Physical simulation experiment method for stress sensitivity of liquid injection and energy supplement reservoir of tight oil reservoir

Abstract

The invention discloses a physical simulation experiment method for stress sensitivity of a liquid injection and energy supplement reservoir of a tight oil reservoir. The physical simulation experiment method comprises the following steps: preparing a rock core sample; putting the rock core sample into a testing device, and obtaining a T2 spectrum of the sample in a saturated oil state; after the T2 spectrum of the sample in the saturated oil state is obtained, a displacement experiment is conducted on the sample, and the permeability and porosity change of the sample in the liquid injection energy supplementing process is obtained. Aiming at stress sensitivity characteristics in a tight reservoir large-scale liquid injection energy supplementation development process, a physical simulation method for real-time online testing of permeability, porosity and micro-pore structure change characteristics is established, and reservoir parameter changes caused by formation pressure changes in the energy supplementation development process are further clarified; and a reference basis is made for a development scheme.

Description

Technical Field

[0001] This invention relates to the field of reservoir development technology, specifically to a physical simulation experimental method for stress sensitivity of tight oil reservoirs undergoing fluid injection and energy replenishment. Background Technology

[0002] Tight oil reservoirs suffer from low recovery rates and rapid production decline, necessitating the exploration of development strategies to improve the effectiveness of tight oil reserve utilization. Tight oil reservoirs are characterized by small micropore throats, low pressure coefficients, and insufficient natural energy. Depletion-driven development inevitably leads to rapid production decline, thus requiring the replenishment of formation energy to enhance recovery rates. While the current "horizontal well + volumetric fracturing" development method can achieve initial-scale development of such unconventional reservoirs, as development continues, formation pressure rapidly decreases, leading to insufficient formation energy and deteriorating development results. Therefore, high-intensity injection of various fluids is commonly used in the field to replenish energy and improve production capacity. However, high-intensity fluid injection into the formation can alter reservoir porosity and permeability parameters and pore structure stress sensitivity, also affecting the final development outcome. Therefore, analyzing the reservoir stress sensitivity characteristics under high-intensity injection and production conditions is crucial, and physical simulation experiments are an important tool for this research and analysis.

[0003] Currently, most studies on physical simulation experiments for reservoir stress sensitivity use core gas drive to change confining pressure, analyzing the changes in permeability and porosity caused by these pressure variations. However, this method cannot reflect the actual process of large-scale fluid injection and energy replenishment in oil reservoirs. Therefore, a new experimental method is needed to simulate reservoir stress sensitivity during large-scale fluid injection and energy replenishment in tight oil reservoirs, providing a theoretical reference for the application of this technology. Summary of the Invention

[0004] The purpose of this invention is to provide a physical simulation experimental method for reservoir stress sensitivity in tight oil reservoirs, which solves the technical problem that existing physical simulation experimental methods for reservoir stress sensitivity cannot reflect the changes in permeability and porosity during large-scale fluid injection and energy replenishment development of actual oil reservoirs.

[0005] To achieve the above objectives, one embodiment of the present invention provides a physical simulation experimental method for stress sensitivity of tight oil reservoirs undergoing fluid injection and energy replenishment, comprising the following steps:

[0006] Preparation of core samples;

[0007] The core sample was placed in the testing device to obtain the T2 spectrum of the sample under saturated oil conditions;

[0008] After obtaining the T2 spectrum of the sample in saturated oil state, a displacement experiment was conducted on the sample to obtain the changes in permeability and porosity of the sample during the liquid injection and energy replenishment process.

[0009] One preferred embodiment of the present invention is a method for obtaining changes in sample permeability and porosity during liquid injection and energy replenishment, comprising the following steps:

[0010] Displacement experiments were conducted using an online nuclear magnetic resonance (NMR) testing system. The prepared core samples were placed in the NMR holder of the online NMR testing system.

[0011] After the sample is placed, the inlet and outlet pressures of several NMR holders are set, and the pressure difference, flow rate and T2 spectrum of the sample under the inlet and outlet pressure conditions are obtained.

[0012] The permeability values ​​under different pressure conditions are calculated based on the pressure difference and flow rate. The variation characteristics of pores of different sizes during the pressure ingress and depressurization processes are analyzed based on the T2 spectrum.

[0013] One preferred embodiment of the present invention is a method for obtaining the pressure difference, flow rate, and T2 spectrum of a sample under pressurization and depressurization conditions, comprising the following steps:

[0014] The prepared core sample was placed in the NMR holder, and the NMR holder parameters were set.

[0015] After the NMR holder parameters are set, the pressure difference is set, and single-phase displacement is performed at the inlet and outlet pressures of several NMR holders to obtain the pressure difference, flow rate and T2 spectrum of the sample under the inlet pressure state.

[0016] Unload the inlet and outlet pressures of the NMR holder and obtain the pressure difference, flow rate, and T2 spectrum of the sample under depressurization conditions.

[0017] In one preferred embodiment of the present invention, the parameters of the nuclear magnetic resonance (NMR) clamp include the NMR clamp temperature and the NMR clamp confining pressure.

[0018] In one preferred embodiment of the present invention, after the confining pressure of the NMR holder is stabilized, kerosene is used to purge the outlet and inlet of the NMR holder.

[0019] In one preferred embodiment of the present invention, the inlet pressure of the MRI clamp is set to 16 MPa, 19 MPa, 22 MPa, 25 MPa and 27 MPa, respectively, and the outlet pressure of the MRI clamp is set to 12 MPa, 15 MPa, 18 MPa, 21 MPa and 23 MPa, respectively.

[0020] In one preferred embodiment of the present invention, the online nuclear magnetic resonance testing system needs to be preheated before testing, and the preheating needs to continue until the offset of the echo signal results of the standard sample in two measurements is less than 1%.

[0021] One preferred embodiment of the present invention is a method for preparing core samples, comprising the following steps:

[0022] Pre-treatment of core samples;

[0023] The length, diameter, porosity, and permeability of the pretreated samples were measured.

[0024] The samples that have been measured are then evacuated and saturated with oil.

[0025] One preferred embodiment of the present invention is a pretreatment method in which the oil and salt of the sample to be tested are removed, and the sample is obtained after ventilation, drying and cooling.

[0026] In one preferred embodiment of the present invention, the vacuum pressure during the evacuation process is less than -0.1 MPa.

[0027] In summary, the beneficial effects of the present invention are as follows:

[0028] 1. This invention addresses the stress sensitivity characteristics during large-scale fluid injection and energy replenishment development of tight reservoirs by establishing a physical simulation method for real-time online testing of permeability, porosity, and microstructure changes. This method further clarifies the changes in reservoir parameters caused by formation pressure variations during energy replenishment development, providing a reference for development scheme formulation.

[0029] 2. This invention employs an online nuclear magnetic resonance (NMR) testing system. Compared to offline NMR equipment, the experimental process does not require pressure relief or temperature reduction, enabling real-time NMR testing that simulates displacement processes under geological conditions. Combined with three-directional gradient coils and a dedicated radio frequency sequence, phase encoding of the sample can be performed, achieving sample vector T2 relaxation spectrum layering measurement and arbitrary-direction imaging slices.

[0030] 3. This invention addresses the stress sensitivity characteristics during large-scale fluid injection and energy replenishment development of tight reservoirs by establishing a physical simulation method for real-time online testing of permeability, porosity, and microstructure changes. This method further clarifies the changes in reservoir parameters caused by formation pressure variations during energy replenishment development, providing a reference for development plan formulation. Attached Figure Description

[0031] Figure 1 This is a flowchart of the physical simulation experiment method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment according to the present invention;

[0032] Figure 2 This is a T2 spectrum of different pressure injection processes in one embodiment of the present invention;

[0033] Figure 3 This is a T2 spectrum during different depressurization processes in one embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the structure of an online nuclear magnetic resonance testing system in one embodiment of the present invention;

[0035] Figure 5 This is a graph showing the permeability of rock sample No. 1 as a function of pore pressure in Example 1 of the present invention.

[0036] Figure 6 This is a graph showing the permeability of rock sample No. 2 in Example 1 of the present invention as a function of pore pressure.

[0037] Figure 7 This is the T2 spectrum of rock sample No. 1 during the pressure test in Example 1 of the present invention;

[0038] Figure 8 This is the T2 spectrum of rock sample No. 1 during the decompression process in Example 1 of the present invention;

[0039] Figure 9 This is the T2 spectrum of rock sample No. 2 during the pressure test in Example 1 of the present invention;

[0040] Figure 10 This is the T2 spectrum of rock sample No. 2 during the decompression process in Example 1 of the present invention;

[0041] Figure 11 This is a graph showing the rate of change of macropore throat pore size under different pore pressures for rock samples No. 1 and No. 2 in Example 1 of the present invention.

[0042] Figure 12 This is a graph showing the rate of change of total porosity under different pore pressures for rock samples No. 1 and No. 2 in Example 1 of the present invention.

[0043] Among them, 1-plunger pump, 2-intermediate container, 3-inlet pressure monitoring gauge, 4-core sample, 5-NMR holder, 6-outlet pressure monitoring gauge, 7-industrial control computer, 8-confining pressure circulation pump, 9-back pressure valve, 10-manual pump. Detailed Implementation

[0044] This invention provides a physical simulation experimental method for stress sensitivity of tight oil reservoirs undergoing fluid injection and energy replenishment, such as... Figure 1 As shown, it includes the following steps:

[0045] Step (1): Prepare core sample 4;

[0046] Step (2): Place core sample 4 into the testing device and obtain the T2 spectrum of the sample under saturated oil conditions;

[0047] Step (3): After obtaining the T2 spectrum of the sample in the saturated oil state, a displacement experiment was conducted on the sample to obtain the changes in permeability and porosity of the sample during the liquid injection and energy replenishment process.

[0048] The method for preparing core sample 4 in step (1) includes the following steps:

[0049] Step (11): Pre-treatment of core sample 4. Specifically, oil and salt are removed from the sample to be tested, and then it is placed in a fume hood for ventilation for 48 hours. After that, it is taken out and dried at a constant temperature of 110℃ in an oven for 24 hours, and then cooled naturally in the oven.

[0050] Step (12): Measure the length, diameter, porosity and permeability of the pretreated core sample 4. Specifically, use vernier calipers to measure the length and diameter of the sample. Take the average of three measurement data and then measure the porosity and permeability of the sample.

[0051] Step (13): The core sample 4 that has been measured is evacuated and saturated with oil. Specifically, the sample is placed in an evacuation and saturation device for evacuation. The vacuum pressure must be lower than -0.1 MPa and last for more than 24 hours. Then, the sample is saturated with aviation kerosene. During the saturation process, evacuation continues for more than 6 hours. After completion, the sample is transferred to an intermediate container 2 filled with kerosene. The pressure is increased to more than 20 MPa. After continuous pressurization and saturation for 24 hours, the sample preparation is completed.

[0052] The preparation of core sample 4 can be done by selecting samples with different permeability and different pore structures, depending on the needs of the experimental research.

[0053] In step (2), the method for placing core sample 4 into the testing device and obtaining the T2 spectrum of the sample under saturated oil conditions is as follows: using a domestic online nuclear magnetic resonance testing system, the core sample 4 after being saturated with oil is placed into the nuclear magnetic clamp 5 of the domestic online nuclear magnetic resonance testing system, and the T2 spectrum of the sample under saturated oil conditions is obtained after the equipment is stabilized.

[0054] Step (3) involves obtaining the changes in sample permeability and porosity during the liquid injection and energy replenishment process, including the following steps:

[0055] Step (31): Displacement experiment was carried out using an online nuclear magnetic resonance testing system. The prepared core sample 4 was placed in the nuclear magnetic clamp 5 of the online nuclear magnetic resonance testing system.

[0056] Step (32): After the sample is placed, set the inlet and outlet pressures of several NMR holders 5, and obtain the pressure difference, flow rate, and T2 spectrum of the sample under the inlet and outlet pressure conditions; specifically including the following steps:

[0057] Step (321): Place the prepared core sample 4 into the NMR holder 5 and set the parameters of the NMR holder 5. Specifically, set the temperature and confining pressure of the NMR holder 5 according to the experimental requirements. After the confining pressure stabilizes, use kerosene to purge the outlet and inlet of the NMR holder 5. After no more bubbles are produced at the purging port, close the purging valves at the inlet and outlet of the holder.

[0058] Step (322): After the parameters of the NMR holder 5 are set, the pressure difference is set, and single-phase displacement is performed under several inlet and outlet pressures of the NMR holder 5 to obtain the pressure difference, flow rate and T2 spectrum of the sample under the inlet pressure state; specifically, the outlet back pressure of the NMR holder 5 is set, and then the valves of the inlet and outlet connecting pipelines of the NMR holder 5 are opened. The plunger pump 1 is started to pressurize the inlet and outlet of the NMR holder 5. First, the outlet pressure is increased to a pressure value slightly lower than the outlet back pressure. After the inlet and outlet pressures of the NMR holder 5 are stable, the inlet and outlet connecting pipelines are closed. The valve on the line disconnects the inlet and outlet of the NMR holder 5. With the differential pressure set to remain constant at 4 MPa, kerosene single-phase displacement is performed at inlet pressures of 16 MPa, 19 MPa, 22 MPa, 25 MPa, and 27 MPa, and outlet pressures of 12 MPa, 15 MPa, 18 MPa, 21 MPa, and 23 MPa, respectively, while maintaining the confining pressure at 29 MPa. After the flow rate stabilizes, the sample differential pressure and flow rate are recorded. The oil phase permeability of the sample under the corresponding conditions is calculated, and the NMR T2 spectrum under these conditions is measured. Figure 2 As shown, it is the T2 spectrum recorded during the pressurization process. Starting from the saturated oil state, the spectrum is recorded after each pressure stabilization. This spectrum can reflect the distribution of fluid in the 4 pores of the core sample. The increase and decrease characteristics of each type of pore can be calculated through the fluid distribution.

[0059] Step (323): Unload the inlet and outlet pressures of the NMR holder 5, and obtain the pressure difference, flow rate, and T2 spectrum of the sample under depressurization conditions; specifically, unload the inlet and outlet pressures of the NMR holder 5 along the original path, record the sample pressure difference and flow rate after the flow rate stabilizes, calculate the corresponding oil phase permeability, and measure the NMR T2 spectrum under this condition, such as... Figure 3 As shown, it is the T2 spectrum recorded during the depressurization process. The spectrum is recorded after each pressure is reduced and stabilized. This spectrum can also reflect the distribution of fluid in the 4 pores of the core sample. The recovery characteristics of each type of pore during the depressurization process can be calculated through the fluid distribution.

[0060] Step (33): Calculate the permeability value under different pressure conditions based on the pressure difference and flow rate, and analyze the change characteristics of pores of different sizes during the pressure injection and pressure reduction process based on the T2 spectrum; specifically, calculate the permeability value under different pressure conditions based on the inlet and outlet pressures and flow rates obtained in the experimental process; based on a series of T2 relaxation spectra of the sample obtained in the experimental process, the T2 spectrum can be corresponding to different pore sizes, and the change characteristics of pores of different sizes during different pressure injection and pressure pushing processes can be analyzed to obtain the stress sensitivity characteristics of the large-scale liquid injection and energy replenishment reservoir.

[0061] The experimental equipment of this invention uses a domestically produced online nuclear magnetic resonance testing system as the testing device, such as... Figure 4As shown, the experimental equipment includes a plunger pump 1, an intermediate container 2, an inlet pressure monitoring gauge 3, an outlet pressure monitoring gauge 6, a nuclear magnetic resonance (NMR) magnet, a manual pump 10, a back pressure valve 9, a confining pressure circulation pump 8, an industrial control computer 7, a gradient module, and a radio frequency (RF) module. The NMR magnet includes an NMR holder 5. The plunger pump 1 provides the injection pressure; the intermediate container 2 holds the injected fluid; the inlet pressure monitoring gauge 3 and the outlet pressure monitoring gauge 6 monitor and measure the injection pressure; the NMR magnet is the core component of the online NMR system and can test T2 spectra; the manual pump 10 and the back pressure valve 9 provide outlet back pressure, maintaining a pressure difference of 4 MPa with the inlet pressure; the confining pressure circulation pump 8 provides confining pressure for the core sample 4; and the industrial control computer 7, the gradient module, and the RF module are used for monitoring and recording the NMR spectra.

[0062] This device integrates nuclear magnetic resonance relaxation analysis and imaging functions. The magnet uses a rare-earth neodymium iron boron permanent magnet with a strength of 0.3±0.05T and a core frequency of 12MHz. Equipped with a fully digital spectrometer, it offers diverse functions and is easy to operate. The device provides multiple RF probe options, including offline probes with apertures of 2.5cm, 3.8cm, and full diameter (≥10cm); the online probe, also known as the online NMR holder (probe), uses a special alloy and new materials, and the 2.5cm probe aperture can be used for the core region of NMR imaging.

[0063] Nuclear magnetic resonance (NMR) equipment has specific requirements for the experimental environment. The equipment needs to be in a constant temperature environment, and the surrounding electromagnetic environment must be relatively stable. Before testing, the equipment needs to be preheated for more than 6 hours. Then, a tetramethylsilane standard sample is used to locate the center frequency of the magnet, determine the frequency offset of the RF coil, and subsequently set appropriate RF parameters. The nuclear T2 relaxation spectrum of the standard sample is measured one hour apart to obtain the echo signal. The preheating is considered complete when the offset between two measurements is less than 1%.

[0064] Compared to offline NMR equipment, the experiment does not require unloading pressure or lowering temperature, and can simulate real-time NMR testing of displacement processes under formation conditions. With the aid of three-directional gradient coils and a dedicated radio frequency sequence, phase encoding of the sample can be performed, enabling sample vector T2 relaxation spectrum layering and arbitrary-direction imaging slices.

[0065] Example 1

[0066] Two core samples from a typical block of a tight oil reservoir in China were selected to conduct a physical simulation experiment involving changing pore fluid pressure under a fixed confining pressure. By varying the displacement results under different pore pressures, the characteristics of reservoir permeability and porosity changes with pore pressure were analyzed and evaluated. This experimental study can obtain the changes in permeability and porosity with pressure.

[0067] The parameters of the core samples are shown in Table 1.

[0068] Table 1: Basic parameters of rock samples

[0069] serial number Length / cm Diameter / cm Porosity / % Permeability / mD 1 7.29 2.531 11.95 0.058 2 7.34 2.524 11.67 0.120

[0070] (1) Evaluate the impact of pore pressure changes on reservoir permeability by calculating based on Darcy's formula;

[0071] The calculation formula is as follows:

[0072] K i =QμL / AΔP

[0073] In the formula, K i Here, Q represents the permeability, and Q is the flow rate through the rock sample at a pressure difference of 4 MPa, expressed in cm³. 3 / s; A is the cross-sectional area of ​​the rock sample, in cm². 2 L is the length of the rock sample in cm; μ is the viscosity of kerosene in mPa·s, and the viscosity of kerosene at room temperature, 2 mPa·s, is selected here; ΔP is the pressure difference in atm.

[0074] K in each state i The ratio of the initial state K to the change in permeability is the value of the change in permeability.

[0075] (2) Evaluate the impact of pore pressure changes on reservoir porosity by evaluating the amplitude of T2 spectra obtained under different pressure conditions and the amplitude and ratio under saturated oil conditions.

[0076] (3) Data Analysis

[0077] ① Characteristics of permeability variation with pore pressure

[0078] The permeability of rock samples as a function of pore pressure was analyzed using a graph. The graph shows that with increasing pore pressure, the flow rate increases, the fluid flow in the oleophobic pores (such as the large pore throats) is enhanced, and the fluid flow resistance decreases, mainly due to the flow resistance at the hydrophilic pore walls. Consequently, the permeability of the rock samples increases. For example, the permeability of rock sample 1 increased from 0.0078 mD to 0.0157 mD during pressure increase, as shown in the figure. Figure 5 As shown, the permeability of rock sample No. 2 increased from 0.0129 mD to 0.0256 mD. Furthermore, the smaller the permeability of the rock sample, the larger the inflection point of the pore pressure at which the permeability increase abruptly changes. The results are as follows: Figure 6As shown, for reservoirs with low permeability, significantly replenishing formation energy is an effective means to improve reservoir permeability. When pore pressure is unloaded, the flow rate decreases, and the fluid flow in oleophobic pores such as large pore throats weakens. Fluid flow in oleophilic pores such as small and medium pore throats becomes dominant. These pores have strong wall adsorption, large specific surface area, high roughness, small pore size, and greater turbulence effect within a single pore, affecting the seepage of shale oil in porous media, manifested as increased seepage resistance and decreased permeability. The permeability of rock sample 1 decreased from 0.0156 mD to 0.0080 mD, and the permeability of rock sample 2 decreased from 0.0256 mD to 0.0150 mD. The higher the permeability of the rock samples, the gentler the decrease trend during pore pressure unloading, and the smaller the magnitude and rate of permeability decrease. Therefore, the higher the reservoir permeability, the less interference the unloading pressure has on the reservoir. Furthermore, the permeability after pore pressure unloading was slightly higher than before the experiment, indicating that the rock sample did not undergo irreversible deformation during the pore pressure loading and unloading process and did not cause damage to the reservoir.

[0079] ② Characteristics of porosity variation with pore pressure

[0080] Based on research by domestic scholars, relaxation times of 0.1–10 ms are considered small pore throats, 10–100 ms are considered medium pore throats, and greater than 100 ms are considered large pore throats.

[0081] The variation of macropore throat NMR spectrum amplitude with pore pressure was analyzed using T2 NMR spectra of rock samples at different displacement stages. The T2 NMR spectra of the rock samples at different displacement stages show that, with increasing pore pressure during intrusion, the macropore throat NMR spectrum amplitude gradually increases, as shown in the results. Figure 7 and Figure 9 As shown; during depressurization, the amplitude of the macropore throat MRI spectrum gradually decreased, as shown in the following results. Figure 8 and Figure 10 As shown.

[0082] The change rate of macropore throat porosity under different pore pressures was used to observe the variation of macropore throat porosity with pore pressure. From the graphs, it can be seen that: as pore pressure increases, the macropore throat porosity change rate of rock sample 1 gradually increases from 9.49% to 22.73%, and that of rock sample 2 gradually increases from 1.90% to 14.48%; when pore pressure decreases, the macropore throat porosity change rate of rock sample 1 gradually decreases from 22.73% to 8.84%, and that of rock sample 2 gradually decreases from 14.48% to 3.82%. The results are as follows... Figure 11 As shown.

[0083] The change in total porosity with pore pressure was observed using a graph showing the change rate of total porosity under different pore pressures. From the graph, it can be seen that during the pressure increase process, the total porosity of rock sample 1 gradually increased from 10.22% to 24.49%, and the total porosity of rock sample 2 gradually increased from 3.09% to 15.09%. When the pore pressure was unloaded, the total porosity of rock sample 1 gradually decreased from 24.49% to 3.25%, and the total porosity of rock sample 2 gradually decreased from 15.09% to 4.71%. The results are as follows... Figure 12 As shown.

[0084] from Figure 11 and Figure 12 It can be concluded that when the pore pressure is low, fluid flow is dominant in oleophilic pores such as small and medium pore throats. As the pore pressure increases, the flow rate increases, and the fluid flow in oleophobic pores such as large pore throats intensifies. Therefore, the total porosity change rate and the porosity change rate of large pore throats gradually increase. As the pore pressure is unloaded, the flow rate decreases, some fluid flows out of the oleophobic pores, and both the total porosity change rate and the porosity change rate of large pore throats decrease. For matrix reservoirs with high permeability, the interference of unloading pressure on the porosity change rate is smaller.

[0085] In summary, the above analysis shows that as the injection fluid pressure increases, the permeability of the rock sample increases by 100%; as the injection fluid pressure increases, the porosity of the rock sample also increases, with large pores or microcracks being the main pore types affecting the porosity change.

[0086] In summary, increasing injection pressure and injection volume are effective means to improve reservoir permeability; increasing the injection fluid helps to form microfractures or cause microfracture re-opening, providing necessary basis for water injection and huffing / puffing decisions.

[0087] Although specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

Claims

1. A physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment, characterized in that, Includes the following steps: Preparation of core samples; The core sample was placed in the testing device to obtain the T2 spectrum of the sample under saturated oil conditions; After obtaining the T2 spectrum of the sample in saturated oil state, a displacement experiment was conducted on the sample to obtain the changes in permeability and porosity of the sample during the liquid injection and energy replenishment process.

2. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 1, characterized in that, The method for obtaining changes in sample permeability and porosity during the injection and energy replenishment process includes the following steps: Displacement experiments were conducted using an online nuclear magnetic resonance (NMR) testing system. The prepared core samples were placed in the NMR holder of the online NMR testing system. After the sample is placed, the inlet and outlet pressures of several NMR holders are set, and the pressure difference, flow rate and T2 spectrum of the sample under the inlet and outlet pressure conditions are obtained. The permeability values ​​under different pressure conditions are calculated based on the pressure difference and flow rate. The variation characteristics of pores of different sizes during the pressure ingress and depressurization processes are analyzed based on the T2 spectrum.

3. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 2, characterized in that, The method for obtaining the pressure difference, flow rate, and T2 spectrum of a sample under pressure ingress and pressure regress conditions includes the following steps: The prepared core sample was placed in the NMR holder, and the NMR holder parameters were set. After the NMR holder parameters are set, the pressure difference is set, and single-phase displacement is performed at the inlet and outlet pressures of several NMR holders to obtain the pressure difference, flow rate and T2 spectrum of the sample under the inlet pressure state. Unload the inlet and outlet pressures of the NMR holder and obtain the pressure difference, flow rate, and T2 spectrum of the sample under depressurization conditions.

4. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 3, characterized in that: The parameters of the NMR holder include the NMR holder temperature and the NMR holder confining pressure.

5. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 4, characterized in that: After the confining pressure of the nuclear magnetic resonance (NMR) holder is stabilized, kerosene is needed to purge the outlet and inlet of the NMR holder.

6. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 2 or 3, characterized in that: The inlet pressures of the NMR holders are set to 16 MPa, 19 MPa, 22 MPa, 25 MPa and 27 MPa, respectively, and the outlet pressures of the NMR holders are set to 12 MPa, 15 MPa, 18 MPa, 21 MPa and 23 MPa, respectively.

7. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 2, characterized in that: The online nuclear magnetic resonance testing system needs to be preheated before testing, and the preheating needs to continue until the offset of the echo signal results of the standard sample in two measurements is less than 1%.

8. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 1, characterized in that, The method for preparing core samples includes the following steps: Pre-treatment of core samples; The length, diameter, porosity, and permeability of the pretreated sample were measured. The samples that have been measured are then evacuated and saturated with oil.

9. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 8, characterized in that, The pretreatment method is as follows: oil and salt are removed from the sample to be tested, and the sample is obtained after ventilation, drying and cooling.

10. The physical simulation experimental method for stress sensitivity of tight oil reservoirs during fluid injection and energy replenishment as described in claim 8, characterized in that: The vacuum pressure during the evacuation process is less than -0.1 MPa.

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