A method and apparatus for identifying gas and water in a compact water-bearing gas reservoir

Abstract

The application provides a method and device for identifying gas and water in a compact water-bearing gas reservoir, and the method comprises the following steps: acquiring well logging curves and reservoir interpretation parameters of a target reservoir gas reservoir, wherein the reservoir interpretation parameters comprise lithological parameters, electrical parameters, physical parameters and gas-bearing parameters; dividing the target reservoir gas reservoir into at least one gas group according to the sedimentary environment, diagenetic conditions, lithological parameters and physical parameters of the target reservoir gas reservoir; performing primary division on each gas group according to the electrical parameters, physical parameters and gas-bearing parameters to obtain a pure gas layer area, a gas layer and a gas-water layer mixed area, a pure gas-water layer area and boundaries of each area; and performing secondary division on the gas layer and the gas-water layer mixed area according to the well logging curves to obtain a gas layer area and a gas-water layer area and boundaries. The method provided by the application can obtain accurate boundaries of different fluid property areas of a reservoir gas reservoir, and is beneficial to improving the reliability of natural gas reserve calculation, reasonably deploying exploration and development, reducing gas testing cost and improving development economy.

Description

Technical Field

[0001] This article relates to the field of oil and gas exploration and development technology, and in particular to a method and device for identifying gas and water in tight water-bearing gas reservoirs. Background Technology

[0002] The exploration and development of tight water-bearing gas reservoirs is characterized by poor reservoir properties, strong intra- and inter-layer heterogeneity, underdeveloped source rocks, and limited resources. This results in some gas reservoirs being unsaturated during natural gas charging and lacking a unified gas-water interface. Consequently, in most reservoirs, the influence of the rock skeleton on resistivity is far greater than that of the fluid. The response characteristics of acoustic transit time, density, and compensated neutron curves are mostly skeletal information and not very sensitive to fluids. Therefore, it is common to see high-resistivity gas and water co-emerging and low-resistivity producing pure gas, making gas-water identification difficult.

[0003] In recent years, with the deepening of research on reservoir fluid identification, experimental methods and techniques have been continuously enriched and improved, resulting in many research achievements. However, judging from the current research status at home and abroad, there is still a lack of a systematic and comprehensive methodology to solve the problem of gas and water identification in water-bearing gas reservoirs with complex gas-water relationships. In tight water-bearing gas reservoirs, research on gas-water identification and evaluation technologies is still in the exploratory stage.

[0004] In view of this, this paper aims to provide a method and apparatus for identifying gas and water in tight water-bearing gas reservoirs. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this paper aims to provide a method and apparatus for identifying gas and water in tight water-bearing gas reservoirs, thereby improving the accuracy of gas and water identification in existing technologies and providing reliable support for gas field exploration and development.

[0006] To solve the above-mentioned technical problems, the specific technical solution presented in this paper is as follows:

[0007] Firstly, this paper provides a method for identifying gas and water in tight water-bearing gas reservoirs, including:

[0008] Obtain well logging curves and reservoir interpretation parameters of the target gas reservoir, including lithological parameters, electrical parameters, physical properties and gas-bearing parameters;

[0009] Based on the sedimentary environment, diagenetic conditions, lithological parameters, and physical properties of the target gas reservoir, the target gas reservoir is divided into at least one gas group.

[0010] Based on the electrical parameters, physical parameters, and gas-containing parameters, each gas group is divided into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region.

[0011] Based on the well logging curves, the gas layer and the gas-water co-layer mixing zone are divided into two sub-zones to obtain the gas layer zone, the gas-water co-layer zone, and their boundaries.

[0012] Preferably, the lithological parameters include at least clay content, the electrical parameters include at least resistivity, the physical parameters include at least porosity, and the gas-bearing parameters include at least water saturation.

[0013] Furthermore, based on the electrical parameters, physical properties, and gas content parameters, each gas group is divided into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region, including:

[0014] Based on the resistivity, porosity, and water saturation of the gas sampling points of each gas group, the first cross plot was drawn.

[0015] Based on the first intersection diagram, the pure gas layer region, the gas layer and gas-water co-layer mixed region, the pure gas-water co-layer region, and the boundaries of each region are obtained.

[0016] Preferably, before dividing each gas group into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region based on the electrical parameters, the physical properties, and the gas content parameters, the method further includes:

[0017] Based on the resistivity and mud content of the gas sampling points of each gas group, a second cross plot was drawn.

[0018] Based on the second cross plot, the lithological boundaries of each gas group were determined;

[0019] When the lithological limit is less than or equal to a preset value, the gas group is determined to have development value and a first division step of the gas group is performed.

[0020] Specifically, the logging curves of the target gas reservoir include deep lateral resistivity curves and shallow lateral resistivity curves.

[0021] Furthermore, based on the well logging curves, the gas layer and the gas-water co-layer mixing zone are further divided to obtain the gas layer zone and the gas-water co-layer zone and their boundaries, including:

[0022] Calculate the difference between the deep lateral resistivity and the shallow lateral resistivity at each gas sampling point in the gas layer and the gas-water co-layer mixing zone;

[0023] Draw a third cross plot of the difference versus resistivity;

[0024] Based on the third intersection diagram, the gas layer and the gas-water co-layer mixing zone are divided a second time.

[0025] Furthermore, based on the third cross-plot, the gas layer and the gas-water co-layer mixing zone are further subdivided, including:

[0026] Based on the third intersection diagram, determine the threshold value for dividing the gas layer region and the gas-water co-layer region;

[0027] When the difference between the gas sampling points is less than the difference threshold, the gas sampling point is determined to correspond to the gas-water co-layer zone.

[0028] When the difference between the gas sampling points is greater than or equal to the difference threshold, the gas sampling point is determined to correspond to a gas layer region.

[0029] Secondly, this paper also provides a gas-water identification device for tight water-bearing gas reservoirs, comprising:

[0030] The acquisition module is used to acquire the logging curves and reservoir interpretation parameters of the target gas reservoir, including lithological parameters, electrical parameters, physical property parameters and gas-bearing parameters;

[0031] The gas group division module is used to divide the target gas reservoir into at least one gas group based on the sedimentary environment, diagenetic conditions, lithological parameters, and physical property parameters of the target gas reservoir.

[0032] The primary division module is used to divide each gas group into a pure gas layer region, a gas layer and gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region based on the electrical parameters, the physical parameters, and the gas content parameters.

[0033] The secondary division module divides the gas layer and the gas-water co-layer mixing zone into two layers based on the well logging curve, thereby obtaining the gas layer zone, the gas-water co-layer zone, and their boundaries.

[0034] Thirdly, this document also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method provided by the above-described technical solution.

[0035] Fourthly, this document also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method provided by the above-described technical solution.

[0036] Using the above technical solution, this paper provides a method and device for identifying gas and water in tight water-bearing gas reservoirs. It divides gas groups into different zones based on factors influencing gas formation, such as reservoir sedimentary environment and diagenetic conditions. Then, using the four properties of the reservoir, it divides the reservoir into pure gas zones, gas-water mixed zones, and pure gas-water co-layer zones. Finally, based on well logging curves, it further divides the gas zones and gas-water co-layer zones within the gas-water mixed zones, ultimately obtaining accurate boundaries between different fluid property ranges in the reservoir. This method is beneficial for improving the reliability of natural gas reserve calculations, rationally deploying exploration and development, reducing testing costs, and improving development economics. Furthermore, the method is simple, inexpensive, and can be used for the division of gas and water layers in any water-bearing gas reservoir.

[0037] To make the above and other objects, features and advantages of this document more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments or prior art described herein, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this article. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This document illustrates a step-by-step diagram of a method for identifying gas and water in a tight water-bearing gas reservoir, as provided in an embodiment of this paper.

[0040] Figure 2 This document illustrates a schematic diagram of the steps involved in dividing each gas group in an embodiment of the invention.

[0041] Figure 3 The first cross plot of gas group A is shown;

[0042] Figure 4 The first cross plot of gas group B is shown;

[0043] Figure 5 This document illustrates the steps involved in determining whether a gas assembly has development value in an embodiment of the invention.

[0044] Figure 6 The second cross plot of gas group A is shown;

[0045] Figure 7 The second cross plot of gas group B is shown;

[0046] Figure 8 This diagram illustrates the steps involved in the secondary division of the gas layer and the gas-water co-layer mixing zone in this embodiment.

[0047] Figure 9This diagram shows a logging profile of a tight reservoir in a well section where the fluid properties are gas-bearing.

[0048] Figure 10 This diagram shows a logging profile of a tight reservoir in a well section where the fluid properties are gas and water co-layered.

[0049] Figure 11 This shows the third cross-sectional diagram of the gas layer and the gas-water co-mixing zone in gas group A;

[0050] Figure 12 This shows the third cross-sectional diagram of the gas layer and the gas-water co-mixing zone in Group B;

[0051] Figure 13 This document shows a schematic diagram of the structure of a gas-water identification device for a tight water-bearing gas reservoir provided in an embodiment of the present invention;

[0052] Figure 14 A schematic diagram of the structure of a computer device provided in an embodiment of this article is shown.

[0053] Explanation of symbols in the attached drawings:

[0054] 1310. Acquisition Module;

[0055] 1320. Gas group division module;

[0056] 1330. First-time module division;

[0057] 1340. Secondary partitioning module;

[0058] 1402. Computer equipment;

[0059] 1404, Processor;

[0060] 1406. Memory;

[0061] 1408. Drive mechanism;

[0062] 1410. Input / Output Module;

[0063] 1412. Input devices;

[0064] 1414. Output devices;

[0065] 1416. Presentation equipment;

[0066] 1418. Graphical User Interface;

[0067] 1420. Network interface;

[0068] 1422. Communication link;

[0069] 1424. Communication bus. Detailed Implementation

[0070] The technical solutions in the embodiments described below will be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments described herein, and not all of the embodiments. Based on the embodiments described herein, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this document.

[0071] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings herein are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0072] Current technologies still lack a systematic and comprehensive method to solve the problem of gas and water identification in water-bearing gas reservoirs with complex gas-water relationships. As a result, research on gas and water identification and evaluation technologies in tight water-bearing gas reservoirs is still in the exploratory stage. To address the above issues, this paper provides a method and apparatus for gas and water identification in tight water-bearing gas reservoirs. Figure 1 This is a schematic diagram illustrating the steps of a method for identifying gas and water in a tight water-bearing gas reservoir provided in this embodiment. This specification provides the operational steps of the method described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual system or device products, the methods shown in the embodiments or accompanying drawings can be executed sequentially or in parallel. Specifically, as shown in the embodiments or accompanying drawings... Figure 1 As shown, the method may include:

[0073] S110: Obtain the logging curves and reservoir interpretation parameters of the target gas reservoir, including lithological parameters, electrical parameters, physical parameters and gas-bearing parameters.

[0074] In the embodiments of this specification, the lithological parameters include at least clay content (Vsh); the electrical parameters include at least resistivity, specifically deep lateral resistivity (Rt); the physical properties include at least porosity (POR); and the gas-bearing parameters include at least water saturation (Sw), the range of which reflects the gas-bearing capacity of the reservoir. By obtaining the lithological, electrical, physical, and gas-bearing parameters of the target gas reservoir, the embodiments of this specification can be used to identify gas layers with industrial exploitation value, meeting industry standard requirements; and are easy to implement in production, with strong operability.

[0075] S120: Based on the sedimentary environment, diagenetic conditions, lithological parameters, and physical property parameters of the target gas reservoir, the target gas reservoir is divided into at least one gas group.

[0076] Due to factors such as sedimentary environment, diagenetic conditions, lithological parameters, physical properties, and natural gas migration distance, the boundaries of gas layers in different formations are different. If gas layers with different boundaries are uniformly divided into pure gas layer areas, gas-water co-layer areas, etc., it will lead to inaccurate gas layer division and reduce the economic efficiency of gas layer extraction.

[0077] For example, in the embodiments of this specification, a target gas reservoir is divided into gas group A and gas group B. It should be noted that the number of gas groups is related to the actual situation of the target gas reservoir.

[0078] S130: Based on the electrical parameters, physical parameters, and gas-containing parameters, each gas group is divided into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region.

[0079] In the embodiments of this specification, a pure gas layer zone means that the area contains only industrial gas layers; a pure gas-water co-layer zone means that the area contains only industrial gas and water co-layers; and a mixed gas layer and gas-water co-layer zone means that the industrial gas layer and industrial gas-water co-layers are mixed together in the area. A pure gas layer zone is the optimal industrial producing layer, meaning it has the highest extraction value; the extraction value of a gas-water co-layer is lower than that of a pure gas layer zone. In addition, the reservoir environment may also include poor gas layers and water layers. Poor gas layers refer to layers where gas production does not reach industrial extraction value, while water layers indicate that the area is a water environment. The gas-water identification method for tight water-bearing gas reservoirs provided in the embodiments of this specification aims to clearly distinguish between pure gas layer zones, pure gas-water co-layer zones, and poor gas layer zones.

[0080] S140: Based on the well logging curve, the gas layer and the gas-water co-layer mixing zone are divided into two sub-zones to obtain the gas layer zone and the gas-water co-layer zone and their boundaries.

[0081] Step S140 involves further separating the mixed gas layer and gas-water co-layer regions obtained in step S130. Ultimately, this ensures that the gas layers and gas-water co-layers of each gas group are identified, facilitating natural gas reserve calculations, exploration and development deployment planning, reducing testing costs, and improving the economic efficiency of extraction.

[0082] This specification provides a gas-water identification method for tight water-bearing gas reservoirs. It divides gas groups based on factors influencing reservoir sedimentary environment and diagenetic conditions. Then, it performs a primary division of gas groups using reservoir properties (lithology, electrical properties, physical properties, and gas-bearing properties) and logging curves, followed by a secondary division of the gas layers and gas-water mixed zones obtained from the primary division. This method not only distinguishes between low-resistivity gas layers and high-resistivity water layers but also separates the gas and water layers within the mixed zones, significantly improving the logging interpretation accuracy. It has shown good application results in logging for gas reservoirs with complex gas-water relationships, providing strong support for the efficient development of tight gas reservoirs and offering important theoretical basis for the comprehensive adjustment and development planning of gas fields.

[0083] Specifically, such as Figure 2 As shown, step S130: Based on the electrical parameters, physical properties, and gas content parameters, each gas group is divided into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region. This may further include:

[0084] S210: Draw the first cross plot based on the resistivity, porosity and water saturation of the gas sampling points of each gas group.

[0085] In the embodiments of this specification, by analyzing each gas sampling point, it can be determined whether the reservoir fluid corresponding to the gas sampling point is a gas layer, a gas-water co-layer, a gas-water differential layer, or a water layer. Subsequently, the four properties parameters of these gas sampling points with known reservoir fluid properties are used to provide a basis for the first classification.

[0086] S220: Based on the first intersection diagram, the pure gas layer region, the gas layer and gas-water co-layer mixed region, the pure gas-water co-layer region, and the boundaries of each region are obtained.

[0087] like Figure 3 and Figure 4 The figures shown are the first cross-plots of gas group A and gas group B, respectively. It can be seen that the parameters at the sampling points differ significantly between the different gas groups. In the figures, the horizontal axis represents porosity; the vertical axis represents deep lateral resistivity; and the diagonal line passing through the origin represents water saturation, with the slope of the line representing different levels of water saturation. From... Figure 3 and Figure 4As can be seen, some gas sampling points with reservoir fluid properties of gas layers agglomerate, which corresponds to pure gas layer areas; some gas sampling points with reservoir fluid properties of gas and water co-layers agglomerate, which corresponds to pure gas and water co-layer areas; and some gas sampling points with reservoir fluid properties of gas layers are mixed with some gas sampling points with reservoir fluid properties of gas and water co-layers, which corresponds to mixed gas layer and gas and water co-layer areas.

[0088] Therefore, based on the first cross-plot, the following can be determined: In Gas Group A, the boundary of the pure gas layer region is: POR ≥ 7%, Rt > 50 Ω·m and Sw ≤ 50%; the boundary of the pure gas-water co-layer region is: POR ≥ 7%, Rt ≥ 11 Ω·m, 60% ≥ Sw > 55%, or POR > 14%, 9 Ω·m ≤ Rt < 11 Ω·m, Sw ≤ 60%; and the boundary of the gas layer and the gas-water co-layer mixed region is: POR ≥ 7%, 11 Ω·m ≤ Rt ≤ 50 Ω·m, Sw ≤ 55%.

[0089] In Group B, the boundaries of the pure gas layer region are: POR ≥ 6%, Rt > 60 Ω·m, Sw ≤ 50%; the boundaries of the pure gas-water co-layer region are: POR ≥ 6%, Rt ≥ 16 Ω·m, 60% ≥ Sw > 55%; and the boundaries of the gas layer and the gas-water co-layer mixed region are: POR ≥ 6%, 16 Ω·m ≤ Rt ≤ 60 Ω·m, Sw ≤ 55%.

[0090] If we consider the gas sampling points in the pure gas layer zone and the pure gas-water co-layer zone as completely separated sampling points, and consider the mixed zone of pure gas layer and pure gas-water co-layer as only half-matched, then the logging interpretation consistency rate for gas group A is 40%, and the logging interpretation consistency rate for gas group B is only 35%. This logging interpretation consistency rate is insufficient to meet development needs. By dividing the gas groups, it can be seen that regardless of whether it is gas group A or gas group B, due to the existence of gas layers and mixed zones of gas and water, a considerable portion of the gas layers and gas-water co-layers cannot be separated, resulting in a low logging interpretation consistency rate (i.e., the degree of separation between the gas layers and gas-water co-layers, and between both and other layers).

[0091] like Figure 5 As shown, preferably, before step S130: dividing each gas group into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region based on the electrical parameters, the physical properties, and the gas content parameters, the method further includes:

[0092] S510: Draw the second cross plot based on the resistivity and mud content of the gas sampling points of each gas group.

[0093] like Figure 6 and Figure 7The figures shown are the second cross plots of gas group A and gas group B, respectively. The horizontal axis represents resistivity, and the vertical axis represents clay content.

[0094] S520: Determine the lithological boundaries of each gas group based on the second cross plot.

[0095] like Figure 6 As shown, in Gas Group A, the maximum clay content at each gas sampling point in the gas layer and at each gas sampling point in the gas-water co-layer is 16%, meaning the lithological boundary of Gas Group A is Vsh≤16%. Similarly, in Gas Group B, the maximum clay content at each gas sampling point in the gas layer and at each gas sampling point in the gas-water co-layer is 14%, meaning the lithological boundary of Gas Group B is Vsh≤14%.

[0096] S530: When the lithological limit is less than or equal to a preset value, the gas group is determined to have development value and a first division step of the gas group is performed.

[0097] That is, if the lithological boundary of a gas group is greater than a preset value, the gas group is determined to have no development value, and there is no need to perform subsequent primary or secondary division of the gas group. It should be noted that the preset values ​​of the lithological boundary are not the same for different gas groups. In the embodiments of this specification, the lithological boundary Vsh≤16% for gas group A and Vsh≤14% for gas group B are exemplary.

[0098] Water avoidance is a crucial aspect of natural gas development. If gas-bearing and gas-water co-development occurs, recovery rates and economic benefits will be significantly reduced. Therefore, in the embodiments of this specification, the logging curves of the target gas reservoir include deep lateral resistivity curves (RLLD) and shallow lateral resistivity curves (RLLS), and as... Figure 8 As shown, based on the well logging curves, the gas layer and the gas-water co-layer mixing zone are divided into two sub-zones to obtain the gas layer zone and the gas-water co-layer zone and their boundaries. This can include the following steps:

[0099] S810: Calculate the difference between the deep lateral resistivity and the shallow lateral resistivity at each gas sampling point in the gas layer and the gas-water co-mixing zone.

[0100] This specification's embodiments, through observations of gas layers and gas-water co-layers, as well as gas layers and gas-water co-layers in the gas-water co-layer region, creatively reveal that: under a low natural gamma GR background, the main differences between gas layers and gas-water co-layers include: the resistivity of the gas layer at varying depths generally exhibits a decreasing resistance intrusion, i.e., RLLD > RLLS. Figure 9 As shown in the sixth section; the resistivity of the gas and water layers at different depths generally shows an increasing resistance intrusion, i.e., RLLD < RLLS, as... Figure 10 The sixth path in the text is shown.

[0101] Therefore, in the embodiments of this specification, the subtle differences in resistivity invasion characteristics at different depths during well logging interpretation are quantitatively expressed as ΔRt, where ΔRt = RLLD - RLLS. ΔRt is used as the basis for secondary division of the gas layer and the gas-water co-mixing zone.

[0102] S820: Draw a third cross plot of the difference versus resistivity.

[0103] like Figure 11 and Figure 12 The figures shown are the third cross-sectional diagrams of the gas layer and the gas-water co-mixing zone in gas group A and gas group B, respectively. Figure 11 and Figure 12 In the figure, the horizontal axis is ΔRt, and the vertical axis is Rt (deep lateral resistivity).

[0104] S830: Based on the third intersection diagram, the gas layer and the gas-water co-layer mixing zone are divided a second time.

[0105] The gas-water identification method for tight water-bearing gas reservoirs provided in this specification analyzes well logging curves, summarizes the characteristics that can characterize the differences in reservoir fluid properties between gas layers and gas-water co-layers, and transforms them into a quantitative characterization method. This allows for secondary separation of gas layers and gas-water co-layers in the gas layer and gas-water co-layer mixing zone, which can greatly improve the accuracy of well logging interpretation and provide a more accurate reference for reservoir development.

[0106] Further, S830: Based on the third cross-plot, the gas layer and the gas-water co-layer mixing zone are further divided, which may specifically include the following steps:

[0107] Based on the third intersection diagram, the difference threshold for dividing the gas layer region and the gas-water co-layer region is determined.

[0108] like Figure 11 As shown, in gas group A, the minimum difference between the deep lateral resistivity curve and the shallow lateral resistivity at each gas sampling point in the gas layer region is -0.3 Ω·m. Therefore, in gas group A, the boundary between the gas layer region and the gas-water co-layer region is ΔRt=-0.3Ω·m; similarly, as... Figure 12 As shown, in gas group B, the minimum difference between the gas sampling points in the gas layer region is -0.5Ω·m. Therefore, the boundary between the gas layer region and the gas-water co-layer region in gas group B is ΔRt=-0.5Ω·m.

[0109] It should be noted that, since gas layers are the best industrial production layers with the highest exploitation value, in the embodiments of this specification, it is preferred that the difference threshold be set to the difference in lateral resistivity between shallow and deep layers that can include all gas sampling points in all gas layer areas.

[0110] When the difference between the gas sampling points is less than the difference threshold, the gas sampling point is determined to correspond to the gas-water co-layer zone; and when the difference between the gas sampling points is greater than or equal to the difference threshold, the gas sampling point is determined to correspond to the gas layer zone.

[0111] In Group A, the boundary of the gas layer is ΔRt ≥ -0.3 Ω·m, and the boundary of the gas-water co-layer is ΔRt < -0.3 Ω·m; in Group B, the boundary of the gas layer is ΔRt ≥ -0.5 Ω·m, and the boundary of the gas-water co-layer is ΔRt < -0.5 Ω·m.

[0112] After secondary identification of the gas layer and the gas-water co-layer mixing zone, the logging interpretation accuracy of gas group A reached 93%, and that of gas group B reached 92%. Compared with the interpretation accuracy obtained without secondary classification, the logging interpretation accuracy of gas group A and gas group B increased by 53% and 57%, respectively.

[0113] Finally, the boundaries of the different fluid properties of the target reservoir gas layer are shown in Table 1.

[0114] Table 1

[0115]

[0116] In summary, the gas-water identification method for tight water-bearing gas reservoirs provided in this specification first divides the gas groups by factors influencing gas groups, such as reservoir sedimentary environment and diagenetic conditions. Then, using the four properties of the reservoir, it divides the pure gas layer zone, the gas layer and gas-water co-layer mixed zone, the pure gas-water co-layer zone, and the boundaries of each zone. Finally, based on the subtle differences in the intrusion characteristics of the lateral resistivity at varying depths, it further divides the gas layer zone and the gas-water co-layer zone within the gas layer and gas-water co-layer mixed zone, ultimately obtaining accurate boundaries of different fluid properties in the reservoir. This method is beneficial for improving the reliability of natural gas reserve calculations, rationally deploying exploration and development, reducing testing costs, and improving development economics. Furthermore, the method is simple, inexpensive, and can be used for the division of gas and water layers in any water-bearing gas reservoir.

[0117] like Figure 13 As shown in the figure, this specification also provides a schematic diagram of the structure of a gas-water identification device for tight water-bearing gas reservoirs, the device comprising:

[0118] The acquisition module 1310 is used to acquire the logging curves and reservoir interpretation parameters of the target gas reservoir, wherein the reservoir interpretation parameters include lithological parameters, electrical parameters, physical property parameters and gas-bearing parameters;

[0119] The gas group division module 1320 is used to divide the target gas reservoir into at least one gas group based on the sedimentary environment, diagenetic conditions, lithological parameters and physical property parameters of the target gas reservoir.

[0120] The primary division module 1330 is used to divide each gas group into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region based on the electrical parameters, the physical parameters, and the gas content parameters.

[0121] The secondary division module 1340 performs secondary division of the gas layer and the gas-water co-layer mixing zone based on the well logging curve, thereby obtaining the gas layer zone and the gas-water co-layer zone and their boundaries.

[0122] The beneficial effects obtained by the apparatus provided in the embodiments of this specification are consistent with the beneficial effects obtained by the methods described above, and will not be repeated here.

[0123] like Figure 14 As shown, a computer device is provided in the embodiments of this document. The tight water-bearing gas reservoir gas-water identification device provided in the embodiments of this specification can be the computer device to execute the methods provided in the embodiments of this document. The computer device 1402 may include one or more processors 1404, such as one or more central processing units (CPUs), each processing unit can implement one or more hardware threads. The computer device 1402 may also include any memory 1406 for storing information of any kind, such as code, settings, data, etc. Non-limitingly, for example, the memory 1406 may include any one or more combinations of the following: any type of RAM, any type of ROM, flash memory device, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Further, any memory can provide volatile or non-volatile retention of information. Further, any memory can represent a fixed or removable component of the computer device 1402. In one case, when the processor 1404 executes associated instructions stored in any memory or combination of memories, the computer device 1402 can perform any operation of the associated instructions. The computer device 1402 also includes one or more drive mechanisms 1408 for interacting with any memory, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0124] Computer device 1402 may also include an input / output module 1410 (I / O) for receiving various inputs (via input device 1412) and providing various outputs (via output device 1414). A specific output mechanism may include a presentation device 1416 and an associated graphical user interface (GUI) 1418. In other embodiments, the input / output module 1410 (I / O), input device 1412, and output device 1414 may be omitted, and the device may function solely as a computer device within a network. Computer device 1402 may also include one or more network interfaces 1420 for exchanging data with other devices via one or more communication links 1422. One or more communication buses 1424 couple the components described above together.

[0125] Communication link 1422 can be implemented in any way, such as via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication link 1422 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0126] Corresponding to Figures 1 to 2 , Figure 5 and Figure 8 In addition to the method shown in the embodiments herein, this embodiment also provides a computer-readable storage medium on which a computer program is stored, which, when executed by a processor, performs the steps of the above-described method.

[0127] This embodiment also provides a computer-readable instruction, wherein when a processor executes the instruction, the program therein causes the processor to perform the following: Figures 1 to 2 , Figure 5 and Figure 8 The method shown.

[0128] This embodiment also provides a computer program product, including at least one instruction or at least one program segment, wherein the at least one instruction or the at least one program segment is loaded and executed by a processor to implement [the program]. Figures 1 to 2 , Figure 5 and Figure 8 The method shown.

[0129] It should be understood that in the various embodiments of this document, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this document.

[0130] It should also be understood that, in the embodiments herein, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following associated objects have an "or" relationship.

[0131] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this document.

[0132] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0133] In the embodiments provided herein, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0134] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described herein, depending on actual needs.

[0135] Furthermore, the functional units in the various embodiments of this document can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0136] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this paper, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this paper. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0137] This document uses specific embodiments to illustrate the principles and implementation methods of this document. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this document. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this document. Therefore, the content of this specification should not be construed as a limitation of this document.

Claims

1. A method for identifying gas and water in tight water-bearing gas reservoirs, characterized in that, include: Obtain well logging curves and reservoir interpretation parameters of the target gas reservoir, including lithological parameters, electrical parameters, physical properties and gas-bearing parameters; Based on the sedimentary environment, diagenetic conditions, lithological parameters, and physical properties of the target gas reservoir, the target gas reservoir is divided into at least one gas group. Based on the electrical parameters, physical parameters, and gas-containing parameters, each gas group is divided into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region. Based on the well logging curves, the gas layer and the gas-water co-layer mixed zone are divided into two sub-zones to obtain the gas layer zone, the gas-water co-layer zone, and their boundaries. The logging curves of the target reservoir gas reservoir include deep lateral resistivity curves and shallow lateral resistivity curves; Based on the well logging curves, the gas layer and the gas-water co-layer mixing zone are further divided into gas layer zones and gas-water co-layer zones, and their boundaries are obtained, including: Calculate the difference between the deep lateral resistivity and the shallow lateral resistivity at each gas sampling point in the gas layer and the gas-water co-layer mixing zone; Draw a third cross plot of the difference versus resistivity; Based on the third intersection diagram, the gas layer and the gas-water co-layer mixing zone are divided into two subdivisions. Based on the third cross-plot, the gas layer and the gas-water co-mixing zone are further subdivided, including: Based on the third intersection diagram, determine the threshold value for dividing the gas layer region and the gas-water co-layer region; When the difference between the gas sampling points is less than the difference threshold, the gas sampling point is determined to correspond to the gas-water co-layer zone. When the difference between the gas sampling points is greater than or equal to the difference threshold, the gas sampling point is determined to correspond to a gas layer region.

2. The method according to claim 1, characterized in that, The lithological parameters include at least clay content, the electrical parameters include at least resistivity, the physical parameters include at least porosity, and the gas-bearing parameters include at least water saturation.

3. The method according to claim 2, characterized in that, Based on the electrical parameters, physical properties, and gas-containing parameters, each gas group is divided into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region, further including: Based on the resistivity, porosity, and water saturation of the gas sampling points of each gas group, the first cross plot was drawn. Based on the first intersection diagram, the pure gas layer region, the gas layer and gas-water co-layer mixed region, the pure gas-water co-layer region, and the boundaries of each region are obtained.

4. The method according to claim 1, characterized in that, Before dividing each gas group into a pure gas layer region, a gas layer and a gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region based on the electrical parameters, physical properties, and gas content parameters, the method further includes: Based on the resistivity and mud content of the gas sampling points of each gas group, a second cross plot was drawn. Based on the second cross plot, the lithological boundaries of each gas group were determined; When the lithological limit is less than or equal to a preset value, the gas group is determined to have development value and a first division step of the gas group is performed.

5. A gas-water identification device for tight water-bearing gas reservoirs, characterized in that, include: The acquisition module is used to acquire the logging curves and reservoir interpretation parameters of the target gas reservoir, including lithological parameters, electrical parameters, physical property parameters and gas-bearing parameters; The gas group division module is used to divide the target gas reservoir into at least one gas group based on the sedimentary environment, diagenetic conditions, lithological parameters, and physical property parameters of the target gas reservoir. The primary division module is used to divide each gas group into a pure gas layer region, a gas layer and gas-water co-layer mixed region, a pure gas-water co-layer region, and the boundaries of each region based on the electrical parameters, the physical parameters, and the gas content parameters. The secondary division module divides the gas layer and the gas-water co-layer mixing zone into two layers based on the well logging curves, thereby obtaining the gas layer zone, the gas-water co-layer zone, and their boundaries. The secondary segmentation module is further used to ensure that the logging curves of the target reservoir gas reservoir include deep lateral resistivity curves and shallow lateral resistivity curves. Based on the well logging curves, the gas layer and the gas-water co-layer mixing zone are further divided into gas layer zones and gas-water co-layer zones, and their boundaries are obtained, including: Calculate the difference between the deep lateral resistivity and the shallow lateral resistivity at each gas sampling point in the gas layer and the gas-water co-layer mixing zone; Draw a third cross plot of the difference versus resistivity; Based on the third intersection diagram, the gas layer and the gas-water co-layer mixing zone are divided into two subdivisions. Based on the third cross-plot, the gas layer and the gas-water co-mixing zone are further subdivided, including: Based on the third intersection diagram, determine the threshold value for dividing the gas layer region and the gas-water co-layer region; When the difference between the gas sampling points is less than the difference threshold, the gas sampling point is determined to correspond to the gas-water co-layer zone. When the difference between the gas sampling points is greater than or equal to the difference threshold, the gas sampling point is determined to correspond to a gas layer region.

6. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 4.

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