Shale oil yield increase test equipment and method

Abstract

The embodiment of the invention provides shale oil yield increase testing equipment and method. The equipment comprises a true triaxial confining pressure assembly used for forming an accommodating bin for accommodating a to-be-tested experimental rock sample and pressurizing the experimental rock sample to simulate formation pressure; the transformer assembly comprises a graphite electrode and a variable voltage power supply, and the graphite electrode is fixed in the accommodating bin and is used for heating the experimental rock sample; the variable-voltage power supply is connected with the graphite electrode and used for providing electric energy for the graphite electrode; the gas adjusting assembly is connected with the containing bin and used for adjusting gas parameters in the containing bin; the environmental parameter sensing assembly is connected with the accommodating bin and is used for acquiring environmental parameters in the accommodating bin; and the component analysis assembly is connected with the accommodating bin and is used for obtaining a product obtained after the experimental rock sample generates a carbonization channel under a preset condition and is subjected to in-situ cracking through normal-pressure alternating current heating, and analyzing the components of the product. The equipment and the corresponding test method are used for achieving the effect of improving the test accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of reservoir development, and in particular to a shale oil production increase testing device and method. Background Art

[0002] Underground in-situ mining of low-middle maturity organic-rich shale refers to the direct cracking of low-middle maturity organic-rich shale in-situ underground. Generally, heat is transferred to low-middle maturity organic-rich shale by certain heat transfer means, so that kerogen organic matter is directly heated and cracked underground to produce oil and gas, which are then transported to the ground through corresponding pipelines or wells for separation to obtain the required oil and gas. Compared with ground development technology, underground in-situ mining technology has the advantages of high efficiency, environmental friendliness and low energy consumption.

[0003] Currently, the underground in-situ mining work can be started after the carbonization channel is formed in the shale by heating the formation environment with high voltage. Among them, the internal and external factors such as water content, oil content and electric field strength in the real formation environment all have an impact on the formation of carbonization channels. In the existing technology, the research and experiment on the formation mechanism of shale carbonization channels has the problem of low accuracy. Summary of the invention

[0004] The embodiments of the present application provide a shale oil production increase testing device and method, which are used to improve the test accuracy.

[0005] In a first aspect, an embodiment of the present application provides a shale oil production increase testing device, comprising:

[0006] A true triaxial confining pressure assembly is used to form a containing chamber to contain the experimental rock sample to be tested, and to pressurize the experimental rock sample to simulate the formation pressure;

[0007] The transformer assembly includes a graphite electrode and a variable voltage power supply. The graphite electrode is fixed in the containing chamber and is used to heat the experimental rock sample. The variable voltage power supply is connected to the graphite electrode and is used to provide electrical energy to the graphite electrode.

[0008] A gas regulating component, connected to the containing chamber, for regulating gas parameters in the containing chamber;

[0009] An environmental parameter sensing component, connected to the storage bin, for obtaining environmental parameters in the storage bin;

[0010] The component analysis component is connected to the containing chamber and is used to obtain the products obtained after the carbonization channel of the experimental rock sample is generated under preset conditions and the in-situ cracking is carried out by normal pressure alternating current heating, and analyze the composition of the products.

[0011] In one possible implementation, the gas regulating assembly includes:

[0012] An oxygen-free gas source is connected to the containing chamber via a first stop valve and a three-way valve, and is used to introduce an oxygen-free gas into the containing chamber so as to place the experimental rock sample in an oxygen-free environment;

[0013] The vacuum pump is connected to the containing chamber via a vacuum gauge, a second stop valve and a three-way valve, and is used for evacuating the containing chamber.

[0014] In a possible implementation, the environmental parameter sensing component includes:

[0015] A pressure sensor is disposed between the first stop valve and the three-way valve, and is used to obtain the pressure value of the oxygen-free gas;

[0016] A temperature sensor is arranged in the containing chamber and is used to obtain the temperature value of the experimental rock sample;

[0017] The data acquisition terminal is connected to the pressure sensor and the temperature sensor, and is used to receive the pressure value and the temperature value, and store and analyze the pressure value and the temperature value; wherein the environmental parameters include the pressure value and the temperature value.

[0018] In one possible implementation, the component analysis component includes:

[0019] A gas-water separation device is connected to the containing bin via a back pressure valve and a third stop valve, and is used to separate gas and water from the product to obtain a gas-water separation product;

[0020] The product analysis terminal is connected to the gas-water separation device and is used to analyze the components of the gas-water separation product.

[0021] In a second aspect, an embodiment of the present application provides a shale oil production increase testing method, which is based on the shale oil production increase testing device of the first aspect, and includes:

[0022] Sealing the experimental rock samples in a containing chamber;

[0023] Start the gas regulating component to adjust the gas parameters in the containing chamber so that the experimental rock sample is in a gas environment with preset parameters;

[0024] By adjusting the true triaxial confining pressure assembly, the experimental rock sample is subjected to confining pressure to provide a preset pressure environment to the experimental rock sample;

[0025] Starting the transformer assembly to allow the graphite electrode to heat the experimental rock sample and generate a carbonization channel in the experimental rock sample;

[0026] The environmental parameters of the experimental rock sample when the carbonization channel is generated are obtained through the environmental parameter sensing component;

[0027] The composition and analysis results of the product are obtained through the component analysis component.

[0028] In a possible implementation, starting the transformer assembly so that the graphite electrode heats the experimental rock sample and generates a carbonization channel in the experimental rock sample includes:

[0029] Setting the initial voltage of the variable voltage power supply to preheat the experimental rock sample to a preset temperature;

[0030] Adjust the output voltage of the variable voltage power supply, pass high voltage alternating current to the experimental rock sample, and monitor the current value of the graphite electrode and the temperature value of the experimental rock sample;

[0031] Based on the change of current value and temperature value, the output voltage is dynamically adjusted until the change of current value and temperature value reach the preset conditions; wherein the preset conditions are the reaction conditions for the experimental rock sample to produce a carbonization channel.

[0032] In a possible implementation, the preset conditions include: the increase in the current value per unit time is greater than or equal to a preset threshold, and the temperature value continues to rise;

[0033] Dynamically adjust the output voltage based on the change of current value and temperature value, including:

[0034] If the increase in the current value per unit time is less than the preset threshold value and the temperature value does not continue to rise, the output voltage of the variable voltage power supply is increased;

[0035] If the increase in the current value per unit time is greater than or equal to the preset threshold value and the temperature value does not continue to rise, the output voltage of the variable voltage power supply is switched to the preset voltage value to heat the experimental rock sample.

[0036] In a possible implementation, starting the gas regulating component to adjust the gas parameters in the containing chamber so that the experimental rock sample is in a gas environment with preset parameters includes:

[0037] The containing chamber is evacuated to place the experimental rock sample in a vacuum environment;

[0038] Anoxic gas is introduced into the containing chamber to keep the experimental rock samples in an oxygen-free environment.

[0039] In a possible implementation, the method further includes:

[0040] Using different parameter combinations, experiments were conducted on experimental rock samples with the same physical parameters, and the time and energy consumption required for the experimental rock samples to produce carbonization channels under each parameter combination were obtained;

[0041] Among the first times and energy consumptions of each group, determine the target group time and energy consumption that meets the target conditions; the target conditions include the shortest time and / or the lowest energy consumption;

[0042] Based on the target group time and energy consumption, the corresponding target parameter combination is determined.

[0043] In a possible implementation, the method further includes:

[0044] Experiments are performed using experimental rock samples of different target components to obtain corresponding groups of second times required for the experimental rock samples of each target component to generate carbonization channels;

[0045] In each group of second times, determine the shortest target time;

[0046] Based on the target time, the corresponding target component is determined.

[0047] The shale oil production increase test equipment and method provided in the embodiment of the present application are provided with a true triaxial confining pressure assembly to form a containing chamber to contain the experimental rock sample to be tested, and to pressurize the experimental rock sample to simulate the formation pressure; a transformer assembly, including a graphite electrode and a variable voltage power supply, the graphite electrode is fixed in the containing chamber, and is used to heat the experimental rock sample; the variable voltage power supply is connected to the graphite electrode, and is used to provide electrical energy to the graphite electrode; a gas regulating assembly, connected to the containing chamber, is used to adjust the gas parameters in the containing chamber; an environmental parameter sensing assembly, connected to the containing chamber, is used to obtain the environmental parameters in the containing chamber; a component analysis assembly, connected to the containing chamber, is used to obtain the carbonization channel generated by the experimental rock sample under preset conditions and the product obtained after in-situ cracking by normal pressure alternating current heating, and the composition of the product is analyzed, and the real formation pressure is simulated by the true triaxial confining pressure assembly, and the gas regulating assembly simulates the real formation gas parameters, so as to achieve the effect of improving the test accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0049] Figure 1 A schematic diagram of the structure of the shale oil production increase testing equipment provided for this application;

[0050] Figure 2 A schematic diagram of the process of the shale oil production increase testing method provided in this application;

[0051] Figure 3 A dual-coordinate chart of the time and energy consumption required to form a carbonized channel in relation to the electric field intensity drawn based on the shale oil production increase test method provided in the present application in one embodiment;

[0052] Figure 4 This is a coordinate chart showing the time t required to form a carbonization channel as a function of water content, drawn based on the shale oil production increase test method provided in the present application in an embodiment.

[0053] Reference numerals:

[0054] 1-vacuum pump; 2-vacuum gauge; 3-second stop valve; 4-three-way valve; 5-first stop valve; 6-nitrogen gas storage bottle; 7-loading plate; 8-graphite electrode; 9-temperature sensor; 10-axial loading shaft; 11-data acquisition instrument; 12-transformer; 13-third stop valve; 14-back pressure valve; 15-product analyzer; 16-gas-water separation device; 17-loading shaft; 18-true triaxial instrument bracket; 19-pressure sensor.

[0055] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0056] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0057] Medium-low maturity organic-rich shales have been in a state of high temperature and high pressure deep underground for a long time. The deep rocks are in an anisotropic stress field, that is, they are subjected to triaxial stress (vertical stress, normal stress, and shear stress). In the actual medium-low maturity organic-rich shale reservoir environment, the magnitudes of the three stresses to which the shale is subjected are also different.

[0058] The embodiment of the present application aims to use true triaxial simulation of the formation environment to study the formation of carbonization channels in shale by high voltage heating in the formation environment, and then in-situ conversion by normal pressure power frequency electric heating. By burying two electrodes in the shale and passing high voltage alternating current into the shale through the electrodes, carbonization channels are generated inside the shale, and its resistivity is greatly reduced; then normal pressure alternating current is passed, and the surrounding shale is heated and cracked by the Joule heat effect of the shale itself, so that the kerogen is cracked and converted into oil and gas.

[0059] The process of forming carbonization channels by high-voltage electric heating in the formation environment is analyzed and studied, and the influence of internal and external factors such as water content, oil content and electric field strength on the formation of carbonization channels is explored under real formation conditions. Experiments under different experimental conditions are carried out to evaluate the process of forming carbonization channels from the perspectives of electric field strength, required time and energy consumption, and analyze and discuss the influencing mechanism under the action of various internal and external factors.

[0060] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0061] Figure 1 The structural diagram of the shale oil production increase testing equipment provided for this application is as follows: Figure 1 As shown, the device includes:

[0062] The true triaxial confining pressure assembly (not shown in the figure) is used to form a containing chamber to contain the experimental rock samples to be tested, and is used to pressurize the experimental rock samples to simulate the formation pressure.

[0063] Specifically, the true triaxial confining pressure assembly may include a loading plate 7, an axial loading shaft 10, a loading shaft 17 and a true triaxial instrument bracket 18. Among them, multiple loading plates 7 can be enclosed to form a storage chamber, which can also be called a sample chamber. Exemplarily, the axial loading shaft 10 is connected to the horizontally arranged loading plate 7, and the loading plate 7 applies vertical pressure to the experimental rock sample in the sample chamber through the vertical extension and contraction of the axial loading shaft 10. The loading shaft 17 is connected to the vertically arranged loading plate 7, and the loading plate 7 applies horizontal pressure to the experimental rock sample in the sample chamber through the horizontal extension and contraction of the loading shaft 17. Among them, the experimental rock sample can also be called a test rock sample or

[0064] The transformer assembly includes a graphite electrode and a variable voltage power supply. The graphite electrode is fixed in the containing chamber and is used to heat the experimental rock sample. The variable voltage power supply is connected to the graphite electrode and is used to provide electrical energy to the graphite electrode.

[0065] Among them, the loading plate 7 may be provided with a through hole, and the graphite electrode 8 may be fixed in the storage bin via the through hole. When an experimental rock sample is placed in the storage bin and the graphite electrode is connected to a variable voltage power supply, the graphite electrode can heat the experimental rock sample. Exemplarily, the variable voltage power supply may be a transformer 12, which outputs variable voltage AC power by connecting to an AC power supply and transforming the voltage of the AC power supply. In other examples, the variable voltage power supply may also be other DC variable voltage power supplies or AC variable voltage power supplies.

[0066] The gas regulating component is connected to the containing chamber and is used to adjust the gas parameters in the containing chamber.

[0067] In one possible implementation, the gas regulating assembly includes:

[0068] The oxygen-free gas source is connected to the storage bin via the first stop valve 5 and the three-way valve 4, and is used to introduce the oxygen-free gas into the storage bin so that the experimental rock sample is in an oxygen-free environment. For example, the oxygen-free gas source may be a nitrogen gas storage bottle 6.

[0069] The vacuum pump 1 is connected to the containing chamber via a vacuum gauge 2, a second stop valve 3 and a three-way valve 4, and is used for evacuating the containing chamber.

[0070] The environmental parameter sensing component is connected to the storage bin and is used to obtain the environmental parameters in the storage bin.

[0071] In a possible implementation, the environmental parameter sensing component may include:

[0072] The pressure sensor 19 is disposed between the first stop valve 5 and the three-way valve 4 and is used to obtain the pressure value of the oxygen-free gas.

[0073] The temperature sensor 9 is arranged in the containing chamber and is used to obtain the temperature value of the experimental rock sample.

[0074] The data acquisition terminal is connected to the pressure sensor 19 and the temperature sensor 9, and is used to receive the pressure value and the temperature value, and store and analyze the pressure value and the temperature value; wherein the environmental parameters include the pressure value and the temperature value. Exemplarily, the data acquisition terminal can be a data acquisition instrument 11, or a terminal including but not limited to a mobile phone, a laptop computer, a server, etc. having data acquisition and analysis processing functions.

[0075] The component analysis component is connected to the containing chamber and is used to obtain the products obtained after the carbonization channel of the experimental rock sample is generated under preset conditions and the in-situ cracking is carried out by normal pressure alternating current heating, and analyze the composition of the products.

[0076] In one possible implementation, the component analysis component includes:

[0077] The gas-water separation device 16 is connected to the containing bin via the third stop valve 13 and the back pressure valve 14, and is used to separate gas and water from the product to obtain a gas-water separation product.

[0078] The product analysis terminal is connected to the gas-water separation device and is used to analyze the components of the gas-water separation product. Exemplarily, the product analysis terminal can be a product analyzer 15, or a terminal including but not limited to a mobile phone, a laptop computer, a server, etc. having data collection and analysis processing functions.

[0079] In order to further explain the scheme of the embodiment of the present application, a specific example is provided below. The shale oil production increase test equipment can also be referred to as a high-voltage electric carbonization expansion-power frequency electric cracking experimental device under simulated formation stress conditions. Exemplarily, it can also be referred to as a simulation device.

[0080] like Figure 1 As shown, it includes a true triaxial confining pressure assembly, a transformer assembly, a vacuum pump 1, a three-way valve 4, a nitrogen gas storage cylinder 6, a temperature sensor 9, a back pressure valve 14, a gas-water separator 16, and a pressure sensor 19. The rock sample to be tested is fixed in the sample compartment of the true triaxial confining pressure assembly, and the confining pressure is applied to the rock sample to be tested by the true triaxial confining pressure assembly; the transformer assembly includes a transformer and a graphite electrode connected thereto; the nitrogen gas storage cylinder 6 is connected to the vacuum pump 1 suction port through the three-way valve 4 through a pipeline, and is connected to the rock sample to be tested inside the sample compartment; the back pressure valve 14 outlet is connected to the gas inlet of the gas-water separator 16, and the gas outlet of the gas-water separator 16 is connected to a product analyzer; the temperature sensor 9 is connected to the rock sample to be tested inside the sample compartment. The nitrogen gas storage cylinder 6 is connected to the first inlet of the three-way valve 4, the vacuum pump 1 suction port is connected to the second inlet of the three-way valve 4, and the outlet of the three-way valve 4 is connected to the rock sample to be tested inside the sample compartment through a pipeline. The pipeline between the nitrogen gas storage cylinder 6 and the first inlet of the three-way valve 4 is connected with a first stop valve 5 and a pressure sensor 19; the pipeline between the vacuum pump 1 exhaust port and the second inlet of the three-way valve 4 is connected with a second stop valve 3 and a vacuum gauge 2, and the vacuum gauge 2 is located between the second stop valve 3 and the vacuum pump 1. The air inlet of the back pressure valve 14 is connected with a third stop valve 13, the air outlet of the back pressure valve 14 is connected with the inlet of the gas-water separator 16, and the outlet of the gas-water separator 16 is connected with the product analyzer 15. The back pressure valve 14 is set for the following two purposes: 1) After the rock sample to be tested reaches the pressure and temperature simulating the real formation conditions, the third stop valve needs to be opened to connect the back pressure valve with the rock sample to be tested to keep the pressure stable; 2) After the carbonization channel is formed, the rock sample to be tested is continuously heated by alternating current to simulate the in-situ transformation of the formation, and the free liquid and gas molecules generated increase, resulting in an increase in pressure, which exceeds the setting value of the back pressure valve, and the product enters the gas-water separator 16 through the back pressure valve 14, and then enters the product analyzer 15 after gas-water separation. The sample bin includes an insulating heat-resistant sealing rubber sleeve for covering the rock sample to be tested, with a first interface and a second interface corresponding to the graphite electrode 8 on both sides of the insulating heat-resistant sealing rubber sleeve, a third interface connected to the nitrogen gas storage bottle 6 and the vacuum pump 1 suction port is provided on the top of the insulating heat-resistant sealing rubber sleeve, and a fourth interface connected to the air inlet of the back pressure valve 14 is provided on the top of the insulating heat-resistant sealing rubber sleeve. The four sides of the insulating heat-resistant sealing rubber sleeve are in contact with the loading plate 7, and the loading plate 7 is provided with a through hole for avoiding the first interface and the second interface. The upper opening of the insulating heat-resistant sealing rubber sleeve is sealed and connected to the plug cover.

[0081] Based on the above shale oil production increase testing equipment, the present application also provides a shale oil production increase testing method. Figure 2 A schematic diagram of the shale oil production increase test method provided in this application, such as Figure 2 As shown, the method includes:

[0082] S201. Seal the experimental rock sample in a storage chamber.

[0083] Specifically, in order to prevent electric current from causing harm to experimental personnel and experimental equipment, the experimental rock sample can first be placed in an insulating and heat-resistant sealing rubber sleeve, and then the experimental rock sample can be fixed by a true triaxial confining pressure assembly.

[0084] S202, start the gas regulating component to adjust the gas parameters in the containing chamber so that the experimental rock sample is in a gas environment with preset parameters.

[0085] In a possible implementation, it is necessary to provide an oxygen-free environment for the experimental rock sample, and the gas environment with preset parameters is a gas environment with an oxygen content of 0. Starting the gas regulating component may include:

[0086] S2021. Evacuate the containing chamber to place the experimental rock samples in a vacuum environment.

[0087] S2022. Introduce anoxic gas into the containing chamber to place the experimental rock samples in an oxygen-free environment.

[0088] Based on the above simulation device, the second stop valve 3 can be opened, the first stop valve 5 and the third stop valve 13 can be closed, and the vacuum pump 1 can be turned on to evacuate the rock sample to be tested. Observe the reading of the vacuum gauge 2, and after reaching the set vacuum degree, close the second stop valve 3 and the vacuum pump 1 in turn. Open the first stop valve 5 and the nitrogen gas storage bottle 6, and introduce nitrogen to prevent the generated combustible gas and other products from being oxidized in large quantities to generate gases such as CO2, and then close the first stop valve 5.

[0089] S203, performing confining pressure on the experimental rock sample by adjusting the true triaxial confining pressure assembly to provide a preset pressure environment to the experimental rock sample.

[0090] Specifically, the true triaxial confining pressure component can be started to apply confining pressure to the rock sample to be tested to simulate the real stress environment of the rock sample in the formation, making the experimental results closer to actual production conditions.

[0091] S204, starting the transformer assembly to allow the graphite electrode to heat the experimental rock sample and generate a carbonization channel in the experimental rock sample.

[0092] In a possible implementation, starting the transformer assembly so that the graphite electrode heats the experimental rock sample and generates a carbonization channel in the experimental rock sample includes:

[0093] S2041. Set the initial voltage of the variable voltage power supply to preheat the experimental rock sample to a preset temperature.

[0094] Specifically, the graphite electrode 8 can be powered by the transformer 12 to be preheated to the formation environment temperature where the rock sample to be tested is located.

[0095] S2042. Adjust the output voltage of the variable voltage power supply, pass high voltage alternating current into the experimental rock sample, and monitor the current value of the graphite electrode and the temperature value of the experimental rock sample.

[0096] For example, the third stop valve 13 can be opened, the transformer can be adjusted to set the initial voltage, and high voltage AC can be introduced. At the same time, the temperature value of the experimental rock sample can be obtained based on the environmental parameter sensor component, and the current value of the graphite electrode can be obtained based on the ammeter or the combination of the ammeter and the data acquisition instrument.

[0097] S2043. Based on the change of the current value and the change of the temperature value, dynamically adjust the output voltage until the change of the current value and the change of the temperature value reach a preset condition; wherein the preset condition is the reaction condition for the experimental rock sample to produce a carbonization channel.

[0098] In a possible implementation, the preset conditions include: the increase in the current value per unit time is greater than or equal to a preset threshold, and the temperature value continues to rise. Among them, the increase in the current value per unit time is greater than or equal to the preset threshold, which can be expressed as a sharp increase in the current value, and the preset threshold is a larger value. The temperature value continues to rise, which can be expressed as the increase in the temperature value per unit time is greater than a preset threshold, and the size of the threshold is not limited.

[0099] The step of dynamically adjusting the output voltage based on the change of the current value and the change of the temperature value may include the following steps:

[0100] S20431, if the increase in the current value per unit time is less than the preset threshold value, and the temperature value does not continue to rise, then increase the output voltage of the variable voltage power supply;

[0101] S20432. If the increase in the current value per unit time is greater than or equal to the preset threshold value, and the temperature value does not continue to rise, switch the output voltage of the variable voltage power supply to the preset voltage value to heat the experimental rock sample.

[0102] Specifically, if the current value does not increase sharply after the voltage is applied for a period of time, and the temperature of the rock sample to be tested does not continue to rise, it is judged that no carbonization channel appears under this voltage. If the current value increases sharply, switch to normal voltage (220V) AC to heat the rock sample to be tested. If the temperature of the rock sample to be tested continues to rise, it is judged that a carbonization channel is generated inside the rock sample to be tested; otherwise, increase the voltage and repeat the above steps until the current value increases sharply and the temperature of the rock sample to be tested continues to rise.

[0103] S205. Obtain the environmental parameters of the experimental rock sample when the carbonization channel is generated through the environmental parameter sensing component.

[0104] Furthermore, high voltage alternating current is introduced, and after a carbonization channel is generated inside the test rock sample, normal pressure power frequency electricity is introduced for in-situ cracking and conversion, that is, in-situ cracking is performed by switching to power frequency electricity.

[0105] S206. Obtain the composition and analysis results of the product through the composition analysis component.

[0106] Specifically, the temperature value can be obtained and recorded through the temperature sensor, the pressure value can be obtained and recorded through the pressure sensor, and the time spent on the experiment and energy consumption data can also be recorded for further analysis and optimization of the experiment. After obtaining the composition and analysis results of the product through the component analysis component, it can also be matched and compared with the environmental parameters of the experiment to further determine the most suitable experimental environmental parameters for the production of a certain component.

[0107] The shale oil production increase test method provided in the embodiment of the present application simulates the real formation pressure through the true triaxial confining pressure component and simulates the real formation gas parameters through the gas regulating component, so as to achieve the effect of improving the test accuracy. And by collecting the environmental parameters during the experiment and the component analysis results of the experimental product, the most suitable experimental environmental parameters for the production of a certain component can be further determined, which provides a guiding basis for the environmental parameters required for subsequent shale mining.

[0108] In a possible implementation, the method further includes:

[0109] S301, using different parameter combinations to conduct experiments on experimental rock samples with the same physical parameters, respectively, to obtain the time and energy consumption required for the experimental rock samples to generate carbonization channels under each parameter combination;

[0110] S302, determining a target group time and energy consumption that meets a target condition among the first time and energy consumption of each group; the target condition includes the shortest time and / or the lowest energy consumption;

[0111] S303: Determine a corresponding target parameter combination based on the target group time and energy consumption.

[0112] Specifically, a high-voltage electric carbonization expansion-industrial frequency electric cracking experimental device simulating formation stress conditions can be used to explore the effect of electric field strength on the formation of carbonization channels, and to explore the critical electric field strength and optimal electric field strength under the same water content.

[0113] In an actual experimental scenario, no carbonization channels were formed in the shale in the experiments with electric field strengths of 40V / cm, 50V / cm and 60V / cm. In the experiments with electric field strengths of 70V / cm, 110V / cm and 150V / cm, carbonization channels were formed in the shale after a period of time, taking 269s, 53s and 20s respectively, and consuming 22152J, 18475J and 10610J respectively. A larger electric field strength will generate a higher current in the shale, and the Joule heating effect of the shale conductive channel will be enhanced, generating more heat, causing the shale to reach the critical energy faster, thereby shortening the time for the carbonization channel to form. However, as the electric field strength increases, the Joule heating effect of the conductive channel in the shale increases in a square ratio, resulting in higher local temperatures in the shale, a greater temperature difference between the high temperature zone and the surrounding environment, and an increasing heat dissipation rate, which slows down the actual heat generation rate of the superposition of heat generation and heat dissipation, resulting in a shortened time and a slowing trend. As the electric field strength increases, the energy consumption required to form the carbonization channel continues to decrease, and the decreasing trend increases. In summary, there should be a critical electric field strength that enables shale to form a carbonization channel; there should be an optimal electric field strength that shortens the time to form the carbonization channel, reduces the energy consumption of forming the carbonization channel, and saves costs.

[0114] By using the aforementioned high-voltage electric carbonization expansion-industrial frequency electric cracking experimental device under simulated formation stress conditions and following the operating steps in the manual, the critical electric field strength for the formation of carbonization channels in rock samples can be found.

[0115] Based on the critical electric field strength found, a reasonable electric field strength difference is set, and multiple groups of experiments are designed to record the time and energy consumption required to form a carbonization channel when the electric field strength is gradually increased. A double-coordinate graph of the time and energy consumption required to form a carbonization channel and the electric field strength is drawn. Figure 3 This is a dual-coordinate chart of the time and energy consumption required to form a carbonization channel based on the shale oil production increase test method provided in this application in an embodiment, as shown in FIG. Figure 3 As shown, the table contains two curves, a curve of the time required to form a carbonization channel with respect to the electric field strength and a curve of the energy consumption required to form a carbonization channel with respect to the electric field strength. In order to find the optimal electric field strength, the above curves are fitted, the corresponding function relationship is obtained and the optimization calculation is performed.

[0116] According to the data, the functional relationship between the time and electric field intensity required to form the carbonization channel is fitted:

[0117] T=5.45×10 8 E -3.423

[0118] Wherein: T is the time required to form the carbonized channel, in minutes (min); E is the electric field intensity, in volts per meter (V / cm).

[0119] The energy consumption during the breakdown process is calculated as follows:

[0120]

[0121] Wherein: Q is the energy consumption in the breakdown process, in joule (J); U is the voltage, in volt (V); I is the current, in ampere (A); t is the time, in seconds (s); to is the time for forming the carbonization channel, in seconds (s).

[0122] The functional relationship between the energy consumption and electric field strength required to form the carbonization channel was fitted. Since the subsequent calculations need to be performed in a unified order of magnitude, the units are converted to 10 2 J:

[0123] Q=-0.013E 2 +1.4365E+185.09

[0124] Where: Q is energy consumption, unit is 10 2 J; E is the electric field strength, measured in volts per meter (V / cm).

[0125] Under the condition of controlling consumption and ensuring safety, within a certain range of electric field strength, the maximum value of the sum of the absolute values ​​of the instantaneous change rate of the function between the time required to form the carbonization channel and the electric field strength and the function between the energy consumption required to form the carbonization channel and the electric field strength is obtained. The optimization method is as follows:

[0126] Find the first-order derivatives of two functions with respect to x:

[0127] T=5.45×10 8 E -3.423

[0128]

[0129] Q=-0.013E 2 +1.4365E+185.09

[0130] Q′=-0.026(E-55.25)

[0131] Assume max|T′|+|Q′|,stE≤160;

[0132] Define the Lagrangian:

[0133]

[0134] The derivative of the Lagrangian with respect to E is:

[0135]

[0136] Setting conditions:

[0137]

[0138] E≤160

[0139] To solve:

[0140] (1)

[0141] (2)

[0142] exist |Q′|=0, However, since no carbonization channel was formed in the experiments with electric field strengths of 50 V / cm and 60 V / cm, the rock with this physical property was discarded.

[0143] exist When , the solution is E<0, so it is discarded.

[0144] The optimal electric field strength for forming carbonization channels in this rock is 160V / cm.

[0145] In a possible implementation, the method further includes:

[0146] S401, using experimental rock samples of different target components to respectively conduct experiments to obtain corresponding groups of second times required for the experimental rock samples of each target component to generate carbonization channels;

[0147] S402, determining the shortest target time in each group of second times;

[0148] S403: Determine the corresponding target component based on the target time.

[0149] Specifically, a high-voltage electric carbonization expansion-industrial frequency electric cracking experimental device that simulates formation stress conditions can be used to explore the effect of water content on the formation of carbonization channels and to explore the optimal water content under the same electric field intensity.

[0150] The original shale sample has a moisture content of 3.3%. The original shale sample was dried at 200°C in a nitrogen environment in a reactor for 10 hours to obtain a dried shale sample with a moisture content of 0. The shale was then placed in a vacuum pump and kept in an anhydrous vacuum for 12 hours; a simulated formation water solution was added until it was submerged, and nitrogen was injected into the reactor to pressurize it to 0.8MPa, and the shale was soaked for 24 hours to obtain a saturated shale sample with a moisture content of 5.5%. The dried shale sample with a moisture content of 0, the sample with a moisture content of 3.3%, and the sample with a moisture content of 5.5% were operated according to the operating steps in the manual at an electric field strength of 70V / cm and an electric field strength of 110V / cm, and the time required to form a carbonization channel was recorded.

[0151] Table 1 shows the formation time of carbonization channel for rock samples with different water contents under an electric field strength of 70 V / cm.

[0152] Table 1

[0153]

[0154] As shown in Table 1, under the electric field strength of 70V / cm, the dried shale sample did not form a carbonization channel, and the time for the original sample and the saturated sample to form a carbonization channel was 264s and 337s respectively; under the electric field strength of 110V / cm, the dried shale sample did not form a carbonization channel, and the time for the original sample and the saturated sample to form a carbonization channel was 57s and 436s respectively. After the sample was dried, the electric field strengths shown in the experiment could not achieve the formation of carbonization channels in the shale sample, indicating that water promotes the formation of carbonization channels in shale and is also a necessary condition for shale to form carbonization channels. Too low water content will lead to a longer time to form carbonization channels and an increase in heat dissipation, resulting in an increase in energy consumption for forming carbonization channels; too high water content will also lead to a longer time to form carbonization channels, water evaporation takes away more heat, and energy consumption will also increase. According to the analysis of the experimental results, there should be an optimal water content to keep the time and energy consumption for forming carbonization channels at a low level.

[0155] Saturated shale samples with different water contents were obtained by performing different water saturation operations on dried rock samples with a water content of 0.

[0156] Experiments were conducted on each sample under the same electric field strength according to the operating steps in the manual, the time required to form the carbonized channel was recorded, and a coordinate graph of the time t required to form the carbonized channel versus the water content was drawn. Figure 4 This is a coordinate chart showing the time t required to form a carbonization channel versus water content, drawn based on the shale oil production increase test method provided in the present application in one embodiment, such as Figure 4 As shown in the figure, the lowest point of the curve is the optimal moisture content under the current electric field strength.

[0157] This experimental device can be used to simulate high-voltage electric carbonization expansion-power frequency electric cracking experiments under formation stress conditions. And by replacing loading plates and rock samples of different sizes, different graphite electrode spacing experiments can be realized. Considering that the carbonization channels formed in the experiment may be closed under formation conditions, the physical properties such as sample resistance value are different from those under conventional experimental conditions. It is necessary to simulate formation conditions to obtain more realistic experimental data. Provide strong data support for on-site conversion and mining of low-maturity shale oil.

[0158] When there is enough experimental data, machine learning can be used to predict the critical electric field strength for the formation of carbonization channels in unfamiliar rock samples. During the high-voltage AC stage, the rock sample temperature, heating power, energy consumption, etc. are monitored in real time, and the transformer is fed back in real time to predict the critical electric field strength and adjust the electric field strength immediately, so that the rock sample can form a carbonization channel in one experiment. This achieves the purpose of accurately predicting the formation of carbonization channels, saving energy consumption, and reducing the waste of precious shale samples.

[0159] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: Read-Only Memory (ROM), Random Access Memory (RAM), a disk or an optical disk, and other media that can store program codes.

[0160] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A shale oil production increase testing device, characterized in that: include: A true triaxial confining pressure assembly is used to form a containing chamber to contain the experimental rock sample to be tested, and to pressurize the experimental rock sample to simulate the formation pressure; A transformer assembly, comprising a graphite electrode and a variable voltage power supply, wherein the graphite electrode is fixed in the containing chamber and is used to heat the experimental rock sample; the variable voltage power supply is connected to the graphite electrode and is used to provide electrical energy to the graphite electrode; A gas regulating component, connected to the containing chamber, and used for regulating gas parameters in the containing chamber; An environmental parameter sensing component, connected to the containing chamber, and used to obtain environmental parameters in the containing chamber; A component analysis component is connected to the containing chamber and is used to obtain the product obtained after the carbonization channel of the experimental rock sample is generated under preset conditions and the in-situ cracking is carried out by normal pressure alternating current heating, and analyze the composition of the product.

2. The device according to claim 1, characterized in that The gas regulating assembly comprises: an oxygen-free gas source connected to the containing chamber via a first stop valve and a three-way valve, and used to introduce an oxygen-free gas into the containing chamber so as to place the experimental rock sample in an oxygen-free environment; A vacuum pump is connected to the containing chamber via a vacuum gauge, a second stop valve and the three-way valve, and is used for evacuating the containing chamber.

3. The device according to claim 1, characterized in that The environmental parameter sensing component comprises: A pressure sensor is disposed between the first stop valve and the three-way valve, and is used to obtain the pressure value of the oxygen-free gas; A temperature sensor is disposed in the containing chamber and is used to obtain the temperature value of the experimental rock sample; A data acquisition terminal is connected to the pressure sensor and the temperature sensor, and is used to receive the pressure value and the temperature value, and store and analyze the pressure value and the temperature value; wherein the environmental parameters include the pressure value and the temperature value.

4. The device according to claim 1, characterized in that The component analysis component includes: A gas-water separation device, connected to the containing bin via a back pressure valve and a third stop valve, for separating gas and water from the product to obtain a gas-water separation product; The product analysis terminal is connected to the gas-water separation device and is used to analyze the components of the gas-water separation product.

5. A shale oil production increase testing method, characterized in that: The method is based on the shale oil production increase testing device according to any one of claims 1 to 4, and the method comprises: The experimental rock samples are sealed in a containing chamber; Starting the gas regulating component to adjust the gas parameters in the containing chamber so that the experimental rock sample is in a gas environment with preset parameters; By adjusting the true triaxial confining pressure assembly, the experimental rock sample is subjected to confining pressure to provide a preset pressure environment to the experimental rock sample; Starting the transformer assembly to allow the graphite electrode to heat the experimental rock sample and generate a carbonized channel in the experimental rock sample; Obtaining environmental parameters of the experimental rock sample when the carbonization channel is generated through an environmental parameter sensing component; The composition and analysis results of the product are obtained through the component analysis component.

6. The method according to claim 5, characterized in that The starting transformer assembly is used to heat the experimental rock sample with a graphite electrode and generate a carbonization channel in the experimental rock sample, including: Setting the initial voltage of the variable voltage power supply to preheat the experimental rock sample to a preset temperature; Adjusting the output voltage of the variable voltage power supply, supplying high voltage alternating current to the experimental rock sample, and monitoring the current value of the graphite electrode and the temperature value of the experimental rock sample; Based on the change of the current value and the change of the temperature value, the output voltage is dynamically adjusted until the change of the current value and the change of the temperature value reach a preset condition; wherein the preset condition is a reaction condition for the experimental rock sample to produce a carbonization channel.

7. The method according to claim 6, characterized in that The preset conditions include: the increase of the current value per unit time is greater than or equal to a preset threshold, and the temperature value continues to rise; The dynamically adjusting the output voltage based on the change of the current value and the change of the temperature value comprises: If the increase of the current value per unit time is less than a preset threshold value and the temperature value does not continue to rise, then increasing the output voltage of the variable voltage power supply; If the increase in the current value per unit time is greater than or equal to a preset threshold value, and the temperature value does not continue to rise, the output voltage of the variable voltage power supply is switched to a preset voltage value to heat the experimental rock sample.

8. The method according to claim 5, characterized in that The starting gas regulating component is used to adjust the gas parameters in the containing chamber so that the experimental rock sample is in a gas environment with preset parameters, including: The containing chamber is subjected to a vacuum treatment so that the experimental rock sample is in a vacuum environment; An oxygen-free gas is introduced into the containing chamber to place the experimental rock sample in an oxygen-free environment.

9. The method according to any one of claims 5 to 8, characterized in that: The method further comprises: Using different parameter combinations, experiments are conducted on experimental rock samples with the same physical parameters to obtain the time and energy consumption required for the experimental rock samples to generate carbonization channels under each parameter combination; Determine the target group time and energy consumption that meets the target conditions among the first time and energy consumption of each group; the target conditions include the shortest time and / or the lowest energy consumption; Based on the target group time and energy consumption, a corresponding target parameter combination is determined.

10. The method according to any one of claims 5 to 8, characterized in that: The method further comprises: Experiments are performed using experimental rock samples of different target components to obtain corresponding groups of second times required for the experimental rock samples of each target component to generate carbonization channels; Determine the shortest target time among the groups of second times; Based on the target time, a corresponding target component is determined.

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