Reservoir underground pore connectivity transformation simulation equipment, system and evaluation method

Abstract

The invention discloses reservoir underground pore connectivity transformation simulation equipment, a reservoir underground pore connectivity transformation simulation system and an evaluation method. The equipment comprises a rock core transformation clamping device, a first magnet, a second magnet, a nuclear magnetic resonance signal controller, a storage and collection tank and a fluid displacement device, wherein a magnetic induction coil is arranged in the rock core transformation clamping device, and the first magnet and the second magnet are oppositely arranged on the two sides of the rock core transformation clamping device; the nuclear magnetic resonance signal controller is electrically connected with the first magnet, the second magnet and the magnetic induction coil respectively and is used for controlling the magnetic field intensity formed by the first magnet, the second magnet and the magnetic induction coil and measuring a nuclear magnetic signal of a rock core sample in the rock core transformation clamping device; the rock core modification clamping device comprises a fluid inlet, the fluid inlet is communicated with the storage and collection tank, and the fluid displacement device is connected with the storage and collection tank, so that fluid is displaced into the rock core modification clamping device under the action of the fluid displacement device, and modification and evaluation on the pore connectivity of the rock core sample under different fluid pressures are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of reservoir transformation in the technical field of oil and gas exploration and development, and in particular to a reservoir downhole pore connectivity transformation simulation device, system and evaluation method. Background Art

[0002] As oil and gas exploration and development targets shift from traditional high-permeability reservoirs to low- and ultra-low-permeability tight reservoirs and unconventional oil and gas reservoirs, the low permeability of tight reservoirs precludes direct production after drilling and completion, necessitating appropriate production-enhancing measures. Improving horizontal well drilling technology and employing hydraulic fracture stimulation are key methods for increasing the productivity of these reservoirs. To meet the needs of diverse reservoirs, reservoir stimulation technologies are continuously evolving. The purpose of reservoir volume stimulation is to maximize the contact area of ​​fractures or fracture networks within the rock, a key goal pursued in the development of unconventional oil and gas reservoirs.

[0003] Currently, hydraulic fracturing is commonly used to reshape reservoir volume. This involves fracturing low-permeability reservoirs using more fluid, lower proppant concentrations, and higher pumping rates to create sufficient fracture geometry and conductivity for commercial oil flow. Fresh water, 2% KCl brine, or colloidal solutions are used as the primary fluids, with the primary additive being a friction reducer (polyacrylamide at a volume concentration of 0.05% to 0.10%). Other less commonly used additives include antiscalants, oxygen scavengers, biocides, and, occasionally, surfactants. Summary of the Invention

[0004] In order to accurately evaluate the impact of external fluid characteristics on reservoir pore connectivity, and thereby provide data support for the actual transformation work of deep reservoirs (such as shale reservoirs), so as to further improve the guiding significance for production work, an embodiment of the present invention provides a reservoir downhole pore connectivity transformation simulation device, system and evaluation method.

[0005] In a first aspect, an embodiment of the present invention provides a reservoir downhole pore connectivity transformation simulation device, which may include: a core transformation clamping device, a first magnet, a second magnet, a nuclear magnetic resonance signal controller, a storage tank, and a fluid displacement device;

[0006] The core modification clamping device is provided with a magnetic induction coil, and the first magnet and the second magnet are arranged opposite to each other on either side of the core modification clamping device; the nuclear magnetic resonance signal controller is electrically connected to the magnetic induction coil and is used to control the magnetic field strength formed by the first magnet, the second magnet, and the magnetic induction coil, and to measure the nuclear magnetic resonance signal of the core sample placed in the core modification clamping device;

[0007] The core reforming clamping device includes a fluid inlet, which is communicated with the storage tank. The fluid displacement device is connected to the storage tank to displace the target fluid into the core reforming clamping device under the action of the fluid displacement device.

[0008] Optionally, the above-mentioned simulation device may further include: a console; the console is electrically connected to the nuclear magnetic resonance signal controller and the fluid displacement device respectively, and is used to control the nuclear magnetic resonance signal frequency used for measurement by the nuclear magnetic resonance signal controller and to control the fluid pressure output by the fluid displacement device.

[0009] Optionally, the above-mentioned simulation device may further include: a display, which is electrically connected to the console and the nuclear magnetic resonance signal controller respectively, and is used to receive and display the fluid pressure of the fluid displacement device adjusted by the console and the nuclear magnetic resonance signal measured by the nuclear magnetic resonance information controller.

[0010] Optionally, the simulation device may further include: a base, on which the core transformation clamping device, the first magnet, the second magnet, the nuclear magnetic resonance signal controller, the storage tank and the fluid displacement device are arranged.

[0011] Optionally, the core modification clamping device includes an openable and closable shell, and the shell forms a closed space for the core modification clamping device when the shell is in a closed state.

[0012] In the second aspect, an embodiment of the present invention provides a reservoir downhole pore connectivity transformation simulation system, which may include: drying equipment, weighing equipment, vacuum saturation equipment, nuclear magnetic resonance equipment, and the reservoir downhole pore connectivity transformation simulation equipment as described in the first aspect.

[0013] Optionally, the drying device is used to dry the prepared core sample; the weighing device is used to weigh the dried core sample to obtain a first sample weight in a dry weight state; the nuclear magnetic resonance device is used to perform nuclear magnetic resonance scanning on the dried core sample to obtain a base signal in a dry weight state;

[0014] The vacuum saturation device is used to place the dried core sample therein and perform a vacuum treatment, and immerse the core sample in a vacuum state for a preset time to saturate and absorb the target fluid; the weighing device is also used to weigh the saturated core sample to obtain a second sample weight in a saturated state; the nuclear magnetic resonance device is also used to perform a nuclear magnetic resonance scan on the saturated core sample to obtain a nuclear magnetic resonance signal in a saturated state;

[0015] The reservoir downhole pore connectivity transformation simulation device is used to transform the core sample and measure the nuclear magnetic resonance signal of the transformed core sample; based on the first sample weight and base signal in the dry weight state, the second sample weight and nuclear magnetic resonance signal in the saturated state, the volume of the core sample and the nuclear magnetic resonance signal of the transformed core sample, the porosity and connectivity change trend of the core sample during the transformation process by the external target fluid is determined.

[0016] In a third aspect, an embodiment of the present invention provides an application of the reservoir downhole pore connectivity transformation simulation device as described in the first aspect in a reservoir downhole pore connectivity transformation simulation system.

[0017] In a fourth aspect, an embodiment of the present invention provides a method for evaluating downhole pore connectivity reconstruction in a reservoir, comprising:

[0018] Drying the prepared core sample in a drying device, weighing the dried core sample using a weighing device and performing nuclear magnetic resonance scanning using a nuclear magnetic resonance device to obtain a first sample weight and a base signal in a dry weight state;

[0019] The dried core sample is placed in a vacuum saturation device for vacuum treatment, and the core sample is immersed in the vacuum state to saturate and absorb the target fluid for a preset time; the core sample is weighed using the weighing device and the core sample is scanned by nuclear magnetic resonance using the nuclear magnetic resonance device to obtain the weight and nuclear magnetic resonance signal of the second sample in the saturated state;

[0020] Placing the core sample in a core modification clamping device of a reservoir downhole pore connectivity modification simulation device, and displacing the target fluid in a storage tank of the reservoir downhole pore connectivity modification simulation device into the core modification clamping device through a fluid displacement device of the reservoir downhole pore connectivity modification simulation device, so as to modify the core sample;

[0021] The nuclear magnetic resonance signal controller in the reservoir downhole pore connectivity transformation simulation device controls the magnetic field strength formed by the first magnet, the second magnet, and the magnetic induction coil provided in the core transformation clamping device in the reservoir downhole pore connectivity transformation simulation device, and measures the nuclear magnetic resonance signal of the transformed core sample;

[0022] Based on the first sample weight and substrate signal in the dry state, the second sample weight and nuclear magnetic resonance signal in the saturated state, the volume of the core sample and the nuclear magnetic resonance signal of the transformed core sample, the porosity and connectivity change trends of the core sample during the transformation by the external target fluid are determined.

[0023] Optionally, the method may further include: selecting the type of fluid medium and the pressure of the fluid medium in the reservoir transformation process based on the porosity and connectivity change trends of the core sample in the process of being transformed by the external target fluid.

[0024] In a fifth aspect, an embodiment of the present invention provides a reservoir transformation method, which may include: transforming the target reservoir according to the type of fluid medium and fluid medium pressure in the reservoir transformation process selected according to the reservoir downhole pore connectivity transformation evaluation method described in the fourth aspect.

[0025] The beneficial effects of the above technical solutions provided in the embodiments of the present invention include at least:

[0026] The embodiment of the present invention provides a reservoir downhole pore connectivity transformation simulation device, system and evaluation method. The simulation device injects the target fluid into the core transformation clamping device through a fluid displacement device to achieve the pore connectivity transformation of the core sample under different fluid pressures, and the nuclear magnetic signal of the core sample is measured by a nuclear magnetic resonance signal controller to use low-field nuclear magnetic resonance rectangular waves to achieve the application effect of characterizing the change of shale reservoir properties with external fluid properties in actual transformation work, analyze and evaluate the influence of external fluid characteristics on the pore connectivity of shale reservoirs, provide data support for deep shale reservoir transformation work, respond to the call for accelerating the integration of geological engineering work, and the simulation results are accurate and have strong guidance for actual production.

[0027] Furthermore, the above-mentioned reservoir downhole pore connectivity transformation simulation equipment provided in the embodiment of the present invention can measure the hydrogen ion nuclear magnetic resonance signal response characteristics that change with the type and engineering parameters of the external fluid, determine the porosity and connectivity change trend of the shale reservoir pore space affected by the external fluid, establish a "test-in-situ" parameter conversion model based on the stress analysis characteristics of shale samples and actual shale reservoirs, deduce the in-situ shale reservoir pore connectivity transformation effect based on experimental data, and clarify the optimal fluid parameters required for the shale reservoir pore connectivity transformation.

[0028] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 This is a schematic structural diagram of a reservoir downhole pore connectivity reconstruction simulation device provided in an embodiment of the present invention;

[0032] Figure 2 A schematic diagram of the internal structure of a core modification clamping device provided in an embodiment of the present invention;

[0033] Figure 3 A schematic diagram of the pore transformation effect of a core sample provided in an embodiment of the present invention;

[0034] Figure 4 Schematic diagram of the structure of the reservoir downhole pore connectivity reconstruction simulation system provided in an embodiment of the present invention;

[0035] Figure 5 This is a flow chart of a reservoir downhole pore connectivity reconstruction evaluation method provided in an embodiment of the present invention;

[0036] 1- Reservoir downhole pore connectivity transformation simulation equipment; 2- Drying equipment; 3- Weighing equipment; 4- Vacuum saturation equipment; 5- Nuclear magnetic resonance equipment;

[0037] 11-core reforming clamping device; 12-first magnet; 13-second magnet; 14-NMR signal controller; 15-storage tank; 16-fluid displacement device; 17-control console; 18-display; 19-base;

[0038] 111-Magnetic induction coil. DETAILED DESCRIPTION

[0039] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0040] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "back" and the like, indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0042] The inventors have discovered that while current methods for describing and simulating reservoir fractures primarily include seismic techniques, single-porosity media models, and dual-porosity media models, few methods offer efficient and accurate experimental simulations for modifying shale pore connectivity. In light of these challenges, the present invention provides a downhole reservoir pore connectivity simulation device, system, and evaluation method that overcome or at least partially address these issues.

[0043] In the embodiment of the present invention, a reservoir downhole pore connectivity reconstruction simulation device is provided, referring to Figure 1 As shown, the reservoir downhole pore connectivity transformation simulation device 1 may include: a core transformation clamping device 11, a first magnet 12, a second magnet 13, a nuclear magnetic resonance signal controller 14, a storage tank 15 and a fluid displacement device 16; wherein, in combination with Figure 2 As shown, a magnetic induction coil 111 is provided in the core modification clamping device 11, and a first magnet 12 and a second magnet 13 are arranged opposite to each other on both sides of the core modification clamping device 11; a nuclear magnetic resonance signal controller 14 is electrically connected to the magnetic induction coil 111, and is used to control the magnetic field strength formed by the first magnet 12, the second magnet 13 and the magnetic induction coil 111, and to measure the nuclear magnetic resonance signal of the core sample placed in the core modification clamping device 11; the core modification clamping device 11 may include a fluid inlet, which is connected to the storage tank 15, and a fluid displacement device 16 is connected to the storage tank 15 so that the target fluid is displaced into the core modification clamping device 11 under the action of the fluid displacement device 16.

[0044] It should be noted that the structure of the core modification clamping device in the embodiment of the present invention is similar to that of a core clamp, but there are also differences. The purpose of this core modification clamping device is to clamp a core sample. Therefore, after the core sample is placed, it is completely closed and the target fluid is injected through a fluid inlet opened on it, unlike the conventional core clamp, which is open at both ends. The fluid displacement device in the embodiment of the present invention is based on a displacement pump as the main structure. It can be located inside or outside the reservoir tank. The reservoir tank contains a piston-like component to drive the target fluid in the reservoir tank into the core modification clamping device, thereby providing fluid pressure and target fluid to modify the pore connectivity of the core sample. The reservoir tank in this embodiment can be removably connected to the fluid inlet of the core modification clamping device via a fluid connection valve (or flexible conduit), ensuring that the target fluid selected during the modification of the core sample is displaced into the core modification clamping device. Of course, the reservoir tank can also be provided with a liquid inlet to ensure timely replenishment of the target fluid.

[0045] It should be noted that the first and second magnets in the embodiment of the present invention are permanent magnets. Figure 2 As shown, the magnetic induction coil is arranged vertically in the core modification clamping device, and the core sample is also placed vertically when placed in the core modification clamping device. The application of the first magnet, the second magnet, the magnetic induction coil, and the nuclear magnetic resonance signal controller is prior art, and its purpose is to ensure that the core sample is in a stable and uniform magnetic field environment and to ensure the accuracy of the nuclear magnetic resonance signal measurement. For example, the existing nuclear magnetic resonance detection equipment of Suzhou Newmai Analytical Instrument Co., Ltd. describes the use method of the first magnet, the second magnet, and the magnetic induction coil, as well as the specific method of measuring the nuclear magnetic resonance signal. For example, the publication number CN218674807U, the utility model name "A Detection Device and Performance Analyzer", or the publication number CN101793147A, the invention name "Online Nuclear Magnetic Resonance Drilling Fluid Oil Analysis Detection Device" and other related patent documents have introduced them, and the embodiments of the present invention will not be repeated here.

[0046] The above-mentioned reservoir downhole pore connectivity transformation simulation equipment provided in the embodiment of the present invention injects the target fluid into the core transformation clamping device through the fluid displacement device to realize the pore connectivity transformation of the core sample under different fluid pressures, and the nuclear magnetic signal of the core sample is measured by the nuclear magnetic resonance signal controller to use the low-field nuclear magnetic resonance rectangular wave to realize the application effect of characterizing the change of shale reservoir properties with external fluid properties in actual transformation work, analyze and evaluate the influence of external fluid characteristics on the pore connectivity of shale reservoir, provide data support for deep shale reservoir transformation work, respond to the call for accelerating the integration of geological engineering work, and the simulation results are accurate and have strong guidance for actual production.

[0047] Furthermore, the above-mentioned reservoir downhole pore connectivity transformation simulation equipment provided in the embodiment of the present invention can measure the hydrogen ion nuclear magnetic resonance signal response characteristics that change with the type and engineering parameters of the external fluid, determine the porosity and connectivity change trend of the shale reservoir pore space affected by the external fluid, establish a "test-in-situ" parameter conversion model based on the stress analysis characteristics of shale samples and actual shale reservoirs, deduce the in-situ shale reservoir pore connectivity transformation effect based on experimental data, and clarify the optimal fluid parameters required for the shale reservoir pore connectivity transformation.

[0048] In an optional embodiment, the reservoir downhole pore connectivity transformation simulation device 11 may also include: a console 17; the console 17 is electrically connected to the nuclear magnetic resonance signal controller 14 and the fluid displacement device 16 respectively, and is used to control the nuclear magnetic resonance signal frequency used for measurement by the nuclear magnetic resonance signal controller 14 and to control the fluid pressure output by the fluid displacement device 16.

[0049] The console in the embodiment of the present invention is an input device for inputting parameters of an external device, and is used to input different nuclear magnetic resonance signal frequencies and fluid pressures. Figure 3 As shown, the transformation effects under different fluid pressures of 5 MPa, 15 MPa, 25 MPa and 30 MPa are measured respectively. The specific value of the displacement pressure of the target fluid is input by the console and controlled by the fluid displacement device.

[0050] In another optional embodiment, the reservoir downhole pore connectivity transformation simulation device 11 may also include: a display 18, which is electrically connected to the console 17 and the nuclear magnetic resonance signal controller 14, respectively, and is used to receive and display the fluid pressure of the fluid displacement device 16 adjusted by the console 17 and the nuclear magnetic resonance signal measured by the nuclear magnetic resonance information controller.

[0051] The above-mentioned display in the embodiment of the present invention is a signal terminal display device, which receives the nuclear magnetic resonance signal measured by the above-mentioned nuclear magnetic resonance signal controller and the fluid pressure adjusted by the console to realize visual observation of information such as fluid pressure and the corresponding nuclear magnetic resonance signal inside the core sample.

[0052] In another optional embodiment, the reservoir downhole pore connectivity modification simulation device 11 may further include a base 19, on which the core modification clamping device 11, the first magnet 12, the second magnet 13, the nuclear magnetic resonance signal controller 14, the storage tank 15, and the fluid displacement device 16 are disposed. The base in this embodiment of the present invention may be truncated cone-shaped, so that the bottom of the instrument is heavy and has a large contact area, thereby ensuring that the instrument does not shake and maintains stability during fluid-driven modification of the pore connectivity of the core sample.

[0053] In another optional embodiment, the core modification clamping device 11 includes an openable and closable housing. When the housing is closed, the core modification clamping device 11 forms a sealed space. The core modification clamping device in this embodiment of the present invention comprises a housing with a magnetic induction coil disposed therein. When closed, the housing forms a sealed space, i.e., a pore modification chamber for a core sample (e.g., a shale columnar core sample), providing a support and placement space for the core sample.

[0054] Based on the same inventive concept, the present invention also provides a reservoir downhole pore connectivity reconstruction simulation system, referring to Figure 4 As shown, the system may include: a drying device 2, a weighing device 3, a vacuum saturation device 4, a nuclear magnetic resonance device 5 and a reservoir downhole pore connectivity transformation simulation device 1.

[0055] In an optional embodiment, the working process between the various devices in the above system is as follows:

[0056] (1) Preliminary preparation, including sample preparation, sample drying, and sample vacuum saturation with target fluid.

[0057] Sample preparation: The core sample prepared in the embodiment of the present invention is a shale columnar core sample, for example, a cylindrical core with a length of 5 cm and a diameter of 25 mm.

[0058] The drying equipment is used to dry the prepared core sample; the weighing equipment is used to weigh the dried core sample to obtain the first sample weight in the dry weight state; the nuclear magnetic resonance equipment is used to perform nuclear magnetic resonance scanning on the dried core sample to obtain the base signal in the dry weight state;

[0059] In specific implementation, the sample is placed in a drying device (drying box) and dried at 100° C. for 48 hours to remove moisture inside the sample. The dry weight is measured and recorded as m dry , and the sample base signal is tested.

[0060] The vacuum saturation device is used to place the dried core sample in it and perform a vacuum treatment, and then immerse the core sample in the vacuum state to saturate and absorb the target fluid for a preset time; the weighing device is also used to weigh the saturated core sample to obtain the weight of the second sample in the saturated state; the nuclear magnetic resonance device is also used to perform nuclear magnetic resonance scanning on the saturated core sample to obtain the nuclear magnetic resonance signal in the saturated state;

[0061] In specific implementation, the sample is placed in a vacuum saturation device, vacuumed, and then immersed in the target fluid under vacuum environment for saturated absorption for 24 hours. The saturated weight of the sample is measured and recorded as msaturation, and the T2 spectrum signal of the sample is tested.

[0062] (2) Experimental stage

[0063] The reservoir downhole pore connectivity transformation simulation equipment is used to transform core samples and measure the nuclear magnetic resonance signals of the transformed core samples;

[0064] In practice, the sample is placed in a core manipulation fixture for manipulation. The reservoir is filled with the target fluid. The pressure of the external fluid impacting the sample is adjusted on the console, and the NMR signal controller is used to continuously measure the NMR response characteristics. The sample's pore characteristics can also be further modified by increasing the external fluid impact pressure, and the NMR response characteristics can be measured. To measure the differences in the ability of multiple fluids to modify the sample's pore connectivity, new parallel samples should be selected and the test repeated.

[0065] (3) Data analysis and evaluation

[0066] Based on the weight and base signal of the first sample in the dry state, the weight and nuclear magnetic resonance signal of the second sample in the saturated state, the volume of the core sample and the nuclear magnetic resonance signal of the transformed core sample, the porosity and connectivity change trends of the core sample during the transformation by the external target fluid are determined.

[0067] In practice, the porosity of the sample is calculated based on its dry weight, saturated weight, and volume. The volume of fluid that can enter the sample after external fluid stimulation and the resulting porosity are calculated based on the sample's basement signal, saturated fluid signal, and the corresponding pressure nuclear magnetic resonance signal. Based on the results of fluid type and pressure on shale sample porosity, the optimal fluid medium type and pressure for actual shale reservoir stimulation are deduced.

[0068] Based on the same inventive concept, an embodiment of the present invention further provides an application of the above-mentioned reservoir downhole pore connectivity transformation simulation device in a reservoir downhole pore connectivity transformation simulation system.

[0069] Based on the same inventive concept, the present invention also provides a reservoir downhole pore connectivity reconstruction evaluation method, referring to Figure 4 As shown, the method may include the following steps:

[0070] Step S51: drying the prepared core sample in a drying device, weighing the dried core sample using a weighing device and performing nuclear magnetic resonance scanning using a nuclear magnetic resonance device to obtain a first sample weight and a base signal in a dry weight state.

[0071] Step S52: Place the dried core sample in a vacuum saturation device for vacuum treatment, and immerse the core sample in a vacuum state to saturate and absorb the target fluid for a preset time; use a weighing device to weigh it and use a nuclear magnetic resonance device to perform nuclear magnetic resonance scanning to obtain a second sample weight and nuclear magnetic resonance signal in a saturated state.

[0072] Step S53: Place the core sample in the core transformation clamping device of the reservoir downhole pore connectivity transformation simulation device, and use the fluid displacement device of the reservoir downhole pore connectivity transformation simulation device to displace the target fluid in the storage tank of the reservoir downhole pore connectivity transformation simulation device into the core transformation clamping device to transform the core sample.

[0073] Step S54: Control the magnetic field strength formed by the first magnet, the second magnet, and the magnetic induction coil provided in the core modification clamping device in the reservoir downhole pore connectivity modification simulation device through the nuclear magnetic resonance signal controller in the reservoir downhole pore connectivity modification simulation device, and measure the nuclear magnetic resonance signal of the modified core sample.

[0074] Step S55: Based on the weight and base signal of the first sample in the dry state, the weight and nuclear magnetic resonance signal of the second sample in the saturated state, the volume of the core sample and the nuclear magnetic resonance signal of the transformed core sample, determine the porosity and connectivity change trend of the core sample during the transformation by the external target fluid.

[0075] In another alternative embodiment, referring to Figure 3 As shown, the above method may further include: step S56, selecting the type of fluid medium and the fluid medium pressure in the reservoir transformation process based on the porosity and connectivity change trend of the core sample during the transformation process by the external target fluid.

[0076] Combine Figure 3 As shown in the figure, based on the results of pore transformation of shale samples by fluid type and pressure, it is deduced that which fluid medium type and fluid medium pressure are more preferred in the actual shale reservoir transformation process.

[0077] The above method in the embodiment of the present invention is a high-precision method for evaluating the mixed wettability of reservoir pores. It uses (shale) reservoir downhole pore connectivity transformation simulation equipment to measure the shale sample pore connectivity transformation effect, and measures the hydrogen nuclear magnetic signal response characteristics that change with the type and engineering parameters of the external fluid. The porosity and connectivity change trend of the shale reservoir pore space affected by the external fluid is determined. Based on the stress analysis characteristics of the sample and the actual reservoir, a "test-in-situ" parameter conversion model is established. The in-situ reservoir pore connectivity transformation effect is deduced based on the experimental data, and the optimal fluid parameters required for the reservoir pore connectivity transformation are clarified.

[0078] Based on the same inventive concept, a reservoir transformation method is also provided in an embodiment of the present invention, which may include: transforming the target reservoir according to the type of fluid medium and fluid medium pressure in the reservoir transformation process selected according to the above-mentioned reservoir downhole pore connectivity transformation evaluation method.

[0079] The specific implementation and beneficial effects of the above-mentioned reservoir downhole pore connectivity transformation simulation system, the above-mentioned reservoir downhole pore connectivity transformation evaluation method, and the application of the reservoir downhole pore connectivity transformation simulation device in the reservoir downhole pore connectivity transformation simulation system provided in the embodiments of the present invention can refer to the description of the above-mentioned reservoir downhole pore connectivity transformation simulation device, and the embodiments of the present invention will not be repeated here.

[0080] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. The present disclosure is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and variations may be made without departing from the scope of the present disclosure. The scope of the present disclosure is limited solely by the appended claims. Thus, to the extent such modifications and variations fall within the scope of the claims and their equivalents, the present disclosure is intended to include such modifications and variations.

Claims

1. A reservoir downhole pore connectivity transformation simulation device, characterized in that: include: a core reforming clamping device, a first magnet, a second magnet, a nuclear magnetic resonance signal controller, a storage tank, and a fluid displacement device; The core modification clamping device is provided with a magnetic induction coil, and the first magnet and the second magnet are arranged opposite to each other on either side of the core modification clamping device; the nuclear magnetic resonance signal controller is electrically connected to the magnetic induction coil and is used to control the magnetic field strength formed by the first magnet, the second magnet, and the magnetic induction coil, and to measure the nuclear magnetic resonance signal of the core sample placed in the core modification clamping device; The core reforming clamping device includes a fluid inlet, which is communicated with the storage tank. The fluid displacement device is connected to the storage tank to displace the target fluid into the core reforming clamping device under the action of the fluid displacement device.

2. The simulation device according to claim 1, characterized in that Also includes: console; The console is electrically connected to the nuclear magnetic resonance signal controller and the fluid displacement device, respectively, and is used to control the frequency of the nuclear magnetic resonance signal measured by the nuclear magnetic resonance signal controller and to control the fluid pressure output by the fluid displacement device.

3. The simulation device according to claim 2, characterized in that Also includes: A display is electrically connected to the console and the nuclear magnetic resonance signal controller respectively, and is used to receive and display the fluid pressure of the fluid displacement device adjusted by the console and the nuclear magnetic resonance signal measured by the nuclear magnetic resonance information controller.

4. The simulation device according to any one of claims 1 to 3, characterized in that Also includes: A base is provided on which the core modification clamping device, the first magnet, the second magnet, the nuclear magnetic resonance signal controller, the storage tank and the fluid displacement device are arranged.

5. The simulation device according to any one of claims 1 to 3, characterized in that: The core modification clamping device comprises an openable and closable shell, and when the shell is in a closed state, the core modification clamping device forms a sealed space.

6. A reservoir downhole pore connectivity transformation simulation system, characterized in that: include: Drying equipment, weighing equipment, vacuum saturation equipment, nuclear magnetic resonance equipment, and the reservoir downhole pore connectivity transformation simulation device according to any one of claims 1 to 5.

7. The system according to claim 6, characterized in that: The drying device is used to dry the prepared core sample; the weighing device is used to weigh the dried core sample to obtain a first sample weight in a dry weight state; the nuclear magnetic resonance device is used to perform nuclear magnetic resonance scanning on the dried core sample to obtain a base signal in a dry weight state; The vacuum saturation device is used to place the dried core sample therein and perform a vacuum treatment, and immerse the core sample in a vacuum state for a preset time to saturate and absorb the target fluid; the weighing device is also used to weigh the saturated core sample to obtain a second sample weight in a saturated state; the nuclear magnetic resonance device is also used to perform a nuclear magnetic resonance scan on the saturated core sample to obtain a nuclear magnetic resonance signal in a saturated state; The reservoir downhole pore connectivity transformation simulation device is used to transform the core sample and measure the nuclear magnetic resonance signal of the transformed core sample; Based on the first sample weight and substrate signal in the dry state, the second sample weight and nuclear magnetic resonance signal in the saturated state, the volume of the core sample and the nuclear magnetic resonance signal of the transformed core sample, the porosity and connectivity change trends of the core sample during the transformation by the external target fluid are determined.

8. Use of the reservoir downhole pore connectivity transformation simulation device according to any one of claims 1 to 5 in a reservoir downhole pore connectivity transformation simulation system.

9. A method for evaluating reservoir downhole pore connectivity reconstruction, characterized in that: include: Drying the prepared core sample in a drying device, weighing the dried core sample using a weighing device and performing nuclear magnetic resonance scanning using a nuclear magnetic resonance device to obtain a first sample weight and a base signal in a dry weight state; The dried core sample is placed in a vacuum saturation device for vacuum treatment, and the core sample is immersed in a vacuum state to saturate and absorb the target fluid for a preset time; Weighing the sample using the weighing device and performing nuclear magnetic resonance scanning using the nuclear magnetic resonance device to obtain a weight and a nuclear magnetic resonance signal of the second sample in a saturated state; Placing the core sample in a core modification clamping device of a reservoir downhole pore connectivity modification simulation device, and displacing the target fluid in a storage tank of the reservoir downhole pore connectivity modification simulation device into the core modification clamping device through a fluid displacement device of the reservoir downhole pore connectivity modification simulation device, so as to modify the core sample; The nuclear magnetic resonance signal controller in the reservoir downhole pore connectivity transformation simulation device controls the magnetic field strength formed by the first magnet, the second magnet, and the magnetic induction coil provided in the core transformation clamping device in the reservoir downhole pore connectivity transformation simulation device, and measures the nuclear magnetic resonance signal of the transformed core sample; Based on the first sample weight and substrate signal in the dry state, the second sample weight and nuclear magnetic resonance signal in the saturated state, the volume of the core sample and the nuclear magnetic resonance signal of the transformed core sample, the porosity and connectivity change trends of the core sample during the transformation by the external target fluid are determined.

10. The method according to claim 9, characterized in that Also includes: Based on the porosity and connectivity change trends of the core sample during the transformation process by the external target fluid, the type of fluid medium and the fluid medium pressure during the reservoir transformation process are selected.

11. A reservoir transformation method, characterized in that: include: The target reservoir is transformed according to the reservoir downhole pore connectivity transformation evaluation method according to claim 9 or 10, wherein the fluid medium type and fluid medium pressure in the reservoir transformation process are selected.

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