Experimental device and method for integrally evaluating displacement and imbibition effects of tight oil reservoir

Abstract

The invention discloses an experimental device and method for integrally evaluating the displacement and imbibition effect of a tight oil reservoir, an injection pump is connected with an intermediate container, the intermediate container contains formation water, the intermediate container is connected with a first inlet of a core holder, and a second inlet of the core holder is connected with a second inlet of the core holder; an outlet of the core holder I is respectively connected with inlets of a core holder II, a core holder III and a core holder IV; fractured rock cores are placed in the first rock core holder and the second rock core holder, and matrix rock cores are placed in the third rock core holder and the fourth rock core holder; the pressure pump is respectively connected with the first core holder, the second core holder, the third core holder and the fourth core holder. The device can better simulate the actual water injection displacement imbibition process of a mine field, is suitable for water injection displacement experiments under the conditions of different pressures and soaking time, and calibrates the displacement imbibition action range and the use pore throat under different conditions.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of petroleum engineering-oil and gas field development engineering, and relates to an experimental device and method for integrally evaluating displacement and imbibition effects of a tight oil reservoir. BACKGROUND

[0002] In recent years, tight oil has achieved great success in the field of oil and gas exploration and development, and has preliminarily formed the conditions for industrialized scale reserves and effective development. With the increasing demand for oil and gas resources in China, unconventional oil and gas resources such as tight oil have become a strategic replacement target for increasing reserves and production. However, due to the extremely low permeability and underdeveloped porosity of tight oil and gas layers, fracturing is generally required to increase production to form industrial production capacity. The fluids introduced into the reservoir during hydraulic fracturing can greatly affect the physical properties of the reservoir. During the soaking process, displacement under pressure difference and imbibition under capillary force occur simultaneously, and the ranges of use of different scale pores and fractures in the two processes are different. The imbibition of the reservoir for fracturing fluid and the interaction between the reservoir and the fracturing fluid are key issues affecting the productivity of the reservoir. Imbibition usually occurs in some very fine matrix flow channels such as micro-fractures, joint fractures and pore edge crevices. In the case of matrix rock blocks being saturated with non-wetting phase and fracture network being saturated with wetting phase, if the capillary force, gravity and displacement pressure difference are conducive to displacing oil and gas in the matrix rock blocks to the fracture system, then the imbibition process occurs. The narrow pore throat of tight reservoirs leads to more obvious imbibition phenomenon than conventional reservoirs. At present, the research on imbibition in unconventional reservoirs mainly focuses on the influence of imbibition on the physical properties of the reservoir and the effective compatibility of displacement speed, and there is still a lack of understanding of the imbibition limit of the reservoir during the soaking process and its action mechanism.

[0003] In view of the complexity and importance of dynamic imbibition, domestic and foreign scholars have carried out a series of researches. These researches mainly focus on the following aspects: the oil recovery mechanism of dynamic imbibition and the corresponding theoretical model construction; which types of oil reservoirs are suitable for imbibition technology, and the influence mechanism thereof at the micro level; the kinetic characteristics of imbibition and the key factors affecting the imbibition efficiency. However, these researches mainly use traditional displacement devices, and there are limitations in measuring the volume of oil displaced by imbibition, especially when dealing with tight oil / shale oil cores, the error of experimental results is large.

[0004] In order to more accurately study the imbibition characteristics of tight oil / shale oil, some scholars have adopted more advanced experimental methods, such as online nuclear magnetic resonance, CT scanning, microfluidic model experiment and numerical simulation method. These methods not only can observe and analyze the imbibition process more carefully, but also can conduct basic research on the imbibition utilization law of tight oil / shale oil.

[0005] Despite these advances, there are still some limitations in current research. Most of the research mainly focuses on the qualitative evaluation of the influence of reservoir fluid properties on dynamic imbibition efficiency and the optimization of injection-production parameters. However, from the perspective of micro-pore scale, there are relatively few studies on the in-depth analysis of the oil displacement development mechanism and influencing factors of dynamic imbibition. Especially for tight oil / shale oil reservoirs, there are few reports on the quantitative and visualized research on the production mechanism and dynamic development characteristics of pore throat fluid under the coupling mode of matrix and fracture at different development stages.

[0006] In the current published experimental studies, the imbibition and displacement are mainly studied separately. The commonly used core imbibition device mainly includes a constant-pressure imbibition device, a balance method constant-pressure imbibition device, and a core holder high-pressure imbibition device. The displacement device is mainly a conventional core holder displacement. It is difficult to realize the division of the displacement and imbibition regions in the same device. The combined action of imbibition and displacement is mainly studied by numerical simulation. There is a lack of integrated evaluation of the displacement and imbibition effect of tight oil reservoirs in the laboratory physical experiment to verify and support the research results of the mathematical model. SUMMARY

[0007] The purpose of the present application is to overcome the above-mentioned shortcomings of the prior art, and to provide an experimental device and method for integrated evaluation of the displacement and imbibition effect of tight oil reservoirs, which can better simulate the actual water injection displacement and imbibition process in the field, and is suitable for water injection displacement experiments under different pressure and soak time conditions. The displacement and imbibition range and producing pore throat under different conditions are calibrated. At the same time, the device has the advantages of simplicity, easy operation, and low cost, which can further guide the development of oilfield development technology policy.

[0008] To achieve the above-mentioned purpose, the following technical solutions are adopted in the present application:

[0009] An experimental device for integrated evaluation of the displacement and imbibition effect of tight oil reservoirs, comprising an injection pump, an intermediate container, a pressure pump, a core holder No. 1, a core holder No. 2, a core holder No. 3, and a core holder No. 4.

[0010] The injection pump is connected to the intermediate container, and the intermediate container contains formation water. The intermediate container is connected to the inlet of the core holder No. 1. The outlet of the core holder No. 1 is connected to the inlets of the core holder No. 2, the core holder No. 3, and the core holder No. 4, respectively.

[0011] The core holder No. 1 and the core holder No. 2 are placed with fractured cores, and the core holder No. 3 and the core holder No. 4 are placed with matrix cores.

[0012] The pressure pump is connected to the core holder No. 1, the core holder No. 2, the core holder No. 3, and the core holder No. 4, respectively.

[0013] Preferably, the core holder No. 1, the core holder No. 2, the core holder No. 3 and the core holder No. 4 are provided with pressure gauges and valves at the inlet and outlet.

[0014] Preferably, the core holder No. 2, the core holder No. 3 and the core holder No. 4 are provided with back pressure valves at the outlet.

[0015] Preferably, the pressure pump is connected to the core holder No. 1, the core holder No. 2, the core holder No. 3 and the core holder No. 4 through the six-way No. 2, and the six-way No. 2 is connected with the pressure gauge No. 6.

[0016] An experimental method based on the experimental device for evaluating the displacement and imbibition effect of the tight oil reservoir, comprising the following steps:

[0017] S1, applying confining pressure to the core holder No. 1, the core holder No. 2, the core holder No. 3 and the core holder No. 4 by the pressure pump to simulate the formation pressure;

[0018] S2, opening the inlet and outlet of the core holder No. 1, opening the inlet and closing the outlet of the core holder No. 2, the core holder No. 3 and the core holder No. 4, and injecting the formation water in the intermediate container into the core holder No. 1 at a constant injection rate by the injection pump;

[0019] S3, closing the injection pump and the inlet of the core holder No. 1, and observing the static pressure change of the whole system;

[0020] S4, after the soaking is completed, opening the inlet and outlet of the core holder No. 1 and the core holder No. 2 for displacement, opening the inlet and closing the outlet of the core holder No. 3 and the core holder No. 4 for dialysis, injecting the formation water in the intermediate container into the core holder No. 1 at a constant injection rate by the injection pump, calibrating the core producing area and pore throat range by the nuclear magnetic resonance technology, calculating the displacement and imbibition recovery degree in the experimental system, and then obtaining the displacement and imbibition recovery contribution degree, and reproducing the underground seepage condition of the tight oil reservoir fluid.

[0021] Preferably, the injection rate of S2 and S4 is 0.05-0.2ml / min.

[0022] Preferably, the injection is stopped when the water is injected to 100%-180% of the formation pressure in S2.

[0023] Preferably, the soaking time is 1-3h in S3.

[0024] Preferably, the injection is stopped after 2-8pv in S4.

[0025] Preferably, before S1, the basic physical properties of the core are tested, the core pore volume is calculated, the core pore throat size is calibrated using nuclear magnetic resonance technology, and the formation water is saturated; then the core bound water saturation and oil saturation are calculated; then the formation conditions are maintained for 48-72 hours to simulate hydrocarbon accumulation and aging, and the core saturation oil content is calibrated using nuclear magnetic resonance technology.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention places fractured cores within core holders No. 1 and No. 2 to simulate the main flow path of an actual oil reservoir, directly participating in water drive flow. Core holders No. 3 and No. 4 place matrix cores to simulate unaffected or insufficiently affected areas of the reservoir, participating in pressure-retaining and seepage absorption. Simulating the formation oil-water conversion displacement and seepage absorption process under two pathways—injection well-production well (high-permeability zone-low-permeability zone) and fractured zone-matrix tight zone—a dynamic seepage physical simulation experiment based on nuclear magnetic resonance (NMR) was designed. By using NMR to calibrate different displacement and seepage activation areas and pore throat ranges, the degree of displacement and seepage recovery in the experimental system can be calculated, thus obtaining the contribution of displacement and seepage to the recovery rate and reproducing the underground seepage situation of tight oil reservoir fluids. This device is applicable to tight oil displacement and permeation experiments under different pressures and simmering times, calibrating the displacement and permeation range and the pore throats under different conditions, and has a wide range of applications; it has good sealing properties, is not easily affected by the environment, and greatly improves the detection accuracy; it does not require expensive large equipment, and the device is simple, easy to operate, and has a low cost. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the experimental apparatus for evaluating the displacement and permeation effects of tight oil reservoirs according to the present invention.

[0029] Figure 2 The image shows the nuclear magnetic resonance curves of the core holder No. 1 before and after core extrusion and seepage combined mining in the fractured core of this invention.

[0030] Figure 3 The image shows the nuclear magnetic resonance curves of the core holder No. 2 in the fractured core before and after combined mining with seepage drainage.

[0031] Figure 4 The image shows the nuclear magnetic resonance curves of the core holder No. 3 in the fractured rock core before and after the combined mining process of seepage control and extraction.

[0032] Figure 5 This is a bar chart showing the degree of water injection displacement and contribution ratio of the cores displaced by core holder No. 1 and core holder No. 2, and the cores absorbed by core holder No. 3 and core holder No. 4 in this invention.

[0033] The components are: 1. Injection pump, 2. Intermediate container, 3. Two-way valve No. 1, 4. Pressure gauge No. 1, 5. Two-way valve No. 2, 6. Core holder No. 1, 7. Two-way valve No. 3, 8. Six-way valve, 9. Two-way valve No. 4, 10. Core holder No. 2, 11. Two-way valve No. 5, 12. Pressure gauge No. 2, 13. Back pressure valve No. 1, 14. Two-way valve No. 6, 15. Two-way valve No. 7, 16. Back pressure valve. 17. Pressure gauge No. 3, 18. Two-way valve No. 8, 19. Core holder No. 3, 20. Two-way valve No. 9, 21. Pressure gauge No. 4, 22. Two-way valve No. 10, 23. Core holder No. 4, 24. Two-way valve No. 11, 25. Pressure gauge No. 5, 26. Back pressure valve No. 3, 27. Two-way valve No. 12, 28. Hand pump, 29. Pressure gauge No. 6, 30. Six-way valve No. 2. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terms “installation,” “connection,” and “linkage” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; a mechanical connection, an electrical connection, or a connection that allows communication; a direct connection or an indirect connection via an intermediate medium; or a connection within two elements or an interaction between two elements. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0039] like Figure 1The diagram shows the integrated experimental apparatus for evaluating the displacement and permeation effects of tight oil reservoirs as described in this application, comprising: an injection pump 1, an intermediate container 2, a two-way valve 1 3, a pressure gauge 1 4, a two-way valve 2 5, a core holder 1 6, a two-way valve 3 7, a six-way valve 1 8, a two-way valve 4 9, a core holder 2 10, a two-way valve 5 11, a pressure gauge 2 12, a back pressure valve 1 13, and a two-way valve 6. 14. Two-way valve No. 7 15. Back pressure valve No. 2 16. Pressure gauge No. 3 17. Two-way valve No. 8 18. Core holder No. 3 19. Two-way valve No. 9 20. Pressure gauge No. 4 21. Two-way valve No. 10 22. Core holder No. 4 23. Two-way valve No. 11 24. Pressure gauge No. 5 25. Back pressure valve No. 3 26. Two-way valve No. 12 27. Hand pump 28. Pressure gauge No. 6 29. and six-way valve No. 2 30.

[0040] Injection pump 1 is connected to intermediate container 2, which contains formation water. Intermediate container 2 is connected to the inlet of core holder 6. A two-way valve 3, pressure gauge 4, and two-way valve 5 are installed between them to measure the inlet pressure of the system. Core holder 6 is connected to core holders 10, 19, 23, and pressure gauge 21 via six-way valve 8. Pressure gauge 21 measures the outlet pressure of core holder 6 and the inlet pressures of core holders 10, 19, 23, and 23. The outlets of core holders No. 3 (19) and No. 4 (23) are respectively connected to back pressure valves No. 1 (13), No. 2 (16), and No. 3 (26), and pressure gauges No. 2 (12), No. 3 (17), and No. 5 (25) to measure the outlet pressure of core holders No. 2 (10), No. 3 (19), and No. 4 (23). Core holders No. 1 (6) and No. 2 (10) contain fractured cores, while core holders No. 3 (19) and No. 4 (23) contain matrix cores. The outlets of back pressure valves No. 1 (13), No. 2 (16), and No. 3 (26) are respectively connected to two-way valves to control their outlet opening and closing.

[0041] The output end of the hand-cranked pump 28 is connected to core holders 1 (6), 2 (10), 3 (19), and 4 (23) via a six-way connector 2 (30) for applying confining pressure. Pressure gauge 6 (29) is connected to the six-way connector 2 (30).

[0042] In operation, firstly, use the hand-cranked pump 28 to apply confining pressure to core holders 1 (6), 2 (10), 3 (19), and 4 (23). The magnitude of the confining pressure can be read from pressure gauge 6 (29). Then, turn on injection pump 1 and open two-way valves 1 (3), 2 (5), 3 (7), 4 (9), 5 (11), 8 (18), 9 (20), 10 (22), and 11 (24). Close all other two-way valves. Use injection pump 1 to displace the formation water in intermediate container 2 into the system. The inlet pressure of core holder 1 is read from pressure gauge 1 (4), and the outlet pressure is read from pressure gauge 4 (21). Simultaneously, the reading on pressure gauge 4 (21) represents the inlet pressure of core holders 2 (10), 3 (19), and 4 (23). The outlet pressures of core holders No. 2 (10), No. 3 (19), and No. 4 (23) are read from pressure gauges No. 2 (12), No. 3 (17), and No. 5 (25). When pressure gauge No. 4 (21) of the system reaches 130% of the formation pressure, injection pump 1 is shut down, two-way valves No. 1 (3) and No. 2 (5) are closed, and two-way valves No. 3 (7), No. 4 (9), No. 9 (9), and No. 10 (22) are opened to begin the pressure-locking process. The static pressure changes during the pressure-locking process are observed using pressure gauges No. 1 (4), No. 2 (12), No. 3 (17), No. 4 (21), and No. 5 (25). After the well is shut off, start injection pump 1, and open two-way valves 1-3, 2-way valve 5, 2-way valve 3-7, 2-way valve 4-9, 2-way valve 5-11, 2-way valve 6-14, 2-way valve 8-18, 2-way valve 9-20, 2-way valve 10-22, and 2-way valve 11-24. Close all other two-way valves. Use injection pump 1 to displace the formation water in intermediate container 2 to displace the system crude oil. Stop injection after displacing 5PV. Six-way valve 1-8 connects core holder 1-6, core holder 2-10, core holder 3-19, core holder 4-23, and pressure gauge 4-21. Six-way valve 2-30 connects the confining pressure of core holder 1-6, core holder 2-10, core holder 3-19, core holder 4-23, and pressure gauge 6-29.

[0043] The experimental method of this invention includes the following steps:

[0044] (1) Test the basic physical properties of the core: measure the core mass, length, diameter, permeability and porosity, calculate the core pore volume, use nuclear magnetic resonance technology to calibrate the core pore throat size, and saturate the formation with formation water.

[0045] (2) Establish bound water saturation using a conventional experimental displacement apparatus with dead oil: Oil samples were injected into the core at a constant displacement rate, and the displacement pressure and water flow rate at the core outlet were recorded every 1 hour. Bound water saturation was considered established when the water flow rate at the outlet ceased to increase. The bound water saturation and oil saturation of the core were then calculated.

[0046] The formulas for calculating bound water saturation and oil saturation are as follows:

[0047]

[0048] In the formula:

[0049] L—Core length, cm;

[0050] h—core diameter, cm;

[0051] φ—Core porosity, %;

[0052] π — Pi (the mathematical constant of a circle).

[0053] V 出口 —Outlet water volume, cm 3 .

[0054]

[0055] (3) The formation conditions were maintained for 48-72 hours to simulate hydrocarbon accumulation and aging. In this embodiment, 72 hours was preferred. The saturated oil content of the core was determined using nuclear magnetic resonance technology. The fractured core was loaded into core holder 1 (6) and core holder 2 (10), and the matrix core was loaded into core holder 3 (19) and core holder 4 (23).

[0056] (4) Integrated flooding and seepage control experiment: Two paths were set up to simulate the formation oil-water conversion, displacement, and seepage absorption process under two pathways: a core-based water injection well-production well (high-permeability zone-low-permeability zone) and a fracture zone-matrix compaction zone. A combined flooding and seepage control method was implemented, and nuclear magnetic resonance was used to monitor the degree of pore throat activation before and after displacement and seepage. ① The back pressure was set to 14.5 MPa to simulate formation pressure; ② Two-way valves 1-3, 2-5, 3-7, 4-9, 5-11, 8-18, 9-20, 10-22, and 11-24 were opened, while all other two-way valves were closed. Injection pump 1 injected formation water from intermediate container 2 into the device at a constant injection rate of 0.05-0.2 ml / min. In this embodiment, 0.05-0.2 ml / min is preferred. The inlet and outlet of core holder 1-6 were opened. ① Open the core inlets of core holders No. 2 (10), No. 3 (19), and No. 4 (23), and close the outlets. Maintain the water injection pressure of the entire system at 100%-180% of the formation pressure. In this embodiment, 130% (18.85 MPa) is preferred. ② Close injection pump 1 and two-way valve No. 2 (5) to put the entire system in a pressurized state. Observe the static pressure change of the entire system. The pressurization time is 1-3 hours, and in this embodiment, 2 hours is preferred. ③ After the pressurization is completed, open two-way valves No. 1 (3), No. 2 (5), and No. 3 (23). 7. Two-way valves 4 (9), 5 (11), 8 (18), 9 (20), 10 (22), and 11 (24), with all other two-way valves closed, inject water into core holder 1 (6) at a constant injection rate of 0.05-0.2 ml / min. In this embodiment, 0.05-0.2 ml / min is preferred. Keep the inlet and outlet of core holder 1 (6) and core holder 2 (10) open for displacement. Keep the inlet of core holder 3 (19) and core holder 4 (23) open and the outlet closed for percolation. Core holders 1 (6) and 2 (10) directly participate in water drive flow, simulating the mainstream of the actual oil reservoir. Core holders 3 (19) and 4 (23) participate in pressure suppression and seepage, simulating areas of the reservoir that are not affected or are not sufficiently affected. Water injection is stopped after 2-8 pv, with 5 pv being preferred in this embodiment. Nuclear magnetic resonance technology is used to calibrate the core activation area and pore throat range, which can calculate the degree of displacement and seepage recovery in the experimental system, and thus obtain the contribution of displacement and seepage recovery rate, reproducing the underground seepage of tight oil reservoir fluids.

[0057] Figure 2 This is the nuclear magnetic resonance curve of the core before and after the combined mining of the fracture core in core holder No. 16, which shows the main area of ​​displacement.

[0058] Figure 3 This is the nuclear magnetic resonance curve of the fractured core in core holder No. 2-10 before and after the combined mining of seepage and displacement, which shows the main area of ​​displacement.

[0059] Figure 4 This is the nuclear magnetic resonance curve of the matrix core in core holder No. 3-19 before and after mining, showing the main area of ​​seepage absorption.

[0060] Figure 5 The extent and contribution of water injection to the extraction of cores displaced by core holders No. 1 (6), No. 2 (10), No. 3 (19), and No. 4 (23) are as follows:

[0061] This patented method clarifies the specific ratio of displacement and permeation during oil production, calibrates the range of displacement and permeation under different conditions and the pore throats to be activated, and has the advantages of simple device, easy operation and low cost. It innovatively forms a wellless injection-production rotation method with the highest total recovery rate, enriches the development methods of tight oil, and has good guiding significance for the formulation of technology policies for the development of ultra-low permeability reservoirs.

[0062] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0063] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. An integrated experimental apparatus for evaluating the displacement and permeation effects of tight oil reservoirs, characterized in that, Including injection pump (1), intermediate container (2), pressure pump, core holder No. 1 (6), core holder No. 2 (10), core holder No. 3 (19) and core holder No. 4 (23); The injection pump (1) is connected to the intermediate container (2), which contains formation water. The intermediate container (2) is connected to the inlet of the first core holder (6), and the outlet of the first core holder (6) is connected to the inlet of the second core holder (10), the third core holder (19), and the fourth core holder (23). Cracked cores were placed in core holder No. 1 (6) and core holder No. 2 (10), and matrix cores were placed in core holder No. 3 (19) and core holder No. 4 (23). The pressure pumps are connected to core holder No. 1 (6), core holder No. 2 (10), core holder No. 3 (19) and core holder No. 4 (23) respectively.

2. The integrated experimental apparatus for evaluating the displacement and permeation effects of tight oil reservoirs according to claim 1, characterized in that, Pressure gauges and valves are installed at the inlet and outlet of core clamps No. 1 (6), No. 2 (10), No. 3 (19) and No. 4 (23).

3. The integrated experimental apparatus for evaluating the displacement and permeation effects of tight oil reservoirs according to claim 1, characterized in that, Back pressure valves are installed at the outlets of core holder No. 2 (10), core holder No. 3 (19) and core holder No. 4 (23).

4. The integrated experimental apparatus for evaluating the displacement and permeation effects of tight oil reservoirs according to claim 1, characterized in that, The pressure pump is connected to core holder No. 1 (6), core holder No. 2 (10), core holder No. 3 (19) and core holder No. 4 (23) respectively through six-way No. 2 (30). Pressure gauge No. 6 (29) is connected to six-way No. 2 (30).

5. An integrated experimental method for evaluating the displacement and permeation effects of tight oil reservoirs based on the experimental apparatus described in any one of claims 1-4, characterized in that, Includes the following processes: S1, a pressure pump was used to apply confining pressure to core holder No. 1 (6), core holder No. 2 (10), core holder No. 3 (19) and core holder No. 4 (23) to simulate formation pressure; S2, the inlet and outlet of core holder No. 1 (6) are opened, the inlet of core holder No. 2 (10), core holder No. 3 (19) and core holder No. 4 (23) are opened and the outlet is closed. The injection pump (1) injects the formation water in the intermediate container (2) into core holder No. 1 (6) at a constant injection rate. S3, shut off the injection pump (1), shut off the inlet of core holder No. 1 (6), so that the whole system is in a simmering state, and observe the static pressure change of the whole system; S4. After the well is shut off, the inlet and outlet of core holder No. 1 (6) and core holder No. 2 (10) are opened for displacement; the inlet of core holder No. 3 (19) and core holder No. 4 (23) is opened and the outlet is closed for percolation; the injection pump (1) injects the formation water in the intermediate container (2) into core holder No. 1 (6) at a constant injection rate. The core activation area and pore throat range are calibrated using nuclear magnetic resonance technology, and the degree of displacement and percolation recovery in the experimental system is calculated. Then, the degree of contribution of displacement and percolation recovery rate is obtained, and the underground seepage of tight oil reservoir fluid is reproduced.

6. The experimental method for integrated evaluation of displacement and permeation effects in tight oil reservoirs according to claim 5, characterized in that, The water injection rate for both S2 and S4 is 0.05-0.2 ml / min.

7. The experimental method for integrated evaluation of displacement and permeation effects in tight oil reservoirs according to claim 5, characterized in that, When water is injected into S2 to 100%-180% of the formation pressure, water injection is stopped.

8. The experimental method for integrated evaluation of displacement and permeation effects in tight oil reservoirs according to claim 5, characterized in that, The simmering time in S3 is 1-3 hours.

9. The experimental method for integrated evaluation of displacement and permeation effects in tight oil reservoirs according to claim 5, characterized in that, After injecting 2-8 pv of water into S4, stop injecting water.

10. The experimental method for integrated evaluation of displacement and permeation effects in tight oil reservoirs according to claim 5, characterized in that, Before S1, the basic physical properties of the core were tested, the core pore volume was calculated, the core pore throat size was calibrated using nuclear magnetic resonance technology, and the formation water was saturated. Then the core bound water saturation and oil saturation were calculated. Then the formation conditions were maintained for 48-72 hours to simulate hydrocarbon accumulation and aging, and the core saturation oil content was calibrated using nuclear magnetic resonance technology.

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