A method for depicting remaining gas distribution based on post-pressure interfitting technology

Abstract

The application discloses a method for depicting remaining gas distribution based on post-pressure fracture network iterative fitting technology, and relates to the field of shale gas development.The method fully considers geological data of gas wells in a well area, well structure, fracturing construction, microseismic monitoring, gas production profile, gas well production data and fracturing interference data, uses unstable production analysis, geological modeling and numerical simulation and other methods, iteratively implements gas well reserve production conditions, depicts remaining gas distribution, is suitable for remaining gas distribution research of various types of shale gas reservoirs at home and abroad, can guide shale gas development adjustment well deployment and development technical policy making, significantly improves block recovery and gas field development benefit, and has wide popularization prospect.

Description

Technical Field

[0001] This application relates to the field of shale gas development, and more specifically, to a method for characterizing the distribution of residual gas based on post-compression fracture network iterative fitting technology. Background Technology

[0002] my country has abundant shale gas resources with great development potential. As a clean energy source, efficient development of shale gas can greatly alleviate the domestic energy shortage, effectively promote the transformation of the country's energy production and consumption structure, and enhance national energy security.

[0003] Shale reservoirs are relatively dense and have low permeability, making direct extraction of shale gas difficult in their natural state. Currently, hydraulic fracturing technology is primarily used to create artificial fractures, allowing these natural fractures to interconnect and forming a more complex fracture network. This aims to increase the connectivity and fluidity of the shale gas reservoir, thereby improving shale gas production and ultimately achieving substantial extraction volumes. During the development of shale gas reservoirs, the process typically progresses from "initial large-well-spacing development" to "small-well-spacing infill development" and then to "stratified three-dimensional development." Therefore, characterizing the distribution patterns of residual gas in the well area is crucial for the development and utilization of shale gas. Summary of the Invention

[0004] The purpose of this application is to provide a method for characterizing the distribution of residual gas based on post-fracturing fracture network iterative fitting technology. This method fully considers the gas well reservoir, geological structure, geomechanics, fracturing operation, gas well production data, dynamic monitoring data, and fracturing interference data in the work area. It uses methods such as unstable production analysis, geological modeling, and numerical simulation to iteratively determine the utilization status of gas well reserves and characterize the distribution of residual gas. This method is applicable to the study of residual gas distribution in various types of shale gas reservoirs at home and abroad. It can guide the adjustment of well location deployment and the formulation of development technology policies for shale gas development, and significantly improve the recovery rate of blocks and the development efficiency of gas fields.

[0005] The embodiments of this application are implemented as follows:

[0006] This application provides a method for characterizing residual gas distribution based on iterative fitting technology of post-pressed seam mesh, which includes the following steps:

[0007] S1. Obtain the required basic data, including well area geological data, well structure, fracturing construction parameters, production data, microseismic monitoring data, gas production profile data, and fracturing interference data.

[0008] S2. Based on the reservoir characteristics, horizontal section length, well inclination, perforation parameters, and historical production data of shale gas horizontal wells, dynamic production analysis is carried out using the unstable production analysis method to obtain the average fracture length and average fracture height of shale gas horizontal wells.

[0009] S3. Based on the average fracture length and average fracture height of the shale gas horizontal well obtained in step S2, and combined with the segmented fracturing construction parameters, the segmented equivalent fracture length and segmented equivalent fracture height of the shale gas horizontal well are obtained.

[0010] S4. Establish a correspondence between the segmented fracture length and segmented fracture height results from microseismic monitoring and the segmented fracturing interference data of shale gas horizontal wells that have implemented microseismic monitoring. Then, combine the segmented equivalent fracture length and segmented equivalent fracture height data and the segmented fracturing interference data from step S3 to obtain the segmented non-equivalent fracture length and segmented non-equivalent fracture height data of shale gas horizontal wells that have not implemented microseismic monitoring.

[0011] S5. Establish a geological model of the well area, fit the fracturing construction parameters, obtain a three-dimensional morphological model of the fracture network after fracturing of the shale gas horizontal well, and then import the geological model into the numerical model to fit historical production data. Using the segmented non-equivalent fracture length and segmented non-equivalent fracture height obtained in step S4 as constraints, iterative fitting is performed until the fitting result is accurate, and the final segmented non-equivalent fracture length and final segmented non-equivalent fracture height are determined.

[0012] S6. Based on the actual well trajectory of the shale gas horizontal well and the final segmented non-equivalent fracture length and final segmented non-equivalent fracture height determined in step S5, determine the vertical reserve utilization status.

[0013] S7. Based on the segmented non-equivalent fracture length determined in step S5 and the vertical reserve utilization determined in step S6, determine the segmented recoverable reserve distribution of the horizontal wells in the sub-layers of shale gas.

[0014] S8. Determine the residual gas distribution characteristics of the strata by combining the original geological reserves and the segmented recoverable reserves distribution of horizontal wells in the shale gas sub-layers.

[0015] In some optional implementations, the fracturing interference data in step S1 is the wellhead pressure of the adjacent old well during the fracturing of the new well, including the horizontal and depth-direction interference of the adjustment well on the adjacent well.

[0016] In some optional implementations, the fracturing parameters in step S3 include the sand addition scale and the fluid addition scale, the segmented equivalent fracture length is the bilaterally symmetrical fracture length in the plane without considering the difference between the two sides of the well trajectory, and the segmented equivalent fracture height refers to the vertically symmetrical fracture length without considering the vertical difference.

[0017] In some alternative implementations, the segmented non-equivalent fracture length in step S4 refers to the fracture length corrected based on fracturing interference data from both sides of the shale gas horizontal well; the segmented non-equivalent fracture height refers to the upper and lower fracture heights corrected based on fracturing interference data in the depth direction.

[0018] In some alternative implementations, the iterative fitting in step S5 refers to adjusting the shale gas horizontal well fracture length and height data in the numerical model and then fitting again when the fitting result does not meet the requirements, using the segmented non-equivalent fracture length and segmented non-equivalent fracture height as constraints, until the fitting result is accurate.

[0019] In some alternative implementations, in step S6, when determining the vertical reserve utilization status, the calculation should be done in segments. Only when the actual trajectory of a shale gas horizontal well in a certain segment crosses a certain sub-layer or the fracture height reaches a certain sub-layer is the sub-layer considered to have been utilized. If the trajectory of a certain segment does not cross the sub-layer or the fracture height does not reach the sub-layer, then the segment has not been utilized in that sub-layer.

[0020] The beneficial effects of this application are as follows: The method for characterizing the distribution of residual gas based on post-fracturing fracture network iterative fitting technology provided in this application includes the following steps: S1. Obtain the required basic data, including well area geological data, well structure, fracturing construction parameters, production data, microseismic monitoring data, gas production profile data, and fracturing interference data; S2. Based on the reservoir characteristics, horizontal section length, well inclination, perforation parameters, and historical production data of shale gas horizontal wells, conduct dynamic production analysis through unstable production analysis methods to obtain the average fracture length and average fracture height of shale gas horizontal wells; S3. Based on the average fracture length and average fracture height of shale gas horizontal wells obtained in step S2 and combined with the segmented fracturing construction parameters, obtain the segmented equivalent fracture length and segmented equivalent fracture height of shale gas horizontal wells; S4. Establish a correspondence between the segmented fracture length and segmented fracture height results from microseismic monitoring and the segmented fracturing interference data of shale gas horizontal wells under microseismic monitoring, and then combine the segmented equivalent fracture length and segmented equivalent fracture height data from step S3 and the segmented fracturing interference data. S5. Using fracture interference data, obtain the segmented non-equivalent fracture length and segmented non-equivalent fracture height data for shale gas horizontal wells without microseismic monitoring; S6. Establish a geological model of the well area, fit the fracturing operation parameters, obtain a three-dimensional morphological model of the fracture network after fracturing of the shale gas horizontal well, and then import the geological model into the numerical model to fit historical production data. Using the segmented non-equivalent fracture length and segmented non-equivalent fracture height obtained in step S4 as constraints, perform iterative fitting until the fitting result is accurate, and determine the final segmented non-equivalent fracture length and final segmented non-equivalent fracture height. S6. Based on the actual well trajectory of the shale gas horizontal well and the final segmented non-equivalent fracture length and final segmented non-equivalent fracture height determined in step S5, determine the vertical reserve utilization status; S7. Based on the segmented non-equivalent fracture length determined in step S5 and the vertical reserve utilization status determined in step S6, determine the segmented recoverable reserve distribution of the shale gas horizontal well in the sub-layers; S8. Combine the original geological reserves and the segmented recoverable reserve distribution of the shale gas horizontal well in the sub-layers to determine the residual gas distribution characteristics of the strata. The method for characterizing residual gas distribution based on post-fracturing fracture network iterative fitting technology provided in this application fully considers the gas well reservoir, geological structure, geomechanics, fracturing operation, gas well production data, dynamic monitoring data, and fracturing interference data in the work area. It uses methods such as unstable production analysis, geological modeling, and numerical simulation to iteratively determine the gas well reserve utilization status and characterize the residual gas distribution. It is applicable to residual gas distribution research in various types of shale gas reservoirs at home and abroad. It can guide the adjustment of well location deployment and the formulation of development technology policies for shale gas development, significantly improve the recovery rate of blocks and the development benefits of gas fields, and has broad prospects for promotion. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 The average fracture length map of shale gas wells obtained by unstable production analysis and analytical method is used in the method for characterizing residual gas distribution based on post-compression fracture network iterative fitting technology provided in the embodiments of this application.

[0023] Figure 2 The three-dimensional morphological model of the post-compression fracture network simulated in the method for characterizing residual gas distribution based on post-compression fracture network iterative fitting technology provided in the embodiments of this application;

[0024] Figure 3 The residual gas distribution map is obtained by combining the utilization range of shale gas wells with the original reserve abundance through iterative calculation in the method for characterizing residual gas distribution based on post-compression fracture network iterative fitting technology provided in the embodiments of this application. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] The following describes in further detail the characterization and performance of the method for characterizing residual gas distribution based on post-pressed seam mesh iterative fitting technology of this application, with reference to embodiments.

[0028] Taking a shale gas development block as an example, this application provides a method for characterizing the residual gas distribution based on post-compression fracture network iterative fitting technology, which includes the following steps:

[0029] S1. Obtain the basic data required for this method, including well area geological data, well structure, fracturing construction parameters, production data, microseismic monitoring data, gas production profile data, fracturing interference data, etc.; fracturing interference data includes horizontal fracturing interference and depth fracturing interference of the adjustment well to adjacent wells.

[0030] S2. Based on reservoir characteristics, horizontal section length, well inclination, perforation parameters, and historical production data of shale gas horizontal wells, dynamic production analysis is conducted using the unstable production analysis method to obtain the average fracture length and average fracture height of the shale gas horizontal wells. Figure 1 As shown;

[0031] S3. Based on the average fracture length and average fracture height of the shale gas well obtained in step S2, and combined with the construction parameters of staged fracturing, the equivalent fracture length and equivalent fracture height of the shale gas horizontal well are obtained; the construction parameters of staged fracturing include the scale of sand addition and the scale of fluid addition.

[0032] S4. Establish a correspondence between the segmented fracture length and segmented fracture height results from microseismic monitoring and the segmented fracturing interference data of shale gas horizontal wells that have undergone microseismic monitoring. Then, combine the segmented equivalent fracture length and segmented equivalent fracture height data and the segmented fracturing interference data from step S3 to obtain the segmented non-equivalent fracture length and segmented non-equivalent fracture height data of shale gas water wells that have not undergone microseismic monitoring. The correspondence includes the relationship between half-fracture length and fracturing interference, as well as the relationship between fracture height and fracturing interference.

[0033] S5. Establish a geological model of the well area, fit the fracturing operation parameters, and obtain a three-dimensional morphological model of the fracture network after fracturing in a shale gas horizontal well, such as... Figure 2 As shown; then the geological model is imported into the numerical model to fit historical production data. The segmented non-equivalent joint length and segmented non-equivalent joint height obtained by S4 are used as constraints to perform iterative fitting until the fitting result is accurate, and the final segmented non-equivalent joint length and final segmented non-equivalent joint height are determined.

[0034] S6. Based on the actual well trajectory of the shale gas horizontal well traversing the stratigraphic layers, and the final segmented non-equivalent fracture length and height determined in S5, determine the vertical reserve utilization status. When determining the vertical reserve utilization status, calculations should be performed segment by segment. Only when the actual well trajectory of a certain shale gas horizontal well traverses or the fracture height reaches a certain sub-layer is the sub-layer considered utilized. If the well trajectory of a certain segment does not traverse to the sub-layer and the fracture height does not reach the sub-layer, then the segment has not utilized the sub-layer.

[0035] S7. Based on the segmented non-equivalent fracture length determined in S5 and the vertical reserve utilization determined in S6, the segmented recoverable reserve distribution of the horizontal well in the sub-layer shale gas is determined. The gas production profile results show that there is a good correlation between the segmented gas production contribution rate and the segmented half fracture length. Therefore, the segmented recoverable reserves can be determined based on the fracture length.

[0036] S8. Combining the original geological reserves and the segmented recoverable reserves distribution of horizontal wells in small-layer shale gas formations, determine the residual gas distribution characteristics of each layer, such as... Figure 3 As shown; remaining gas refers to remaining reserves, which is calculated to take into account the recoverable reserves of the implemented shale gas horizontal wells. The original reserves minus the recoverable reserves are the remaining reserves.

[0037] The method for characterizing residual gas distribution based on post-fracturing fracture network iterative fitting technology provided in this application fully considers the reservoir, geological structure, geomechanics, fracturing operation parameters, well production data, dynamic monitoring data, and fracturing interference data of shale gas fields. It uses methods such as unstable production analysis, geological modeling, and numerical simulation to iteratively determine the well reserve utilization status and characterize the residual gas distribution. This method is applicable to residual gas distribution research in various types of shale gas reservoirs both domestically and internationally. It can guide the adjustment of well location deployment and the formulation of development technology policies for shale gas development, significantly improving block recovery rates and gas field development efficiency, and has broad prospects for promotion in shale gas areas.

[0038] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for characterizing residual gas distribution based on iterative fitting technology of post-pressed seam mesh, characterized in that, It includes the following steps: S1. Obtain the required basic data, including well area geological data, well structure, fracturing construction parameters, production data, microseismic monitoring data, gas production profile data, and fracturing interference data. S2. Based on the reservoir characteristics, horizontal section length, well inclination, perforation parameters, and historical production data of shale gas horizontal wells, dynamic production analysis is carried out using the unstable production analysis method to obtain the average fracture length and average fracture height of shale gas horizontal wells. S3. Based on the average fracture length and average fracture height of the shale gas horizontal well obtained in step S2, and combined with the segmented fracturing construction parameters, the segmented equivalent fracture length and segmented equivalent fracture height of the shale gas horizontal well are obtained. S4. Establish a correspondence between the segmented fracture length and segmented fracture height results from microseismic monitoring and the segmented fracturing interference data of shale gas horizontal wells that have implemented microseismic monitoring. Then, combine the segmented equivalent fracture length and segmented equivalent fracture height data and the segmented fracturing interference data from step S3 to obtain the segmented non-equivalent fracture length and segmented non-equivalent fracture height data of shale gas horizontal wells that have not implemented microseismic monitoring. S5. Establish a geological model of the well area, fit the fracturing construction parameters, obtain a three-dimensional morphological model of the fracture network after fracturing of the shale gas horizontal well, and then import the geological model into the numerical model to fit historical production data. Using the segmented non-equivalent fracture length and segmented non-equivalent fracture height obtained in step S4 as constraints, iterative fitting is performed until the fitting result is accurate, and the final segmented non-equivalent fracture length and final segmented non-equivalent fracture height are determined. S6. Based on the actual well trajectory of the shale gas horizontal well and the final segmented non-equivalent fracture length and final segmented non-equivalent fracture height determined in step S5, determine the vertical reserve utilization status. S7. Based on the segmented non-equivalent fracture length determined in step S5 and the vertical reserve utilization determined in step S6, determine the segmented recoverable reserve distribution of the horizontal wells in the sub-layers of shale gas. S8. Determine the residual gas distribution characteristics of the strata by combining the original geological reserves and the segmented recoverable reserves distribution of horizontal wells in the shale gas sub-layers.

2. The method for characterizing residual gas distribution based on post-pressed seam mesh iterative fitting technology according to claim 1, characterized in that, In step S1, the fracturing interference data refers to the wellhead pressure of adjacent old wells during the fracturing of a new well, including the horizontal and depth-direction interference of the adjustment well on the adjacent wells.

3. The method for characterizing residual gas distribution based on post-pressed seam mesh iterative fitting technology according to claim 1, characterized in that, The fracturing parameters in step S3 include the sand addition scale and the fluid addition scale. The segmented equivalent fracture length is the bilaterally symmetrical fracture length on the plane without considering the difference between the two sides of the well trajectory. The segmented equivalent fracture height refers to the vertically symmetrical fracture length without considering the vertical difference.

4. The method for characterizing residual gas distribution based on post-pressed seam mesh iterative fitting technology according to claim 1, characterized in that, In step S4, the segmented non-equivalent fracture length refers to the fracture length after correction based on the fracturing interference data on both sides of the shale gas horizontal well; the segmented non-equivalent fracture height refers to the upper fracture height and lower fracture height after correction based on the fracturing interference data in the depth direction.

5. The method for characterizing residual gas distribution based on post-pressed seam mesh iterative fitting technology according to claim 1, characterized in that, In step S5, iterative fitting means that when the fitting result does not meet the requirements, the data of shale gas horizontal well fracture length and fracture height in the numerical model are adjusted and then fitted again, using the segmented non-equivalent fracture length and segmented non-equivalent fracture height as constraints, until the fitting result is accurate.

6. The method for characterizing residual gas distribution based on post-pressed seam mesh iterative fitting technology according to claim 1, characterized in that, In step S6, when determining the utilization of vertical reserves, the calculation should be done in segments. Only when the actual trajectory of a shale gas horizontal well in a certain segment passes through or the fracture height reaches a certain sub-layer is it considered that the segment has been utilized in that sub-layer. If the trajectory of a certain segment does not pass through the sub-layer and the fracture height does not reach the sub-layer, then the segment has not been utilized in that sub-layer.

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