Nuclear magnetic detection and quantitative characterization method for tight oil production efficiency under simulated formation condition

Abstract

The invention provides a simulated formation condition tight oil production efficiency nuclear magnetic detection and quantitative characterization method, and belongs to the technical field of oil exploration and development, the method comprises the following steps: S1, respectively measuring nuclear magnetic resonance T2 spectrums of a core sample in a dry state, a water-containing and oil-free state and an oil-containing state; obtaining the oil saturation of the core sample by contrasting the change characteristics of the nuclear magnetic T2 spectrums and the change of the semaphore; and S2, respectively measuring the permeability and porosity of the core sample in a dry state, establishing a quantitative characterization model of the fluid utilization efficiency, and calculating the fluid utilization efficiency. According to the method, the calculation problem of the tight oil production efficiency under the influence of multiple factors is solved by researching the influence of pore pressure, oil saturation and reservoir physical properties on the tight oil production efficiency.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil exploration and development, and particularly relates to a method for detecting and quantitatively characterizing tight oil mobilization efficiency under simulated formation conditions. BACKGROUND

[0002] The economic benefits of deep / ultra-deep tight oil development are closely related to oil prices, construction costs and single-well productivity, and the single-well productivity is restricted by resource abundance and oil mobility. Therefore, it is of great significance to establish a method for quantitatively characterizing tight oil mobilization and an evaluation model for optimizing the development interval and evaluating the productivity of tight oil.

[0003] The following theories or methods have been proposed for the research on tight oil mobility at home and abroad:

[0004] 1. Extraction method and pyrolysis method, which basically characterizes the free oil content to explain the mobility of shale oil through relevant experiments. However, this method has problems. In the formation, the changes in temperature and pressure will affect the occurrence state of crude oil, but in production, the free oil content is always taken as the maximum movable oil content, and the recovery rate of shale oil is low.

[0005] 2. The method of characterizing tight oil mobilization efficiency and mobilization lower limit based on supercritical CO2 displacement, which clarifies the relationship between the mobilizable oil rate and the reservoir properties. This method represents the maximum oil production in the existing technology in the tight reservoir, but due to the cost limitation, supercritical CO2 displacement cannot be implemented on a large scale in actual production, resulting in a large difference between the actual oil production and the theoretical maximum oil production.

[0006] 3. Establishing a digital core to explore the percolation law of fluid in a small space, but due to the strong heterogeneity of unconventional reservoirs, the digital core model has the problem of insufficient representation, and it is also difficult to popularize and apply.

[0007] The actual application of tight oil / shale oil development mode is based on hydraulic fracturing for oil production. In the development process of this mode, there are mainly two oil displacement mechanisms: ① percolation and imbibition oil displacement between fracturing fluid and crude oil in matrix pores; and ② fluid elastic energy oil displacement in matrix pores. The influence of different reservoir properties, bottom hole pressure and temperature on oil mobility will affect the oil displacement efficiency of the two oil displacement mechanisms.

[0008] At present, the existing technologies for studying oil displacement efficiency have not considered the influence of various factors to varying degrees, resulting in the problems of unscientific oil displacement efficiency evaluation mechanism and inaccurate evaluation results, which deviate greatly from the actual situation. Therefore, it is urgent to propose a method for characterizing tight oil mobilization efficiency under simulated formation conditions. SUMMARY

[0009] To solve the above problems of the prior art, the present application provides a method for detecting and quantitatively characterizing tight oil producing efficiency under simulated formation conditions, aiming to study the influence of oil saturation and reservoir properties on tight oil producing efficiency and solve the problem of calculating tight oil producing efficiency under the influence of multiple factors.

[0010] To achieve the above-mentioned object, the present application provides the following technical scheme:

[0011] A method for detecting and quantitatively characterizing tight oil producing efficiency under simulated formation conditions, comprising:

[0012] Step S1, respectively measuring the nuclear magnetic resonance T2 spectrum of the core sample in a dry state, a water-only state and an oil-water mixed state, and obtaining the oil saturation of the core sample by comparing the change characteristics and signal amount of the multiple nuclear magnetic T2 spectra;

[0013] Step S2, respectively measuring the permeability and porosity of the core sample in a dry state, establishing a quantitative characterization model of fluid producing efficiency, and calculating the fluid producing efficiency, which is expressed as:

[0014]

[0015] In the formula, E is the fluid producing efficiency; K g is the permeability, with the unit of mD; Φ is the porosity; A and B are characteristic parameters related to the oil saturation.

[0016] Further, the step S1 comprises:

[0017] Step S11, washing and drying the core sample to obtain a dry core sample, measuring the nuclear magnetic resonance T2 spectrum of the dry core sample, and generating a base signal;

[0018] Step S12, absorbing water and centrifuging the dry core sample to obtain a water-saturated core sample with a preset water saturation;

[0019] Step S13, saturating the water-saturated core sample with crude oil to obtain an oil-saturated core sample, and measuring the nuclear magnetic resonance T2 spectrum of the oil-saturated core sample;

[0020] Step S14, pressurizing and depressurizing the oil-saturated core sample, and measuring and monitoring the change characteristics of the nuclear magnetic resonance T2 spectrum in real time during the pressurizing and depressurizing process, and calculating the fluid producing efficiency accordingly.

[0021] Further, in the step S11, the specific process of washing and drying the core sample is to wash the sample for a first preset time, and then dry it at a first preset temperature for a second preset time to remove adsorbed water.

[0022] Further, the step S12 comprises:

[0023] Step S121, under the condition of the second preset temperature and the first preset pressure, the dry core sample is placed in water until the mass of the sample does not change, then the water-containing core sample is taken out and the nuclear magnetic resonance T2 spectrum is measured, and after the background signal is removed, the saturated water nuclear magnetic signal is obtained;

[0024] Step S122, the water-containing core sample is subjected to centrifugal treatment, and the nuclear magnetic monitoring is performed in real time, compared with the saturated water signal, and the water saturation value is generated in real time, and the water-containing core sample with the water saturation of the preset value is obtained.

[0025] Further, the specific process of the step S13 of performing the imbibition treatment on the water-containing core sample is that the water-containing core sample with the water saturation of the preset value is placed in crude oil for imbibition under the condition of the second preset temperature and the first preset pressure, and then taken out after the mass no longer changes.

[0026] Further, in the step S14, the pressurization process includes applying confining pressure to the oil-containing core sample and applying pore pressure to both ends of the oil-containing core sample, the value of the confining pressure is the second preset pressure, and the value of the pore pressure is the third preset pressure.

[0027] Further, the pore pressure is applied by filling the oil-containing core sample with fluorinated liquid.

[0028] Further, in the pressurization and depressurization process, the specific process of measuring and monitoring the nuclear magnetic resonance T2 spectrum change characteristics in real time is that the confining pressure is applied to the oil-containing core sample, and the oil-containing core sample is filled with fluorinated liquid, the confining pressure is maintained unchanged during the filling process, and the nuclear magnetic resonance T2 spectrum change characteristics are monitored in real time, until the nuclear magnetic resonance T2 spectrum is stable, the filling of the fluorinated liquid is stopped, and the pore pressure is released until the nuclear magnetic resonance T2 spectrum is stable.

[0029] Further, the nuclear magnetic detection and quantitative characterization method for the tight oil production efficiency under the pseudo formation condition has the characteristics that the porosity measurement method is the gas measurement method, and the calculation expression is:

[0030]

[0031] wherein, V p is the pore volume, unit: cm 3 ; V k is the gas chamber volume, unit: cm 3 ; P k is the equilibrium pressure, unit: Mpa; P is the final pressure of the system after equilibrium, unit: Mpa; V gr is the rock skeleton volume, unit: cm 3 .

[0032] Further, the method for detecting and quantitatively characterizing the tight oil production efficiency under the simulated formation condition has the characteristics that the method for measuring the permeability is a gas-measuring permeability method, and the calculation expression is:

[0033]

[0034] wherein, K g is the permeability, unit: μm 2 ; Q o is the flow rate, cm 3 / s; P o is the atmospheric pressure, atm; A is the core end area, unit: cm2; μ is the viscosity of the gas, unit: mPa.s; L is the core length, unit: cm; P1 is the absolute pressure on the inlet section, unit: atm; and P2 is the absolute pressure on the outlet section, unit: atm.

[0035] Further, the fluid production efficiency includes the oil production efficiency and the water production efficiency, and the fluid production efficiency = the oil production efficiency + the water production efficiency.

[0036] Compared with the prior art, the method has at least the following beneficial effects:

[0037] 1. Through the elastic energy displacement oil experiment under different physical properties (porosity, permeability), oil saturation conditions, the influence of the reservoir physical properties, oil saturation, etc. on the tight oil movable efficiency under the elastic energy depletion mode (fluid volume storage elastic energy release process) is clarified, and the problem that the miscible fluid production efficiency cannot be calculated under the formation condition is solved.

[0038] 2. The movable efficiency of the tight oil is calculated by establishing the quantitative characterization model of the fluid production efficiency, and the influences of the reservoir physical properties, oil saturation, pore pressure, temperature, etc. are considered, so that the accuracy of the calculation result is improved. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 Fig. 1 is a structural schematic diagram of a core sample nuclear magnetic detection device according to an embodiment of the present application;

[0040] Figure 2 Fig. 1 is a structural schematic diagram of a core sample nuclear magnetic detection device according to an embodiment of the present application;

[0041] Figure 3 Fig. 1 is a structural schematic diagram of a core sample nuclear magnetic detection device according to an embodiment of the present application;

[0042] Figure 4 Fig. 1 is a structural schematic diagram of a core sample nuclear magnetic detection device according to an embodiment of the present application;

[0043] Wherein, 1-air compressor, 2-constant speed constant pressure pump, 3-micro flow displacement device, 4-confining pressure pump, 5-core sample, 6-radio frequency device, 7-nuclear magnetic device. DETAILED DESCRIPTION

[0044] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0045] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0046] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be understood broadly, for example, can be fixed connection, or detachable connection, or integral; can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0047] In order to better understand the objects, structure and functions of the present application, the present application will be further described in detail below with reference to the drawings.

[0048] Embodiment 1

[0049] The present application provides a method for detecting and quantitatively characterizing the nuclear magnetic resonance of tight oil under simulated in-situ conditions, comprising:

[0050] Step S1, drilling a core sample from an oil production area or formation that needs to be evaluated, treating the core sample, and measuring the nuclear magnetic resonance T2 spectrum of the core sample in a dry state, a water-containing and oil-free state, and an oil-containing state, respectively, obtaining the oil saturation of the core sample by comparing the variation characteristics and signal amount of the plurality of nuclear magnetic T2 spectra.

[0051] Step S2, measuring the permeability and porosity of the core sample in a dry state, respectively, establishing a quantitative characterization model of fluid displacement efficiency, and calculating the fluid displacement efficiency, the expression of which is:

[0052] Step S2, measuring the permeability and porosity of the core sample in a dry state, respectively, establishing a quantitative characterization model of fluid displacement efficiency, and calculating the fluid displacement efficiency, the expression of which is:

[0053] In the formula, E is the fluid producing efficiency; K g is the permeability, in units of mD; Phi is the porosity; A and B are characteristic parameters related to the oil saturation, which can be represented by So.

[0054] It should be noted that the fluid producing efficiency at the same oil saturation has a good linear relationship with the physical property, and A and B are the characteristic parameters of the linear equation. By changing the oil saturation, the fluid producing efficiency changes, and the parameters A and B also change, and A and B have a good mathematical relationship with the oil saturation, and thus the relationship between the oil saturation and the parameters A and B can be established.

[0055] Embodiment 2

[0056] Different from embodiment 1, the step S1 comprises:

[0057] Step S11, oil washing and drying treatment is performed on the core sample to obtain a dried core sample, a nuclear magnetic resonance T2 spectrum of the dried core sample is measured, and a base signal is generated;

[0058] Step S12, water absorption and centrifugal treatment is performed on the dried core sample to obtain a water-saturated core sample with a preset water saturation;

[0059] Step S13, the water-saturated core sample is subjected to saturated crude oil treatment to obtain an oil-saturated core sample, and a nuclear magnetic resonance T2 spectrum of the oil-saturated core sample is measured;

[0060] Step S14, pressure and pressure relief are performed on the oil-saturated core sample, and the change characteristics of the nuclear magnetic resonance T2 spectrum are measured and monitored in real time during the pressure and pressure relief processes, and the oil saturation of the oil-saturated core sample is generated in real time.

[0061] Embodiment 3

[0062] Different from embodiment 2, in the step S11, the specific process of oil washing and drying of the core sample is to perform oil washing on the sample for a first preset time, and then dry the sample at a first preset temperature for a second preset time to remove adsorbed water;

[0063] The step S12 comprises:

[0064] Step S121, under the condition of a second preset temperature and a first preset pressure, the dried core sample is placed in water until the mass of the sample does not change, then the water-saturated core sample is taken out and the nuclear magnetic resonance T2 spectrum is measured, and after the base signal is removed, a saturated water nuclear magnetic signal is obtained;

[0065] Step S122, centrifugal treatment is performed on the water-containing core sample, and nuclear magnetic monitoring is performed in real time, and a water saturation value is generated in real time, and the water-containing core sample with a water saturation of a preset value is obtained;

[0066] The specific process of the step S13 of performing imbibition treatment on the water-containing core sample is that the water-containing core sample with the water saturation of the preset value is placed in crude oil to perform imbibition under the condition of the second preset temperature and the first preset pressure, and the water-containing core sample is taken out after the mass no longer changes;

[0067] In the step S14, the pressurization process includes applying confining pressure to the oil-containing core sample and applying pore pressure to both ends of the oil-containing core sample, the value of the confining pressure is the second preset pressure, and the value of the pore pressure is the third preset pressure.

[0068] Example 4

[0069] Different from example 3, the first preset time is 10 days, the first preset temperature is 110°C, and the second preset time is 12 hours, that is, the core sample is washed with oil for 10 days, and is dried at 110°C for 12 hours to remove adsorbed water, to obtain a dry core sample;

[0070] The second preset temperature is 90°C, the first preset pressure is 20 MPa, the sample is saturated with water at 90°C until the mass of the sample no longer changes (20 MPa saturation pressure), at this time, it is considered that the water saturation in the water-containing core sample is 100%, and therefore, the nuclear magnetic signal of the measured nuclear magnetic resonance T2 spectrum of the water-containing core sample after the baseline is removed can also be considered as a saturated water signal;

[0071] In this way, the water-containing core sample with a water saturation of 100% is treated by centrifugation, and the water is thrown out due to the centrifugal action, and in this process, online nuclear magnetic monitoring is performed in real time, the water saturation in the water-containing core sample is judged through the change characteristics and signal amount change of the nuclear magnetic T2 spectrum, and the water-containing core sample with a water saturation of a preset value is obtained, such as a water saturation of 75%, 60%, 45%, 30%, etc.

[0072] The water-containing core samples with different water saturations are placed in crude oil at 90°C, and are saturated with crude oil by imbibition under a pressure of 20 MPa until the mass is constant. After imbibition, the pores in the core are invaded by saturated crude oil, and are mixed with water in the core to form a water-oil mixture, to form an oil-containing core sample. The oil-containing core samples obtained from the water-containing core samples with different water saturations have different oil saturations.

[0073] Example 5

[0074] The difference between the embodiment 4 is that the preset pore pressure is 35 MPa (simulating injection pressure of depletion development), that is, the confining pressure (simulating formation pressure) is applied to the oil-bearing core sample until the confining pressure is 38 MPa, and the fluorinated liquid is filled at both ends of the sample to increase the pore pressure of the sample until the pore pressure is 35 MPa; the confining pressure is maintained unchanged during the filling process and the change characteristics of the nuclear magnetic signal T2 spectrum are monitored in real time, the filling pressure is stopped when the nuclear magnetic T2 spectrum is stable, and the experiment is terminated after the pore pressure is completely released and the nuclear magnetic T2 spectrum is stable. The production efficiency of the sample fluid at different oil saturation is calculated by the change characteristics and signal amount of the nuclear magnetic T2 spectrum of the oil-bearing core sample and the nuclear magnetic T2 spectrum after the pore pressure is released.

[0075] Embodiment 6

[0076] The difference between the embodiment 4 is that the preset pore pressure is 35 MPa (simulating injection pressure of depletion development), that is, the confining pressure (simulating formation pressure) is applied to the oil-bearing core sample until the confining pressure is 38 MPa, and the fluorinated liquid is filled at both ends of the sample to increase the pore pressure of the sample until the pore pressure is 35 MPa; the confining pressure is maintained unchanged during the filling process and the change characteristics of the nuclear magnetic signal T2 spectrum are monitored in real time, the filling pressure is stopped when the nuclear magnetic T2 spectrum is stable, and the experiment is terminated after the pore pressure is completely released and the nuclear magnetic T2 spectrum is stable. The production efficiency of the sample fluid at different oil saturation is calculated by the change characteristics and signal amount of the nuclear magnetic T2 spectrum of the oil-bearing core sample and the nuclear magnetic T2 spectrum after the pore pressure is released.

[0077] The measurement method of the porosity is gas measurement method, and the calculation expression is:

[0078]

[0079] Among them, V p is the pore volume, unit cm 3 ; V k is the gas chamber volume, unit cm 3 ; P k is the equilibrium pressure, unit Mpa; P is the final pressure of the system after equilibrium, unit Mpa; V gr is the rock skeleton volume, unit cm 3 .

[0080] Further, the measurement method of the permeability is gas measurement method, and the calculation expression of the permeability is:

[0081]

[0082] In the formula, K g is the permeability, unit μm 2 ; Q o is the flow rate, cm 3 / s; P o is the atmospheric pressure, atm; A is the core end area, unit cm2; μ is the viscosity of the gas, unit mPa.s; L is the core length, unit cm; P1 is the absolute pressure on the inlet section, unit atm; P2 is the absolute pressure on the outlet section, unit atm.

[0083] The characteristic parameters A and B change due to the change of oil saturation, the producing efficiency of the fluid changes, the parameters A and B in the quantitative characterization model also change, and A and B have a good mathematical relationship with the change of oil saturation, and then a relationship between the oil saturation and the parameters A and B can be established.

[0084] The calculation parameters A and B of the producing efficiency of different rock reservoirs are as follows:

[0085] Table 1 Relationship between the parameters A and B of the fluid producing efficiency and the oil saturation of different rock samples

[0086]

[0087] Example 7

[0088] As shown in Figure 3 , Figure 4 , the application of the present application to the formation of an oilfield, based on the fluid producing efficiency quantitative characterization model, the relationship between the characteristic parameters A and B and the oil saturation, the oil producing efficiency quantitative characterization model and the water producing efficiency quantitative characterization model under different oil saturations are established, and the oil and water producing efficiencies are evaluated;

[0089] Among them, the fluid producing efficiency = oil producing efficiency + water producing efficiency;

[0090] And then the movable oil porosity and the movable water porosity are calculated, wherein the movable oil porosity = total porosity x oil saturation x oil producing efficiency;

[0091] The movable water porosity = total porosity x water saturation x water producing efficiency.

[0092] The total porosity is the porosity of the core sample in the dry state.

[0093] After analysis and comparison, it is shown that the high movable oil section of P1f3 segment has large thickness and good lateral continuity, the high movable oil section of P1f22 segment has many layers and thin single layer, and the lateral continuity is poor, and mainly distributed in the middle and lower parts of P1f22 segment.

[0094] The movable oil porosity has a good positive correlation with the single well oil production intensity, and the oil layer with the movable oil porosity exceeding 0.4% is defined as a high-quality oil layer, and the high-quality oil layer includes the I-class oil layer and the II-class oil layer, wherein the movable oil porosity of the I-class oil layer exceeds 0.6%, and the movable oil porosity of the II-class oil layer is between 0.4% and 0.6%.

[0095] It should be noted that, Figure 3 The unclear part in the reduced figure does not affect the understanding of the technical scheme.

[0096] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A method for detecting and quantitatively characterizing the producing efficiency of tight oil under simulated in-situ conditions by nuclear magnetic resonance, characterized in that, The application relates to a method for measuring core sample oil saturation and fluid displacement efficiency. The method comprises the following steps: S1, respectively measuring the nuclear magnetic resonance T2 spectrum of a core sample in a dry state, a water-containing state and an oil-water mixed state, and obtaining the oil saturation of the core sample by comparing the variation characteristics and signal amount of the nuclear magnetic T2 spectrum; where E is the fluid dynamic efficiency; K g is the permeability in mD; Φ is the porosity; A, B are characteristic parameters related to the oil saturation.

2. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 1, wherein, S2, respectively measuring the permeability and porosity of the core sample in the dry state, and establishing a quantitative characterization model of fluid displacement efficiency under different physical properties, wherein the expression of the fluid displacement efficiency is as follows: The step S1 comprises the following steps: S11, washing and drying the core sample to obtain a dry core sample, measuring the nuclear magnetic resonance T2 spectrum of the dry core sample, and generating a base signal; S12, absorbing water and centrifuging the dry core sample to obtain a water-saturated core sample with a preset water saturation; S13, saturating the water-saturated core sample with crude oil to obtain an oil-saturated core sample, and measuring the nuclear magnetic resonance T2 spectrum of the oil-saturated core sample; 3. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 2, wherein, S14, pressurizing and depressurizing the oil-saturated core sample, and measuring and monitoring the variation characteristics of the nuclear magnetic resonance T2 spectrum in real time during the pressurizing and depressurizing process.

4. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 2, wherein, In the step S11, the specific process of washing and drying the core sample is as follows: the sample is washed for a first preset time, and then dried at a first preset temperature for a second preset time to remove the adsorbed water. The step S12 comprises the following steps: S121, placing the dry core sample into water at a second preset temperature and a first preset pressure, and taking out the water-saturated core sample when the mass of the sample does not change, and then measuring the nuclear magnetic resonance T2 spectrum, and obtaining the nuclear magnetic signal of saturated water after removing the base signal; 5. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 2, wherein, S122, centrifuging the water-saturated core sample, and monitoring the nuclear magnetic resonance in real time, comparing with the saturated water signal, and generating the water saturation value in real time to obtain the water-saturated core sample with a preset water saturation.

6. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 2, wherein: The specific process of the step S13 for the imbibition treatment of the water-saturated core sample is as follows: the water-saturated core sample with a preset water saturation is placed into crude oil at a second preset temperature and a first preset pressure for imbibition, and then taken out when the mass does not change.

7. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 6, wherein: In the step S14, the pressurizing process comprises applying confining pressure to the oil-saturated core sample, and applying pore pressure to the two ends of the oil-saturated core sample, wherein the value of the confining pressure is a second preset pressure, and the value of the pore pressure is a third preset pressure.

8. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 6, wherein: The pore pressure is applied by filling the oil-saturated core sample with fluorinated liquid.

9. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 1, wherein, In the step S14, the specific process of measuring and monitoring the variation characteristics of the nuclear magnetic resonance T2 spectrum in real time during the pressurizing and depressurizing process is as follows: confining pressure is applied to the water-saturated and oil-saturated core sample, and the oil-saturated core sample is filled with fluorinated liquid, the confining pressure is kept unchanged during the filling process, the variation characteristics of the nuclear magnetic resonance T2 spectrum are monitored in real time, the filling of the fluorinated liquid is stopped and the pore pressure is released when the nuclear magnetic resonance T2 spectrum is stable, and the nuclear magnetic resonance T2 spectrum is stable. wherein, V p Vp is the pore volume, in cm3 3 ; V k Vc is the chamber volume, in cm3 3 ; P k P is the equilibrium pressure, in MPa; P is the final pressure of the system after equilibration, in MPa; V gr Vr is the rock matrix volume, in cm3 3 .

10. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 1, wherein, The measurement method of the permeability is a gas permeability method, and the calculation expression thereof is: wherein K g is the permeability, in μm 2 ; Q o is the flow rate, in cm 3 / s; P o is the atmospheric pressure, in atm; A is the core end area, in cm2; μ is the gas viscosity, in mPa.s; L is the core length, in cm; Pi is the absolute pressure on the inlet section, in atm; P2is the absolute pressure on the outlet section, in atm.

11. The pseudo-in-situ conditions tight oil producing efficiency nuclear magnetic detection and quantitative characterization method of claim 1, wherein, The porosity is measured by the gas measurement method, and the calculation expression is as follows: The fluid displacement efficiency comprises oil displacement efficiency and water displacement efficiency.

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