Method and system for analyzing enrichment conditions of faulted-dissolved reservoir based on filling and dredging evaluation

Abstract

The application provides a method and system for analyzing enrichment conditions of a fault-dissolution body oil reservoir based on filling and dredging evaluation, which comprises a type identification step, a parameter setting step, a fault filling adjustment condition evaluation step, a fault dredging condition evaluation step, a reservoir condition evaluation step, and an enrichment condition calculation and analysis step. Through the above steps, it is identified whether the fault-dissolution body to be analyzed belongs to a fault-dissolution body in a covered area or a denuded area, and then corresponding calculation list parameters are called to obtain various parameters required for analysis and calculation, and corresponding scores are assigned. Comprehensive evaluation and calculation are realized from three aspects of fault filling adjustment condition, fault dredging condition and reservoir condition, the limitations of existing conventional oil and gas analysis techniques are overcome, accurate analysis of oil and gas enrichment conditions of different types of fault-dissolution bodies is realized based on quantitative research of reservoir filling and dredging, and reliable support is provided for optimized development of related oil fields.

Description

Technical Field

[0001] This invention relates to the field of description and research technology of fault-dissolved oil and gas reservoirs, and in particular to a method and system for analyzing enrichment conditions of fault-dissolved oil reservoirs based on charging and channeling evaluation. Background Technology

[0002] The "fracture-dissolved" reservoir theory is a theory of oil and gas traps first proposed by the Northwest Petroleum Bureau based on its research on reservoir characteristics of fracture, karstification and fault-controlled karst. The theory posits that karst water beneath the strata flows downward along deep fault zones, dissolving into caves similar to large karst caves on and around the main fracture channels. After oil and gas are injected into these caves, a special type of oil and gas trap is formed—the fracture-dissolved trap.

[0003] For fault-knot reservoirs, existing scholars have analyzed the scale, activity stages, and structural styles of karst along faults, summarizing the karst characteristics of fault-knot reservoirs under different fault combinations. Based on the planar distribution morphology of the fault-knot, they have classified it into three reservoir types: banded, sandwich-shaped, and flat (Lu Xinbian, 2015). Preliminary analyses of the characteristics of fault-knot reservoirs have also been conducted, suggesting that they are characterized by segmented charging and accumulation, significant differences in the degree of hydrocarbon charging in each segment, inconsistent oil-water interfaces in each segment, the presence of the same oil-water interface within the same segment, and overall adherence to the principle of differential hydrocarbon accumulation. This has led to a basic understanding of the reservoir formation processes in fault-knot reservoirs, including fault-controlled storage, physical property traps, deep fault-controlled storage, vertical channeling, segmented accumulation, and complex accumulation. Furthermore, this has led to the development of a theory of hydrocarbon trap formation in deep carbonate rocks, deepening the research on carbonate karst traps and other types of traps in the Tarim Basin, and providing reliable geological evidence for the exploration and development of hydrocarbon traps.

[0004] However, as can be seen from the above, existing studies mainly rely on fracture patterns and karst processes for static description. Research on fracture-dissolved reservoirs is limited to understanding macroscopic regularities and genetic structures, lacking descriptions of the influence of specific fracture-dissolved fluids, the charging and channeling of different types of fracture-dissolved reservoirs, and the analysis of differences in charging and channeling.

[0005] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a method and system for analyzing enrichment conditions in fractured-dissolved reservoirs based on charging and channeling evaluation. In one embodiment, the method includes:

[0007] The type identification step involves classifying the fault-dissolved reservoir to be analyzed into two categories based on its geological characteristics: fault-dissolved reservoirs in the overlying area and fault-dissolved reservoirs in the eroded area.

[0008] The parameter setting steps involve pre-setting calculation parameter lists for both the covered area fractured solution and the eroded area fractured solution. The calculation parameter lists include the names of all calculation-related parameters, parameter classification results, corresponding scores for each level, and the weights of the parameters.

[0009] The evaluation steps for fracture charging adjustment conditions are as follows: For fractured karst bodies in the covered area, the formation water salinity, karst balance coefficient, and preset oil and gas charging range are obtained as calculation factors; for fractured karst bodies in the erosion area, the fluid bromide ion concentration, karst balance coefficient, and preset oil and gas charging range are obtained as calculation factors. Then, the calculation parameters are converted into scores according to their respective lists, and the corresponding weights are used to sum and calculate the charging condition adjustment index corresponding to the fractured karst body.

[0010] The evaluation steps for fracture conduction conditions are as follows: for fracture karst in the covered area, information on fracture level, fracture fracture zone width and incision layer is obtained as calculation factors; for fracture karst in the erosion area, information on fracture direction and level is obtained as calculation factors. Then, the respective calculation parameter lists are converted into scores, and the corresponding weights are used to sum and calculate the fracture conduction condition index corresponding to the fracture karst.

[0011] The reservoir condition evaluation steps are as follows: For fault-knot bodies in the overburden area, the reservoir type, reservoir area and vertical seismic reflection characteristics are obtained as calculation factors; for fault-knot bodies in the erosion area, the corresponding structural location, fracture development degree and cavern type are used as calculation factors, and then the respective calculation parameter lists are converted into scores, and the corresponding weights are used to sum and calculate the reservoir condition index corresponding to the fault-knot body.

[0012] The enrichment condition calculation and analysis steps involve summing the obtained charging condition adjustment index, fracture conduction condition index, and reservoir condition index to calculate the target enrichment condition index of the fractured solution, and analyzing the development feasibility and construction plan of the fractured solution based on it.

[0013] Furthermore, in one embodiment, in the parameter setting step, each parameter involved in the calculation is graded and assigned a corresponding score according to its positive correlation with the enrichment conditions of the solution to be analyzed, in descending order.

[0014] As a further improvement of the present invention, in one embodiment, in the evaluation step of fracture charging adjustment conditions, the fluid salinity of the oil and gas charging point corresponding to the fracture solution is used as the formation water salinity of the fracture solution in the covered area; wherein, the oil and gas charging point on the main fracture zone is identified by the mass anomaly of the salinity value.

[0015] Specifically, in one embodiment, in the fracture charging adjustment condition evaluation step, based on the construction threshold of the formation water and oil / gas charging point, the oil / gas charging adjustment range is set to include the following levels:

[0016] Level 1: No adjustment to 0m; Level 2: Adjustment range is close to 0-2000m; Level 3: Adjustment range is relatively close to 2000-4000; Level 4: Adjustment range is relatively far to 4000-8000; Level 5: Adjustment range is far greater than 8000.

[0017] In an optional embodiment, during the fracture conduction condition evaluation step,

[0018] The fracture level information of the fracture solution is determined based on the scale and intercutting relationship of the fault trajectory on the coherence map, as well as the relationship between different fracture levels and principal stress.

[0019] Specifically, in one embodiment, in the fracture conduction condition evaluation step, the incision layer information is set according to the following logic:

[0020] Based on the ability to communicate with oil sources through fractures, it is divided into three levels: Level 1 is cutting down to the T81 gypsum-salt layer, Level 2 is cutting down to the T80 layer, and Level 3 is cutting down to the T76 layer.

[0021] As a further improvement of the present invention, in one embodiment, in the reservoir condition evaluation step, reservoir area information is obtained by dividing the area of ​​reference fracture-cavity units on the plane and the area of ​​attribute reflection features.

[0022] Specifically, in one embodiment, in the reservoir condition evaluation step, the vertical seismic response characteristics are set according to the following logic:

[0023] Based on the degree of development of dissolution cavities in the fractured body, the following levels are defined: Level 1: Strong beaded structure; Level 2: Weak beaded structure; Level 3: Disordered and strong; Level 4: Disordered and weak.

[0024] Based on other aspects of the methods described in any one or more of the above embodiments, the present invention also provides a storage medium storing program code that can implement the methods described in any one or more of the above embodiments.

[0025] Based on the application aspects of the methods described in any one or more of the above embodiments, the present invention also provides an analysis system for enrichment conditions of fractured-dissolved reservoirs based on charging and channeling evaluation, which performs the methods described in any one or more of the above embodiments.

[0026] Compared with the closest prior art, the present invention also has the following beneficial effects:

[0027] This invention provides a method and system for analyzing enrichment conditions in fracture-dissolved reservoirs based on charging and channeling evaluation. The method identifies whether the fracture-dissolved reservoir to be analyzed belongs to a covered or eroded zone, then calls the corresponding calculation list parameters to obtain the various parameters required for analysis and calculation, assigning corresponding scores. It achieves comprehensive evaluation and calculation from three aspects: fracture charging adjustment conditions, fracture channeling conditions, and reservoir conditions. A complete charging-channeling evaluation system for fracture-dissolved reservoirs is established. Based on quantitative research on reservoir charging-channeling, accurate analysis of oil and gas enrichment conditions for different types of fracture-dissolved reservoirs is achieved, clarifying the oil and gas enrichment conditions and differences among different types of fracture-dissolved reservoirs. The calculation process involves clear indicators, is simple and reliable, highly operable, and features multidisciplinary comprehensive analysis, providing extremely important guidance for the development of reservoirs with such requirements.

[0028] 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

[0029] 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:

[0030] Figure 1 This is a flowchart illustrating the enrichment condition analysis method for fractured solution reservoirs based on charging and channeling evaluation provided in an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of the verification of the enrichment conditions of the fault-dissolved reservoir based on the method for analyzing the enrichment conditions of fault-dissolved reservoirs based on the evaluation of charging and channeling, provided in another embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the verification of the enrichment conditions of the fractured solution in the erosion zone of the method for analyzing the enrichment conditions of fractured solution reservoirs based on the evaluation of charging and channeling provided in this embodiment of the invention.

[0033] Figure 4 This is a schematic diagram of the structure of the enrichment condition analysis system for fractured solution reservoirs based on charging and channeling evaluation provided in an embodiment of the present invention. Detailed Implementation

[0034] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples. Those skilled in the art will then fully understand how the present invention uses technical means to solve technical problems and achieve technical effects, and will be able to implement the present invention specifically based on the above-described implementation process. It should be noted that, as long as there is no conflict, the various embodiments and features 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.

[0035] Although the flowchart describes the operations as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. The order of the operations can be rearranged. A process can terminate when its operation is complete, but it may also have additional steps not included in the diagram. A process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0036] Computer equipment includes user equipment and network equipment. User equipment or clients include, but are not limited to, computers, smartphones, PDAs, etc.; network equipment includes, but is not limited to, a single network server, a server group consisting of multiple network servers, or a cloud based on cloud computing consisting of a large number of computers or network servers. Computer equipment can operate independently to implement this invention, or it can connect to a network and implement this invention through interaction with other computer equipment in the network. The network in which the computer equipment is located includes, but is not limited to, the Internet, wide area network, metropolitan area network, local area network, VPN network, etc.

[0037] The terms “first,” “second,” etc., may be used herein to describe various units, but these units should not be limited by these terms; they are used merely to distinguish one unit from another. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. When a unit is referred to as “connected” or “coupled” to another unit, it may be directly connected or coupled to said other unit, or there may be intermediate units present.

[0038] 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.

[0039] Domestic and international scholars, through analyzing the scale, activity periods, and structural styles of karst along faults, have summarized the karst characteristics of fault-knot reservoirs under different fault combinations. Based on the planar distribution morphology of fault-knot bodies, they have classified them into three reservoir types: banded, sandwich-shaped, and flat (Lu Xinbian). Simultaneously, a preliminary analysis of the characteristics of fault-knot reservoirs has been conducted, suggesting that they are characterized by segmented charging and accumulation, significant differences in the degree of hydrocarbon charging in each segment, inconsistent oil-water interfaces in each segment, the presence of a single oil-water interface within the same segment, and overall adherence to the principle of differential hydrocarbon accumulation. This has led to a basic understanding of the hydrocarbon accumulation in fault-knot reservoirs, including fault-controlled storage, physical property traps, deep fault-controlled storage, vertical channeling, segmented accumulation, and complex accumulation. This further enriches the theory of hydrocarbon accumulation traps in deep carbonate rocks, deepens the research on carbonate karst traps and other types of traps in the Tarim Basin, and provides reliable geological evidence for the exploration and development of hydrocarbon traps.

[0040] Currently, research on fault-dissolved reservoirs mainly relies on static descriptions of fracture patterns and karst processes. For example, regarding the hydrocarbon generation system: the Cambrian source rocks in the Tarim Basin are currently considered to be relatively evenly distributed; the channeling system: deep, large faults that connect to the source serve as good channels for channeling and charging, but due to differences in stress and karst, they exhibit segmentation; the adjustment system: karst fissures and cavities developed along the T74 surface provide space for lateral hydrocarbon adjustment, and differences in connectivity lead to differences in reservoir formation. Research remains limited to understanding macroscopic regularities and genetic structures, without analyzing the differences in charging and channeling capabilities of fault-dissolved reservoirs. There is a lack of research on the influence of specific fault-dissolved fluids, descriptions of charging and channeling in different types of fault-dissolved reservoirs, and analyses of the differences in charging and channeling.

[0041] Existing research on fault-dissolved reservoir analysis mainly focuses on qualitative analysis and summarizing phenomena. However, in-depth research has not been conducted on how to evaluate fault-dissolved reservoirs of different scales and types with different fault development, how to quantitatively evaluate them based on oil source conditions, trap conditions, reservoir conditions, and preservation conditions, how to define evaluation parameters, formulate evaluation standards, and conduct a detailed evaluation of the effectiveness of fault-dissolved reservoir formation.

[0042] To address the aforementioned shortcomings, this invention provides a method for analyzing the enrichment conditions of fault-dissolved reservoirs based on charging and channeling evaluation. This method fills the gap in charging-channeling analysis of fault-dissolved reservoirs and is the first to propose a charging-channeling description technique for such reservoirs. It considers the differences in hydrocarbon charging across different fault grades, spatial combinations, and stress structures. By utilizing fault grade, fracture zone width, and incised strata, it assesses the channeling capacity of hydrocarbons within fault zones, clarifying the enrichment conditions and differences among different types of fault-dissolved reservoirs. Furthermore, it analyzes the impact of reservoir type, reservoir area, and longitudinal seismic reflection characteristics on karst fractures and cavities through reservoir conditions. Finally, it performs a weighted evaluation of different types of fault-dissolved reservoirs, thus solving the problem of quantitative analysis of charging-channeling in fault-dissolved reservoirs.

[0043] The following describes the detailed flow of the method according to an embodiment of the present invention with reference to the accompanying drawings, the steps of which can be executed in a computer system containing, for example, a set of computer-executable instructions. Although the logical order of the steps is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than that shown here.

[0044] Example 1

[0045] Figure 1 This diagram illustrates a flowchart of the enrichment condition analysis method for fractured-dissolved reservoirs based on charging and channeling evaluation, as provided in Embodiment 1 of the present invention. (Refer to...) Figure 1 As can be seen, the method includes the following steps.

[0046] The type identification step involves classifying the fault-knot reservoir to be analyzed into two categories based on its geological characteristics: covered fault-knot reservoirs and eroded fault-knot reservoirs. Specifically, the degree of erosion of the strata is analyzed based on seismic data of the corresponding region to classify the covered and eroded areas. For example, seismic data analysis reveals that the Tarim Basin has a high northeast-southwest gradient, with varying stratigraphic distribution. The northeast is an Upper Ordovician eroded area, with varying degrees of erosion in the Middle and Upper Ordovician strata. The Qiaerbake and Lianglitag Formations are completely eroded, while the Yingshan and Yijianfang Formations show varying degrees of erosion; this is referred to as the northern Middle and Upper Ordovician eroded area. The southwest is an Upper Ordovician covered area, with well-developed Upper Ordovician strata; this is referred to as the southwestern Middle and Upper Ordovician covered area. The parameter setting step involves pre-setting calculation parameter lists for both covered and eroded fault-knot reservoirs. These lists include the names of all relevant parameters, parameter classification results, corresponding scores for each level, and parameter weights.

[0047] The evaluation steps for fracture charging adjustment conditions are as follows: For fractured karst bodies in the covered area, the formation water salinity, karst balance coefficient, and preset oil and gas charging range are obtained as calculation factors; for fractured karst bodies in the erosion area, the fluid bromide ion concentration, karst balance coefficient, and preset oil and gas charging range are obtained as calculation factors. Then, the calculation parameters are converted into scores according to their respective lists, and the corresponding weights are used to sum and calculate the charging condition adjustment index corresponding to the fractured karst body.

[0048] The evaluation steps for fracture conduction conditions are as follows: for fracture karst in the covered area, information on fracture level, fracture fracture zone width and incision layer is obtained as calculation factors; for fracture karst in the erosion area, information on fracture direction and level is obtained as calculation factors. Then, the respective calculation parameter lists are converted into scores, and the corresponding weights are used to sum and calculate the fracture conduction condition index corresponding to the fracture karst.

[0049] The reservoir condition evaluation steps are as follows: For fault-knot bodies in the overburden area, the reservoir type, reservoir area and vertical seismic reflection characteristics are obtained as calculation factors; for fault-knot bodies in the erosion area, the corresponding structural location, fracture development degree and cavern type are used as calculation factors, and then the respective calculation parameter lists are converted into scores, and the corresponding weights are used to sum and calculate the reservoir condition index corresponding to the fault-knot body.

[0050] The enrichment condition calculation and analysis steps involve summing the obtained charging condition adjustment index, fracture conduction condition index, and reservoir condition index to calculate the target enrichment condition index of the fractured solution, and analyzing the development feasibility and construction plan of the fractured solution based on it.

[0051] Based on the execution logic of the above embodiments, a comprehensive evaluation system for the charging and channeling of fault-dissolved reservoirs can be established, and the oil and gas enrichment of fault-dissolved reservoirs can be analyzed based on the evaluation results. According to the differences in oil and gas charging in different fault grades, spatial combinations, and stress structure sections, the channeling capacity of oil and gas in fault zones can be evaluated using fault charging adjustment conditions, fault channeling conditions, and reservoir development conditions. This clarifies the oil and gas enrichment conditions and differences of different types of fault-dissolved reservoirs, and establishes a typical fault-dissolved reservoir charging and channeling evaluation technology, thereby laying a solid geological foundation for the refined and efficient development of oilfields.

[0052] The expert evaluation system for enrichment conditions of fault-dissolved reservoirs, proposed for the first time in this invention, has significant practical application value for actual production in the Tarim Oilfield. The effectiveness evaluation of fault-dissolved reservoirs mainly references formation water ion information at the hydrocarbon injection points along the main faults, and is determined by combining the development of faults and reservoirs and their interrelationships. Each geological condition includes several evaluation factors.

[0053] Considering the different oil and gas enrichment conditions in the covered and eroded areas, different expert evaluation indicators and standards need to be established. The main parameters selected for the covered area are formation water salinity, equilibrium coefficient and adjustment range, which reflect the oil and gas charging adjustment conditions; fracture level, width and incision depth, which reflect the fracture conduction conditions; and reservoir space type, reservoir area and vertical seismic reflection characteristics, which reflect the reservoir conditions. The main parameters selected for the eroded area are bromide ions and equilibrium coefficient, which reflect the oil and gas charging adjustment conditions; fracture direction and level, which reflect the fracture conduction conditions; and structural location, fracture development degree and cavern type, which reflect the reservoir conditions (trap conditions).

[0054] Furthermore, in one embodiment, in the parameter setting step, each parameter involved in the calculation is graded and assigned a corresponding score according to its positive correlation with the enrichment conditions of the solution to be analyzed, in descending order.

[0055] In practical applications, during the parameter setting step, calculation parameter lists are pre-set for both the covered zone fault-knot and the eroded zone fault-knot. These lists include the names of all relevant parameters, parameter classification results, corresponding scores for each level, and parameter weights. Based on a weighting system, different levels of calculation parameters are assigned weights: 0.4 for the charging adjustment condition, 0.3 for the secondary mineralization, 0.3 for the balance coefficient, and 0.4 for the adjustment range; 0.3 for the fracture conduction condition, 0.5 for the secondary fracture level, 0.3 for the fracture zone width, and 0.2 for the incised layer; 0.3 for the reservoir condition, 0.6 for the secondary reservoir type, 0.2 for the reservoir area, and 0.2 for the vertical seismic reflection characteristics.

[0056] In another embodiment, in the evaluation step of fracture charging adjustment conditions, the fluid salinity of the oil and gas charging point corresponding to the fracture solution is used as the formation water salinity of the fracture solution in the overlying area; wherein, the oil and gas charging point on the main fracture zone is identified by the mass anomaly of the salinity value.

[0057] Specifically, in one embodiment, in the fracture charging adjustment condition evaluation step, based on the construction threshold of the formation water and oil / gas charging point, the oil / gas charging adjustment range is set to include the following levels:

[0058] Level 1: No adjustment to 0m; Level 2: Adjustment range is close to 0-2000m; Level 3: Adjustment range is relatively close to 2000-4000; Level 4: Adjustment range is relatively far to 4000-8000; Level 5: Adjustment range is far greater than 8000.

[0059] In practical applications, the evaluation of fracture filling adjustment conditions mainly considers mineralization, balance coefficient, and adjustment range;

[0060] Due to reduced erosion in the covered areas and the lack of developed karst systems such as weathering crusts, underground rivers, corridors, and sinkholes, high-salinity fluids from oil and gas injection points along the main faults indicate the main injection points and directions. Massive anomalies in salinity values ​​indicate oil and gas injection points along the main fault zones. Based on fluid distribution analysis, the best injection conditions for salinity-indicating injection points are >240,000 mmol / L; a good range is 200,000-240,000 mmol / L; a moderate range is 150,000-200,000 mmol / L; and a poor range is <150,000 mmol / L. These values ​​can be assigned scores of 1, 0.75, 0.5, and 0.25 respectively, as shown in Table 1 below.

[0061] Table 1. Expert Scoring and Evaluation Criteria for Hydrocarbon Accumulation in Fault-Dissolved Areas Covered by the Coverage

[0062]

[0063] Among them, the mineralization degree is obtained by direct analysis and testing of formation water;

[0064] The carbonate equilibrium coefficient [(rHCO3-+rCO32-)*100 / rCa2+] ranges from 1.8 to 77.97, with an average of 34.83. It indicates the enrichment of oil and gas. The smaller the equilibrium coefficient, the more light components are present in the adjacent reservoir, and the better the sealing. The smaller the equilibrium coefficient, the more oil and gas degrades and desulfurizes, forming more H2S and dissolving more calcium carbonate, increasing the concentration of Ca2+ ions, indicating a richer oil and gas accumulation. A small equilibrium coefficient also indicates a high concentration of low-carbon organic acids (inversely proportional to the equilibrium coefficient), strong dissolution, more caves and fissures, and the development of carbonate reservoirs.

[0065] In practical applications, the carbonate balance coefficient indicates the degree of carbonate dissolution, which indirectly indicates the degree of development of karst fissures and caves. The standard is <0.5 for good, 0.5-0.9 for good, 0.9-1.5 for medium, and >1.5 for poor, with scores assigned to each level as follows: 1, 0.75, 0.5, and 0.25 respectively.

[0066] Based on the above formation water, oil, and gas injection point thresholds, a standard for injection adjustment range was established. No adjustment is 0m, the adjustment range is 0-2000m, the adjustment range is 2000-4000m, the adjustment range is 4000-8000m, and the adjustment range is greater than 8000m. The scores for each level are assigned as follows: 1, 0.8, 0.6, 0.4, and 0.2, respectively.

[0067] The main parameters selected for the erosion zone are bromide ion concentration and equilibrium coefficient, which reflect the adjustment conditions of oil and gas injection; fracture direction and level, which reflect the fracture conduction conditions; and structural location, fracture development degree, and cavern type, which reflect the reservoir conditions (trap conditions), as shown in Table 2 below:

[0068] Table 2. Expert Scoring and Evaluation Criteria for Hydrocarbon Accumulation in Fault-Dissolved Areas of Erosion Zones

[0069]

[0070] Among them, the factors affecting the bromide ion content in carbonate reservoirs include ancient seawater evaporation and concentration (increase), high early crude oil density (increase), and low late crude oil density (decrease). It has strong adsorption properties and indicates low-amplitude structural highs and formation water flow direction.

[0071] Furthermore, in the fracture conduction condition evaluation step, in one embodiment, the fracture level information of the fracture solution is determined based on the scale and mutual cutting relationship of the fault trajectory on the coherence map, as well as the relationship between different levels of fracture and principal stress.

[0072] In another embodiment, during the fracture conduction condition evaluation step, the incision layer information is set according to the following logic:

[0073] Based on the ability to communicate with oil sources through fractures, it is divided into three levels: Level 1 is cutting down to the T81 gypsum-salt layer, Level 2 is cutting down to the T80 layer, and Level 3 is cutting down to the T76 layer.

[0074] In practical applications, the evaluation of fracture conduction conditions mainly considers the fracture level, the width of the fracture fracture zone, and the incised stratum.

[0075] The fracture classification is based on the scale and intersecting relationship of the fault trajectories on the coherence diagram, as well as the relationship between different fracture classifications and principal stresses.

[0076] The faults are divided into five categories: Class I faults are the TP12CX main faults trending northeast, with an evaluation standard of 1; Class II faults trending northeast have an evaluation standard score of 0.8; Class II faults trending northwest have an evaluation standard score of 0.6; Class III faults trending northeast have an evaluation standard score of 0.4; and Class III faults trending northwest have an evaluation standard score of 0.2.

[0077] The width of the fracture zone indicates the amount of oil source drainage. Based on the analysis of the injection port, it can be divided into three types: the width of the fracture zone is more than 300m, the medium is 120-300m, and the small is less than 120m. The scores can be assigned to each level: 1, 0.75 and 0.5 respectively.

[0078] The fracture incision depth indicates the fracture's ability to connect to the oil source, and is divided into three levels: Level 1: incision to the T81 gypsum-salt layer, with a score of 1; Level 2: incision depth reaches T80, with a score of 0.75; Level 3: incision depth reaches T76, with a score of 0.5.

[0079] Erosion zone fracture solution targeting fracture direction The analysis method is consistent with that of the covered area. For example, the Tahe Oilfield mainly develops northeast-trending, northwest-trending, east-west-trending, and near-north-south-trending faults, while Class I and Class II faults are mainly northeast-trending and northwest-trending.

[0080] On the other hand, in one embodiment, the present invention also evaluates the reservoir conditions of fractured solutions. In a preferred embodiment, the reservoir condition evaluation mainly considers reservoir type, reservoir area, and longitudinal seismic reflection characteristics.

[0081] Specifically, in the reservoir condition evaluation step, in one embodiment, reservoir area information is obtained by dividing the area of ​​reference fracture-cavity units on the plane and the area of ​​attribute reflection features.

[0082] Furthermore, in one embodiment, in the reservoir condition evaluation step, different levels of vertical seismic response characteristics are set according to the following logic:

[0083] Based on the degree of development of dissolution cavities in the fractured body, the following levels are defined: Level 1: Strong beaded structure; Level 2: Weak beaded structure; Level 3: Disordered and strong; Level 4: Disordered and weak.

[0084] In practical applications, the reservoir type is classified according to the Northwest Bureau's classification of karst fracture-cavity bodies. The karst cave type is classified as Level 1 with an evaluation standard score of 1, the fracture-cavity type is classified as Level 2 with an evaluation standard score of 0.75, and the fracture type is classified as Level 3 with an evaluation standard score of 0.5.

[0085] The storage area is classified based on the area of ​​the reference slit-hole unit on the plane and the area of ​​the attribute reflection characteristics. Areas larger than 150,000 square meters belong to Level 1, with an evaluation standard score of 1; areas between 100,000 and 150,000 square meters belong to Level 2, with an evaluation standard score of 0.8; areas between 60,000 and 100,000 square meters belong to Level 3, with an evaluation standard score of 0.6; areas between 30,000 and 60,000 square meters belong to Level 4, with an evaluation standard score of 0.4; and areas less than 30,000 square meters belong to Level 5, with an evaluation standard score of 0.2.

[0086] Longitudinal seismic reflection characteristics reflect the degree of development of karst cavities. Strong beaded cavities belong to Level 1, with an evaluation score of 1; weak beaded cavities belong to Level 2, with an evaluation score of 0.8; disordered and strong cavities belong to Level 3, with an evaluation score of 0.6; disordered and weak cavities belong to Level 4, with an evaluation score of 0.4; and continuous cavities belong to Level 5, with an evaluation score of 0.2.

[0087] Furthermore, in the enrichment condition calculation and analysis steps, the target enrichment condition index of the fractured solution is calculated by combining the obtained charging condition adjustment index, fracture conduction condition index and reservoir condition index corresponding to the current fractured solution with the corresponding weights, and the development feasibility and construction plan of the fractured solution are analyzed based on it.

[0088] The method of assigning weights based on different geological classifications assigns weights to different geological conditions. The weight of the filling adjustment condition is 0.5, the weight of the secondary bromide ion concentration is 0.6, and the weight of the balance coefficient is 0.4. Taking a bromide ion concentration >300mg / l as an example, the single item score is 1 multiplied by the weight of the secondary bromide ion concentration of 0.6 multiplied by the weight of the filling adjustment condition of 0.3, and the final single item score is 0.18.

[0089] The weight of the fault conduction condition is 0.2, and the weight of the secondary fault properties is 1. Taking the NE secondary fault as an example, the individual score is 1 multiplied by the secondary fault property score of 1 multiplied by the fault conduction condition score of 0.2, resulting in a final individual score of 0.2.

[0090] The weight of trap conditions is 0.5, the weight of secondary structural location is 0.6, the weight of fracture development degree (balance coefficient) is 0.2, and the weight of cave type is 0.2. Taking the top of a residual hill as an example, the single item score is 1 multiplied by the weight of secondary structural location (0.6) and trap conditions (0.5), resulting in a final single item score of 0.3.

[0091] The evaluation method for the effectiveness of hydrocarbon enrichment in fractured solutions based on expert-set parameter scores has fewer indicators, is simple and reliable, and is highly operable.

[0092] Application examples:

[0093] To address the distinction between covered and eroded areas in the distribution of Middle and Lower Ordovician fault-knot bodies in the Tarim Basin, several single wells were randomly selected from two typical areas for expert evaluation system testing, as shown in Tables 3 and 4 below.

[0094] Table 3. Rapid Evaluation System Test for Hydrocarbon Accumulation in Fault-Dissolved Bodies within Covered Areas

[0095]

[0096] Table 4. Rapid Evaluation System Test for Hydrocarbon Accumulation in Fault-Dissolved Areas of Eroded Zones

[0097]

[0098] Research using the scheme described in this invention revealed that the TK1063X reservoir in the covered area is an oil and gas reservoir located at a charging point on a tension-torsional fault. The fault characteristics are: main fault-tension-torsional segment, width >300m; charging adjustment: columnar; mineralization: 216,000 mg / L; equilibrium coefficient: 0.63, no adjustment; reservoir conditions: cavernous type, strong beaded structure, large reservoir volume, and 1345m³ of lost drilling mud. 3 The well's cumulative production was 216,500 tons of oil, 4,733,300 cubic meters of gas, and 19,000 tons of water. The well's evaluation score for the enrichment conditions of the broken solution was 0.976.

[0099] TP243CH in the covered area is located in an adjusted oil and gas reservoir along the main fault. The fault is a NE-trending main fault-compression-torsion section with a width of 200m. The charging adjustment is as follows: salinity: 183,000 mg / L, equilibrium coefficient: 0.71, and the strike adjustment distance is about 500m. The reservoir conditions are fracture-void type, beaded, medium-sized, with no venting or leakage. The charging enrichment mode is a strike-adjusted enrichment type with a high degree of enrichment. The production characteristics are: the well has produced a cumulative oil production of 123,100 tons, gas of 7,854,000 cubic meters, and water of 14,300 tons. The evaluation score for the oil and gas enrichment conditions of the fracture-dissolution body is 0.835.

[0100] TP145 in the covered area is a distant lateral adjustment type oil and gas reservoir. Fault type: NW-trending secondary fault. Charging adjustment: balance coefficient: 1.33, magnesium ion concentration: 86 mg / L, lateral adjustment distance: 4700 m. Reservoir conditions: fractured, chaotic and weak, small reservoir size, no venting or leakage. Charging enrichment mode: lateral adjustment type (poor enrichment). Production characteristics: the well has produced a cumulative oil production of 0.65 million tons, gas of 0 million cubic meters, and water of 0.07 million tons. Evaluation score for oil and gas enrichment conditions in the fracture-dissolved body: 0.415.

[0101] TK407 in the erosion zone is an oil and gas reservoir on the top of a residual hill. Structural location: top of a residual hill; fault type: NE-trending secondary fault; cavern type: large-scale hall cavern with no venting or leakage; bromide ion concentration: 105 mg / L; equilibrium coefficient: 0.23; charging enrichment mode: lateral charging of weathered crust guiding layer into karst highland enrichment type (top of residual hill, high enrichment); production characteristics: this well has produced a cumulative oil production of 384,900 tons, gas of 1,700,000 cubic meters, and water of 231,400 tons; evaluation score for oil and gas enrichment conditions in the fault-dissolved body: 0.930.

[0102] TK455 in the erosion zone is an oil and gas reservoir on a residual hill slope. Structural location: residual hill slope; fault type: northwest-trending main fault; cave type: sinkhole, hall cave; mud loss: 722 m3; bromide ion concentration: 320 mg / L; equilibrium coefficient: 0.62; charging enrichment mode: direct charging type of main fault (residual hill slope, high enrichment degree); production characteristics: the well has produced a cumulative oil production of 129,500 t, gas of 2,916,000 m3, and water of 38,800 t; evaluation score of oil and gas enrichment conditions in the fault-dissolved body: 0.740.

[0103] TK475CH in the erosion zone is an oil and gas reservoir in a valley area. Structural location: valley area; fault type: northeast-trending main fault; cavern type: small cavern with no venting or leakage; bromide ion concentration: 78 mg / L; equilibrium coefficient: 0.60; charging enrichment mode: direct charging type of main fault (valley area, poor enrichment); production characteristics: the well has produced a cumulative oil production of 8,000 tons, gas of 422,000 cubic meters, and water of 9,400 tons; evaluation score for oil and gas enrichment conditions in the fault-dissolved body: 0.300.

[0104] Generally, the higher the enrichment condition evaluation score of the interrupted solution, the greater the degree of oil and gas enrichment in the interrupted solution, and the higher the effective oil and gas production. Through expert calculation and comparison of multiple single wells in the covered and eroded areas, it was verified that the oil and gas enrichment condition evaluation score and oil production have a strong positive correlation. An example of calculation for the interrupted solution in the covered area can be found here. Figure 2 See the appendix for an example of calculating the dissolution in the erosion zone. Figure 3 The relationship between the evaluation score of single well oil and gas enrichment conditions in the covered area and the cumulative oil production, as shown in the figure, illustrates the usability of the established evaluation method.

[0105] Based on the data recorded in the above application cases, it is evident that the analytical strategy described in the above embodiments of this invention can reliably assess the hydrocarbon enrichment status of fractured solutions. By comprehensively analyzing dynamic and static data, classifying and determining the parameters of influencing factors, and evaluating them using weighted coefficients, a rapid expert evaluation method for the effectiveness of hydrocarbon enrichment in fractured solutions is established. This method has fewer indicators, is simple and reliable, and is highly operable. This method is characterized by its multidisciplinary approach and, for the first time, proposes a method and process for analyzing the hydrocarbon enrichment status of fractured solutions based on the evaluation approach of reservoir charging-drainage technology. This has extremely important guiding significance for the development of this type of reservoir.

[0106] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0107] It should be noted that, in other embodiments of the present invention, the method can also be combined with one or more of the above embodiments to obtain a new method for analyzing enrichment conditions of fractured-dissolve reservoirs, so as to support and optimize the development of fractured-dissolve reservoirs.

[0108] It should be noted that, based on the methods in any one or more embodiments of the present invention described above, the present invention also provides a storage medium storing program code that can implement the methods described in any one or more embodiments. When the program code is executed by the operating system, it can implement the enrichment condition analysis method for fractured solution reservoirs based on charging and channeling evaluation as described above.

[0109] Example 2

[0110] The methods described in the above-disclosed embodiments of the present invention are detailed. These methods can be implemented using various forms of devices or systems. Therefore, based on other aspects of the methods described in any one or more of the above embodiments, the present invention also provides a system for analyzing enrichment conditions in fault-dissolved reservoirs based on charging and channeling evaluation. This system is used to execute the method for analyzing enrichment conditions in fault-dissolved reservoirs based on charging and channeling evaluation described in any one or more of the above embodiments. Specific embodiments are given below for detailed explanation.

[0111] Specifically, Figure 4 The diagram shows a schematic representation of the structure of the fault-solution reservoir enrichment condition analysis system based on charging and channeling evaluation provided in an embodiment of the present invention. Figure 4 As shown, the system includes:

[0112] The type identification module is configured to classify the fault-dissolved reservoir to be analyzed into two categories based on its geological characteristics: fault-dissolved reservoirs in the overlying area and fault-dissolved reservoirs in the eroded area.

[0113] The parameter setting module is configured to pre-set calculation parameter lists for the covered area fracture solution and the eroded area fracture solution, respectively. The calculation parameter lists include the names of all calculation-related parameters, parameter classification results, corresponding scores for each level, and parameter weights.

[0114] The fault-charge adjustment condition evaluation module is configured to obtain formation water salinity, karst balance coefficient, and preset oil and gas charging range as calculation factors for fault-karst bodies in the covered area; and to obtain fluid bromide ion concentration, karst balance coefficient, and preset oil and gas charging range as calculation factors for fault-karst bodies in the erosion area. Then, it combines the respective calculation parameter lists to convert them into scores, and uses the corresponding weights to sum and calculate the charging condition adjustment index corresponding to the fault-karst body.

[0115] The fracture conduction condition evaluation module is configured to obtain fracture level, fracture fracture zone width and incision layer information as calculation factors for fracture-knot bodies in the covered area, and fracture direction and level information as calculation factors for fracture-knot bodies in the erosion area. Then, it combines the respective calculation parameter list to convert them into scores, and supplements them with corresponding weights to sum and calculate the fracture conduction condition index corresponding to the fracture-knot body.

[0116] The reservoir condition evaluation module is configured to obtain reservoir type, reservoir area and longitudinal seismic reflection characteristics as calculation factors for fault-knot bodies in the overburden area; and to calculate reservoir condition index corresponding to fault-knot bodies in the erosion area based on the corresponding structural location, fracture development degree and cavern type. The module then converts each of the calculation parameters into a score and sums the corresponding weights to calculate the reservoir condition index corresponding to the fault-knot body.

[0117] The enrichment condition calculation and analysis module is configured to sum the obtained charging condition adjustment index, fracture conduction condition index and reservoir condition index to calculate the target enrichment condition index of the fractured solution, and analyze the development feasibility and construction plan of the fractured solution based on it.

[0118] In practical applications, in one embodiment, the parameter setting module is configured to classify and assign corresponding scores to each parameter involved in the calculation in descending order of its positive correlation with the enrichment conditions of the broken solution to be analyzed.

[0119] Furthermore, in one embodiment, the fracture charging adjustment condition evaluation module is configured to use the fluid salinity of the oil and gas charging point of the main fracture corresponding to the fracture solution as the formation water salinity of the fracture solution in the overlying area; wherein, the oil and gas charging point on the main fracture zone is identified by the mass anomaly of the salinity value.

[0120] Specifically, in one embodiment, the fracture charging adjustment condition evaluation module is configured to set the oil and gas charging adjustment range to include the following levels based on the construction threshold of the formation water and oil and gas charging point:

[0121] Level 1: No adjustment to 0m; Level 2: Adjustment range is close to 0-2000m; Level 3: Adjustment range is relatively close to 2000-4000; Level 4: Adjustment range is relatively far to 4000-8000; Level 5: Adjustment range is far greater than 8000.

[0122] Furthermore, in one embodiment, the fracture conduction condition evaluation module is configured to perform the following operations:

[0123] The fracture level information of the fracture solution is determined based on the scale and intercutting relationship of the fault trajectory on the coherence map, as well as the relationship between different fracture levels and principal stress.

[0124] On the other hand, in one embodiment, the fracture conduction condition evaluation module is specifically configured to set the incision layer information according to the following logic:

[0125] Based on the ability to communicate with oil sources through fractures, it is divided into three levels: Level 1 is cutting down to the T81 gypsum-salt layer, Level 2 is cutting down to the T80 layer, and Level 3 is cutting down to the T76 layer.

[0126] Furthermore, in one embodiment, the reservoir condition evaluation module is configured to obtain reservoir area information by dividing the area of ​​reference fracture-cavity units on the plane and the area of ​​attribute reflection characteristics.

[0127] Specifically, in one embodiment, the reservoir condition evaluation module is configured to set the vertical seismic response characteristics according to the following logic:

[0128] Based on the degree of development of dissolution cavities in the fractured body, the following levels are defined: Level 1: Strong beaded structure; Level 2: Weak beaded structure; Level 3: Disordered and strong; Level 4: Disordered and weak.

[0129] In the analysis system for enrichment conditions of fractured-dissolved reservoirs based on charging and channeling evaluation provided in this embodiment of the invention, each module or unit structure can be operated independently or in combination according to actual calculation and analysis needs to achieve the corresponding technical effects.

[0130] 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.

[0131] The phrase "an embodiment" in the specification means that a specific 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" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0132] 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 variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for analyzing enrichment conditions in fractured-solution reservoirs based on charging and channeling evaluation, characterized in that, The method includes: The type identification step involves classifying the fault-dissolved reservoir to be analyzed into two categories based on its geological characteristics: fault-dissolved reservoirs in the overlying area and fault-dissolved reservoirs in the eroded area. The parameter setting steps involve pre-setting calculation parameter lists for both the covered area fractured solution and the eroded area fractured solution. The calculation parameter lists include the names of all calculation-related parameters, parameter classification results, corresponding scores for each level, and the weights of the parameters. Evaluation steps for fracture charging adjustment conditions: For fractured karst bodies in the overburden area, obtain formation water salinity, karst balance coefficient, and preset oil and gas charging range as calculation factors; for fractured karst bodies in the erosion area, obtain fluid bromide ion concentration, karst balance coefficient, and preset oil and gas charging range as calculation factors, and then convert them into scores by combining their respective calculation parameter lists, and supplement them with corresponding weights to calculate the charging condition adjustment index corresponding to the fractured karst body; The steps for evaluating fracture conduction conditions are as follows: For fractured karst in the covered area, the fracture level, fracture fracture zone width, and incision layer information are obtained as calculation factors. For fractured karst in the erosion area, the fracture direction and level information are obtained as calculation factors. Then, the respective calculation parameter lists are combined to convert them into scores, and the corresponding weights are used to sum and calculate the fracture conduction condition index corresponding to the fractured karst. Reservoir condition evaluation steps: For fault-knot bodies in the overburden area, the reservoir type, reservoir area, and vertical seismic reflection characteristics are obtained as calculation factors; for fault-knot bodies in the erosion area, the corresponding structural location, fracture development degree, and cavern type are used as calculation factors, and then the respective calculation parameter lists are converted into scores, supplemented by corresponding weights to sum and calculate the reservoir condition index corresponding to the fault-knot body. The enrichment condition calculation and analysis steps involve summing the obtained charging condition adjustment index, fracture conduction condition index, and reservoir condition index to calculate the target enrichment condition index of the fractured solution, and analyzing the development feasibility and construction plan of the fractured solution based on it.

2. The method according to claim 1, characterized in that, In the parameter setting step, each parameter involved in the calculation is classified and assigned a corresponding score according to its positive correlation with the enrichment conditions of the broken solution to be analyzed, in descending order.

3. The method according to claim 1, characterized in that, In the evaluation step of fracture charging adjustment conditions, the fluid salinity of the oil and gas charging point corresponding to the fracture solution is used as the formation water salinity of the fracture solution in the covered area; among them, the oil and gas charging point on the main fracture zone is identified by the blocky anomaly of the salinity value.

4. The method according to claim 1, characterized in that, In the evaluation step of fracture charging adjustment conditions, based on the construction threshold of formation water and oil / gas charging points, the oil / gas charging adjustment range is set to include the following levels: Level 1: No adjustment to 0m; Level 2: Adjustment range is close to 0-2000m; Level 3: Adjustment range is relatively close to 2000-4000; Level 4: Adjustment range is relatively far to 4000-8000; Level 5: Adjustment range is far greater than 8000.

5. The method according to claim 1, characterized in that, In the evaluation step of fracture conduction conditions The fracture level information of the fracture solution is determined based on the scale and intercutting relationship of the fault trajectory on the coherence map, as well as the relationship between different fracture levels and principal stress.

6. The method according to claim 1, characterized in that, In the fault conduction condition evaluation step, the incision horizon information is set according to the following logic: Based on the ability to communicate with oil sources through fractures, it is divided into three levels: Level 1 is cutting down to the T81 gypsum-salt layer, Level 2 is cutting down to the T80 layer, and Level 3 is cutting down to the T76 layer.

7. The method according to claim 1, characterized in that, In the reservoir condition evaluation step, reservoir area information is obtained by dividing the area of ​​reference fracture-cavity units on the plane and the area of ​​attribute reflection characteristics.

8. The method according to claim 1, characterized in that, In the reservoir condition evaluation step, the vertical seismic reflection characteristics are set according to the following logic: Based on the degree of development of dissolution cavities in the fractured body, the following levels are defined: Level 1: Strong beaded structure; Level 2: Weak beaded structure; Level 3: Disordered and strong; Level 4: Disordered and weak.

9. A storage medium, characterized in that, The storage medium stores program code that can implement the method as described in any one of claims 1 to 8.

10. A system for analyzing enrichment conditions in fractured-dissolve reservoirs based on charging and channeling evaluation, characterized in that, The system performs the method as described in any one of claims 1 to 8.

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