A system and method for evaluating dynamic factor controlled fluid pore size distribution

Abstract

This invention discloses a system and method for evaluating the dynamic factors controlling the pore size distribution of fluids, comprising: a solution tank for holding experimental fluids; a suspended robotic arm with a core sample holder at a non-fixed end for detecting the weight of the core sample and placing the sample holder in the experimental fluid; a nuclear magnetic resonance (NMR) measurement mechanism for transmitting radio frequency signals to the core sample and receiving reflected signals; a sample holder constructed as a cubic plate with magnetic pole devices of the NMR measurement mechanism respectively arranged on the outer side of any pair of sides of the plate, wherein a switching mechanism is arranged on the plate surface not in contact with the magnetic pole devices; and a main control mechanism for controlling the dynamic contact factors between the core and the experimental fluid by regulating the switching mechanism to conduct spontaneous percolation experiments, thereby quantitatively analyzing the influence of corresponding dynamic factors on the pore size distribution of the fluid based on the reflected signals under different contact factor conditions.

Description

Technical Field

[0001] This invention relates to the field of oil and gas evaluation technology, and in particular to a system and method for evaluating the pore size distribution of fluids controlled by dynamic factors. Background Technology

[0002] Spontaneous adsorption is a process in which a wetting fluid spontaneously displaces another non-wetting fluid under capillary force. During the development of tight oil and gas reservoirs, adsorption occurs between fracturing fluid and the tight reservoir, resulting in a significant amount of fracturing fluid remaining within the reservoir. The retention of fracturing fluid in tight reservoirs with different pore sizes has varying effects on reservoir permeability. The content of retained fluid in actual reservoirs is difficult to accurately assess, primarily because the boundary conditions between the fluid and reservoir (contact area, interaction mode, and bedding contact direction) dynamically adjust over time during actual tight oil and gas development. Therefore, clarifying the pore size distribution of fluids within tight reservoirs under varying controlling factors can provide guidance for the rational development of shale reservoirs.

[0003] Currently, there are few measurement methods for evaluating the influence of percolation content and boundary conditions on fluid pore size distribution, and most of them suffer from drawbacks such as large experimental errors, which limit the study of fluid distribution in tight reservoirs and thus affect their development. For example, to estimate the fluid content in a sample, it is often necessary to manually interrupt the percolation process multiple times and weigh the sample to obtain the mass of the percolated fluid, and then conduct pore structure characterization experiments on the sample. However, this method can introduce significant errors to the experimental results due to human factors. If the aim is to study the influence of core sample boundary conditions (contact area, interaction mode, and bedding orientation) on percolated fluids, the experiment often involves subdividing the entire sample into multiple small pieces and treating them as a single sample, then placing them under specific boundary conditions for spontaneous percolation, and then studying the fluid pore size distribution within them. The experimental results of this method are greatly affected by the heterogeneity of the sample, and inconsistent experimental conditions and human factors can all have a significant impact on the experimental results.

[0004] Nuclear magnetic resonance (NMR) technology is a commonly used method for characterizing pore structure due to its simplicity, intuitiveness, and non-destructive nature. Current research on spontaneous adsorption processes largely remains at the stage of qualitatively evaluating adsorption capacity using characterization parameters under static conditions. Although a few researchers have invented devices that consider the influence of dynamic boundary conditions on the adsorption process, these only qualitatively evaluate the strength of the sample's adsorption capacity and do not quantitatively characterize the pore size distribution of fluid within tight reservoir cores. Moreover, these device inventions do not consider the important controlling factor of adsorption content.

[0005] In summary, existing technologies need to provide a new device and method to quantitatively evaluate the influence of dynamic control factors on the pore size distribution of shale seepage fluids, while avoiding external interference. Summary of the Invention

[0006] The purpose of this invention is to provide a scheme for quantitatively evaluating the influence of dynamic control factors on the pore size distribution of shale permeable fluids without the need for external interference.

[0007] To address the aforementioned technical problems, embodiments of the present invention provide a system for evaluating the dynamic factors controlling fluid pore size distribution, comprising: a solution tank for holding experimental fluid; a suspended robotic arm with a core sample holder at a non-fixed end for detecting the weight of the core sample and placing the sample holder in the experimental fluid; a nuclear magnetic resonance (NMR) measurement mechanism for measuring the NMR spectrum of the core sample; the sample holder being constructed as a cubic plate, with magnetic pole devices of the NMR measurement mechanism respectively disposed on the outer side of any pair of sides of the plate, wherein a switching mechanism is disposed on the plate surface not in contact with the magnetic pole devices; and a main control mechanism for controlling the dynamic contact factors between the core and the experimental fluid by regulating the switching mechanism to conduct spontaneous percolation experiments, thereby quantitatively analyzing the influence of corresponding dynamic factors on fluid pore size distribution based on the NMR spectra under different contact factor conditions.

[0008] Preferably, the contact factors include permeation content, contact area, core-fluid interaction mode, and bedding contact direction; the plate surface that is not in contact with the magnetic pole device is recorded as the non-contact surface, and any non-contact surface is recorded as the bottom surface of the plate. The bedding direction of the core sample is parallel to the bottom surface of the plate. The sample holder is placed in the experimental fluid with the bottom surface of the plate parallel to the fluid surface.

[0009] Preferably, when the contact factor is percolation content, the switching mechanism includes a sample clamp control door disposed on the bottom surface of the plate. The main control mechanism is further used to conduct spontaneous percolation experiments when the sample clamp control door is in the open state, record the weight change of the core sample and calculate the fluid self-absorption content at different times, and simultaneously control the measurement of nuclear magnetic resonance relaxation time spectra under different self-absorption content conditions. Based on this, the influence of different percolation content conditions on fluid pore size distribution can be quantitatively analyzed to obtain corresponding quantitative analysis results.

[0010] Preferably, when the contact factor is the contact area, the switching mechanism includes a sample clamp control door disposed on the bottom surface of the plate. The main control mechanism is further used to adjust the contact area between the fluid and the core at different opening degrees by controlling the opening state of the sample clamp control door, to conduct spontaneous percolation experiments under different contact area conditions, and to obtain the corresponding nuclear magnetic resonance relaxation time spectrum, thereby quantitatively analyzing the influence of different contact area conditions on the fluid pore size distribution to obtain the corresponding quantitative analysis results.

[0011] Preferably, when the contact factor is the interaction between the core and the fluid, the switching mechanism includes at least two sample clamp control doors respectively disposed on at least two non-contact surfaces. The main control mechanism is further used to adjust the interaction mode of percolation displacement of different numbers of plate surfaces by sequentially controlling the at least two sample clamp control doors to be in the open state, to carry out spontaneous percolation experiments under different interaction mode conditions, and to obtain the corresponding nuclear magnetic resonance relaxation time spectrum, thereby quantitatively analyzing the influence of different interaction mode conditions on the fluid pore size distribution, and obtaining the corresponding quantitative analysis results.

[0012] Preferably, when the contact factor is the lamellar contact direction, the switching mechanism includes: a first sample clamp control door disposed on the bottom surface of the plate and a second sample clamp control door disposed on any non-contact surface adjacent to the bottom surface of the plate. The main control mechanism is further used to adjust the lamellar contact direction by sequentially controlling the first sample clamp control door and the second sample clamp control door to be in an individually open state, to carry out spontaneous percolation experiments under different lamellar contact direction conditions, and to obtain the corresponding nuclear magnetic resonance relaxation time spectrum, thereby quantitatively analyzing the influence of different lamellar contact direction conditions on the fluid pore size distribution, so as to obtain the corresponding quantitative analysis results.

[0013] Preferably, the nuclear magnetic resonance measurement mechanism includes: a radio frequency oscillator, a radio frequency receiver, and two magnetic pole devices, wherein the radio frequency oscillator, the radio frequency receiver, the solution tank, the suspended robotic arm, the magnetic pole devices, and the sample holder are all disposed inside the measurement area chamber. The system further includes a constant temperature control device disposed within the measurement area chamber, wherein the constant temperature control device includes a temperature sensor, a constant temperature controller, and a heater. The main control mechanism is further configured to control the constant temperature controller to adjust the heater power based on the real-time temperature inside the chamber detected by the temperature sensor, so that the temperature inside the chamber reaches a constant temperature state that meets a preset temperature.

[0014] Preferably, the system further includes: a liquid level detector installed on the solution tank for detecting dynamic changes in the liquid level of the experimental fluid; a replenishment pipeline with its end extending into the experimental fluid, wherein the main control mechanism is also used to control the start-up timing of the solution replenisher according to the changes in the liquid level of the experimental fluid, so as to replenish the experimental fluid into the solution tank and make the replenished liquid level reach the initial liquid level.

[0015] Preferably, the system further includes: a solution replenisher and a solution replenishment tank disposed in the solution replenishment and waste liquid collection area, the solution replenishment tank being used to store experimental fluid, wherein the solution replenishment and waste liquid collection area further includes: a waste liquid collection tank and a waste liquid collector, wherein the main control mechanism is further used to control the waste liquid collector and waste liquid suction device to start after the experiment is completed, so as to collect the waste liquid after the experiment into the waste liquid collection tank through the waste liquid suction device of the measurement area box.

[0016] Preferably, the system further includes: a first main control door disposed on the measuring area housing, and a second and a third main control door disposed in the solution replenishment and waste liquid collection area, wherein the second main control door is connected to the waste liquid suction device, and waste liquid collection is automatically processed by controlling the connection between the second main control door and the first main control door; the third main control door is connected to the solution replenishment device, and solution replenishment is automatically processed by controlling the connection between the third main control door and the first main control door.

[0017] Preferably, the sample clamp control door is equipped with a flow meter and a pressure gauge to monitor the dynamic flow pressure data of the spontaneous percolation experiment. The system further includes a conductivity measuring device, which has a conductivity mechanism and a conductivity electrode that extends into the experimental fluid.

[0018] On the other hand, embodiments of the present invention provide a method for evaluating the dynamic factors controlling fluid pore size distribution. The method utilizes the system described above, wherein the method includes: injecting experimental fluid into a solution tank; placing a core sample holder in the experimental fluid via the self-extension control of a suspended robotic arm; controlling the dynamic contact factors between the core and the experimental fluid by adjusting a switching mechanism on the sample holder to conduct a spontaneous percolation experiment; controlling the nuclear magnetic resonance (NMR) spectrum of the core sample under corresponding contact factor conditions using a nuclear magnetic resonance (NMR) measurement mechanism; and quantitatively analyzing the influence of corresponding dynamic factors on fluid pore size distribution based on the reflection signals under different contact factor conditions.

[0019] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0020] This invention proposes a system and method for evaluating the dynamic factors controlling the pore size distribution of fluids. The system and method integrate an infiltration device and a nuclear magnetic resonance (NMR) measurement device into a single setup, constructing a fully automated scheme for evaluating the dynamic factors controlling the pore size distribution of fluids, where the infiltration content and boundary conditions (contact area, interaction mode, and bedding orientation) are dynamically variable. By comparing the changes in the pore size distribution of the fluid within the sample before and after changes in experimental dynamic conditions, the influence of rock water content, contact area, interaction mode, and bedding orientation on the pore size distribution of infiltrated fluids within the reservoir is quantitatively evaluated, providing theoretical support for accurately evaluating the distribution of retained fluids in actual geological reservoirs. This invention can quantitatively evaluate the influence of factors affecting percolation behavior on fluid pore size distribution. It can compare parameters of a single sample laterally or multiple samples longitudinally, ultimately clarifying the specific pore size range affected by factors influencing percolation behavior. It also clarifies the controlling role of factors influencing percolation behavior on fluid pore size distribution from a mechanistic perspective. At the same time, through computer-automated control, it realizes the rapid change of dynamic factors during percolation, eliminating the influence of human operation delays on the experimental process. The entire experiment is conducted in a closed environment, avoiding experimental errors caused by environmental changes during the experiment.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a schematic diagram of the overall structure of a system for evaluating the dynamic factors controlling the pore size distribution of fluid, according to an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of the specific structure of a system for evaluating the dynamic factors controlling the pore size distribution of fluid, according to an embodiment of this application.

[0025] Figure 3 This is an example diagram showing the measurement results of fluid pore size distribution under different percolation contents in a system for evaluating the dynamic factor-controlled fluid pore size distribution according to an embodiment of this application.

[0026] Figure 4 This is a flowchart illustrating the steps of a method for evaluating the dynamic factor-controlled fluid aperture distribution according to an embodiment of this application. Detailed Implementation

[0027] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0028] Furthermore, the steps illustrated in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than that presented here.

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0030] To address one or more of the technical problems mentioned in the background, this application of the present invention provides a system and method for evaluating the pore size distribution of fluids controlled by dynamic factors. This system and method aim to construct a fully automated scheme for evaluating the pore size distribution of fluids controlled by dynamic factors, where the permeate content and boundary conditions (contact area, interaction mode, and bedding orientation) are dynamically variable. By comparing the changes in the pore size distribution of the fluid within the sample before and after changes in experimental dynamic conditions, the system quantitatively evaluates the impact of dynamic conditions on the pore size distribution of permeated fluids in tight reservoirs, providing theoretical support for accurately evaluating the distribution of retained fluids in actual geological reservoirs.

[0031] Figure 1 This is a schematic diagram of the overall structure of a system for evaluating the dynamic factors controlling fluid aperture distribution, according to an embodiment of this application. The following refers to... Figure 1 The specific structure of the system for evaluating the dynamic factor-controlled fluid aperture distribution (also known as the "dynamic factor and aperture distribution relationship evaluation system") described in the embodiments of the present invention will be explained.

[0032] like Figure 1 As shown in the embodiment of the present invention, the dynamic factor and pore size distribution relationship evaluation system includes at least a measurement zone chamber. The interior of the measurement zone chamber includes at least a solution tank, a suspended robotic arm, a (core) sample holder, a nuclear magnetic resonance measurement mechanism, and a main control mechanism.

[0033] refer to Figure 1 The solution tank is used to hold the experimental fluid. A suspended robotic arm is fixed to the top of the measuring chamber. A core sample holder is located at the non-fixed end of the suspended robotic arm. This arm is used to detect the weight of the core sample and to place the sample holder in the experimental fluid via self-extension. The nuclear magnetic resonance (NMR) measurement mechanism is used to measure the NMR spectrum of the core sample under the control of the main control mechanism, under corresponding contact factor conditions.

[0034] like Figure 2 As shown in (b), in this embodiment of the invention, the sample holder is constructed as a cubic plate, and magnetic pole devices of the nuclear magnetic resonance measurement mechanism are respectively arranged on the outer side of any pair of opposite sides of the cubic plate. A switching mechanism is provided on the plate surface of the cubic plate that is not in contact with the magnetic pole devices.

[0035] The main control mechanism is used to control the dynamic contact factors between the core and the experimental fluid by regulating the above-mentioned switching mechanism, so as to carry out spontaneous percolation experiments. After controlling the two magnetic pole devices of the nuclear magnetic resonance measurement mechanism to transmit radio frequency signals to the core sample, the influence of the corresponding dynamic factors on the fluid pore size distribution is quantitatively analyzed based on the nuclear magnetic resonance spectra under different contact factor conditions.

[0036] The sample holder is used to hold the core sample. To ensure the accuracy of the measurement results, the core sample described in this embodiment of the invention is a cubic shale sample with a preset side length. The cubic shale sample is placed inside a cubic plate.

[0037] like Figure 2 As shown in (a), the main control mechanism is implemented using computer equipment. Furthermore, the nuclear magnetic resonance measurement mechanism includes: a radio frequency oscillator, a radio frequency receiver, and two magnetic pole devices. Each magnetic pole device is simultaneously connected to both the radio frequency oscillator and the radio frequency receiver. The magnetic pole devices are coupled to a pair of side surfaces within the cubic plate, such that the radio frequency oscillator and the radio frequency receiver are separated from the magnetic pole devices and housed within the measurement area chamber. Additionally, the magnetic pole devices, along with the sample holder, automatically move with the extension and retraction of the suspended robotic arm.

[0038] Furthermore, the magnetic pole device is equipped with a sweeping coil to transmit radio frequency oscillation signals to the core sample.

[0039] Furthermore, such as Figure 2 As shown in (b), the cubic plate surface that is not in contact with the (two) magnetic pole devices is designated as the non-contact surface. A switching mechanism is provided on the cubic plate surface that is not in contact with the magnetic pole devices. This switching mechanism includes at least one sample clamp control door, which is respectively located on at least one cubic plate surface that is not in contact with the magnetic pole devices; that is, at least one sample clamp control door is respectively located on at least one non-contact surface.

[0040] Each sample holder control door is connected to the main control mechanism, which controls the opening, closing, and degree of opening of the control doors. This ensures that when all control doors are closed, the experimental fluid solution cannot penetrate the sample holder plate and the core sample. Specifically, when a control door is closed, the corresponding control doors interact to prevent the experimental fluid from penetrating between the closed control door and the sample. When open, the control door's opening degree can be adjusted to control the contact area between the fluid and the sample.

[0041] Furthermore, in this embodiment of the invention, any non-contact surface is designated as the bottom surface of the plate. When the suspended robotic arm grasps the sample holder and uses the bottom surface of the plate as the bottom surface of the sample holder, and then places the sample holder into the experimental fluid, the bottom surface of the plate must be parallel to the surface of the experimental fluid to ensure the consistency and reliability of the contact state between the core and the fluid in multiple rounds of spontaneous percolation experiments under the same contact factor conditions.

[0042] Furthermore, a gravity sensor is installed on the controllable suspended robotic arm, which is connected to the main control mechanism to record the weight of the core sample. The main control mechanism can also control the extension and retraction of the suspended robotic arm. In this embodiment of the invention, the gravity sensor's accuracy can reach 0.01 mg.

[0043] Further, refer to Figure 2 (a) The dynamic factor and aperture distribution relationship evaluation system described in this embodiment of the invention further includes: a constant temperature control device. The constant temperature control device is installed inside the measurement zone chamber. This constant temperature control device includes: a temperature sensor, a constant temperature controller, and a heater. The main control mechanism is also used to control the constant temperature controller to adjust the heater power based on the real-time temperature inside the chamber detected by the temperature sensor, so that the temperature inside the measurement zone chamber reaches a constant temperature state that meets the preset temperature.

[0044] The temperature sensor is used to sense the temperature of the fluid self-priming and pore size distribution measurement area. The combined action of the thermostat and the heater is used to regulate the internal temperature of the measurement area chamber to maintain a constant temperature.

[0045] Further, refer to Figure 2 (a) The dynamic factor and pore size distribution relationship evaluation system described in this embodiment of the invention further includes: a liquid level detector and a replenishment pipeline. The liquid level detector is installed on the inner side wall of the solution tank. The liquid level detector is used to detect dynamic liquid level changes of the experimental fluid. The end of the replenishment pipeline extends into the experimental fluid. The main control mechanism is also used to control the start-up timing of the solution replenisher based on the changes in the experimental fluid liquid level, so as to replenish the experimental fluid into the solution tank, ensuring that the replenished liquid level reaches the initial liquid level.

[0046] Furthermore, the dynamic factor and pore size distribution relationship evaluation system described in this embodiment of the invention further includes: a solution replenishment and waste liquid collection area, wherein a solution replenisher and a solution replenishment tank are provided in the solution replenishment and waste liquid collection area. The solution replenishment tank is used to store experimental fluids.

[0047] In this way, the combined action of the solution replenisher, the replenishment pipeline and the liquid level monitor can monitor the dynamic changes in the liquid level of the experimental fluid during the percolation experiment. When the liquid level of the solution changes due to factors such as evaporation and percolation, the solution replenisher automatically replenishes the fluid in the solution tank to the initial liquid level.

[0048] In addition, the solution replenishment and waste liquid collection area also includes a waste liquid collection tank and a waste liquid collector; the measurement area also includes a waste liquid suction device. The main control mechanism is also used to activate the waste liquid collector and waste liquid suction device after the experiment is completed, so that the waste liquid after the experiment can be pumped and collected into the waste liquid collection tank via the waste liquid suction device in the measurement area.

[0049] In one embodiment, such as Figure 2 As shown in (a), the dynamic factor and pore size distribution relationship evaluation system of this embodiment further includes: a first main control gate (control gate A), a second main control gate (control gate B), and a third main control gate (control gate C). The first main control gate is located on the measurement area housing. The second and third main control gates are respectively located in the solution replenishment and waste liquid collection areas. The second main control gate is connected to the waste liquid aspirator, and automatic waste liquid collection is achieved by controlling the connection between the second and first main control gates; the third main control gate is connected to the solution replenishment device, and automatic solution replenishment is achieved by controlling the connection between the third and first main control gates.

[0050] The solution replenisher extends into the solution replenishment tank. When the liquid level monitor in the measurement area detects a drop in the liquid level, the solution replenisher begins to draw solution from the solution replenishment tank to replenish the liquid level to the initial level. After the experiment is completed, the waste liquid collector collects the waste liquid into the waste liquid collection tank through the waste liquid suction device in the measurement area tank. Control door B can be opened to replace the waste liquid in the waste liquid collection tank; control door C can be opened to replenish the solution in the solution tank.

[0051] Therefore, by using equipment such as a suspended robotic arm, a liquid level monitor, a solution replenisher, a replenishment pipeline, a waste liquid collector, and a waste liquid aspirator, the embodiments of the present invention have achieved automatic sample transport and weight measurement, automatic replenishment of experimental fluids, and waste liquid aspiration treatment, thereby reducing the interference of abnormal effects of operational factors on the percolation test results.

[0052] Furthermore, such as Figure 2(a) The dynamic factor and pore size distribution relationship evaluation system described in this embodiment of the invention further includes: a conductivity measuring device. This conductivity measuring device is disposed within the measuring area chamber. The conductivity measuring device comprises: a conductivity mechanism and a conductivity electrode extending into the experimental fluid. Specifically, the conductivity electrode is connected to the conductivity mechanism, and the conductivity mechanism is connected to the main control mechanism. The conductivity electrode, extending into the experimental fluid, can measure the change in the fluid's conductivity, thereby enabling the main control mechanism to dynamically monitor the change in the experimental fluid's conductivity. In this embodiment of the invention, the measurement accuracy of the conductivity mechanism can reach 0.001 mS / cm.

[0053] In this embodiment of the invention, the contact factors (parameters) include, but are not limited to, percolation content, contact area, core-fluid interaction mode, and bedding contact direction. Therefore, this invention can adjust the change of at least one contact factor between the core and the experimental fluid by controlling the switching mechanism through the main control mechanism, and conduct corresponding spontaneous percolation experiments for at least two parameter data corresponding to the same contact factor. Thus, through at least two rounds of spontaneous percolation experiments, the influence of changes in contact factor parameter data under corresponding contact factor conditions on the fluid pore size distribution can be quantitatively analyzed.

[0054] In the first embodiment, when the contact factor is percolation content, the switching mechanism described in this embodiment includes a sample clamp control door disposed on the bottom surface of the plate. The main control mechanism is further configured to conduct a spontaneous percolation experiment when the sample clamp control door (in the first embodiment) is in the open state, record the weight change of the core sample during the experiment, calculate the fluid self-absorption content (i.e., dynamic percolation content) at different experimental moments, and simultaneously control the measurement of nuclear magnetic resonance relaxation time spectra under different self-absorption content conditions. Based on the measured nuclear magnetic resonance relaxation time spectra under different self-absorption content conditions, the influence of different percolation content conditions on the fluid pore size distribution is quantitatively analyzed to obtain corresponding quantitative analysis results.

[0055] Specifically, first, control door A is opened, and a dry core sample (e.g., a regular shale cube with dimensions of approximately 1 cm in length, width, and height) is fixed in the sample holder. The main control mechanism controls the suspended robotic arm to weigh the dry weight m0 of the sample, and then lowers the sample holder into the experimental fluid by extending the suspended robotic arm. The sample holder control door B, located on the bottom surface of the plate, is then opened, and the spontaneous percolation experiment is conducted. The data analysis and recording software in the main control mechanism records the mass m of the core sample in real time. n To calculate the real-time fluid self-absorption content of the core sample.

[0056] Furthermore, the fluid self-absorption content is calculated using the following expression:

[0057]

[0058] Among them, S w The m represents the fluid self-absorption content within a certain calculation period. n This indicates the core weight at the end of the current calculation cycle, where m0 represents the dry weight of the core sample.

[0059] Simultaneously, under the combined action of the radio frequency oscillator, radio frequency receiver, and magnetic pole device with sweeping coil attached inside the sample holder, the nuclear magnetic resonance relaxation time spectrum under the corresponding dynamic percolation content is measured; then, based on the commonly used relaxation time pore size conversion standard, the peak area of ​​the signal amplitude at different relaxation times can be calculated to obtain the fluid distribution in different pore size spaces.

[0060] Measurement results of fluid pore size distribution with dynamic permeation content, such as Figure 3 As shown, the relaxation time range of shale is 0.02-1ms, 1-10ms, 10-100ms and 100-1000ms, which correspond to micropores (2-100nm), small pores (0.1-1μm), mesopores (1-10μm) and macropores (10-100μm), respectively. Then, the peak area of ​​the relaxation time signal amplitude S0.02-1, S1-10, S10-100 and S100-1000 under the corresponding dynamic permeation content can be calculated to obtain the fluid distribution in the space of different pore sizes.

[0061] In the second embodiment, when the contact factor is the contact area, the switching mechanism described in this embodiment includes a sample clamp control door disposed on the bottom surface of the plate. The main control mechanism is further used to adjust the contact area between the fluid and the core at different opening degrees by controlling the opening state of the sample clamp control door (in the second embodiment), to conduct spontaneous percolation experiments under different contact area conditions, and to obtain corresponding nuclear magnetic resonance relaxation time spectra. Based on the measured nuclear magnetic resonance relaxation time spectra under different contact area conditions, the influence of different contact area conditions on the fluid pore size distribution is quantitatively analyzed to obtain corresponding quantitative analysis results.

[0062] Specifically, first, control door A is opened, and a dry core sample (e.g., a regular shale cube with dimensions of approximately 1 cm in length, width, and height) is fixed in the sample holder. The main control mechanism controls the suspended robotic arm to weigh the dry weight m0 of the sample, and lowers the sample holder into the experimental fluid by extending the suspended robotic arm. The sample holder control door B, located on the bottom surface of the plate, is then opened, and the spontaneous percolation experiment is initiated. At this point, the contact area of ​​the experimental sample is A1. After a preset time t, the nuclear magnetic resonance relaxation time spectrum of the contact area A1 is measured under the combined action of the radio frequency oscillator, radio frequency receiver, and the magnetic pole device with a sweeping coil attached to the sample holder. The main control mechanism then controls the sample holder control door B to change the contact area of ​​the experimental sample to A2, and the spontaneous percolation experiment continues. A gravity sensor on the controllable suspension arm records the weight reading in real time. After a preset time t, the nuclear magnetic resonance relaxation time spectrum of contact area A2 is measured under the combined action of the radio frequency oscillator, radio frequency receiver, and magnetic pole device with a sweeping coil attached to the sample holder. This process is repeated to obtain the nuclear magnetic resonance relaxation time spectrum of contact area An. Based on the obtained nuclear magnetic resonance relaxation time spectra of different contact areas A1-An, the peak areas of the relaxation time signal amplitude S0.02-1, S1-10, S10-100, and S100-1000 under different relaxation time areas A1-An are calculated respectively, thus clarifying the influence of dynamic contact area on the fluid distribution in spaces with different aperture sizes.

[0063] In the third embodiment, when the contact factor is the interaction between the core and the experimental fluid, the switching mechanism described in this embodiment includes at least two sample clamp control doors respectively disposed on at least two non-contact surfaces. The main control mechanism is further used to adjust the interaction mode of percolation displacement of different numbers of plate surfaces by sequentially controlling the sample clamp control doors (in the third embodiment) to be in the open state, conducting spontaneous percolation experiments under different interaction conditions, and obtaining corresponding nuclear magnetic resonance relaxation time spectra. Based on the measured nuclear magnetic resonance relaxation time spectra under different interaction conditions, the influence of different interaction conditions on the fluid pore size distribution is quantitatively analyzed to obtain corresponding quantitative analysis results.

[0064] Specifically, first, control door A is opened, and a dry core sample (e.g., a regular shale cube with a length, width, and height of about 1 cm) is fixed in the sample holder. The main control mechanism controls the suspended robotic arm to weigh the dry weight m0 of the sample, and the suspended robotic arm is extended to lower the sample holder into the experimental fluid. The sample holder control door B, located on the bottom surface of the plate, is opened, and the spontaneous percolation experiment is carried out. After experimental time t, under the combined action of the RF oscillator, RF receiver, and magnetic pole device with sweeping coils inside the sample holder, the NMR relaxation time spectrum is measured when the interaction mode is same-sided percolation and displacement. Then, the sample holder control gate C is opened to continue the spontaneous percolation experiment. After a preset experimental time t, under the combined action of the RF oscillator, RF receiver, and magnetic pole device with sweeping coils inside the sample holder, the NMR relaxation time spectrum is measured when the interaction mode is bilateral percolation and displacement. Subsequently, the sample holder control gates A and D are opened sequentially to obtain NMR relaxation time spectra when the interaction modes are three-sided and four-sided percolation and displacement, respectively. Based on the obtained NMR relaxation time spectra for different interaction modes, the peak areas of the relaxation time signal amplitude S0.02⁻¹, S1⁻¹⁰, S1⁻¹⁰⁰, and S1⁻¹⁰⁰⁰⁰ are calculated for different interaction modes, thus clarifying the influence of the dynamic interaction mode on the fluid distribution in different pore sizes.

[0065] In the fourth embodiment, when the contact factor is in the layered contact direction, the switching mechanism described in this embodiment includes: a first sample clamp control door and a second sample clamp control door. The first sample clamp control door is disposed on the bottom surface of the plate, and the second sample clamp control door is disposed on any non-contact surface adjacent to the bottom surface of the plate.

[0066] At this time, the main control mechanism is also used to adjust the stratification contact direction by sequentially controlling the first sample clamp control door and the second sample clamp control door (in the fourth embodiment) to be in an individually open state, to carry out spontaneous percolation experiments under different stratification contact direction conditions, and to obtain the corresponding nuclear magnetic resonance relaxation time spectrum. Based on the nuclear magnetic resonance relaxation time spectrum obtained under different stratification contact direction conditions, the influence of different stratification contact direction conditions on the fluid pore size distribution is quantitatively analyzed to obtain the corresponding quantitative analysis results.

[0067] In one embodiment, the main control mechanism is also used to control the cubic plate to rotate along an annular direction formed by four non-contact surfaces to adjust the contact direction between the permeation direction and the core bedding direction.

[0068] Specifically, first, control door A is opened, and a dry core sample (e.g., a regular shale cube with dimensions of approximately 1 cm in length, width, and height) is fixed inside the sample holder. The main control mechanism controls the suspended robotic arm to weigh the dry weight m0 of the sample, and lowers the sample holder into the experimental fluid by extending the suspended robotic arm. The sample holder control door B, located on the bottom surface of the plate, is then opened, and the spontaneous percolation experiment is initiated. After a preset time t, the nuclear magnetic resonance relaxation time spectrum of percolation along the parallel bedding direction is measured under the combined action of the radio frequency oscillator, radio frequency receiver, and the magnetic pole device with the sweeping coil inside the sample holder. Subsequently, the main control mechanism closes the sample holder control door B and rotates the cube plate, causing the sample holder control door A (or C) to rotate downwards (making sample holder control door A or C the current bottom surface of the plate). The main control mechanism then opens sample holder control door A (or C) to continue the spontaneous percolation experiment. After a preset time t, the nuclear magnetic resonance relaxation time spectrum of fluid permeation along the perpendicular stratification direction was measured under the combined action of the radio frequency oscillator, radio frequency receiver, and magnetic pole device with a sweeping coil attached to the sample holder. Based on the obtained nuclear magnetic resonance relaxation time spectra for different stratification contact directions, the amplitude peak areas S0.02-1, S1-10, S10-100, and S100-1000 of the different relaxation time signals for different contact directions were calculated, thus clarifying the influence of the dynamic stratification contact direction on the fluid distribution in spaces with different pore sizes.

[0069] Furthermore, in this embodiment of the invention, regardless of which one or more contact factors are measured, the interior of at least one sample clamp control door is equipped with a corresponding flow meter and pressure gauge to monitor the dynamic flow pressure data of the corresponding spontaneous percolation experiment.

[0070] Based on the aforementioned evaluation system for the relationship between dynamic factors and pore size distribution, this embodiment of the invention also provides a method for evaluating the pore size distribution of fluids controlled by dynamic factors (also referred to as the "evaluation method for the relationship between dynamic factors and pore size distribution"). This evaluation method for the relationship between dynamic factors and pore size distribution utilizes the aforementioned evaluation system for the relationship between dynamic factors and pore size distribution.

[0071] Figure 4 This is a schematic flowchart illustrating the steps of a method for evaluating the dynamic control of fluid pore size distribution according to an embodiment of this application. Figure 4 As shown, the method for evaluating the relationship between dynamic factors and pore size distribution according to embodiments of the present invention includes at least the following steps:

[0072] Step S401: Inject the experimental fluid into the solution tank;

[0073] Step S402: The core sample holder is placed in the experimental fluid by means of the self-extension control of the suspended robotic arm;

[0074] Step S403: The dynamic contact factors between the core and the experimental fluid are controlled by adjusting the switching mechanism on the sample holder in order to carry out spontaneous percolation experiments.

[0075] Step S404: Control the nuclear magnetic resonance spectrum of the core sample of the nuclear magnetic resonance measurement mechanism under the corresponding contact factor conditions;

[0076] Step S405: Based on the reflection signals under different contact conditions, quantitatively analyze the influence of corresponding dynamic factors on the fluid pore size distribution.

[0077] This invention discloses a system and method for evaluating the dynamic factors controlling the pore size distribution of fluids. The system and method integrate an infiltration device and a nuclear magnetic resonance (NMR) measurement device into a single apparatus, constructing a fully automated scheme for evaluating the dynamic factors controlling the pore size distribution of fluids by dynamically varying infiltration content and boundary conditions (contact area, interaction mode, and bedding orientation). By comparing the changes in the pore size distribution of fluid within the sample before and after changes in experimental dynamic conditions, the system quantitatively evaluates the influence of dynamic conditions such as rock water content, contact area, interaction mode, and bedding orientation on the pore size distribution of infiltrated fluids within the reservoir, providing theoretical support for accurately evaluating the distribution of retained fluids in actual geological reservoirs. This invention can quantitatively evaluate the influence of factors affecting percolation behavior on fluid pore size distribution. It can compare parameters of a single sample laterally or multiple samples longitudinally, ultimately clarifying the specific pore size range affected by factors influencing percolation behavior. It also clarifies the controlling role of factors influencing percolation behavior on fluid pore size distribution from a mechanistic perspective. At the same time, through computer-automated control, it realizes the rapid change of dynamic factors during percolation, eliminating the influence of human operation delays on the experimental process. The entire experiment is conducted in a closed environment, avoiding experimental errors caused by environmental changes during the experiment.

[0078] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0079] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0080] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0081] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0082] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0083] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A system for evaluating the dynamic factors controlling fluid aperture distribution, characterized in that, include: A solution tank used to hold experimental fluids; A suspended robotic arm is equipped with a core sample holder at a non-fixed end for detecting the weight of the core sample and placing the sample holder in the experimental fluid. Nuclear magnetic resonance (NMR) measurement equipment, used to measure the NMR spectrum of core samples; The sample holder is constructed as a cubic plate, and magnetic pole devices of the nuclear magnetic resonance measurement mechanism are respectively arranged on the outer side of any pair of sides of the plate. A switching mechanism is arranged on the plate surface that is not in contact with the magnetic pole devices. The main control mechanism is used to control the dynamic contact factors between the core and the experimental fluid by regulating the switching mechanism to carry out spontaneous percolation experiments, thereby quantitatively analyzing the influence of the corresponding dynamic factors on the fluid pore size distribution based on the nuclear magnetic resonance spectra under different contact factor conditions.

2. The system according to claim 1, characterized in that, The contact factors include permeation content, contact area, core-fluid interaction mode, and bedding contact direction; The plate surface that is not in contact with the magnetic pole device is designated as the non-contact surface, and any non-contact surface is designated as the bottom surface of the plate. The bedding direction of the core sample is parallel to the bottom surface of the plate. The sample holder is placed in the experimental fluid with the bottom surface of the plate parallel to the fluid surface.

3. The system according to claim 2, characterized in that, When the contact factor is percolation content, the switching mechanism includes: a sample clamp control door disposed on the bottom surface of the plate, wherein, The main control mechanism is also used to conduct spontaneous percolation experiments when the control door of the sample clamp is in the open state, record the weight change of the core sample and calculate the fluid self-absorption content at different times, and control the measurement of nuclear magnetic resonance relaxation time spectrum under different self-absorption content conditions. Based on this, the influence of different percolation content conditions on fluid pore size distribution can be quantitatively analyzed to obtain corresponding quantitative analysis results.

4. The system according to claim 2 or 3, characterized in that, When the contact factor is the contact area, the switching mechanism includes: a sample clamp control door disposed on the bottom surface of the plate, wherein, The main control mechanism is also used to adjust the contact area between the fluid and the core under different opening degrees by controlling the opening state of the sample clamp control door, to carry out spontaneous percolation experiments under different contact area conditions, and to obtain the corresponding nuclear magnetic resonance relaxation time spectrum, thereby quantitatively analyzing the influence of different contact area conditions on the fluid pore size distribution, and obtaining the corresponding quantitative analysis results.

5. The system according to any one of claims 2 to 4, characterized in that, When the contact factor is a core-fluid interaction, the switching mechanism includes: at least two sample clamp control doors respectively disposed on at least two non-contact surfaces, wherein, The main control mechanism is also used to adjust the interaction mode of percolation and displacement of different numbers of plate surfaces by sequentially controlling the control doors of at least two sample clamps to be in the open state, to carry out spontaneous percolation experiments under different interaction mode conditions, and to obtain the corresponding nuclear magnetic resonance relaxation time spectrum, thereby quantitatively analyzing the influence of different interaction mode conditions on the fluid pore size distribution, and obtaining the corresponding quantitative analysis results.

6. The system according to any one of claims 2 to 5, characterized in that, When the contact factor is in the layered contact direction, the switching mechanism includes: a first sample clamp control door disposed on the bottom surface of the plate and a second sample clamp control door disposed on any non-contact surface adjacent to the bottom surface of the plate, wherein, The main control mechanism is also used to adjust the stratification contact direction by sequentially controlling the first sample clamp control door and the second sample clamp control door to be in an individually open state, to carry out spontaneous percolation experiments under different stratification contact direction conditions, and to obtain the corresponding nuclear magnetic resonance relaxation time spectrum, thereby quantitatively analyzing the influence of different stratification contact direction conditions on the fluid pore size distribution, so as to obtain the corresponding quantitative analysis results.

7. The system according to any one of claims 3 to 6, characterized in that, The nuclear magnetic resonance (NMR) measurement mechanism includes: a radio frequency (RF) oscillator, an RF receiver, and two magnetic pole devices. The RF oscillator, the RF receiver, the solution tank, the suspended robotic arm, the magnetic pole devices, and the sample holder are all disposed inside the measurement area chamber. The system also includes a temperature control device disposed within the measurement area chamber. This temperature control device further includes a temperature sensor, a temperature controller, and a heater. The main control mechanism is also used to control the thermostat to adjust the power of the heater based on the real-time temperature inside the chamber detected by the temperature sensor, so that the temperature inside the chamber reaches a constant temperature state that meets the preset temperature.

8. The system according to claim 7, characterized in that, The system also includes: A liquid level detector installed on the solution tank is used to detect dynamic changes in the liquid level of the experimental fluid; The supply line, with its end extending into the experimental fluid, contains... The main control mechanism is also used to control the start-up timing of the solution replenisher according to the change in the experimental fluid level, so as to replenish the experimental fluid into the solution tank and make the replenished liquid level reach the initial liquid level.

9. The system according to claim 8, characterized in that, The system further includes: a solution replenisher and a solution replenishment tank disposed in the solution replenishment and waste liquid collection area, wherein the solution replenishment tank is used to store experimental fluid, and the solution replenishment and waste liquid collection area further includes: a waste liquid collection tank and a waste liquid collector, wherein... The main control mechanism is also used to control the waste liquid collector and waste liquid suction device to start after the experiment is completed, so as to collect the waste liquid after the experiment into the waste liquid collection tank through the waste liquid suction device of the measurement area box.

10. The system according to claim 9, characterized in that, The system further includes: a first main control door installed on the measuring area housing, and a second and third main control doors installed in the solution replenishment and waste collection area, wherein... The second main control valve is connected to the waste liquid suction device, and the waste liquid collection and treatment is automatically carried out by controlling the connection between the second main control valve and the first main control valve; The third master control gate is connected to the solution replenisher, and the solution replenishment is automatically processed by controlling the connection between the third master control gate and the first master control gate.

11. The system according to any one of claims 3 to 10, characterized in that, The sample holder control door is equipped with a flow meter and a pressure gauge to monitor the dynamic flow pressure data of the spontaneous percolation experiment. The system also includes a conductivity measuring device, which has a conductivity mechanism and a conductivity electrode that extends into the experimental fluid.

12. A method for evaluating the dynamic factors controlling fluid pore size distribution, characterized in that, The method is implemented using the system as described in any one of claims 1 to 11, wherein the method comprises: Inject the experimental fluid into the solution tank; The core sample holder is placed in the experimental fluid by means of the self-extension control of the suspended robotic arm; The dynamic contact factors between the core and the experimental fluid are controlled by adjusting the switching mechanism on the sample holder in order to carry out spontaneous percolation experiments. Nuclear magnetic resonance (NMR) spectra of core samples from controlled NMR measurement facilities under corresponding contact factor conditions; Based on the reflected signals under different contact conditions, the influence of corresponding dynamic factors on the fluid pore size distribution is quantitatively analyzed.

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