Tight sandstone discrimination and energy storage fracturing process parameter optimization method

Abstract

The invention provides a tight sandstone discrimination and energy storage fracturing process parameter optimization method, which comprises the following steps: firstly, determining tight oil core physical properties and pore structure characteristics to lay a foundation for energy storage fracturing mechanism and scheme optimization, secondly, based on fracturing fluid imbibition and micro-macroscopic oil displacement tests, revealing a main action mechanism of imbibition, and finally, determining the energy storage fracturing process parameters according to the imbibition and micro-macroscopic oil displacement tests. Determining whether tight sandstone has imbibition, imbibition displacement oil displacement capability and imbibition displacement oil displacement mechanism; an oil-water replacement relational expression in the energy storage stage is established by analyzing data of shut-in time after pressure, the average daily pressure drop and the daily pressure drop in the open flow period; through tight oil fracturing productivity influence factor analysis, geological engineering key parameters influencing the tight oil energy storage volume fracturing effect are determined; an energy storage volume fracturing-productivity integrated analysis model is established, whether a tight reservoir needs energy storage or not and the energy storage mode are determined, applicable technical parameter boundaries are put forward, and theoretical and technical supports are provided for improving the energy storage volume fracturing effect and prolonging the effective period of measures.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a method for identifying tight sandstone and optimizing energy storage fracturing process parameters. Background Art

[0002] The permeability and porosity of tight sandstone reservoirs are relatively low, and the formation pressure coefficient is low. The natural production capacity of a single well is low or there is no natural production capacity. Conventional fracturing and volume fracturing processes are generally used to improve the production capacity of a single well. Although certain transformation effects can be achieved, the initial production after fracturing often decreases rapidly, the oil wells produce at a low rate, and the formation energy is insufficient. In conventional oil and gas production, fracturing fluid, as an external fluid, will produce negative effects such as water sensitivity and water lock, which is not conducive to the production of oil and gas wells. For low-permeability, tight sandstone reservoirs, large-scale fracturing fluids are retained after entering the formation, and the return rate after fracturing is very low. At the same time, field production has found that after a period of well sealing after fracturing, it can be mined again. This mining method has a long stable production time and a good oil increase effect.

[0003] Due to the special low porosity and low permeability properties of low permeability reservoirs, energy storage and permeability enhancement based on imbibition is a new measure for the development of low permeability reservoirs. Energy storage fracturing combines volume fracturing transformation with secondary and tertiary oil recovery. Based on the formation of a complex fracture network by large-scale volume fracturing, a non-uniform pressure system is established to achieve displacement between networks, fractures, and segments. At the same time, a large amount of retained fracturing fluid is replaced by oil and water to drive oil, achieving the purpose of fracturing energy replenishment and imbibition oil drive. At the same time, in the continuous operation process of hydraulic fracturing-well blocking-production, the reservoir state at the end of fracturing is the initial condition of the well blocking operation, and the reservoir state at the end of the well blocking constitutes the initial state of the production operation. The three independent operation processes are closely linked, resulting in the final production capacity being greatly affected by both fracturing and well blocking measures.

[0004] The existing technology is usually an implementation method of the on-site energy storage fracturing process, or equipment and experimental methods related to energy storage fracturing. The results of the on-site application of energy storage fracturing show that the production of single wells and horizontal wells in the same block has been significantly improved, but the transformation effects of some well layers vary greatly. The production effects of wells in the same block and wells in different blocks show obvious differences. The understanding of the production increase mechanism of energy storage fracturing is still unclear, and the law of energy storage influence has not been mastered. It is necessary to carry out volume fracturing adaptability test analysis based on specific reservoir characteristics, clarify whether the target belongs to a tight sandstone reservoir, and clarify whether the target tight sandstone reservoir needs energy storage and the energy storage method. At the same time, it provides theoretical and technical support for improving the effect of energy storage volume fracturing and extending the effectiveness of the measures, proposes the applicable technical parameter limits, and establishes a method for tight sandstone identification and energy storage fracturing process parameter optimization. Summary of the invention

[0005] The embodiment of the present application provides a method for identifying tight sandstone and optimizing energy storage fracturing process parameters, which can clarify whether tight sandstone reservoirs require energy storage and the energy storage method, and propose the applicable technical parameter limits, providing theoretical and technical support for improving the energy storage volume fracturing effect and extending the effectiveness of the measures.

[0006] The present application embodiment provides a method for identifying tight sandstone and optimizing energy storage fracturing process parameters, including:

[0007] S1, obtain the basic data, imaging logging data, construction data, well shut-in data and production data of the target well;

[0008] S2, test the core mineral composition, physical properties and pore throat structure through indoor experiments to determine whether it is a tight sandstone;

[0009] S3, conduct fracturing fluid imbibition and oil displacement tests through indoor experiments to clarify whether tight sandstone has imbibition and its imbibition capacity;

[0010] S4, by analyzing the data of the construction curve to identify the fracture extension morphology, obtain the fracture geometry parameters through net pressure fitting, obtain the closure parameters and formation parameters through G function analysis, and determine the main control factors of the fracturing stage;

[0011] S5, determine the main controlling factors of the energy storage stage by combining the target well data with the results of the imbibition experiment;

[0012] S6, based on the energy storage fracturing mathematical model, conduct integrated numerical simulation of energy storage fracturing of the target well;

[0013] S7, with the maximum production capacity as the goal, the recommended parameters of the single-well energy storage fracturing process are obtained.

[0014] Among them, in step S1, the basic data of the construction well include: porosity, permeability, oil saturation, crude oil viscosity, reservoir thickness, formation pressure coefficient, horizontal maximum principal stress, horizontal minimum principal stress, Young's modulus, Poisson's ratio, tensile strength, wetting contact angle; imaging logging data include: natural fracture inclination, natural fracture inclination direction, maximum horizontal principal stress direction; construction data include: time, sand concentration, oil pressure, displacement, stage liquid volume; well soaking data include: well soaking time, average daily pressure drop, daily pressure drop during blowing; production data include: date, daily liquid production, daily oil production, water content, oil pressure.

[0015] Among them, in step S2, the microscopic morphological characteristics of the core in the target well area are obtained by using a scanning electron microscope, the mineral composition of the core is determined by an X-ray diffractometer, and the pore structure of the core is measured by a cast thin section to determine the mineral composition, physical properties and pore structure characteristics of the dense core.

[0016] Among them, in step S3, the fracturing fluid imbibition capacity test experiment is used to clarify whether the tight sandstone has imbibition and its imbibition capacity, and the imbibition displacement experiment is used to evaluate the fracturing imbibition displacement oil recovery capacity.

[0017] Among them, in step S4, by analyzing the construction curve characteristics and pump-off pressure drop curve of the tight sandstone fracturing well in the target well area, the fracture extension mode is identified, the net pressure fitting is used to obtain the fracture geometric parameters, and the early transformation effect is clarified. The construction data and basic data required for the analysis process are obtained in step S1.

[0018] Among them, in step S5, the oil-water replacement efficiency in the energy storage stage is quantitatively evaluated by analyzing the data of the well shut-in time after pressure reduction and the average daily pressure drop and the daily pressure drop during the blowout period, combined with the experimental data in step S3; the main controlling factors in the energy storage stage are comprehensively evaluated by combining the basic data of the construction well in step S1, the natural fracture parameters in the imaging logging and the fracture geometric parameters obtained in step S4 with the production data.

[0019] Among them, in step S6, a single well model is established to simulate the entire process of crack extension in energy storage fracturing, and the rock mechanics parameters and stress data required for the calculation process are obtained in step S1; a mechanism model is established to simulate the entire process of well soaking, percolation and production after energy storage fracturing, and the data required in the calculation process include: the basic data of the target well in step S1 and the pore pressure distribution and fracture conductivity after the crack extension is completed obtained by calculating the fracturing process in step S6.

[0020] Among them, in step S7, based on the integrated mathematical model of energy storage fracturing, the influence of geological conditions and engineering parameters on the overall energy storage fracturing is simulated and analyzed, and with the goal of achieving maximum production capacity, specific process recommended parameters are obtained; geological conditions include reservoir permeability and formation pressure coefficient, and engineering parameters include energy storage fracturing fluid dosage, construction displacement, and energy storage fracturing fluid viscosity.

[0021] The method for identifying tight sandstone and optimizing energy storage fracturing process parameters in the embodiment of the present application has the following beneficial effects:

[0022] This application integrates the energy storage fracturing process of tight sandstone reservoirs by combining indoor experiments, post-fracturing analysis and numerical simulation. First, the physical properties and pore structure characteristics of tight oil cores are determined to lay the foundation for the optimization of energy storage fracturing mechanisms and schemes. Secondly, based on the imbibition of fracturing fluid and micro-macro oil displacement tests, the main mechanism of imbibition is revealed, and it is clarified whether tight sandstone has imbibition, imbibition displacement oil displacement capacity and imbibition displacement oil displacement mechanism; through the data analysis of the post-fracturing well shut-in time and the average daily pressure drop, and the daily pressure drop during the blowout period, the oil-water displacement relationship in the energy storage stage is established; through the analysis of the factors affecting the tight oil fracturing capacity, the key geological engineering parameters affecting the tight oil energy storage volume fracturing effect are clarified; an integrated analysis model of energy storage volume fracturing-capacity is established to clarify whether tight reservoirs need energy storage and the energy storage method, and the applicable technical parameter limits are proposed to provide theoretical and technical support for improving the energy storage volume fracturing effect and extending the effectiveness of the measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic flow chart of a method for optimizing tight sandstone identification and energy storage fracturing process parameters according to an embodiment of the present application;

[0024] Figure 2 This is another flow chart of the method for identifying tight sandstone and optimizing energy storage fracturing process parameters according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0026] In the following introduction, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The following introduction provides multiple embodiments of the present invention, and different embodiments can be replaced or combined, so this application can also be considered to include all possible combinations of the same and / or different embodiments recorded. Therefore, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then this application should also be considered to include embodiments containing one or more of all other possible combinations of features A, B, C, and D, even though the embodiment may not be clearly recorded in the following text.

[0027] Embodiment 1

[0028] like Figure 1As shown, the method for identifying tight sandstone and optimizing the process parameters of energy storage fracturing in the present application includes: S1, obtaining basic data, imaging logging data, construction data, well shut-in data and production data of the target well; S2, testing the mineral composition, physical properties and pore throat structure of the core through indoor experiments to determine whether it belongs to tight sandstone; S3, conducting fracturing fluid imbibition and oil displacement tests through indoor experiments to determine whether tight sandstone has imbibition and its imbibition capacity; S4, identifying the fracture extension morphology through data analysis of the construction curve, obtaining the fracture geometric parameters through net pressure fitting, obtaining the closure parameters and formation parameters through G function analysis, and determining the main controlling factors of the fracturing stage; S5, determining the main controlling factors of the energy storage stage through the target well data combined with the results of the imbibition experiment; S6, conducting integrated numerical simulation of energy storage fracturing of the target well based on the mathematical model of energy storage fracturing; S7, obtaining the recommended parameters of the single-well energy storage fracturing process with the maximum production capacity as the goal.

[0029] This application can clarify whether tight sandstone reservoirs need energy storage and the energy storage method, and propose the applicable technical parameter limits, providing theoretical and technical support for improving the energy storage volume fracturing effect and extending the effectiveness of the measures.

[0030] Embodiment 2

[0031] In view of the shortcomings of the prior art, the present application provides a method for identifying tight sandstone and optimizing energy storage fracturing process parameters, which is used to solve the problem of large differences in the transformation effects of tight oil reservoir wells.

[0032] The present application discloses a method for identifying tight sandstone and optimizing parameters of energy storage fracturing process, including: S1. obtaining cores, basic data, imaging logging, fracturing construction data, well soaking data and production data of target wells; S2. testing the mineral composition, physical properties and pore throat structure of the cores through indoor experiments to determine whether they belong to tight sandstone; S3. conducting fracturing fluid imbibition and oil displacement tests through indoor experiments to determine whether tight sandstone has imbibition and its imbibition capacity; S4. identifying the fracture extension morphology through data analysis of construction curves, obtaining fracture geometric parameters through net pressure fitting, obtaining closure parameters and formation parameters through G function analysis, and determining the main controlling factors of the fracturing stage; S5. determining the main controlling factors of the energy storage stage through combining the target well data with the results of imbibition experiments; S6. conducting integrated numerical simulation of energy storage fracturing of target wells based on the mathematical model of energy storage fracturing; S7. obtaining the recommended parameters of single well energy storage fracturing process with the maximum production capacity as the goal.

[0033] Among them, the basic data of the construction well in step S1 include: porosity, permeability, oil saturation, crude oil viscosity, reservoir thickness, formation pressure coefficient, horizontal maximum principal stress, horizontal minimum principal stress, Young's modulus, Poisson's ratio, tensile strength, and wetting contact angle. The imaging logging data include: natural fracture inclination, natural fracture inclination trend, and maximum horizontal principal stress direction. The construction data include: time, sand concentration, oil pressure, displacement, and stage liquid volume. The soaking well data include: soaking well time, average daily pressure drop, and daily pressure drop during the blowout period. The production data include: date, daily liquid production, daily oil production, water content, and oil pressure.

[0034] Among them, in step S2, a scanning electron microscope is used to obtain the microscopic morphological characteristics of the core in the target well area, an X-ray diffractometer is used to determine the mineral composition of the core, and a cast thin section is used to measure the pore structure of the core to determine the physical properties and pore structure characteristics of the tight sand oil core.

[0035] Among them, in step S3, the fracturing fluid imbibition capacity test experiment is used to clarify whether the tight sandstone has imbibition and its imbibition capacity, and the imbibition displacement experiment is used to evaluate the fracturing imbibition displacement oil recovery capacity.

[0036] Among them, in step S4, by analyzing the construction curve characteristics and pump-off pressure drop curve of the tight sandstone fracturing well in the target well area, the fracture extension mode is identified, the net pressure fitting is used to obtain the fracture geometric parameters, and the early transformation effect is clarified. The construction data and basic data required for the analysis process are obtained in step S1.

[0037] Among them, in step S5, the oil-water replacement efficiency in the energy storage stage is quantitatively evaluated by analyzing the data of the well shut-in time after pressure reduction and the average daily pressure drop and the daily pressure drop during the blowout period, combined with the experimental data in step S3; the main controlling factors in the energy storage stage are comprehensively evaluated by combining the basic data of the construction well in step S1, the natural fracture parameters in the imaging logging and the fracture geometric parameters obtained in step S4 with the production data.

[0038] Among them, step S6 is divided into two parts. First, the single well model is established by using the Pertel software to simulate the entire process of crack extension in energy storage fracturing. The rock mechanics parameters and stress data required for the calculation process are obtained in step S1. Secondly, the mechanism model is established by using the CMG software to simulate the whole process of well soaking, infiltration and production after energy storage fracturing. The data required in the calculation process are the basic data of the target well in step S1 and the pore pressure distribution and fracture conductivity after the crack extension is completed, which are calculated in the fracturing process in step S6.

[0039] Among them, in step S7, based on the integrated mathematical model of energy storage fracturing, the geological conditions such as reservoir permeability, formation pressure coefficient and the engineering parameters such as energy storage fracturing fluid dosage, construction displacement, and energy storage fracturing fluid viscosity are simulated and analyzed to simulate and analyze the impact on the overall energy storage fracturing, and with the goal of achieving maximum production capacity, specific process recommended parameters are obtained.

[0040] The present invention integrates the energy storage fracturing process of tight sandstone reservoirs by combining indoor experiments, post-fracturing analysis and numerical simulation. First, the physical properties and pore structure characteristics of tight oil cores are determined to lay a foundation for the optimization of energy storage fracturing mechanism and scheme. Secondly, based on the imbibition of fracturing fluid and micro-macro oil displacement tests, the main mechanism of imbibition is revealed, and it is clarified whether tight sandstone has imbibition, imbibition displacement oil displacement capacity and imbibition displacement oil displacement mechanism; by analyzing the data of post-fracturing well shut-in time and average daily pressure drop, and daily pressure drop during blowing, the oil-water displacement relationship in the energy storage stage is established; by analyzing the factors affecting the tight oil fracturing capacity, the key geological engineering parameters affecting the tight oil energy storage volume fracturing effect are clarified; an integrated analysis model of energy storage volume fracturing-capacity is established to clarify whether tight reservoirs need energy storage and the energy storage method, and the applicable technical parameter limits are proposed, providing theoretical and technical support for improving the energy storage volume fracturing effect and extending the effective period of measures.

[0041] Embodiment 3

[0042] The method for identifying tight sandstone and optimizing the process parameters of energy storage fracturing in the present application includes: S1. Obtaining the core, basic data, construction data and well-insertion data of the target layer of the fractured well; S2. Testing the mineral composition, physical properties and pore throat structure of the tight core through indoor experiments; S3. Carrying out fracturing fluid imbibition and oil displacement tests through indoor experiments; S4. Identifying the fracture extension morphology through data analysis of the construction curve, obtaining the fracture geometric parameters through net pressure fitting, and obtaining the closure parameters and formation parameters through G function analysis; S5. Determining the main controlling factors of the energy storage stage through combining the target well data with the results of the imbibition experiment; S6. Based on the mathematical model of energy storage fracturing, conducting integrated numerical simulation of energy storage fracturing of the target well; S7. Determining the recommended parameters of the single-well energy storage fracturing process with the maximum production capacity as the goal.

[0043] Among them, the geological data of the construction well in step S1 include: porosity, permeability, oil saturation, crude oil viscosity, reservoir thickness, formation pressure coefficient, horizontal maximum principal stress, horizontal minimum principal stress, Young's modulus, Poisson's ratio, tensile strength, and wetting contact angle. The construction data include: time, sand concentration, oil pressure, displacement, and stage liquid volume. The soaking well data include: soaking well time, average daily pressure drop, and daily pressure drop during the blowout period.

[0044] In step S2, the physical properties and pore structure characteristics of the tight sand oil core are tested by scanning electron microscopy, thin section, X-ray diffraction, and wettability.

[0045] Among them, after S1 was obtained and cored, its microscopic morphological characteristics were observed by a scanning electron microscope at a magnification of 1000-2000 times; its pore structure was observed by a cast thin section; and its rock and mineral composition was tested by an X-ray diffractometer.

[0046] Among them, in step S3, S1 is used to obtain the core for spontaneous and pressurized imbibition experiments. The experiment mainly uses the volume method and the mass method to measure the oil displacement effect of the spontaneous imbibition process of the core. After the core is cut flat, washed with oil, dried, weighed, etc., the core is saturated with simulated oil using a vacuum saturation device, and then the core is placed in an imbibition bottle filled with imbibition liquid to carry out spontaneous and pressurized imbibition processes. By recording the volume of oil imbibed from the imbibition bottle at different time points, the relationship curves of the imbibition oil displacement efficiency and the change of the imbibition oil displacement speed with time under different factors are calculated. Combined with the rock and mineral and wettability test results, it is clarified whether the dense sandstone has the imbibition capacity; at the same time, through the nuclear magnetic resonance imaging microscopic test during the imbibition oil displacement process, the imbibition displacement oil displacement mechanism is revealed, and the fracturing imbibition displacement oil displacement capacity is clarified.

[0047] Among them, the fracture morphology parameters obtained by net pressure fitting in step S4 include: fracture length, fracture height, and fracture conductivity; the construction parameters obtained by G function analysis include: bottom hole pump stop pressure, bottom hole closing pressure, and net pressure; the fracture extension morphology can be divided into the following types according to the change of net pressure: Type I: net pressure rises, the curve slope is 0 to 1, and the fracture expands normally; Type II: filtration loss = injection amount, the curve slope is 0, and the filtration loss is balanced; Type III: the net pressure rises sharply, the curve slope is >1, and sand addition is difficult; Type IV: the net pressure drops, the curve slope is -1 to 0, and the fracture height expands.

[0048] Among them, in step S5, by comparing and analyzing the well shut-in time after pressure release with the average daily pressure drop and the daily pressure drop during the blowout period, the smaller the pressure drop in "well shut-in time→average daily pressure drop, average pressure drop during the blowout period", the higher the replacement efficiency is, and the oil-water replacement efficiency in the energy storage stage is quantitatively evaluated; the main controlling factors in the energy storage stage are comprehensively evaluated by combining the basic data of the target well, imaging logging, fracturing data and well shut-in data with production data, which are in order: permeability, natural fractures, artificial fracture morphology, energy storage fracturing fluid injection amount and injection rate, etc.

[0049] Among them, in step S6, pertel software is used to establish a single well model, and the model for simulating fracture initiation and extension is UFM. For details, see the document "Li Yue, Mou Jianye, Zhang Shicheng, et al. Numerical simulation of fracture extension law in Tahe fracture-cavity carbonate reservoir [J]. Journal of China University of Petroleum (Natural Science Edition), 2022, 46(06): 135-142.".

[0050] Among them, the two-phase imbibition model of energy storage fracturing is established, which specifically includes: capillary imbibition model and porous medium oil-water two-phase imbibition equation. The lower the permeability of the porous medium, the lower the water saturation in the porous medium, and the greater the capillary force. Therefore, the capillary force is the driving force of imbibition, and gravity and viscous resistance are the imbibition resistance. The capillary force term is:

[0051]

[0052] Where: from left to right are capillary force term, viscous resistance term, gravity term and inertia force term.

[0053] The following assumptions are made for the energy storage fracturing capacity model: (1) the reservoir is composed of two phases of oil and water, and conforms to Darcy flow; (2) the rock and fluid in the reservoir matrix fractures are slightly compressible; (3) the fluid flow is isothermal; (4) gravity is ignored. The capacity mechanism model is established, including: matrix system, fracture system, and boundary conditions (constant pressure / constant production).

[0054] Based on the geological model of the target well group of tight sandstone reservoirs, considering the multi-field coupling effects such as oil-water two-phase flow, imbibition displacement, complex fracture extension, oil and gas production, an integrated analysis model of energy storage fracturing is constructed to form an integrated simulation method of energy storage fracturing in tight sandstone reservoirs. The entire process of energy storage fracturing is simulated, and the rock mechanics parameters and stress data required for the calculation process are obtained in step S1. The initial pore pressure and fracture conductivity required in the calculation process are the pore pressure distribution and fracture conductivity after the fracture extension is calculated during the fracturing process.

[0055] Among them, in step S7, based on the integrated mathematical model of energy storage fracturing established in step S6, the influence of geological parameters such as reservoir permeability and formation pressure coefficient and engineering parameters such as energy storage fracturing fluid dosage, construction displacement, and energy storage fracturing fluid viscosity on energy storage fracturing is simulated and analyzed, and the influence of geological parameters and engineering parameters on energy storage fracturing is obtained through single factor and multi-factor analysis. Finally, with the goal of achieving the maximum production capacity of a single well, the recommended parameters for the energy storage fracturing process are obtained in a targeted manner.

[0056] The present invention integrates the entire process of energy storage fracturing in tight sandstone reservoirs by combining indoor experiments, theoretical analysis and numerical simulation, obtains the influencing factors of tight oil fracturing capacity through early construction curve analysis, and clarifies the key geological engineering parameters affecting the effect of tight oil energy storage volume fracturing; based on fracturing fluid imbibition and micro-macro oil displacement tests, reveals the main mechanism of imbibition, and clarifies whether tight sandstone has imbibition, imbibition displacement oil displacement capacity and imbibition displacement oil displacement mechanism; determines the main controlling factors of the energy storage stage through basic data of target wells, imaging logging, fracturing construction data and well shut-in data; finally, establishes an integrated analysis model of energy storage volume fracturing-capacity, proposes its applicable technical parameter limits, can effectively improve the effect of energy storage volume fracturing, and provide theoretical and technical support for extending the validity period of measures.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for identifying tight sandstone and optimizing energy storage fracturing process parameters, characterized in that: include: S1, obtain the basic data, imaging logging data, construction data, well shut-in data and production data of the target well; S2, test the core mineral composition, physical properties and pore throat structure through indoor experiments to determine whether it is a tight sandstone; S3, conduct fracturing fluid imbibition and oil displacement tests through indoor experiments to clarify whether tight sandstone has imbibition and its imbibition capacity; S4, by analyzing the data of the construction curve to identify the fracture extension morphology, obtain the fracture geometry parameters through net pressure fitting, obtain the closure parameters and formation parameters through G function analysis, and determine the main control factors of the fracturing stage; S5, determine the main controlling factors of the energy storage stage by combining the target well data with the results of the imbibition experiment; S6, based on the energy storage fracturing mathematical model, conduct integrated numerical simulation of energy storage fracturing of the target well; S7, with the maximum production capacity as the goal, the recommended parameters of the single-well energy storage fracturing process are obtained.

2. The method for identifying tight sandstone and optimizing energy storage fracturing process parameters according to claim 1, characterized in that: In step S1, the basic data of the construction well include: porosity, permeability, oil saturation, crude oil viscosity, reservoir thickness, formation pressure coefficient, horizontal maximum principal stress, horizontal minimum principal stress, Young's modulus, Poisson's ratio, tensile strength, and wetting contact angle; the imaging logging data include: natural fracture inclination, natural fracture inclination trend, and maximum horizontal principal stress direction; the construction data include: time, sand concentration, oil pressure, displacement, and stage liquid volume; the soaking well data include: soaking well time, average daily pressure drop, and daily pressure drop during blowing; the production data include: date, daily liquid production, daily oil production, water content, and oil pressure.

3. The method for identifying tight sandstone and optimizing energy storage fracturing process parameters according to claim 1 or 2, characterized in that: In step S2, a scanning electron microscope is used to obtain the microscopic morphological characteristics of the core in the target well area, an X-ray diffractometer is used to determine the mineral composition of the core, and a cast thin section is used to measure the pore structure of the core to determine the mineral composition, physical properties and pore structure characteristics of the dense core.

4. The method for identifying tight sandstone and optimizing energy storage fracturing process parameters according to claim 1 or 2, characterized in that: In step S3, a fracturing fluid imbibition capacity test experiment is used to determine whether tight sandstone has imbibition and its imbibition capacity, and an imbibition displacement experiment is used to evaluate the fracturing imbibition displacement oil recovery capacity.

5. The method for identifying tight sandstone and optimizing energy storage fracturing process parameters according to claim 1 or 2, characterized in that: In step S4, by analyzing the construction curve characteristics and pump-off pressure drop curve of the tight sandstone fracturing well in the target well area, the fracture extension mode is identified, the net pressure fitting is used to obtain the fracture geometric parameters, and the early transformation effect is clarified. The construction data and basic data required for the analysis process are obtained in step S1.

6. The method for identifying tight sandstone and optimizing energy storage fracturing process parameters according to claim 1 or 2, characterized in that: In step S5, the oil-water replacement efficiency in the energy storage stage is quantitatively evaluated by analyzing the data of the post-pressure shut-in time and the average daily pressure drop, and the daily pressure drop during the blowout period, combined with the experimental data in step S3; the main controlling factors in the energy storage stage are comprehensively evaluated by combining the basic data of the construction well in step S1, the natural fracture parameters in the imaging logging, and the fracture geometric parameters obtained in step S4 with the production data.

7. The method for identifying tight sandstone and optimizing energy storage fracturing process parameters according to claim 1 or 2, characterized in that: In step S6, a single well model is established to simulate the entire process of crack extension in energy storage fracturing, and the rock mechanics parameters and stress data required for the calculation process are obtained in step S1; a mechanism model is established to simulate the entire process of well soaking, percolation and production after energy storage fracturing. The data required in the calculation process include: the basic data of the target well in step S1 and the pore pressure distribution and fracture conductivity after the crack extension is completed, which are calculated during the fracturing process in step S6.

8. The method for identifying tight sandstone and optimizing energy storage fracturing process parameters according to claim 1 or 2, characterized in that: In step S7, based on the integrated mathematical model of energy storage fracturing, the influence of geological conditions and engineering parameters on the overall energy storage fracturing is simulated and analyzed, and specific process recommended parameters are obtained with the goal of achieving maximum production capacity; geological conditions include reservoir permeability and formation pressure coefficient, and engineering parameters include energy storage fracturing fluid dosage, construction displacement, and energy storage fracturing fluid viscosity.

Images