Method and system for identifying high permeability zones in gas reservoirs

Abstract

The present invention discloses a method and system for identifying high-permeability zones in gas reservoirs. The method comprises the following steps: obtaining a cumulative probability curve of permeability of gas reservoir wells and a statistical table of high-permeability zones in each layer of the gas field; calculating the ratio of the average permeability of the relative high-permeability zone to the average permeability of the reservoir based on the statistical table of high-permeability zones in each layer of the gas field; calculating the ratio of the average permeability of the relative high-permeability zone to the average permeability of the reservoir; zoning and segmenting the high-permeability zones; performing systematic analysis and demonstration based on geological zoning and stratification statistics, and combining dynamic monitoring data to establish a relative high-permeability zone classification standard based on the cumulative probability curve of permeability of gas reservoir wells, the ratio of the average permeability of the relative high-permeability zone to the average permeability of the reservoir, and the ratio of the average permeability of the relative high-permeability zone to the average permeability of the surrounding rock; and effectively identifying high-permeability zones in gas wells based on the relative high-permeability zone classification standard. The present invention can be applied to similar gas reservoirs, effectively implementing water-proofing and water-control measures for the gas reservoirs, and improving the gas reservoir recovery rate.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas extraction, and in particular to a method and system for identifying high-permeability zones in gas reservoirs. Background Art

[0002] A gas reservoir in the Tarim Basin is characterized by thick, abnormally high-pressure, water-bearing formations, measuring 300 to 400 meters thick. Its physical properties are primarily characterized by medium-porosity and medium-to-high permeability. High-permeability zones and fractures are well-developed within the reservoir, creating complex geological conditions and significant variability in water breakthrough characteristics among individual wells. Extensive production logging data from the gas field, combined with geological understanding, indicates that the high-permeability zones are responsible for widespread non-uniform waterlogging in the field, leading to poor reserve utilization in the low-permeability reservoirs and severely impacting reservoir development. This requires urgent adjustments. Research has revealed that while high-permeability zones in oil reservoirs have been extensively and systematically studied, there is currently no method for systematically evaluating and identifying these zones in gas reservoirs. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and system for identifying high-permeability bands in gas reservoirs. In view of the current lack of systematic identification of high-permeability bands in gas reservoirs, this system takes a gas reservoir as an example to identify high-permeability bands, and is consistent with the actual dynamic monitoring results. It can be applied to similar gas reservoirs, effectively implement waterproofing and water control measures for gas reservoirs, and improve the recovery rate of gas reservoirs.

[0004] To achieve the above objectives, the present invention provides the following technical solutions.

[0005] A method for identifying a high permeability zone in a gas reservoir comprises the following steps:

[0006] Obtain the cumulative probability curve of permeability of gas reservoir wells and the statistical table of high permeability zones in each layer of the gas field. Calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir based on the statistical table of high permeability zones in each layer of the gas field, and calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock.

[0007] The high permeability zones are divided and segmented. Through geological zoning and hierarchical statistics, combined with dynamic monitoring data, a systematic analysis and demonstration is conducted to establish a relatively high permeability zone division standard based on the cumulative probability curve of gas reservoir well permeability, the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir, and the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock.

[0008] The high permeability zones of gas wells can be effectively identified based on the relative high permeability zone division standard.

[0009] As a further improvement of the present invention, the relatively high permeability zone division criteria include:

[0010] 1) There is an inflection point value on the cumulative probability curve;

[0011] 2)K 相对高渗带 >a×KP50 ;

[0012] 3)K 相对高渗带 >a×K 围岩 ;

[0013] Where a is a constant, K P50 is the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir, K 围岩 To calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock.

[0014] As a further improvement of the present invention, a is 3.

[0015] As a further improvement of the present invention, the high permeability zone of the gas well is effectively identified based on the relatively high permeability zone division standard by judging whether the three conditions of the relatively high permeability zone division standard are met.

[0016] A system for identifying high-permeability zones in gas reservoirs comprises the following steps:

[0017] An acquisition calculation module is used to obtain the cumulative probability curve of permeability of gas reservoir wells and the statistical table of high permeability zones in each layer of the gas field, calculate the ratio of the average permeability of the relative high permeability zone to the average permeability of the reservoir based on the statistical table of high permeability zones in each layer of the gas field, and calculate the ratio of the average permeability of the relative high permeability zone to the average permeability of the surrounding rock;

[0018] The standard establishment module is used to zoning and segment high permeability zones. Through geological zoning and stratification statistics, combined with dynamic monitoring data, a systematic analysis and demonstration is conducted to establish the relative high permeability zone division standard based on the cumulative probability curve of gas reservoir well permeability, the ratio of the average permeability of the relative high permeability zone to the average permeability of the reservoir, and the ratio of the average permeability of the relative high permeability zone to the average permeability of the surrounding rock.

[0019] The identification module is used to effectively identify the high permeability zones of gas wells based on the relative high permeability zone division standard.

[0020] As a further improvement of the present invention, the relatively high permeability zone division criteria in the standard establishment module include:

[0021] 1) There is an inflection point value on the cumulative probability curve;

[0022] 2)K 相对高渗带 >a×K P50 ;

[0023] 3)K 相对高渗带 >a×K 围岩 ;

[0024] Where a is a constant, K P50 is the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir, K 围岩To calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock.

[0025] As a further improvement of the present invention, a is 3.

[0026] As a further improvement of the present invention, the identification module effectively identifies the high permeability zone of the gas well based on the relatively high permeability zone division standard by judging whether the three conditions of the relatively high permeability zone division standard are met.

[0027] An electronic device comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the method for identifying high-permeability zones in gas reservoirs are implemented.

[0028] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the method for identifying high-permeability zones in gas reservoirs.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention provides a method for identifying high-permeability zones in gas reservoirs. The method establishes a relative high-permeability zone demarcation standard based on the cumulative probability curve of gas reservoir well permeability, the ratio of the average permeability of the relative high-permeability zone to the average permeability of the reservoir, and the ratio of the average permeability of the relative high-permeability zone to the average permeability of the surrounding rock. Based on the relative high-permeability zone demarcation standard, the high-permeability zones in gas wells are effectively identified. By identifying high-permeability zones and aligning them with actual dynamic monitoring results, the method can be applied to similar gas reservoirs, effectively implementing water-proofing and flood control measures for the gas reservoirs, and improving the gas reservoir recovery rate. The method enables the identification of high-permeability zones in gas reservoirs, laying a solid foundation for later-stage adjustment and efficient development of such gas reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings:

[0032] Figure 1 is the cumulative probability curve of permeability of Well A2 in the preferred embodiment of the present invention;

[0033] Figure 2 This is a comprehensive analysis diagram of the gas production profile of Well A8 in Gas Field A, a preferred embodiment of the present invention;

[0034] Figure 3 This is a comprehensive analysis diagram of the gas production profile of Well A5 in Gas Field A, a preferred embodiment of the present invention;

[0035] Figure 4 This is a flow chart of a method for identifying high permeability zones in gas reservoirs according to the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of a system for identifying high-permeability zones in gas reservoirs according to a preferred embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the structure of an electronic device according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0039] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an element centered thereon. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an element centered thereon. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] like Figure 4 As shown, the present invention provides a systematic identification method for high permeability zones in gas reservoirs. The identification and characterization of high permeability zones has important guiding significance for water prevention and control in gas reservoirs. The method includes the following steps:

[0042] Obtain the cumulative probability curve of permeability of gas reservoir wells and the statistical table of high permeability zones in each layer of the gas field. Calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir based on the statistical table of high permeability zones in each layer of the gas field, and calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock.

[0043] The high permeability zones are divided and segmented. Through geological zoning and hierarchical statistics, combined with dynamic monitoring data, a systematic analysis and demonstration is conducted to establish a relatively high permeability zone division standard based on the cumulative probability curve of gas reservoir well permeability, the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir, and the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock.

[0044] The high permeability zones of gas wells can be effectively identified based on the relative high permeability zone division standard.

[0045] This study first summarizes the characteristics of water intrusion in gas reservoirs based on the ratio of high-permeability zones to the average reservoir permeability. Strong tongue water intrusion can occur when the permeability is three times greater than the average reservoir permeability. Analysis of the gas production profile of Gas Field A shows that the permeability of high-yield intervals is generally greater than three times the median of the cumulative probability of permeability, while the zero-yield intervals generally have permeabilities below the median (Table 1).

[0046] Table 1 Analysis of gas production and permeability of the A8 well production layer

[0047]

[0048] Geological research has shown that the overall reservoir properties of Gas Reservoir A are good. However, due to the strong heterogeneity of the reservoir properties, the physical property values ​​vary greatly between different well areas and different layers. Generally, the values ​​in the eastern part are higher than those in the western part. Therefore, the delineation of high permeability zones requires zoning and segmentation. Through statistical analysis of geological zoning and stratification, combined with systematic analysis and demonstration of dynamic monitoring data, we have established three criteria for the delineation of relatively high permeability zones:

[0049] ①Cumulative probability curve inflection point value ( Figure 1 );

[0050] ②K 相对高渗带 >3K P50 ;

[0051] ③K 相对高渗带 >3K 围岩 .

[0052] By meeting the above three conditions, the high permeability zones of gas wells can be effectively identified.

[0053] The specific contents of the present invention are described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Obviously, the method and research changes made by those skilled in the art based on the purpose of the present invention belong to the protection scope of the present invention.

[0055] Example:

[0056] The three conditions of the above invention standard were used to identify the high permeability zone of gas field A. Generally speaking, the value in the east is higher than that in the west. 1+2The value is higher than K1bs3 and K1b (Table 2). Analysis of effective reservoir permeability from 21 wells covering 4994 m of depth indicates a relative high permeability zone thickness of 671.7 m, accounting for approximately 13.5% of the effective sand body thickness. The relative high permeability zone permeability differential (average permeability of the relative high permeability zone / average permeability of the surrounding rock) generally ranges from 4.8 to 13.9. Vertically, the relative high permeability zone is primarily distributed in the central portion of the reservoir.

[0057] Table 2 Statistics of high permeability zones in each layer of gas field A

[0058]

[0059] An analysis of the high-permeability zone between the perforated section and the gas-water interface in 18 wells revealed that the thickness of the formation between the perforated section and the gas-water interface ranged from 59.5 to 228.63 meters, with an average thickness of 162.1 meters. The effective thickness of the sand body ranged from 49.5 to 151.1 meters, with an average thickness of 105.0 meters. The thickness of the relatively high-permeability zone ranged from 4.6 to 31.3 meters, with an average thickness of 14.9 meters. Ten of the wells penetrated the gas-water interface, while the remaining wells did not.

[0060] The analysis results of the thickness and density distribution of the relatively high permeability zone show that the density of the relatively high permeability zone in the east is slightly higher than that in the west.

[0061] The partitioning results are highly consistent with the production test results. Figure 2 、 Figure 3 As can be seen, all producing layers have high permeability zones, while sections without high permeability generally have zero production. This high permeability zone demarcation standard can be used to predict the primary producing layer in wells with no gas production profiles. Because the primary gas-producing layer also constitutes the primary channel for water intrusion, analyzing the high permeability zone provides guidance for water prevention and control.

[0062] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known structures and techniques are not shown in detail in order not to obscure the understanding of this description.

[0063] Similarly, it should be understood that in order to streamline the present disclosure and aid understanding of one or more of the various inventive aspects, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed apparatus should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Accordingly, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the invention.

[0064] It will be appreciated by those skilled in the art that the components of the apparatus in the embodiment may be adaptively changed and arranged in one or more apparatuses different from the embodiment. The components in the embodiment may be combined into one component, and furthermore they may be divided into a plurality of subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all components of any apparatus so disclosed may be combined in any combination, except that at least some of such features are mutually exclusive. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0065] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features that are included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and to form different embodiments. For example, in the claims below, any of the claimed embodiments may be used in any combination. The various component embodiments of the invention may be implemented in hardware, or in any combination thereof.

[0066] The above is only a preferred embodiment of the invention and does not constitute any form of limitation to the invention. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the invention still falls within the scope of the technical solution of the invention.

[0067] like Figure 5 As shown, another object of the present invention is to provide a system for identifying high permeability zones in gas reservoirs, comprising the following steps:

[0068] An acquisition calculation module is used to obtain the cumulative probability curve of permeability of gas reservoir wells and the statistical table of high permeability zones in each layer of the gas field, calculate the ratio of the average permeability of the relative high permeability zone to the average permeability of the reservoir based on the statistical table of high permeability zones in each layer of the gas field, and calculate the ratio of the average permeability of the relative high permeability zone to the average permeability of the surrounding rock;

[0069] The standard establishment module is used to zoning and segment high permeability zones. Through geological zoning and stratification statistics, combined with dynamic monitoring data, a systematic analysis and demonstration is conducted to establish the relative high permeability zone division standard based on the cumulative probability curve of gas reservoir well permeability, the ratio of the average permeability of the relative high permeability zone to the average permeability of the reservoir, and the ratio of the average permeability of the relative high permeability zone to the average permeability of the surrounding rock.

[0070] The identification module is used to effectively identify the high permeability zones of gas wells based on the relative high permeability zone division standard.

[0071] like Figure 6As shown, the third object of the present invention is to provide an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for identifying high permeability zones in gas reservoirs when executing the computer program.

[0072] A fourth object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method for identifying high-permeability zones in gas reservoirs.

[0073] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0074] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0075] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0076] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1A step that specifies a function in one or more boxes.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for identifying high permeability zones in gas reservoirs, characterized in that: The following steps are involved: Obtain the cumulative probability curve of permeability of gas reservoir wells and the statistical table of high permeability zones in each layer of the gas field. Calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir based on the statistical table of high permeability zones in each layer of the gas field, and calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock. The high permeability zones are divided and segmented. Through geological zoning and hierarchical statistics, combined with dynamic monitoring data, a systematic analysis and demonstration is conducted to establish a relatively high permeability zone division standard based on the cumulative probability curve of gas reservoir well permeability, the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir, and the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock. Effectively identify high permeability zones in gas wells based on the relative high permeability zone division standard; The criteria for dividing the relatively high permeability zone include: 1) There is an inflection point value on the cumulative probability curve; 2)K 相对高渗带 >a×K P50 ; 3)K 相对高渗带 >a×K 围岩 ; Where a is a constant, K P50 is the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir, K 围岩 To calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock; The a is 3.

2. The method for identifying high permeability zones in gas reservoirs according to claim 1, characterized in that: The effective identification of gas well high permeability zones based on the relative high permeability zone division standard is determined by satisfying the three conditions of the relative high permeability zone division standard.

3. A system for identifying high permeability zones in gas reservoirs, characterized in that: The following steps are involved: An acquisition calculation module is used to obtain the cumulative probability curve of permeability of gas reservoir wells and the statistical table of high permeability zones in each layer of the gas field, calculate the ratio of the average permeability of the relative high permeability zone to the average permeability of the reservoir based on the statistical table of high permeability zones in each layer of the gas field, and calculate the ratio of the average permeability of the relative high permeability zone to the average permeability of the surrounding rock; The standard establishment module is used to zoning and segment high permeability zones. Through geological zoning and stratification statistics, combined with dynamic monitoring data, a systematic analysis and demonstration is conducted to establish the relative high permeability zone division standard based on the cumulative probability curve of gas reservoir well permeability, the ratio of the average permeability of the relative high permeability zone to the average permeability of the reservoir, and the ratio of the average permeability of the relative high permeability zone to the average permeability of the surrounding rock. Identification module, used to effectively identify high permeability zones in gas wells based on the relative high permeability zone classification standard; The relative high permeability zone division standards in the standard establishment module include: 1) There is an inflection point value on the cumulative probability curve; 2)K 相对高渗带 >a×K P50 ; 3)K 相对高渗带 >a×K 围岩 ; Where a is a constant, K P50 is the ratio of the average permeability of the relatively high permeability zone to the average permeability of the reservoir, K 围岩 To calculate the ratio of the average permeability of the relatively high permeability zone to the average permeability of the surrounding rock; The a is 3.

4. A gas reservoir high permeability zone identification system according to claim 3, characterized in that: In the identification module, the high permeability zone of the gas well is effectively identified based on the relatively high permeability zone division standard by judging whether the three conditions of the relatively high permeability zone division standard are met.

5. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method for identifying a high-permeability zone in a gas reservoir according to any one of claims 1 to 2 when executing the computer program.

6. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the method for identifying a high-permeability zone in a gas reservoir according to any one of claims 1 to 2.

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