Energy storage fracturing process optimization method based on productivity main control factor analysis

Abstract

The invention discloses an energy storage fracturing process optimization method based on productivity main control factor analysis, and belongs to the technical field of oil and gas field development, and the method comprises the following steps: S1, constructing a gas-water two-phase triple medium productivity model; s2, correcting the model; s3, making a productivity simulation scheme and predicting the yield; and S4, determining the primary and secondary relation of the influence factors and the optimal energy storage fracturing process. By the adoption of the energy storage fracturing process optimization method based on productivity main control factor analysis, the problems of insufficient stratum energy, the water locking effect, the low crack complexity and the like are effectively solved, the reservoir permeability and yield are enhanced, comprehensive consideration of productivity influence factors is ensured by comprehensively evaluating related parameters, and the energy storage fracturing process optimization method based on productivity main control factor analysis has the advantages of being high in practicability and the like. Therefore, the production efficiency of a single well and the overall development benefit of a tight reservoir are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to an energy storage fracturing process optimization method based on analysis of production capacity main control factors. Background Art

[0002] The physical properties of tight reservoirs are mostly poor, mainly manifested in low porosity and permeability, low reserve abundance and strong heterogeneity. The production increase effect of traditional hydraulic fracturing technology in such reservoirs is often not obvious, and it often faces problems such as water lock effect and insufficient formation energy, which makes oil and gas development much more difficult than conventional gas reservoirs. Therefore, traditional fracturing technology often faces multiple challenges such as insufficient formation energy and water lock effect in application. In order to solve these problems, it is necessary to propose an energy storage fracturing process method for tight reservoirs to achieve efficient fracturing transformation and production increase. However, the selection of suitable energy storage fracturing media is the key to improving fracturing effect and production capacity. Compared with carbon dioxide, liquid nitrogen is more effective in reservoir energy enhancement, and liquid nitrogen has a stronger ability to relieve water lock effect than carbon dioxide; while carbon dioxide is better at creating complex fracture networks. Under the same conditions, if the tight reservoir needs to form a complex fracture network, pre-CO2 energy storage fracturing is preferred; if the tight reservoir needs to increase the formation pressure, pre-liquid nitrogen energy storage fracturing is preferred; if both energy enhancement and the formation of a complex fracture network are required, pre-CO2 energy storage fracturing is preferred.

[0003] At present, Chinese patent publication CN115099062A proposes a method for designing energy storage fracturing process parameters for tight oil reservoirs, which combines indoor experiments and numerical simulations to quantitatively optimize energy storage fracturing construction parameters. However, the energy storage fracturing medium of this method is water, which is only applicable to oil reservoirs and cannot provide a suitable energy storage fracturing process method for tight gas reservoirs.

[0004] In summary, the existing energy storage fracturing technology is mostly used in low permeability tight oil reservoirs and usually uses water as the energy storage fracturing medium. However, in tight gas reservoirs, water is not suitable as a fracturing medium. Since tight gas reservoirs are susceptible to water lock effect, water injection will aggravate water lock damage, resulting in reduced reservoir permeability and production. Therefore, for tight gas reservoirs, it is urgent to select more suitable energy storage fracturing media and energy storage fracturing process methods. Summary of the invention

[0005] The purpose of the present invention is to provide a method for optimizing energy storage fracturing technology based on the analysis of the main controlling factors of production capacity. The method effectively solves the problems of insufficient formation energy and water lock, enhances the reservoir permeability and production, and ensures a comprehensive consideration of the factors affecting production capacity by comprehensively evaluating relevant parameters, thereby significantly improving the production efficiency of a single well and the overall development benefits of a tight reservoir.

[0006] To achieve the above object, the present invention provides a method for optimizing an energy storage fracturing process based on analysis of the main controlling factors of production capacity, comprising the following steps:

[0007] S1. Combining the embedded discrete fracture model, dual medium model and single medium model, a gas-water two-phase triple medium productivity model for tight reservoir fractured horizontal wells is established;

[0008] S2, using field data to calibrate the gas-water two-phase triple medium productivity model for tight reservoir fractured horizontal wells established in S1;

[0009] S3. Formulate a production capacity simulation example plan based on the target reservoir parameters; use the calibrated tight reservoir fracture horizontal well gas-water two-phase triple medium production capacity model to execute the production capacity simulation example plan to obtain the simulated expected production data;

[0010] S4. Use grey correlation analysis to process the simulated production data from step S3, determine the influence of various factors on the simulated production data and sort them, and select an energy storage fracturing scheme suitable for the target block according to the sorting results.

[0011] Preferably, in S1, the seepage area of ​​the gas-water two-phase triple medium productivity model of the tight reservoir fractured horizontal well includes the matrix, the fracturing transformation area and the hydraulic fracture. The matrix seepage area is simplified to a single medium, the fracturing transformation area is characterized by a dual medium model, and the hydraulic fracture is characterized by an embedded discrete fracture model.

[0012] Preferably, in S2, a finite difference method is used to solve the gas-water two-phase triple medium productivity model of a tight reservoir fractured horizontal well established in S1.

[0013] Preferably, in S3, the target reservoir parameters include geological and engineering parameters of the target reservoir block, which are used to determine the matrix water saturation, formation pressure, area of ​​the fracturing transformation area, permeability of the fracturing transformation area and range of hydraulic fracture conductivity.

[0014] Preferably, in S3, an arithmetic difference method is used to select level values ​​within the target reservoir parameter range to formulate a production capacity simulation example plan.

[0015] Preferably, in S4, the treatment methods of energy storage fracturing in the target block include: method 1 pre-injection of liquid nitrogen for energy enhancement, method 2 pre-injection of CO2 for energy enhancement, method 3 increasing the intensity of liquid use and method 4 increasing the intensity of sand addition. The energy storage fracturing scheme for the target block obtained according to the above methods is specifically as follows: (1) if the top two main controlling factors are matrix water saturation and formation pressure, the energy storage fracturing process based on method 1 is adopted;

[0016] (2) If the top two controlling factors are matrix water saturation and SRV zone permeability, and matrix water saturation ranks first, the energy storage fracturing process based on method 1 is adopted; if SRV zone permeability ranks first, the energy storage fracturing process based on method 2 is adopted;

[0017] (3) If the top two controlling factors are matrix water saturation and SRV area, the energy storage fracturing process combining method 1 and method 3 is used;

[0018] (4) If the top two controlling factors are matrix water saturation and main fracture conductivity, the energy storage fracturing process combining method 1 and method 4 is adopted;

[0019] (5) If the top two controlling factors are formation pressure and SRV zone permeability, and formation pressure ranks first, the energy storage fracturing process based on method 1 is adopted; if SRV zone permeability ranks first, the energy storage fracturing process based on method 2 is adopted;

[0020] (6) If the top two controlling factors are formation pressure and SRV area, the energy storage fracturing process combining method 1 and method 3 is adopted;

[0021] (7) If the top two controlling factors are formation pressure and main fracture conductivity, the energy storage fracturing process combining method 1 and method 4 is adopted;

[0022] (8) If the top two controlling factors are SRV zone permeability and SRV zone area, the energy storage fracturing process combining method 2 and method 3 is adopted;

[0023] (9) If the top two controlling factors are SRV zone permeability and main fracture conductivity, the energy storage fracturing process combining method 2 and method 4 is adopted;

[0024] (10) If the top two controlling factors are SRV area and main fracture conductivity, the energy storage fracturing process combining methods 1, 3 and 4 is adopted.

[0025] Therefore, the present invention adopts the above-mentioned energy storage fracturing process optimization method based on the analysis of the main controlling factors of production capacity. Compared with the prior art, the present invention has the following significant beneficial effects: it provides an energy storage fracturing method suitable for tight gas reservoirs that does not use water as an energy-enhancing medium, which can effectively supplement the formation energy, improve the water lock effect, and increase the complexity of the fractures. At the same time, by determining the main controlling factors (geological parameters, engineering parameters) of different reservoirs on production, targeted energy storage fracturing process plans suitable for various reservoirs are formulated, providing a scientific basis and technical support for reservoir development.

[0026] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic flow chart of an optimization method of an energy storage fracturing process optimization method based on the analysis of the main control factors of production capacity of the present invention;

[0028] Figure 2 A schematic diagram of a reservoir physical model of an energy storage fracturing process optimization method based on analysis of production capacity main control factors of the present invention;

[0029] Figure 3 This is a validation data diagram of a gas-water two-phase triple medium productivity model for a tight reservoir fracturing horizontal well of an energy storage fracturing process optimization method based on productivity main control factor analysis of the present invention;

[0030] Figure 4 It is a contour map of micro-fracture pressure at different times of an energy storage fracturing process optimization method based on the analysis of the main control factors of production capacity of the present invention, Figure 4 a in the figure represents the SRV pressure contour map after 1 day; Figure 4 b in the figure shows the contour map of SRV pressure after 10 days; Figure 4 The c in the figure represents the SRV pressure contour map after 100 days. Figure 4 The d in the figure shows the SRV pressure contour map after 450 days;

[0031] Figure 5 It is a contour map of matrix pressure at different times of an energy storage fracturing process optimization method based on the analysis of the main control factors of productivity of the present invention, Figure 5 a in the figure represents the contour map of matrix pressure after 1 day. Figure 5 b in the figure shows the contour map of matrix pressure after 10 days. Figure 5 c in the figure represents the contour map of matrix pressure after 100 days; Figure 5 The d in the figure shows the contour map of matrix pressure after 450 days;

[0032] Figure 6 This is a ranking diagram of the influence degree of various factors in a method for optimizing an energy storage fracturing process based on analysis of main control factors of production capacity according to the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meaning understood by people with general skills in the field to which the present invention belongs.

[0034] Embodiment 1

[0035] like Figure 1As shown, a method for optimizing an energy storage fracturing process based on analysis of production capacity main controlling factors of the present invention comprises the following steps:

[0036] S1, such as Figure 2 As shown in the figure, the Y block of the tight sandstone gas reservoir in a certain area is set as the target block, and the Y block includes the YL well. Based on the embedded discrete fracture model and the dual medium model, the complex fractures formed by the tight reservoir energy storage fracturing are characterized, and the triple medium flow characteristics of matrix, SRV zone and hydraulic fracture are fully considered after the tight reservoir energy storage fracturing transformation. The gas-water two-phase triple medium productivity model of the tight reservoir fracturing horizontal well is established. The seepage area of ​​the model includes three seepage areas: matrix, SRV zone and hydraulic fracture.

[0037] S2, such as Figure 3-Figure 5 As shown in the figure, the finite difference method is used to solve the gas-water two-phase triple medium productivity model of the tight reservoir fractured horizontal well established in S1, and the actual field data of a horizontal well (YL well) in a specific block (Y block) is used to fit and verify the model. Specifically, the production cycle of daily gas production is set to 450 days, the daily gas production is set according to the actual production data on site, and the bottom hole pressure data is fitted. Through this process, the effectiveness and accuracy of the model are verified;

[0038] After about 100 days of production, the pressure drop in the SRV zone (Stimulated Reservoir Volume, i.e., the fracturing zone) quickly spread to the matrix zone, indicating that the energy transfer effect was very ideal. This phenomenon further proves that formation pressure has a significant impact on increasing production capacity, and also shows that the gas-water two-phase triple medium production capacity model of tight reservoir fracturing horizontal wells can accurately reflect the dynamic changes in actual production, ensuring the basic reliability of subsequent process optimization.

[0039] S3. First, the geological and engineering parameters of the target reservoir block Y are counted to determine the range of matrix water saturation, formation pressure, SRV area, SRV permeability and main fracture conductivity. The specific parameter ranges are shown in Table 1 below:

[0040] Table 1 Range of geological engineering parameters in Block Y

[0041] Parameter Type Block parameter range Water saturation 0.3～0.6 Formation pressure, unit: MPa 15～27 SRV area, unit: m*m 90*270～120*360 SRV permeability, unit: mD 1～10 Main fracture conductivity, unit: D·cm 2～20

[0042] Based on the above parameter range, the present invention adopts the arithmetic difference method to select different level values ​​and formulates a detailed capacity simulation example scheme. In this way, it is ensured that each parameter can be fully considered within a reasonable range, thereby providing diversified basic data for subsequent production forecasts. The specific example scheme design is shown in the table below:

[0043] Table 2 Simulation example scheme

[0044]

[0045]

[0046] The simulated production data is obtained through the capacity simulation example solution, as shown in the following table:

[0047] Table 3 Simulated production data

[0048]

[0049]

[0050] S4, such as Figure 6 As shown, the simulated yield data from step S3 are processed by grey correlation analysis to obtain the influence degree ranking of the influencing factors on the simulated yield data, as shown in Table 4:

[0051] Table 4 Ranking of the influence of each factor

[0052] Evaluation items Relevance Ranking factor Formation pressure 0.7063 1 Geology Main fracture conductivity 0.6568 2 project SRV Area 0.6461 3 project SRV penetration 0.6414 4 project Matrix water saturation 0.6103 4 Geology

[0053] The treatment methods for energy storage fracturing in the target block include: method one, pre-injection of liquid nitrogen for energy enhancement. The high-pressure gas generated by the vaporization of liquid nitrogen and its diffusion can increase the local pressure of the gas reservoir; method two, pre-injection of CO2 for energy enhancement can locally increase the formation pressure, connect the formation pores, drive out the pore fluids, and induce the outflow of fluids in the non-active area. Method three, increasing the intensity of fluid use. High-intensity fluid use can provide higher fracture driving pressure, make the fractures longer and wider, and help more areas of the reservoir to be activated; method four, increasing the intensity of sand addition. More proppants fill the fractures to form high-conductivity channels, thereby slowing down the closure of the fractures and improving the long-term conductivity of the fractures. The energy storage fracturing scheme for the target block obtained according to the above methods is specifically as follows: (1) If the top two main controlling factors are matrix water saturation and formation pressure, the energy storage fracturing process based on method one is adopted;

[0054] (2) If the top two controlling factors are matrix water saturation and SRV zone permeability, and matrix water saturation ranks first, the energy storage fracturing process based on method 1 is adopted; if SRV zone permeability ranks first, the energy storage fracturing process based on method 2 is adopted;

[0055] (3) If the top two controlling factors are matrix water saturation and SRV area, the energy storage fracturing process combining method 1 and method 3 is adopted;

[0056] (4) If the top two controlling factors are matrix water saturation and main fracture conductivity, the energy storage fracturing process combining method 1 and method 4 is adopted;

[0057] (5) If the top two controlling factors are formation pressure and SRV zone permeability, and formation pressure ranks first, the energy storage fracturing process based on method 1 is adopted; if SRV zone permeability ranks first, the energy storage fracturing process based on method 2 is adopted;

[0058] (6) If the top two controlling factors are formation pressure and SRV area, the energy storage fracturing process combining method 1 and method 3 is adopted;

[0059] (7) If the top two controlling factors are formation pressure and main fracture conductivity, the energy storage fracturing process combining method 1 and method 4 is adopted;

[0060] (8) If the top two controlling factors are SRV zone permeability and SRV zone area, the energy storage fracturing process combining method 2 and method 3 is adopted;

[0061] (9) If the top two controlling factors are SRV zone permeability and main fracture conductivity, the energy storage fracturing process combining method 2 and method 4 is adopted;

[0062] (10) If the top two controlling factors are SRV area and main fracture conductivity, the energy storage fracturing process combining methods 1, 3 and 4 is used. Based on the results of the primary and secondary relationship analysis of the influencing factors determined by the grey correlation method, formation pressure and main fracture conductivity are confirmed to be the main factors affecting production capacity. Therefore, the energy storage fracturing process combining pre-injection of liquid nitrogen to increase energy and increase sand intensity is adopted. The specific design includes 250sm 3 / min liquid nitrogen displacement, 270sm 3 / m liquid nitrogen strength and sand adding strength are 1.5 times that of conventional sand adding strength in Block Y. By implementing the above technology, the fracture network transformation effect of Well YL was significant, specifically: the formation pressure coefficient of Block Y was increased from 1.2 to 1.4; the daily gas production of a single well exceeded 8.9×10 4 m 3 ; Compared with the energy storage fracturing process that does not use this technology, the production volume increased by 75%.

[0063] This optimized energy storage fracturing process not only improves the energy state of the reservoir, but also significantly increases the production efficiency of oil and gas wells, proving its effectiveness and superiority in practical applications.

[0064] Therefore, the present invention adopts the above-mentioned method for optimizing the energy storage fracturing process based on the analysis of the main controlling factors of production capacity. This method effectively solves the water lock problem, enhances the reservoir permeability and production, and ensures a comprehensive consideration of the factors affecting production capacity by comprehensively evaluating relevant parameters, thereby significantly improving the production efficiency of a single well and the overall development benefits of tight reservoirs.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for optimizing energy storage fracturing technology based on analysis of production capacity main controlling factors, characterized in that: The following steps are involved: S1. Combining the embedded discrete fracture model, dual medium model and single medium model, a gas-water two-phase triple production capacity model for tight reservoir fractured horizontal wells is established; S2, using field data to calibrate the gas-water two-phase triple medium productivity model for tight reservoir fractured horizontal wells established in S1; S3. Formulate a production capacity simulation example plan based on the target reservoir parameters, and use the calibrated tight reservoir fracture horizontal well gas-water two-phase triple medium production capacity model to execute the production capacity simulation example plan to obtain the simulated expected production data; S4. Use grey correlation analysis to process the simulated production data from step S3, determine the influence of factors on the simulated production data and sort them, and recommend an energy storage fracturing scheme suitable for the target block based on the sorting results.

2. The method for optimizing the energy storage fracturing process based on the analysis of the main controlling factors of production capacity according to claim 1, characterized in that: In S1, the seepage area of ​​the gas-water two-phase triple medium productivity model of tight reservoir fractured horizontal wells includes matrix, fracture transformation area and hydraulic fractures. The matrix seepage area is simplified to a single medium, the fracture transformation area is represented by a dual medium model, and the hydraulic fracture is represented by an embedded discrete fracture network.

3. The method for optimizing the energy storage fracturing process based on the analysis of the main controlling factors of production capacity according to claim 1, characterized in that: In S2, the finite difference method is used to solve the gas-water two-phase triple medium productivity model of the tight reservoir fractured horizontal well established in S1.

4. The method for optimizing the energy storage fracturing process based on the analysis of the main controlling factors of production capacity according to claim 1, characterized in that: In S3, the target reservoir parameters include the geological and engineering parameters of the target reservoir block, which are used to determine the matrix water saturation, formation pressure, area of ​​the fracturing transformation area, permeability of the fracturing transformation area and range of hydraulic fracture conductivity.

5. The method for optimizing the energy storage fracturing process based on the analysis of the main controlling factors of production capacity according to claim 4, characterized in that: In S3, the arithmetic difference method is used to select level values ​​within the target reservoir parameter range to formulate a production capacity simulation example plan.

6. The method for optimizing energy storage fracturing process based on analysis of production capacity main controlling factors according to claim 1, characterized in that: In S4, the treatment methods of energy storage fracturing in the target block include: method 1 pre-injection of liquid nitrogen for energy enhancement, method 2 pre-injection of CO2 for energy enhancement, method 3 increasing the intensity of liquid use and method 4 increasing the intensity of sand addition. The energy storage fracturing scheme of the target block obtained according to the above methods is as follows: (1) if the top two main controlling factors are matrix water saturation and formation pressure, the energy storage fracturing process based on method 1 is adopted; (2) If the top two controlling factors are matrix water saturation and SRV zone permeability, and matrix water saturation ranks first, the energy storage fracturing process based on method 1 is adopted; if SRV zone permeability ranks first, the energy storage fracturing process based on method 2 is adopted; (3) If the top two controlling factors are matrix water saturation and SRV area, the energy storage fracturing process combining method 1 and method 3 is adopted; (4) If the top two controlling factors are matrix water saturation and main fracture conductivity, the energy storage fracturing process combining method 1 and method 4 is adopted; (5) If the top two controlling factors are formation pressure and SRV zone permeability, and formation pressure ranks first, the energy storage fracturing process based on method 1 is adopted; if SRV zone permeability ranks first, the energy storage fracturing process based on method 2 is adopted; (6) If the top two controlling factors are formation pressure and SRV area, the energy storage fracturing process combining method 1 and method 3 is adopted; (7) If the top two controlling factors are formation pressure and main fracture conductivity, the energy storage fracturing process combining method 1 and method 4 is adopted; (8) If the top two controlling factors are SRV zone permeability and SRV zone area, the energy storage fracturing process combining method 2 and method 3 is adopted; (9) If the top two controlling factors are SRV zone permeability and main fracture conductivity, the energy storage fracturing process combining method 2 and method 4 is adopted; (10) If the top two controlling factors are SRV area and main fracture conductivity, the energy storage fracturing process combining methods 1, 3 and 4 is adopted.

Images