-slip fault reservoirs according to the reservoir depth, fault zone width, oil and gas leakage sources and their associated components.

[0033] During the deployment of geochemical survey lines, lines are deployed either perpendicular to or along strike-slip faults. Lines perpendicular to the fault strike are centered on the strike-slip fault zone, with lateral lines extending at least 2.5 km to 3.0 km in length. The length of lines along strike-slip faults is determined based on exploration requirements. The spacing between points on lines perpendicular to strike-slip faults is generally 0.10 km to 0.50 km, depending on the required exploration accuracy, while the spacing between points on lines along strike-slip faults is generally 0.25 km to 2.0 km, depending on the required exploration accuracy.

[0034] Furthermore, this invention determines the spacing between vertical survey lines and the spacing between survey lines along strike-slip faults based on the exploration objectives. These objectives include: targeting favorable areas with a high probability of containing oil and gas, and targeting target areas with an extremely high probability of containing oil and gas.

[0035] In one embodiment, if a favorable oil and gas-bearing area is preferred, the spacing between the measurement points perpendicular to the strike-slip fault is 0.25km-0.5km, and the spacing between the measurement points along the strike-slip fault is 0.5km-2km.

[0036] In another embodiment, if the target area containing oil and gas is preferred, the spacing between the measuring points perpendicular to the strike-slip fault is 0.1km-0.25km; and the spacing between the measuring points along the strike-slip fault is 0.25km-0.5km.

[0037] Next, step S110 will collect near-surface samples at each measuring point in the area to be explored according to the deployed survey lines, thus proceeding to step S120.

[0038] Based on the fact that hydrocarbons in deep strike-slip fault-controlled fracture-vuggy oil and gas reservoirs mainly dissipate vertically to the surface through inherited secondary fractures and microfracture systems in the overlying strata at the end of the strike-slip fault extension, resulting in a strip-like distribution of geochemical anomalies within a certain range on the surface, this invention employs an economical and effective meshing method to capture comprehensive oil and gas leakage information and tracer indicators related to the hydrocarbon-bearing properties of deep strike-slip faults, in order to evaluate the hydrocarbon-bearing properties of fracture-vuggy reservoirs controlled by deep strike-slip faults.

[0039] In step S120, firstly, geochemical indicators sensitive to faults and hydrocarbons are selected, and the experimental methods used to determine each geochemical indicator are determined. Then, according to the determined experimental methods, multiple geochemical indicators are tested on near-surface samples collected from each location, thereby obtaining measured results containing geochemical anomaly information.

[0040] In this embodiment of the invention, the geochemical indicators include: a first type of indicator reflecting micro-leaking of active light hydrocarbons, a second type of indicator reflecting the characteristics of associated gas and light hydrocarbons in reservoirs controlled by deep strike-slip faults, a third type of indicator reflecting micro-leaking of semi-active light hydrocarbons, and a fourth type of indicator reflecting the genesis and properties of oil and gas.

[0041] Specifically, in the first embodiment, the experimental methods used to determine the aforementioned first type of indicators include: free hydrocarbon determination experiments, headspace light hydrocarbon determination experiments, and oil and gas microbial determination experiments. Thus, this embodiment of the invention obtains free hydrocarbon determination data, headspace light hydrocarbon determination data, and oil and gas microbial determination data through hydrocarbon determination experiments for different purposes, and utilizes these determination data to characterize the microleakage characteristics of active light hydrocarbons in oil and gas.

[0042] In the second embodiment, the experimental methods used to determine the aforementioned second type of indicators include: experiments measuring free He, Ne, and H2, and experiments measuring He, Ne, and H2 in headspace gas. Thus, this embodiment of the invention obtains measurement data of free He, Ne, and H2 and headspace He, Ne, and H2 through gas measurement experiments in different occurrence states, and uses this measurement data to characterize the light hydrocarbon associated gas characteristics of reservoirs controlled by deep strike-slip fault zones.

[0043] In the third embodiment, the experimental method used to determine the aforementioned third type of index includes: a pyrolytic hydrocarbon determination experiment. Therefore, this embodiment of the invention obtains pyrolytic hydrocarbon determination data through the pyrolytic hydrocarbon determination experiment, and uses this data to characterize the light hydrocarbon associated gas characteristics of reservoirs controlled by deep strike-slip fault zones.

[0044] In the fourth embodiment, the experimental methods used to determine the aforementioned fourth type of index include: a methane stable carbon isotope determination experiment and a three-dimensional fluorescence spectroscopy determination experiment. Thus, this embodiment of the invention obtains methane stable carbon isotope determination data and fluorescence spectroscopy determination data through methane stable carbon isotope and three-dimensional fluorescence spectroscopy determination experiments, and uses these determination data to characterize the genetic and property characteristics of oil and gas.

[0045] Therefore, in this embodiment of the invention, multiple measurement data (free hydrocarbon measurement data; headspace light hydrocarbon measurement data; oil and gas microbial measurement data; free gas He, Ne and H2 measurement data; headspace gas He, Ne and H2 measurement data; pyrolytic hydrocarbon measurement data; methane stable carbon isotope measurement data; and three-dimensional fluorescence spectroscopy measurement data) can be obtained for each sample at each location, thus proceeding to step S130.

[0046] Step S130 analyzes the relationship between seismic characteristics and geochemical anomalies based on the seismic feature map of the area to be explored and the geophysical and chemical measurement results of samples obtained in step S120, thereby identifying the hydrocarbon potential and distribution characteristics of the area to be explored. The seismic feature map includes at least two components: a seismic coherence map and a seismic amplitude map.

[0047] In step S130, firstly, based on the measured results of each sample obtained in step S120, geochemical anomalies and background separation processing are performed on the current exploration area to identify the morphology and intensity characteristics of geochemical anomalies in the current area. Then, based on the morphology and intensity characteristics of geochemical anomalies throughout the entire area, and according to the seismic coherence map and seismic amplitude map of the current exploration area, the relationship between the distribution of faults, fracture-vuggy reservoirs, and comprehensive geochemical anomalies is analyzed, thereby obtaining the evaluation results of the hydrocarbon potential and distribution range of the current exploration area.

[0048] In this way, by evaluating the oil and gas content and distribution range of the current exploration area, favorable oil and gas areas or target areas can be selected and delineated, thereby completing the oil and gas content detection task of the current exploration area.

[0049] Furthermore, to improve the success rate of oil and gas exploration in the current exploration area, geochemical observation results of previously discovered deep, large-scale strike-slip fault-controlled fracture-vuggy reservoirs can be used to construct a neural network-based identification and prediction model. Specifically, firstly, a basic neural network model is constructed. Then, using the geochemical observation results of discovered deep, large-scale strike-slip fault-controlled fracture-vuggy reservoirs (including a dataset of geochemical anomalies above known deep, large-scale strike-slip fault-controlled fracture-vuggy reservoirs and a dataset of geochemical background samples from blank areas), deep learning is performed to analyze the correlation between historical observation results and the evaluation results of hydrocarbon distribution range. This training of the aforementioned basic neural network model then constructs an identification and prediction model. Finally, when applying this identification and prediction model, the geochemical observation results of the current exploration area are used as model input. The model is then used to predict the hydrocarbon potential and hydrocarbon distribution of the deep, large-scale strike-slip fault-controlled fracture-vuggy reservoirs in the current exploration area.

[0050] Example 1

[0051] The aforementioned hydrocarbon detection method was applied to the middle section of the Shunbei 5 fault zone (a deep strike-slip fault zone) in the Shuntogole area of ​​the Tarim Basin, and an hydrocarbon exploration test (target selection) was conducted. The exploration results revealed a distinct banded anomaly zone along the Shunbei 5 fault zone, with geochemical indicators forming a clear banded anomaly. This anomaly zone contains two extremely high-value anomaly areas, located at the northern and southern ends of the Shunbei 5 fault zone within the work area, respectively. This indicates the heterogeneity of hydrocarbon reservoirs within the Shunbei 5 fault zone in the work area, and the exploration results show good agreement with the underlying hydrocarbon distribution.

[0052] On the other hand, based on the above-mentioned method for detecting hydrocarbon content, this embodiment of the invention also provides a system for detecting hydrocarbon content in deep strike-slip fault reservoirs. Figure 3 This is a schematic diagram of the structure of an hydrocarbon detection system for the Shenzhen-Dalian strike-slip fault reservoir, according to an embodiment of this application. Figure 3 As shown, the oil and gas content detection system includes: a survey line deployment module 31, an index selection and testing module 32, and an experimental result analysis module 33.

[0053] The survey line deployment module 31 is implemented according to the method described in step S110 above. It is configured to deploy survey lines in the exploration area of ​​the reservoir controlled by the underlying deep strike-slip fault based on the reservoir burial depth, fault zone width, and oil and gas leakage sources and their associated components, and collect near-surface samples according to the deployed survey lines. The index selection and testing module 32 is implemented according to the method described in step S120 above. It is configured to select geochemical indices sensitive to faults and oil and gas and determine the experimental method for each index. Then, it tests each geochemical index on the collected near-surface samples one by one according to the determined experimental method to obtain the measured results containing geochemical anomaly information. The measured result analysis module 33 is implemented according to the method described in step S130 above. It is configured to identify the oil and gas distribution characteristics of the exploration reservoir area by analyzing the relationship between seismic characteristics and geochemical anomaly characteristics based on the seismic feature map and geochemical measured results of the exploration reservoir area.

[0054] Furthermore, in the survey line deployment module 31, geochemical exploration survey lines are deployed both perpendicular to and along strike-slip faults. Specifically, survey lines perpendicular to the fault strike are centered on the strike-slip fault, with lateral lines extending at least 2.5 km to 3.0 km in length. Survey lines along strike-slip faults have lengths determined according to exploration requirements. The spacing between survey points perpendicular to the strike-slip fault is 0.1 km to 0.5 km, while the spacing between survey points along strike-slip faults is 0.25 km to 2.0 km.

[0055] In addition, the hydrocarbon detection system described in this embodiment of the invention further includes: a prediction model construction module (unnumbered). The prediction model construction module is used to first construct a basic neural network model, and then, based on the basic neural network model, according to a known dataset of geochemical anomalies above deep, large strike-slip fault-controlled fracture-vuggy hydrocarbon reservoirs and a dataset of geochemical background samples from blank areas, to construct an identification and prediction model through training the basic neural network model. Finally, based on the geochemical measurement results, the identification and prediction model is used to predict the hydrocarbon content and distribution of deep, large strike-slip fault-controlled fracture-vuggy reservoirs in the current exploration area.

[0056] This invention discloses a method and system for detecting hydrocarbon potential in reservoirs controlled by deep strike-slip faults. This method and system belong to the field of oil and gas exploration. Addressing the lack of low-cost, specific geochemical techniques in existing detection methods for hydrocarbon potential in fracture-vuggy (fault-dissolved) reservoirs controlled by deep strike-slip faults, this invention establishes a geochemical technique for detecting hydrocarbon potential in fracture-vuggy reservoirs controlled by deep strike-slip faults, integrating grid deployment, index selection, experimental method selection, and anomaly evaluation. This invention provides theoretical and practical basis for geochemical exploration of fracture-vuggy oil and gas reservoirs controlled by deep strike-slip faults, improves exploration results, and has achieved good results in the exploration of fracture-vuggy oil and gas reservoirs controlled by strike-slip faults in the Shunbei area of ​​the Tarim Basin.

[0057] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0058] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0059] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0060] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0061] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0062] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for detecting oil and gas potential for deep large strike-slip fault controlled reservoirs, characterized in that, include: Based on the burial depth of the oil and gas reservoir, the width of the fault zone, and the oil and gas leakage sources and their associated components, survey lines are deployed in the exploration area of ​​the reservoir controlled by the underlying deep strike-slip fault, and near-surface samples are collected according to the deployed survey lines. Geochemical indicators sensitive to faults and hydrocarbons were selected, and experimental methods for each indicator were determined. Then, each geochemical indicator was tested on the collected near-surface samples according to the determined experimental methods to obtain measured results containing geochemical anomaly information. The geochemical indicators include: a first category of indicators reflecting micro-leaking of active light hydrocarbons; a second category of indicators reflecting the associated gas characteristics of light hydrocarbons in reservoirs controlled by deep strike-slip faults; a third category of indicators reflecting micro-leaking of semi-active light hydrocarbons; and a fourth category of indicators reflecting the genesis and properties of hydrocarbons. The experimental methods for determining the first category of indicators include free hydrocarbon determination, headspace light hydrocarbon determination, and hydrocarbon microbial determination. The experimental methods for determining the second category of indicators include the determination of free gas He, Ne, and H2, and the determination of headspace gas He, Ne, and H2. The experimental methods for determining the third category of indicators include the determination of pyrolytic hydrocarbons. The experimental methods for determining the fourth category of indicators include the determination of stable carbon isotopes of methane and three-dimensional fluorescence spectroscopy. Based on the seismic feature map and geochemical measurement results of the area to be explored, the hydrocarbon potential and distribution characteristics of the area to be explored are identified by analyzing the relationship between the seismic features and the geochemical anomalies. The seismic feature map includes a seismic coherence map and a seismic amplitude map.

2. The method for detecting oil and gas content according to claim 1, characterized in that, The deployment of geochemical exploration survey lines includes: deployment perpendicular to and along strike-slip faults. The survey line perpendicular to the fault strike is centered on the strike-slip fault, and the length of the lateral lines to both sides is not less than 2.5km-3.0km. The length of the survey line along the strike-slip fault is determined according to the exploration requirements. Specifically, the spacing between survey points perpendicular to the strike-slip fault is 0.1km-0.5km, and the spacing between survey points along the strike-slip fault is 0.25km-2.0km.

3. The method for detecting oil and gas content according to claim 2, characterized in that, The spacing of the survey lines is determined according to the exploration objective, among which... If the area contains favorable oil and gas, the spacing between the measuring points perpendicular to the strike-slip fault is 0.25km-0.5km, and the spacing between the measuring points along the strike-slip fault is 0.5km-2km. If the target area contains oil and gas, the spacing between the survey points perpendicular to the strike-slip fault is 0.1km-0.25km; the spacing between the survey points along the strike-slip fault is 0.25km-0.5km.

4. The method for detecting oil and gas content according to any one of claims 1 to 3, characterized in that, The step of identifying the hydrocarbon potential and distribution characteristics of the area to be explored by analyzing the relationship between seismic features and geochemical anomalies based on the seismic feature map of the area to be explored and the geochemical measurement results includes: Based on the geochemical measurement results, geochemical anomalies and background are separated in the area to be explored to identify the morphology and intensity characteristics of regional geochemical anomalies. Based on the morphology and intensity characteristics of the geochemical anomalies, and according to the seismic coherence map and the seismic amplitude map, the relationship between the distribution of faults, fracture-vuggy reservoirs and the comprehensive geochemical anomalies is analyzed and studied, thereby obtaining the evaluation results of the hydrocarbon potential and distribution range of the area to be explored.

5. The method for detecting oil and gas content according to any one of claims 1 to 3, characterized in that, The method for predicting hydrocarbon potential also includes: Construct a basic neural network model; Based on the aforementioned neural network basic model, and using the known dataset of geochemical anomalies above deep strike-slip fault-controlled fracture-cavity oil and gas reservoirs, as well as the dataset of geochemical background samples in blank areas, an identification and prediction model is constructed by training the aforementioned neural network basic model. Based on the geochemical measurement results, the identification and prediction model is used to predict the hydrocarbon potential and distribution of deep strike-slip fault-controlled fracture-cavity reservoirs in the current exploration area.

6. A hydrocarbon detection system for the Shenzhen-Dalian strike-slip fault-controlled reservoir, characterized in that, include: The survey line deployment module is used to deploy survey lines in the exploration area of ​​the reservoir controlled by the underlying deep strike-slip fault based on the reservoir burial depth, fault zone width, oil and gas leakage source and its associated components, and to collect near-surface samples according to the deployed survey lines. The index selection and testing module is used to select geochemical indices sensitive to faults and hydrocarbons and determine the experimental methods for each index. Then, according to the determined experimental methods, each geochemical index is tested on the collected near-surface samples one by one to obtain measured results containing geochemical anomaly information. The geochemical indices include: a first category of indices reflecting micro-leaches of active light hydrocarbons; a second category of indices reflecting the associated gas characteristics of light hydrocarbons in reservoirs controlled by deep strike-slip faults; a third category of indices reflecting micro-leaches of semi-active light hydrocarbons; and a fourth category of indices... The fourth category of indicators reflects the genesis and properties of oil and gas. Among them, the experimental methods used to determine the first category of indicators include the determination of free hydrocarbons, the determination of light hydrocarbons in the headspace, and the determination of oil and gas microorganisms; the experimental methods used to determine the second category of indicators include the determination of free gas He, Ne, and H2, and the determination of headspace gas He, Ne, and H2; the experimental methods used to determine the third category of indicators include the determination of pyrolytic hydrocarbons; and the experimental methods used to determine the fourth category of indicators include the determination of stable carbon isotopes of methane and the determination of three-dimensional fluorescence spectroscopy. The measured result analysis module is used to identify the hydrocarbon content and distribution characteristics of the area to be explored by analyzing the relationship between the seismic feature map and the geochemical anomaly features based on the seismic feature map and the geochemical measured results. The seismic feature map includes a seismic coherence map and a seismic amplitude map.

7. The oil and gas content detection system according to claim 6, characterized in that, In the survey line deployment module, geochemical exploration survey lines are deployed both perpendicular to and along strike-slip faults. The survey line perpendicular to the fault strike is centered on the strike-slip fault, and the length of the lateral lines to both sides is not less than 2.5km-3.0km. The length of the survey line along the strike-slip fault is determined according to the exploration requirements. Specifically, the spacing between survey points perpendicular to the strike-slip fault is 0.1km-0.5km, and the spacing between survey points along the strike-slip fault is 0.25km-2.0km.

8. The oil and gas content detection system according to claim 6 or 7, characterized in that, The oil and gas content detection system also includes: The prediction model construction module is used to construct a basic neural network model. Then, based on the basic neural network model, and according to the known geochemical anomaly sample dataset above the deep strike-slip fault-controlled fracture-vuggy oil and gas reservoir and the geochemical background sample dataset of the blank area, the recognition and prediction model is constructed by training the basic neural network model. Finally, based on the geochemical measurement results, the recognition and prediction model is used to predict the hydrocarbon potential and hydrocarbon distribution of the deep strike-slip fault-controlled fracture-vuggy reservoir in the current exploration area.

Images