A method and system for reconstructing a horizontal well in a complex fractured water-bearing oil and gas reservoir

Abstract

The application discloses a reconstruction method and system for a complex fracture type water-containing oil and gas reservoir horizontal well, belongs to the field of fracturing reconstruction process technology of low-permeability tight oil and gas fields, and has the advantages that the development characteristics of a fracture zone are determined according to the sand body geological characteristics and seismic data of a horizontal well control area; the fracture type reservoir type corresponding to the position of each fracturing section in the direction of the horizontal well cylinder is determined according to the development characteristics of the fracture zone and the relative position relationship of the horizontal well; the differential fracturing process parameters of each fracturing section are determined according to the fracture type reservoir type and the effective fracture reconstruction range on both sides of the perforation points of the corresponding fracturing section, and fracturing reconstruction is carried out; the method is designed by avoiding the reconstruction method of the fracture zone, the water-containing layer of the fracture zone and the fracture-induced fracture is avoided, the probability of water outflow of the horizontal well is reduced, and the implementation effect of the segmented fracturing reconstruction of the water-containing oil and gas reservoir horizontal well is improved.

Description

Technical Field

[0001] This invention relates to the field of fracturing and stimulation technology in the development of low-permeability tight oil and gas fields, specifically to a method and system for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs. Background Technology

[0002] With the continuous development of unconventional oil and gas resources such as tight gas and shale oil and gas, hydraulic fracturing technology has made significant progress. In particular, breakthroughs in horizontal well drilling technology and staged volumetric fracturing technology over the past two decades have provided irreplaceable technical support for the efficient exploration and development of unconventional oil and gas reservoirs. Staged volumetric fracturing technology in horizontal wells, as a highly efficient production enhancement measure, is currently the main process for exploiting low-permeability and tight oil and gas. Its main technical principle is: staged perforation is performed at different locations along the horizontal section of the wellbore, and fracturing fluid is injected into the formation through each perforation, causing the formation to open one or more artificial fracture networks, forming a high-speed flow channel for oil and gas from the formation to the wellbore, and then flowing out from the wellbore to the surface wellhead.

[0003] For production enhancement measures in low-permeability tight oil and gas reservoirs, the industry at home and abroad mainly adopts the horizontal well segmented volumetric fracturing process. This is because it has significant advantages in single-well production enhancement and mature supporting technologies, and it has obvious process targeting and adaptability to low-permeability tight oil and gas reservoirs. On the one hand, by using integrated horizontal well drilling and completion technology, the length of the horizontal section and the level of cementing and completion technology are continuously improved, the wellbore completion quality is improved, and the contact area between the wellbore and the reservoir matrix sand bodies is expanded. On the other hand, the segmented and clustered volumetric fracturing technology is fully utilized to "break up" the reservoir matrix, forming a volumetric three-dimensional fracture network. This maximizes the contact area between the fracture wall and the reservoir matrix, minimizes the seepage distance of oil and gas in the matrix to the fractures, and minimizes the resistance of matrix fluids to seepage into the fractures. This greatly improves the overall seepage capacity of the reservoir fracture network, realizing "three-dimensional transformation" of the reservoir in the length, width, and height directions, and improving the initial and stable production capacity of oil and gas wells.

[0004] Based on the evaluation of post-fracturing artificial fracture network volumetric fracturing technology in horizontal wells, including monitoring, testing, and production data, it is evident that this technology is effective for reservoirs with predominantly lacustrine and marine sedimentary systems, simple geological structures, underdeveloped fractures and fractures, simple gas-water relationships, and weak planar heterogeneity. It can achieve three-dimensional fracture network volumetric fracturing, resulting in high and stable post-fracturing gas production. However, for tight sandstone reservoirs with predominantly braided river sedimentary systems, well-developed fractures and fractures at different stages, complex geological structures and gas-water relationships, strong planar heterogeneity, and rapid lateral variations in sand bodies, the current horizontal well segmented volumetric fracturing technology, which employs uniform fracture distribution, similar perforation, and construction parameters, suffers from inconsistent geological structures, fracture and fracture development, and gas-water relationships across different sections within the wellbore. This results in a lack of targeted fracturing, and local structural and fracture-guiding effects limit or over-fracturing volume. The horizontal wells, after being subjected to high-level stimulation, have low production rates and varying degrees of water production in different sections, failing to meet the technical requirements for volume stimulation of tight, low-permeability oil and gas reservoirs. There is an urgent need to optimize the stimulation process and technology, fully considering the regional geological structure, fracture and fracture development, and gas-water superposition relationships. This involves optimizing the design of each fracture section and construction parameters to achieve precise stimulation that avoids fracture zones and water layers. This will allow for full communication between the main fracture, branch fractures, and oblique fractures without water layers, thereby increasing horizontal well production, reducing the probability and amount of water production, and improving the overall efficiency of single oil and gas wells.

[0005] Currently, the main methods used in the industry and market to improve the effectiveness of horizontal well stimulation in fractured oil and gas reservoirs are complete abandonment of fracture zone stimulation and intensive fracturing and extraction of fractured reservoirs. However, the overall production improvement and economic benefits of these methods are unsatisfactory. On the one hand, the complete abandonment of fracture zone stimulation results in insufficient overall reservoir utilization and inadequate fracturing, leaving a large amount of untapped oil and gas resources. On the other hand, the intensive fracturing and extraction method for fractured reservoirs has high requirements for development well network and well spacing, as well casing conditions. The intensive fracturing and extraction mode also suffers from technical defects such as excessively large stimulation scale parameters, interference between wells and fractures, excessive fracturing between fractures, and high post-fracturing extraction costs, resulting in very limited market application prospects for these two similar technologies. Therefore, continuously optimizing and improving the volumetric fracturing stimulation technology for horizontal wells in complex fractured reservoirs is of great guiding significance for the economical and efficient development of low-permeability tight oil and gas reservoirs. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a method and system for the stimulation of horizontal wells in complex fractured water-bearing oil and gas reservoirs. This method, through the design of fracture avoidance stimulation, avoids connecting the fracture zone with the water-bearing layer of fracture-induced fractures, thereby reducing the probability of water production in the horizontal well and improving the stimulation effect of water-bearing oil and gas reservoirs.

[0007] This invention is achieved through the following technical solution: Firstly, this application proposes a method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs, including: The characteristics of the fault zone development were determined based on the geological features of the sand bodies and seismic data in the area controlled by the horizontal well. Based on the development characteristics of the fracture zone and the relative positions of the horizontal wells, the fracture reservoir type corresponding to each fracturing section along the horizontal wellbore direction is determined; Based on the fractured reservoir type and the effective fracture modification range on both sides of the perforation point of the corresponding fractured section, the fracturing process of each fracturing section is determined and fracturing modification is carried out.

[0008] Preferably, the determination of the fault zone development characteristics includes: Based on the geological structure undulations, sand body distribution characteristics, channel sand body extension length and width, local micro-scale structures and planar heterogeneity characteristics of the horizontal well controlled area, and combined with the three-dimensional seismic data of the oil and gas reservoir, the fault zone development characteristics were interpreted.

[0009] Preferably, determining the type of fractured reservoir based on the development characteristics of the fracture zone and the relative positions of horizontal wells includes: The fracture zone reservoir is determined by projecting the fracture zone onto the horizontal well. Then, the distance between the intersection of the main fracture extension line of the fractured section and the fracture zone and the perforation point of the fractured section is determined. Based on the distance, the type of fractured reservoir in the fractured section is determined.

[0010] Preferably, the distance between the intersection point and the perforation point is compared with a set threshold to determine the type of fractured reservoir; When the distance is less than the first set distance, the fractured reservoir is a fracture zone reservoir; When the distance is greater than or equal to the first set distance and less than the second set distance, the fracture-type reservoir is a near-fracture zone reservoir; When the distance is greater than the second set distance, the fractured reservoir is a remote fracture zone reservoir.

[0011] Preferably, the fracturing process of the fracturing section includes: Based on the positional relationship between each fracturing section and the fault zone, the effective fracture modification range on the side of the fracturing section closest to the fault zone is determined. Then, based on the reservoir sand body characteristics on the other side of the fracturing section, the effective fracture modification range on the side of the fracturing section furthest from the fault zone is determined. Based on the effective fracture modification range on both sides of the fracturing section and in conjunction with the established fracturing modification principles, the fracturing process on both sides of the fracturing section is determined.

[0012] Preferably, the fracturing modification principles include: The fault zone reservoir is not modified, while the modification scale of the near-fault zone reservoir and the far-fault zone reservoir increases sequentially. During the modification process, the fracture extension parameters are controlled to avoid the fault zone.

[0013] Preferably, the reservoir near the fracture is not modified, while the side away from the fracture is treated with directional perforation. The near-fracture zone reservoir uses a spiral perforation process on the side close to the fracture zone and a directional perforation process on the side far from the fracture zone. The reservoir in the far-fault zone is treated with a spiral perforation process on the side closer to the fault and a directional perforation process on the side farther from the fault.

[0014] Preferably, the following steps are also included: During the fracturing process of the fractured reservoir, the formation fracture extension parameters are obtained to determine its extension trend. Based on the extension trend of the formation fracture, it is predicted whether the formation fracture will connect with the fault zone. If the extension trend of the formation fracture will connect with the fault zone, the fracturing process parameters are adjusted and an early warning response is output.

[0015] Secondly, this application proposes a system for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs, including... The fault zone module is used to determine the development characteristics of fault zones based on the sand body geological features and seismic data of the horizontal well controlled area. The reservoir segmentation module is used to determine the type of fractured reservoir corresponding to each fractured section along the horizontal wellbore direction based on the characteristics of fracture zone development and the relative position of horizontal wells. The fracturing stimulation module is used to determine the fracturing process for each fracturing section and carry out fracturing stimulation based on the fractured reservoir type and the effective fracture stimulation range on both sides of the perforation point of the corresponding fracturing section.

[0016] Thirdly, this application proposes an electronic device comprising: Memory, used to store computer programs; A processor is used to execute the computer program to implement the steps of the method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This application presents a method for the stimulation of horizontal wells in complex fractured water-bearing oil and gas reservoirs. Based on the geological characteristics of the sandstone body and seismic data within the controlled area of ​​the horizontal well, the development characteristics of the fracture zone are determined. Then, based on the positional relationship between the fracturing zones and the various fracturing zones within the horizontal well, the fractured reservoir is finely divided into different fractured reservoir types. Finally, considering the effective fracture stimulation range of each reservoir, differentiated and precise fracturing designs are implemented for each fracturing stage. This method effectively develops complex fractured water-bearing oil and gas reservoirs, maximizing oil and gas recovery and reducing the risks associated with blind fracturing or poor fracturing results. This contributes to ensuring the safety and stability of oil and gas field development. This method is applicable to the field requirements of staged fracturing stimulation of horizontal wells in various complex fractured water-bearing oil and gas reservoirs, and exhibits high technological adaptability and a wide range of applications for various lithological reservoirs such as sandstone, carbonate rocks, and limestone.

[0018] This application also proposes a stimulation system for horizontal wells in complex fractured water-bearing oil and gas reservoirs, an electronic device, and a computer storage medium, which possess all the advantages of the aforementioned stimulation methods for horizontal wells in complex fractured water-bearing oil and gas reservoirs. Attached Figure Description

[0019] 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.

[0020] Figure 1 This is a flowchart of the method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs according to the present invention; Figure 2 This is a schematic diagram of the fault zone reservoir type in Embodiment 1 of the present invention.

[0021] Figure 3 This is a schematic diagram of the fault zone reservoir type in Embodiment 2 of the present invention.

[0022] Figure 4 This is a structural block diagram of the stimulation system for horizontal wells in complex fractured water-bearing oil and gas reservoirs according to the present invention. Detailed Implementation

[0023] 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.

[0024] 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.

[0025] In response to the complex geological and structural characteristics of oil and gas reservoirs, including widespread development of fractures from different phases and complex gas-water relationships, after preliminary horizontal well segmented volumetric fracturing tests, field monitoring of the gas and fluid production contributions of horizontal well volumetric fracturing technology was conducted. The results showed that the poorer-than-expected performance of some fracturing sections was mainly due to the complex structure and gas-water relationships in some complex water-bearing oil and gas reservoirs, the wide range of fracture influence, and the strong heterogeneity of the reservoir plane along the wellbore direction. The degree of fracture influence varied significantly between different fracturing sections: some sections had perforation locations directly penetrated by fractures, resulting in significant pressure drops during perforation; monitoring indicated a small contribution to oil and gas production but a large contribution to water production. Other sections did not experience pressure drops during perforation but did during proppant fracturing; monitoring indicated a small contribution to oil and gas production but a large contribution to water production. Still other sections did not experience pressure drops during either perforation or proppant fracturing; monitoring indicated a large contribution to oil and gas production but a very small contribution to water production. The uneven distribution of fracture zones and fracture-induced fractures in the overall construction process resulted in fewer effective oil and gas contributing fractures and more water-contributing fractures in some sections that were more affected by fractures. This led to limited overall production of horizontal wells and higher water production in some sections.

[0026] Based on the above geological and engineering analysis, this application proposes a method and system for the stimulation of horizontal wells in complex fractured reservoirs using volumetric fracturing technology. The following is a detailed description of this application with reference to embodiments and accompanying drawings.

[0027] like Figure 1 The diagram illustrates a method for stimulating a horizontal well in a complex fractured water-bearing oil and gas reservoir, comprising the following steps: S10. Determine the development characteristics of the fault zone based on the sand body geological characteristics and seismic data of the horizontal well-controlled area; This fault zone is a fracture or fault zone formed in the crust within the area controlled by a horizontal well. The development characteristics of the fault zone can characterize its extension direction and length, thereby determining the distribution characteristics of the fault zone within the horizontal well-controlled area. Through comprehensive analysis of sand body geological characteristics and seismic data, the development characteristics of the fault zone can be accurately determined, providing a basis for subsequent reservoir stimulation.

[0028] S20. Based on the characteristics of fracture zone development and the relative positions of horizontal wells, determine the type of fracture reservoir corresponding to each fracture section along the horizontal wellbore direction; The area corresponding to the horizontal well in the fracture zone is represented as a fracture reservoir. In order to achieve differentiated fracturing, the fracture reservoir is finely divided according to the positional relationship between the fracturing zone and each fracturing zone in the horizontal well, forming different fracture reservoir types. Then, fracturing is carried out on different fracture reservoir types respectively.

[0029] S30. Based on the fractured reservoir type and the effective fracture modification range on both sides of the perforation point of the corresponding fractured section, determine the differentiated fracturing process parameters for each fracturing section, and carry out differentiated and precise fracturing modification for the fracturing sections corresponding to each fractured reservoir type.

[0030] This method achieves differentiated and precise fracturing by separately fracturing different fractured reservoir types and determining fracturing process parameters based on the reservoir type and the effective fracture stimulation range on both sides of the perforation point. This allows for more effective development of complex fractured water-bearing oil and gas reservoirs, maximizing reservoir recovery and reducing risks caused by blind fracturing or poor fracturing results. This contributes to ensuring the safety and stability of oil and gas field development.

[0031] Example 1 A method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs includes: Step 1: Obtain the geological characteristics of the sand body in the horizontal well-controlled area and evaluate the geological characteristics of the sand body. At the same time, combine the seismic data of the controlled area to determine the fault development characteristics of the horizontal well-controlled area.

[0032] The geological characteristics of sand bodies in the horizontal well-controlled area include geological structural undulations, sand body distribution characteristics, the length and width of channel sand bodies, as well as local micro-scale structures and planar heterogeneity. Seismic data of the controlled area were obtained in conjunction with 3D seismic data from the oil and gas reservoir to assess the fault development characteristics of the horizontal well-controlled area; the characteristics of different phases of fault zone development, fault attributes and occurrence, extension direction, and extension length were also assessed.

[0033] Step 2: Determine the fractured reservoir in the horizontal well-controlled area based on the fracture zone development characteristics. Divide the fractured reservoir according to the layout parameters of the fractured reservoir and the horizontal well, and determine the type of fractured reservoir corresponding to each fractured section along the horizontal wellbore direction.

[0034] The layout parameters of horizontal wells include the well spacing of the horizontal well network, the wellbore trajectory path, and the relative distance between the perforation points of each section. Based on the layout parameters of the horizontal wells, the maximum extension length of the main fracture in each fracturing section along the wellbore direction is evaluated. Based on the plane intersection relationship between the maximum extension length of the main fracture and the fracture zone, the type of fracture reservoir corresponding to each fracturing section is determined.

[0035] In this embodiment, the type of fracture reservoir in a fracturing section is determined by the distance between the intersection of the main fracture extension line and the fracture zone in each fracturing section and the perforation point of that fracturing section.

[0036] The main fracture refers to the primary fracture formed in the reservoir rock during fracturing operations due to the high-pressure hydraulic fracturing. Main fractures have a large aperture and a relatively long length, and their propagation direction is typically along the direction of the maximum principal stress. During fracturing operations, fracturing fluid is injected into the reservoir, creating a high-pressure environment that causes rock fracturing. The main fractures are the most prominent and primary fractures among these, playing a crucial role in improving reservoir permeability and increasing oil and gas flow. The extension direction of the main fracture is influenced by the geostress field and typically extends along the direction of the maximum principal stress.

[0037] By analyzing the intersection of the main fracture extension line and the fault zone in each fracturing section, and considering the distance to the perforation point in that section, the fracture type of the reservoir can be determined. This is because the fault zone has a significant impact on reservoir permeability and fracture development, and the extension direction and location of the main fracture can reflect these influences. Therefore, by analyzing the relationship between the main fracture and the fault zone, the reservoir type can be further determined.

[0038] When the distance between the intersection of the main fracture extension line and the fracture zone and the perforation point is less than the first set distance, the type of the fracturing section is a fracture reservoir. When the distance between the intersection of the main fracture extension line and the fracture zone and the perforation point is greater than or equal to the second set distance, the type corresponding to the fracturing section is a fracture zone reservoir. When the distance between the intersection of the main fracture extension line and the fracture zone and the perforation point is greater than or equal to the second set distance and less than the third set distance, the type of the fracturing section is a near-fracture zone reservoir. When the distance between the intersection of the main fracture extension line and the fracture zone and the perforation point is greater than the second set distance, the type corresponding to this fracturing section is a far-fracture zone reservoir.

[0039] The distances of the first and second preset distances increase sequentially.

[0040] S30. Based on the type of fractured reservoir and the effective fracture stimulation range on both sides of the perforation point of the corresponding fractured section, formulate the horizontal well stimulation process plan corresponding to each fractured reservoir section.

[0041] The aforementioned formulation of differentiated horizontal well stimulation schemes for different fractured reservoir sections refers to: based on the location of the fracture zone reservoir, near-fracture zone reservoir, and far-fracture zone reservoir and the corresponding fracturing section, and following the main technical approach of minimizing stimulation of the fracture zone reservoir, controlling the scale of stimulation of the near-fracture zone reservoir, and increasing the scale of stimulation of the far-fracture zone reservoir, formulating fracturing stimulation processes for each fracturing section, combining helical and directional perforation techniques, different borehole diameters, and different penetration depths for different fracturing sections, and different designing of fracture initiation morphologies on both sides of the fracture zone reservoir, near-fracture zone reservoir, and far-fracture zone reservoir, while simultaneously formulating different fracturing construction parameters to precisely control the fracture extension distance and range.

[0042] Since the fracture zone is located on one side of the fracturing section, the fracture modification range on both sides of the fracturing section is different. Therefore, it is necessary to formulate corresponding fracturing modification processes for both sides of the fracturing section according to the fracture modification range. For the side of the fracturing section that is close to the fracture zone, it is necessary to avoid the fracture zone in order to reduce the impact of the fracture zone on the reservoir modification.

[0043] In this embodiment, the stimulation methods for fault zone reservoirs, near-fault zone reservoirs, and far-fault zone reservoirs are as follows: See again Figure 1 The fracturing section is defined as follows: the side closer to the fracture zone is called side A, and the side farther from the fracture zone is called side C. The stimulation schemes for fracture zone reservoirs, near-fracture zone reservoirs, and far-fracture zone reservoirs are as follows: 1. Fault zone reservoir stimulation scheme: The side of the fracturing section closest to the fault (side A) is abandoned and not stimulated; the side of the fracturing section furthest from the fault (side C) adopts directional perforation technology to avoid longitudinal communication to the fault as much as possible, and uses the minimum penetration depth and minimum diameter perforating bullets, while minimizing parameters such as discharge rate, sand volume, and liquid volume. 2. Stimulation scheme for reservoirs near the fault zone while avoiding the fault zone: On the side of the fracturing section closest to the fault zone (side A), a spiral perforation process is adopted to minimize lateral extension to the fault. Small-depth and small-diameter perforating guns are used, and parameters such as discharge rate, sand volume, and fluid volume are relatively small. On the side of the fracturing section furthest from the fault zone (side C), a directional perforation process is adopted to maximize lateral extension of the fracture length. Conventional-depth and conventional-diameter perforating guns are used, and parameters such as discharge rate, sand volume, and fluid volume are designed according to conventional methods. 3. Stimulation scheme for reservoirs far from the fracture zone: On the side of the fracturing section close to the fracture (side A), use spiral perforation technology to avoid lateral extension to the fracture as much as possible. Use perforating guns with conventional penetration depth and diameter, and follow conventional design for discharge rate, sand volume, and fluid volume. On the side of the fracturing section far from the fracture (side C), use directional perforation technology to extend the fracture length laterally as much as possible. Use perforating guns with increased penetration depth and diameter, and follow increased scale design for discharge rate, sand volume, and fluid volume.

[0044] Step 4: Based on the fracturing stimulation process formulated for each fracturing section in Step 3, the reservoir corresponding to each fracturing section is stimulated segment by segment. During the stimulation process, the fluid inlet channel of the stimulated section is kept unobstructed, while the fluid inlet channels of other reservoir sections are temporarily blocked.

[0045] During the storage modification process, based on the fracturing technology determined for each reservoir, differentiated construction operations are carried out for each stage according to the designed perforation technology, fracture size, and construction parameters. Following the construction procedure, each stage of fracturing is completed before proceeding to the next stage. When constructing a certain stage, it is ensured that the fluid inlet channels of other stages have been temporarily blocked. Modification construction is carried out strictly in accordance with the design requirements.

[0046] Step 5: Monitor the condition of the main fracture and fracture zone during the fracturing process, and output early warning response and adjust the fracturing process based on the monitoring results.

[0047] The aforementioned fracture monitoring and real-time early warning response during the differential stimulation of horizontal wells refers to the following: during the construction of differential stimulation schemes for different reservoirs in complex fractured horizontal wells, fracture monitoring technology is used to track and evaluate the scale and parameters of formation fractures in real time; when there are signs that the fracture leads to the fracture zone, digital means are used to provide real-time feedback and early warning, and the construction command center adjusts the construction parameters at any time by reducing the construction flow rate, adding sealing materials, and correcting the fracture morphology to ensure normal fracturing construction and effective fracturing of fracture control volume.

[0048] Example 2 See Figure 2 A method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs, comprising: Step 10: Based on the main geological characteristics of the block and control area where the horizontal well is located, it was determined that the regional structure is gently undulating, the sand bodies are stably distributed, the channel sand bodies extend longer than the horizontal section, the sand body width in the horizontal well control area is greater than 600m, local micro-scale structures are not well developed, and the planar heterogeneity is relatively weak. At the same time, using the three-dimensional seismic data of the oil and gas reservoir, it was determined that a major fault zone has developed in the horizontal well control area. The fault attributes and occurrence are stable, and it extends along the trajectory of the horizontal well with an extension length of more than 800m.

[0049] Step 20: Based on the development characteristics of the fault zones and the location of the horizontal wells, classify the various fault reservoir types.

[0050] Within the controlled area of ​​the horizontal well, a main fracture zone obliquely crosses the horizontal well. Considering the well spacing of the horizontal well network is 600m, the relative distance between the wellbore trajectory and the perforation points of each section, and based on the geological characteristics of the planar sand body, the maximum extension length of the main fracture along the wellbore direction is evaluated to be 290-295m. The planar intersection relationship between the fracture and the main fracture is analyzed, that is, the distance between the intersection point of the main fracture extension line and the fracture zone and the perforation point.

[0051] In this embodiment, the first set distance is 100m and the second set distance is 300m, dividing the fault zone reservoir into 7 segments. The distance between the intersection point B4 of the main fracture extension line and the fault zone and the perforation point in this section is 60 m, which is less than 100 m. Therefore, reservoir section 4 is a fault zone reservoir.

[0052] The distance between the intersection point B of the main fracture extension line and the fracture and the perforation point is between 100-300m, corresponding to reservoir sections 3 and 5. Reservoir sections 3 and 5 are near-fracture zone reservoirs.

[0053] The distance between the intersection point B of the main fracture extension line and the fault zone and the perforation point is greater than 300m, and the corresponding reservoir segments are 1, 2, 6 and 7. This reservoir segment is a near-fault zone reservoir.

[0054] Step 30: Based on the positional relationship between the fracture zone reservoir, the near-fracture zone reservoir, and the far-fracture zone reservoir and the fracture zone, formulate corresponding fracturing stimulation processes for each reservoir.

[0055] Differential stimulation scheme for fault zone reservoirs: abandon the side close to the fault (side A) and do not stimulate it; adopt directional perforation technology on the side far from the fault (side C) to avoid longitudinal communication with the fault as much as possible, use perforation bullets with a minimum penetration depth of 300mm and a minimum hole diameter of 6mm, and minimize parameters such as construction flow rate of 6 cubic meters / minute, sand volume of 30 cubic meters, and liquid volume. Near-fracture zone reservoir differential stimulation scheme: On the (A side) side, a spiral perforation process is adopted to minimize lateral extension to the fracture, using perforation shells with a small penetration depth of 400mm and a small diameter of 8mm, while the construction flow rate is 8 cubic meters per minute, the sand volume is 50 cubic meters, and the liquid volume is relatively small; On the side away from the fracture (C side) side, a directional perforation process is adopted to maximize the lateral extension of the fracture length, using perforation shells with a conventional penetration depth of 600mm and a conventional diameter of 10mm, while the construction flow rate is 10 cubic meters per minute, the sand volume is 80 cubic meters, and the liquid volume is designed according to conventional parameters; Differential stimulation scheme for reservoirs far from the fault zone: On the side close to the fault (side A), a spiral perforation process is adopted to avoid lateral extension to the fault as much as possible. Conventional penetration depth and conventional diameter perforating guns are used, and the discharge rate, sand volume, and liquid volume are designed according to conventional methods. On the side far from the fault (side C), a directional perforation process is adopted to extend the fracture length laterally as much as possible. Perforating guns with an increased penetration depth of 800 mm and an increased diameter of 12 mm are used, and the discharge rate of 12 cubic meters per minute, sand volume of 100 cubic meters, and liquid volume are designed according to the scale-up method. Step 40: Implement differential stimulation schemes for different reservoirs in complex fractured horizontal wells.

[0056] Based on the different reservoir stimulation plans for horizontal wells, differentiated construction operations were carried out in each stage according to the designed perforation technology, fracture size, and construction parameters. Following the construction procedure, each stage of fracturing was completed before proceeding to the next stage. When constructing a certain stage, it was ensured that the fluid inlet channels of other stages were temporarily blocked. The modification construction was carried out strictly in accordance with the design requirements of the plan.

[0057] Step 50: Crack monitoring and real-time early warning response during horizontal well differential modification construction.

[0058] During the construction of complex fractured horizontal wells with different reservoir stimulation schemes, advanced microseismic fracture monitoring methods are used to track and evaluate the scale and parameters of formation fractures in real time. If monitoring detects signs that the fracture front section connects to the fault zone, a real-time early warning is provided using the microseismic digital monitoring system. The construction command center then adjusts the construction parameters as needed, using methods such as reducing the fracturing flow rate, adding sealing materials, and correcting the fracture morphology to ensure normal fracturing operations and effective fracturing volume control.

[0059] This application presents a method for the stimulation of horizontal wells in complex fractured water-bearing oil and gas reservoirs. By combining reservoir geology and seismic understanding, it accurately delineates the relative positional relationship between fracture zones and the horizontal wellbore trajectory. This improves the degree of differentiated and refined stimulation of different reservoirs within horizontal well sections, increases the effective fracture control volume in different fractured reservoir sections, reduces water production risk, and improves fracturing effects. It meets the field technical and economic requirements of segmented fracturing stimulation of horizontal wells in major oil and gas fields. The method is highly adaptable to various lithological reservoirs such as sandstone, carbonate rocks, and limestone, and has a wide range of applications. It enables differentiated stimulation construction to avoid fractures under existing technological conditions, with a simple process flow and low construction costs.

[0060] This invention provides a method for fracturing horizontal wells in complex fractured, low-permeability, tight water-bearing oil and gas reservoirs, addressing the common and pressing issue of low-precision horizontal well fracturing and high water-producing risk leading to untapped remaining reserves under complex geological conditions and fracture development. This method improves the utilization of oil and gas resources in horizontal wells, thereby increasing oil and gas production and preventing water production. Compared with similar fracturing technologies both domestically and internationally, its main technical indicators are leading-edge, solving common problems faced by the industry. Furthermore, it is cost-effective, has simple construction procedures, and generates significant economic and social benefits in terms of cost reduction and efficiency improvement, with broad market application prospects.

[0061] See Figure 4 Based on the above-mentioned method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs, this application also proposes a system for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs, which may include: The fault zone module is used to determine the development characteristics of fault zones based on the sand body geological features and seismic data of the horizontal well controlled area. The reservoir segmentation module is used to determine the type of fractured reservoir corresponding to each fractured section along the horizontal wellbore direction based on the characteristics of fracture zone development and the relative position of horizontal wells. The fracturing stimulation module is used to determine the fracturing process parameters of each fracturing segment based on the type of fractured reservoir and the effective fracture stimulation range on both sides of the perforation point of the corresponding fracturing segment, and to carry out differentiated and precise fracturing stimulation of the fracturing segments corresponding to each type of fractured reservoir.

[0062] It should be noted that, in the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules may be combined or integrated into another device, or some features may be ignored or not executed. The modules described as separate components may or may not be physically separated. The components shown as modules may be one or more physical units, that is, they may be located in one place or distributed in multiple different places. Some or all of the modules can be selected to achieve the purpose of the solution in this embodiment according to actual needs.

[0063] Furthermore, in the various embodiments of the present invention, the modules can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit. The integrated unit described above can be implemented in hardware or as a software functional unit.

[0064] An electronic device provided in this application includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs as described in any of the above embodiments.

[0065] Another electronic device provided in this application embodiment may further include: an input port connected to a processor for transmitting multimodal data collected by an external acquisition device to the processor; a display unit connected to the processor for displaying the processor's processing results to the outside world; and a communication module connected to the processor for enabling communication between the electronic device and the outside world. The display unit may be a display panel, a laser scanning display, etc.; the communication method adopted by the communication module includes, but is not limited to, Mobile High Definition Link (HML), Universal Serial Bus (USB), High Definition Multimedia Interface (HDMI), and wireless connection (including Wi-Fi, Bluetooth, Bluetooth Low Energy, and IEEE 802.11s-based communication technology).

[0066] This application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the steps of the method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs as described in any of the above embodiments.

[0067] The computer-readable storage media involved in this application include random access memory (RAM), memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage media known in the art.

[0068] For descriptions of relevant parts of the stimulation system, electronic equipment, and computer-readable storage medium for horizontal wells in complex fractured water-bearing oil and gas reservoirs provided in this application's embodiments, please refer to the detailed descriptions of the corresponding parts in the power load forecasting method provided in this application's embodiments; they will not be repeated here. Furthermore, parts of the technical solutions provided in this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0069] For descriptions of relevant parts of the stimulation system, electronic equipment, and computer-readable storage medium for horizontal wells in complex fractured water-bearing oil and gas reservoirs provided in this application's embodiments, please refer to the detailed descriptions of the corresponding parts in the stimulation method for horizontal wells in complex fractured water-bearing oil and gas reservoirs provided in this application's embodiments; they will not be repeated here. Furthermore, parts of the technical solutions provided in this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0070] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs, characterized in that, include: The characteristics of the fault zone development were determined based on the geological features of the sand bodies and seismic data in the area controlled by the horizontal well. Based on the development characteristics of the fracture zone and the relative positions of the horizontal wells, the fracture reservoir type corresponding to each fracturing section along the horizontal wellbore direction is determined; Based on the fractured reservoir type and the effective fracture modification range on both sides of the perforation point of the corresponding fractured section, the fracturing process of each fracturing section is determined and fracturing modification is carried out.

2. The method for stimulating a horizontal well in a complex fractured water-bearing oil and gas reservoir according to claim 1, characterized in that, The determination of the development characteristics of the fault zone includes: Based on the geological structure undulations, sand body distribution characteristics, channel sand body extension length and width, local micro-scale structures and planar heterogeneity characteristics of the horizontal well controlled area, and combined with the three-dimensional seismic data of the oil and gas reservoir, the fault zone development characteristics were interpreted.

3. A method for stimulating a horizontal well in a complex fractured water-bearing oil and gas reservoir according to claim 1 or 2, characterized in that, The determination of the type of fracture reservoir based on the development characteristics of the fracture zone and the relative position of horizontal wells includes: The fracture zone reservoir is determined by projecting the fracture zone onto the horizontal well. Then, the distance between the intersection of the main fracture extension line of the fractured section and the fracture zone and the perforation point of the fractured section is determined. Based on the distance, the type of fractured reservoir in the fractured section is determined.

4. The method for stimulating a horizontal well in a complex fractured water-bearing oil and gas reservoir according to claim 3, characterized in that, The distance between the intersection point and the perforation point is compared with a set threshold to determine the type of fractured reservoir. When the distance is less than the first set distance, the fractured reservoir is a fracture zone reservoir; When the distance is greater than or equal to the first set distance and less than the second set distance, the fracture-type reservoir is a near-fracture zone reservoir; When the distance is greater than the second set distance, the fractured reservoir is a remote fracture zone reservoir.

5. A method for stimulating a horizontal well in a complex fractured water-bearing oil and gas reservoir according to claim 1 or 4, characterized in that, The fracturing process for the fracturing section is determined to include: Based on the positional relationship between each fracturing section and the fault zone, the effective fracture modification range on the side of the fracturing section closest to the fault zone is determined. Then, based on the reservoir sand body characteristics on the other side of the fracturing section, the effective fracture modification range on the side of the fracturing section furthest from the fault zone is determined. Based on the effective fracture modification range on both sides of the fracturing section and in conjunction with the established fracturing modification principles, the fracturing process on both sides of the fracturing section is determined.

6. The method for stimulating a horizontal well in a complex fractured water-bearing oil and gas reservoir according to claim 5, characterized in that, The principles of fracturing stimulation include: The fault zone reservoir is not modified, while the modification scale of the near-fault zone reservoir and the far-fault zone reservoir increases sequentially. During the modification process, the fracture extension parameters are controlled to avoid the fault zone.

7. The method for stimulating a horizontal well in a complex fractured water-bearing oil and gas reservoir according to claim 6, characterized in that, The reservoir near the fault zone is left unmodified, while the side away from the fault zone is treated with directional perforation. The near-fracture zone reservoir uses a spiral perforation process on the side close to the fracture zone and a directional perforation process on the side far from the fracture zone. The reservoir in the far-fault zone is treated with a spiral perforation process on the side closer to the fault and a directional perforation process on the side farther from the fault.

8. A method for stimulating a horizontal well in a complex fractured water-bearing oil and gas reservoir according to claim 1 or 6, characterized in that, It also includes the following steps: During the fracturing process of the fractured reservoir, the formation fracture extension parameters are obtained to determine its extension trend. Based on the extension trend of the formation fracture, it is predicted whether the formation fracture will connect with the fault zone. If the extension trend of the formation fracture will connect with the fault zone, the fracturing process parameters are adjusted and an early warning response is output.

9. A system for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs, characterized in that, include The fault zone module is used to determine the development characteristics of fault zones based on the sand body geological features and seismic data of the horizontal well controlled area. The reservoir segmentation module is used to determine the type of fractured reservoir corresponding to each fractured section along the horizontal wellbore direction based on the characteristics of fracture zone development and the relative position of horizontal wells. The fracturing stimulation module is used to determine the fracturing process for each fracturing section and carry out fracturing stimulation based on the fractured reservoir type and the effective fracture stimulation range on both sides of the perforation point of the corresponding fracturing section.

10. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the method for stimulating horizontal wells in complex fractured water-bearing oil and gas reservoirs as described in any one of claims 1-8.

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