Rock mass damage detection equipment in shale oil exploitation process

Abstract

The invention provides rock mass damage detection equipment in a shale oil exploitation process. The rock mass damage detection equipment comprises a gas injection device, a high-temperature reaction device and a testing device, the high-temperature reaction device is provided with a reaction cavity, and the reaction cavity is configured to place and heat a shale sample; the gas injection device is communicated with the reaction cavity, and the gas injection device is configured to introduce high-pressure gas into the reaction cavity; the testing device comprises a sound wave transmitting unit and a sound wave receiving unit, and at least part of structures of the sound wave transmitting unit and the sound wave receiving unit are inserted into the reaction cavity; the sound wave transmitting unit and the sound wave receiving unit are in contact with the two ends of the shale sample respectively so as to detect the sound wave conduction rate of the shale sample at different temperatures and air pressures. According to the equipment provided by the invention, the real-time damage degree of shale pyrolysis in different environments can be detected, and the detection accuracy is improved.

Description

Technical Field

[0001] The present application relates to a rock damage detection device, and in particular to a rock damage detection device in a shale oil production process. Background Art

[0002] There are two main ways to crack kerogen during shale oil extraction: ground distillation and in-situ pyrolysis. Among them, in-situ pyrolysis does not require the rocks to be transported to the ground, which can protect the environment and reduce energy consumption. However, during the pyrolysis process, the rocks will undergo physical deformation or chemical reactions and be damaged in the high temperature and high pressure environment. Studying damage factors helps to understand these damage mechanisms and thus optimize the pyrolysis process and conditions. By quantifying the damage factors, researchers can evaluate the changes in the mechanical properties of rocks during pyrolysis, which helps predict the geological risks and damage that may occur in actual mining.

[0003] At present, conventional research is to heat the rocks with heating plates to make them in a high-temperature state, and use ultrasonic testing to analyze the damage to the rocks under high-temperature conditions.

[0004] However, the existing technology only heats the rock through a heating plate. The rock damage is quite different from the damage in the actual shale oil extraction process. In addition, there is the influence of interference waves, which can easily cause errors and affect the quantification of the damage factor. Summary of the invention

[0005] The present application provides a rock damage detection device for the shale oil extraction process, which can simulate the high temperature and high pressure environment during actual shale oil extraction, allowing the rock to be heated more evenly, while eliminating the influence of interference waves, detecting the degree of shale damage in real time, quantifying the damage factor, and avoiding the errors caused by conventional ultrasonic testing.

[0006] The present application provides a rock damage detection device for a shale oil production process, comprising a gas injection device 100, a high-temperature reaction device and a testing device 200; the high-temperature reaction device has a reaction chamber 221, and the reaction chamber 221 is configured to place and heat a shale sample; the gas injection device 100 is connected to the reaction chamber 221, and the gas injection device 100 is configured to introduce high-pressure gas into the reaction chamber 221.

[0007] The testing device includes an acoustic wave transmitting unit and an acoustic wave receiving unit, and at least part of the structure of the acoustic wave transmitting unit and the acoustic wave receiving unit is inserted into the reaction chamber 221; the acoustic wave transmitting unit and the acoustic wave receiving unit are respectively in contact with two ends of the shale sample to detect the acoustic wave conduction rate of the shale sample at different temperatures and air pressures.

[0008] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein the high-temperature reaction device includes a reaction shell 203, a heating element 202, a fixing element 208 and a heat insulating element 201, wherein the reaction shell 203 is used to enclose a reaction chamber 221, the heating element 202 is connected to the outer wall of the reaction shell 203, and the heat insulating element 201 is attached to the side of the heating element 202 away from the reaction shell 203; the fixing element 208 is connected to the inner wall of the reaction shell 203, and the fixing element 208 is configured to fix a shale sample.

[0009] A gas heating chamber 206 is disposed in the reaction chamber 221 , and the gas injection device 100 is in communication with the gas heating chamber 206 . The high-pressure gas heated in the gas heating chamber 206 is configured to flow toward the shale sample.

[0010] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein a heating element 202 is arranged around the circumferential outer wall of a reaction shell 203; a heat insulating element 201 is arranged around the circumferential outer side of the heating element 202, and the heat insulating element 201 covers the surface of the heating element 202 facing away from the reaction shell 203.

[0011] The fixing member 208 has a ventilation cavity 223 , and the inner wall of the fixing member 208 is provided with a plurality of air outlet holes 224 connected to the ventilation cavity 223 , and the plurality of air outlet holes 224 are distributed along the axial spiral of the fixing member 208 ; the detection equipment also includes a nitrogen bottle 218 , and the nitrogen bottle 218 is connected to the ventilation cavity 223 .

[0012] As an optional method, the present application provides a rock damage detection device for shale oil production process, wherein the high-temperature reaction device also includes a sound insulation layer 209, which is arranged on the surface of the fixing member 208, and the sound insulation layer 209 is located between the fixing member 208 and the shale sample.

[0013] The sound insulation layer 209 includes a glass fiber layer and a calcium silicate layer.

[0014] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein the reaction shell 203 includes a shell body and two end plates, the shell body having a cavity with both ends passing through, the two end plates being respectively connected to the axial ends of the shell body and sealed to the shell body to enclose and form a reaction chamber 221.

[0015] The heating element 202 is disposed around the outer side of the shell body; the end plate is provided with an air inlet, and the gas injection device 100 is connected to the air inlet.

[0016] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein the gas injection device 100 includes a gas cylinder, a pressure pump 105, a gas tank 107 and a pressure regulating valve 108, the gas cylinder is connected to the pressure pump 105, the pressure pump 105 is connected to the gas tank 107, the gas tank 107 is connected to the reaction chamber 221, the pressure regulating valve 108 is disposed between the gas tank 107 and the reaction chamber 221, and the pressure regulating valve 108 is configured to control the gas pressure of the gas tank 107 entering the reaction chamber 221.

[0017] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein the gas storage cylinder includes an air bottle 101 and an oxygen-reduced air bottle 102, the air bottle 101 and the oxygen-reduced air bottle 102 are respectively connected to a pressure pump 105, and control valves 104 are respectively arranged between the air bottle 101 and the oxygen-reduced air bottle 102 and the pressure pump 105.

[0018] The detection device also includes a first pressure sensor 103, a second pressure sensor 106 and a third pressure sensor 109. The outlets of the air bottle 101 and the oxygen-reduced air bottle 102 are respectively provided with a first pressure sensor 103, a second pressure sensor 106 is provided between the booster pump 105 and the gas storage tank, and a third pressure sensor 109 is provided at the air inlet of the reaction chamber 221.

[0019] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein the sound wave transmitting unit includes an ultrasonic transmitter 213 and a first ceramic fiber waveguide tube 211, and the sound wave receiving unit includes an ultrasonic receiver 214 and a second ceramic fiber waveguide tube 212, and the ultrasonic transmitter 213 and the ultrasonic receiver 214 are both arranged on the outside of the reaction chamber 221.

[0020] One end of the first ceramic fiber waveguide 211 is connected to the ultrasonic transmitter 213, and the other end of the first ceramic fiber waveguide 211 is inserted into the reaction chamber 221 and contacts the first end of the shale sample; one end of the second ceramic fiber waveguide 212 is connected to the ultrasonic receiver 214, and the other end of the second ceramic fiber waveguide 212 is inserted into the reaction chamber 221 and contacts the second end of the shale sample.

[0021] As an optional method, the present application provides a shale oil extraction process rock damage detection device, the detection device also includes a first temperature sensor 215, a second temperature sensor 219 and a controller 300, the first temperature sensor 215 is arranged in the gas heating chamber 206, the first temperature sensor 215 is configured to detect the temperature inside the gas heating chamber 206; the second temperature sensor 219 is arranged in the ventilation cavity 223, the second temperature sensor 219 is configured to detect the temperature inside the ventilation cavity 223; the first temperature sensor 215, the second temperature sensor 219, the ultrasonic transmitter 213, and the ultrasonic receiver 214 are all electrically connected to the controller 300.

[0022] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein the detection device also includes a collecting bin 400 and a discharge valve 220, wherein the collecting bin 400 is connected to one end of the reaction chamber 221 away from the gas injection device 100, and the discharge valve 220 is connected to one end of the collecting bin 400 and the reaction chamber 221.

[0023] The present application provides a shale oil mining process rock damage detection device, including a gas injection device 100, a high temperature reaction device and a testing device; the high temperature reaction device has a reaction chamber 221, and the reaction chamber 221 is configured to place and heat a shale sample; the gas injection device 100 is connected to the reaction chamber 221, and the gas injection device 100 is configured to pass high-pressure gas into the reaction chamber 221; the testing device includes a sound wave transmitting unit and a sound wave receiving unit, and both the sound wave transmitting unit and the sound wave receiving unit have partial structures inserted into the reaction chamber 221; the sound wave transmitting unit and the sound wave receiving unit are respectively in contact with the two ends of the shale sample to detect the sound wave conduction rate of the shale sample at different temperatures and air pressures. The present application adds a gas injection device 100 and a high temperature reaction device on the basis of a conventional ultrasonic shale damage detection device, which is closer to the environment in the actual shale oil mining process and eliminates the errors caused by conventional detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A schematic diagram of the structure of a rock damage detection device for shale oil production process provided in one embodiment of the present application;

[0026] Figure 2 A cross-sectional view of a high-temperature reaction device and a detection device provided in one embodiment of the present application.

[0027] In the figure: 100-gas injection device; 101-air bottle; 102-oxygen-reduced air bottle; 103-first pressure sensor; 104-control valve; 105-pressurization pump; 106-second pressure sensor; 107-gas storage tank; 108-pressure regulating valve; 109-third pressure sensor; 200-high temperature reaction and detection device; 201-insulation; 202-heating element; 203-reaction shell; 204-end plate; 205-pressure gauge; 206-gas heating chamber; 207-connecting valve; 208-fixing element ; 209-sound insulation layer; 210-sealing flange; 211-first ceramic fiber waveguide tube; 212-second ceramic fiber waveguide tube; 213-ultrasonic transmitter; 214-ultrasonic receiver; 215-first temperature sensor; 216-gas volume regulating valve; 217-nitrogen bottle pressure gauge; 218-nitrogen bottle; 219-second temperature sensor; 220-discharge valve; 221-reaction chamber; 222-core placement chamber; 223-venting chamber; 224-air outlet; 300-controller; 400-collection bin. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] The terms "first", "second", "third", "fourth", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances. For example, without departing from the scope of this document, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information.

[0030] The word "if" as used herein may be interpreted as "when" or "when" or "in response to determining," depending on the context.

[0031] Furthermore, as used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context indicates otherwise.

[0032] It should be further understood that the terms “comprises” and “includes” indicate the existence of features, steps, operations, elements, components, items, types, and / or groups, but do not exclude the existence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, types, and / or groups.

[0033] The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Thus, "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". An exception to this definition will only occur when a combination of elements, functions, steps or operations are inherently mutually exclusive in some manner.

[0034] Shale oil is an unconventional oil resource, which is stored in dense rock formations such as shale. Most of the organic matter (kerogen) in shale oil exists in solid state. Kerogen is a complex macromolecular organic matter that cannot flow directly from the rock formation. Kerogen can be cracked into smaller hydrocarbons, that is, liquid or gaseous oil and gas, by heating. There are two main ways to crack kerogen in the process of shale oil extraction: ground distillation and in-situ pyrolysis. Among them, in-situ pyrolysis does not require the rocks to be transported to the ground, which can protect the environment and reduce energy consumption. However, during the pyrolysis process, the rocks will be physically deformed or chemically damaged, causing the geological conditions to be destroyed. Studying damage factors helps to understand these damage mechanisms and optimize the pyrolysis process and conditions. By quantifying the damage factors, researchers can evaluate the changes in the mechanical properties of rocks during pyrolysis, which helps to predict the geological risks and damage that may occur in actual mining. At present, conventional research is to heat the rocks with a heating plate, test them with ultrasound, and analyze the damage of the rocks. However, the existing technology only heats the rock through a heating plate, which cannot simulate the high temperature and high pressure conditions in the actual shale oil extraction process. The damage to the rock is quite different from the damage in the actual shale oil extraction process. When the rock is heated, the fixing device will interfere with the ultrasonic wave passing through the rock, which is easy to cause errors and affect the quantification of the damage factor.

[0035] In order to solve the above problems, the embodiment of the present application provides a rock damage detection device in the shale oil production process, which adds a gas injection device and a high-temperature reaction device to the conventional ultrasonic detection device to simulate the high temperature and high pressure environment in the actual shale oil in-situ production process, while allowing the rock to be heated more evenly to avoid the influence of interference waves on the detection results, and to respond to the degree of damage to the shale sample in real time through a data processing device, which can better avoid errors, quantify damage factors, and evaluate changes in the mechanical properties of shale during pyrolysis. It has guiding significance for optimizing the pyrolysis process and conditions in the shale oil production process and predicting possible geological risks and damage. The technical solution of the present application is described in detail with specific embodiments below.

[0036] like Figure 1 , Figure 2 As shown, this embodiment provides a rock damage detection device for shale oil production process, including a gas injection device 100, a high-temperature reaction device and a testing device 200; the high-temperature reaction device has a reaction chamber 221, and the reaction chamber 221 is configured to place and heat a shale sample; the gas injection device 100 is connected to the reaction chamber 221, and the gas injection device 100 is configured to pass high-pressure gas into the reaction chamber 221.

[0037] The testing device 200 includes an acoustic wave transmitting unit and an acoustic wave receiving unit, and both the acoustic wave transmitting unit and the acoustic wave receiving unit have partial structures inserted into the reaction chamber 221; the acoustic wave transmitting unit and the acoustic wave receiving unit are respectively in contact with two ends of the shale sample to detect the acoustic wave conduction rate of the shale sample at different temperatures and air pressures.

[0038] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein the high-temperature reaction device includes a reaction shell 203, a heating element 202, a fixing element 208 and a heat insulating element 201, wherein the reaction shell 203 is used to enclose a reaction chamber 221, the heating element 202 is connected to the outer wall of the reaction shell 203, and the heat insulating element 201 is attached to the side of the heating element 202 away from the reaction shell 203; the fixing element 208 is connected to the inner wall of the reaction shell 203, and the fixing element 208 is configured to fix a shale sample.

[0039] A gas heating chamber 206 is disposed in the reaction chamber 221 , and the gas injection device 100 is in communication with the gas heating chamber 206 . The high-pressure gas heated in the gas heating chamber 206 is configured to flow toward the shale sample.

[0040] Among them, the reaction shell 203 is a high-temperature reactor, and its material can be metal, such as stainless steel, or non-metal, such as ceramic, glass lining; the heating element 202 can be set as a segmented controlled annular heating element 202, and the material can be a metal resistor; the fixing part 208 is a core clamp, and the core clamp and the two end covers and flanges form a closed core placement chamber 222; the insulation part 201 material can be ceramic fiber, rock wool, calcium silicate and other insulation materials; the gas heating chamber 206 is a closed cavity, one end of which is connected to the gas storage tank 107 through a pipeline and receives high-pressure gas. When the gas is heated to a preset temperature, the shale sample is injected through the pipeline at the other end, and the opening and closing are controlled by the connecting valve 207.

[0041] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein a heating element 202 is arranged around the circumferential outer wall of a reaction shell 203; a heat insulating element 201 is arranged around the circumferential outer side of the heating element 202, and the heat insulating element 201 covers the surface of the heating element 202 facing away from the reaction shell 203.

[0042] The fixing member 208 has a ventilation cavity 223 , and the inner wall of the fixing member 208 is provided with a plurality of air outlet holes 224 connected to the ventilation cavity 223 , and the plurality of air outlet holes 224 are distributed along the axial spiral of the fixing member 208 ; the detection equipment also includes a nitrogen bottle 218 , and the nitrogen bottle 218 is connected to the ventilation cavity 223 .

[0043] Among them, the heating element 202 is a two-section annular heating element 202, one section is used to heat the air in the gas heating chamber 206, and the other section is used to preheat the shale sample in the core placement chamber 222 and to keep the shale sample warm when the internal temperature of the core placement chamber 222 reaches a preset temperature. The two sections of the annular heating element 202 can be controlled separately; the insulation element 201 can keep the reaction chamber 221 warm and prevent people from being scalded; the fixing element 208 has an interlayer, and the ventilation cavity 223 formed inside the interlayer receives the high-temperature and high-pressure gas in the gas heating chamber 206 through a pipeline, and the high-temperature and high-pressure gas uniformly heats and reacts various positions of the core through the spirally distributed air outlets 224 on the inner side of the interlayer; the interlayer is connected to a pressure gauge 205, which can detect the internal pressure of the core placement chamber 222; the nitrogen bottle 218 is connected to the ventilation cavity 223 through a pipeline, and a gas volume regulating valve 216 and a nitrogen bottle pressure gauge 217 are arranged in the middle of the pipeline, which can control the nitrogen injection to adjust the internal temperature of the core placement chamber 222.

[0044] As an optional method, the present application provides a rock damage detection device for shale oil production process, wherein the high-temperature reaction device also includes a sound insulation layer 209, which is arranged on the surface of the fixing member 208, and the sound insulation layer 209 is located between the fixing member 208 and the shale sample.

[0045] The sound insulation layer 209 includes a glass fiber layer and a calcium silicate layer, which is resistant to high temperatures. The glass fiber layer wraps the calcium silicate layer and directly contacts the shale sample. The sound insulation layer 209 is provided with an air outlet 224 corresponding to the air outlet 224 of the fixing part. The sound insulation layer 209 can isolate noise at the physical level to ensure detection accuracy.

[0046] As an optional method, the reaction shell 203 includes a shell body and two end plates 204. The shell body has a cavity with two ends passing through. The two end plates 204 are respectively connected to the axial ends of the shell body and are sealed with the shell body to enclose and form a reaction chamber 221.

[0047] The heating element 202 is disposed around the outer side of the shell body; the end plate 204 is provided with an air inlet, and the gas injection device 100 is connected to the air inlet.

[0048] Optionally, the two end plates 204 are two reactor flange sealing covers, which are connected to the shell body through sealing screws to form a closed space to prevent gas leakage.

[0049] As an optional method, the gas injection device 100 includes a gas cylinder, a pressure pump 105, a gas tank 107 and a pressure regulating valve 108. The gas cylinder is connected to the pressure pump 105, the pressure pump 105 is connected to the gas tank 107, the gas tank 107 is connected to the reaction chamber 221, and the pressure regulating valve 108 is arranged between the gas tank 107 and the reaction chamber 221. The pressure regulating valve 108 is configured to control the gas pressure of the gas tank 107 entering the reaction chamber 221. The gas injection device 100 can provide high-pressure air or high-pressure oxygen-reduced air for the high-temperature reactor.

[0050] As an optional method, the gas storage cylinder includes an air cylinder 101 and an oxygen-reduced air cylinder 102, the air cylinder 101 and the oxygen-reduced air cylinder 102 are respectively connected to a pressure pump 105, and a control valve 104 is respectively provided between the air cylinder 101 and the oxygen-reduced air cylinder 102 and the pressure pump 105.

[0051] Optionally, the gas in the air cylinder 101 and the oxygen-reduced air cylinder 102 can be configured with pure nitrogen and oxygen to simulate high-pressure air and high-pressure oxygen-reduced air, and can also be replaced with other gases such as carbon dioxide according to test requirements.

[0052] As an optional method, the detection device further includes a first pressure sensor 103, a second pressure sensor 106 and a third pressure sensor 109. The outlets of the air bottle 101 and the oxygen-reduced air bottle 102 are respectively provided with the first pressure sensor 103, the second pressure sensor 106 is provided between the booster pump 105 and the gas storage tank 107, and the third pressure sensor 109 is provided at the air inlet of the reaction chamber 221. The first pressure sensor 103, the second pressure sensor 106 and the third pressure sensor 109 can monitor the pressure change in real time, and the gas storage tank 107 can be a high-pressure gas storage tank that can store high-pressure gas, and cooperate with the control valve 104 and the pressure regulating valve 108 to control the pressure to ensure that the gas pressure is the pressure required for the experiment.

[0053] As an optional method, the present application provides a rock damage detection device for a shale oil extraction process, wherein the sound wave transmitting unit includes an ultrasonic transmitter 213 and a first ceramic fiber waveguide tube 211, and the sound wave receiving unit includes an ultrasonic receiver 214 and a second ceramic fiber waveguide tube 212, and the ultrasonic transmitter 213 and the ultrasonic receiver 214 are both arranged on the outside of the reaction chamber 221.

[0054] Among them, one end of the first ceramic fiber waveguide 211 is connected to the ultrasonic transmitter 213, and the other end of the first ceramic fiber waveguide 211 is inserted into the reaction chamber 221 and contacts the first end of the shale sample; one end of the second ceramic fiber waveguide 212 is connected to the ultrasonic receiver 214, and the other end of the second ceramic fiber waveguide 212 is inserted into the reaction chamber 221 and contacts the second end of the shale sample.

[0055] It should be noted that the first ceramic fiber waveguide 211 and the second ceramic fiber waveguide 212 used as acoustic wave sensors have a heat resistance temperature exceeding 1000° C., which increases the temperature that can be set in the experiment.

[0056] As an optional method, the present application provides a shale oil mining process rock damage detection device, the detection device also includes a first temperature sensor 215, a second temperature sensor 219 and a controller 300, the first temperature sensor 215 is arranged in the gas heating chamber 206, and the first temperature sensor 215 is configured to detect the temperature in the gas heating chamber 206; the second temperature sensor 219 is arranged in the ventilation cavity 223, and the second temperature sensor 219 is configured to detect the temperature in the ventilation cavity 223; the first temperature sensor 215, the second temperature sensor 219, the ultrasonic transmitter 213, and the ultrasonic receiver 214 are all electrically connected to the controller 300. The real-time temperature of the gas heating chamber 206 can be displayed by the first temperature sensor 215, the real-time temperature of the ventilation cavity 223 can be displayed by the second temperature sensor 219, and the annular heating element 202 is controlled by the controller 300 to set different experimental temperatures and different insulation times, so as to explore the rate at which ultrasonic waves pass through shale under different conditions and reflect the damage of shale in real time. Among them, the controller 300 can be a data processor.

[0057] As an optional method, the present application provides a shale oil mining process rock damage detection device, the detection device also includes a collection bin 400 and a discharge valve 220, the collection bin 400 is connected to the end of the reaction chamber 221 away from the gas injection device 100, and the discharge valve 220 is connected to the collection bin 400 and one end of the reaction chamber 221. The discharge valve 220 can control the discharge of oil and gas, and the collection bin 400 is a product collection device for collecting oil and gas generated during the reaction process.

[0058] In order to make the purpose, features and advantages of this application clearer and easier to understand, this application is further described in detail below with reference to the accompanying drawings and specific test steps.

[0059] This invention patent provides a rock damage detection device for shale oil mining process. The specific test steps are as follows:

[0060] Step 1: Connect the equipment as described above. After the connection is complete, check the air tightness of the equipment and whether the equipment can be used normally. If the instrument is abnormal or leaking, repair and reconnect the instrument. If the instrument is normal, conduct the experiment.

[0061] Step 2, close the control valve 104, the pressure regulating valve 108, the pressure pump 105, the discharge valve 220, the ultrasonic transmitter 213, the ultrasonic receiver 214, the segmented control annular heating element 202, the connecting valve 207, and the gas volume regulating valve 216.

[0062] Step three, take a shale sample with a diameter of 25 mm and a length not exceeding 50 mm and sealed, remove the right reactor flange sealing cover and the closed core placement chamber sealing flange 210, place the sample in the closed core placement chamber 222, and reset the right reactor flange sealing cover and the closed core placement chamber sealing flange 210.

[0063] Step 4: Use the data collection processor to control the ultrasonic transmitter 213 and the ultrasonic receiver 214 to work, with an ultrasonic frequency of 1000 kHz, measure the ultrasonic signal of the original shale sample, and calculate the longitudinal wave velocity of the sample according to the following formula:

[0064]

[0065] Where l is the sample length (m), and t is the time when the first direct peak appears after ultrasonic signal processing (s).

[0066] It is known that l is 0.05m. This step uses the time domain signal processing method to process the received ultrasonic signal and measures the time when the first direct peak of the ultrasonic signal appears, including:

[0067] S1 Set the time window: By setting a specific time window, only the signal within the time interval of the direct wave is retained, thereby excluding the interference of other delayed waves (such as scattered waves and reflected waves). Ultrasonic waves propagate at a known speed in rocks, so the direct wave will reach the receiving end within a specific time period. Set a reasonable time window and only retain the signals within this window range to avoid interference waves. Through preliminary experiments, determine the average time required for ultrasonic waves from emission to reception, and estimate the expected arrival time of the direct wave. Set a time window, such as extracting signals from a certain range before and after the expected arrival time. Only analyze the signals within this time window and filter out the delayed reflection and scattered signals.

[0068] S2 pulse envelope analysis: Detect the signal envelope to obtain the main signal components, effectively identify the energy concentration area of ​​the direct wave, and eliminate the interference of non-linear propagation signals. The direct wave usually appears as a single peak on the time axis, while the scattered wave and reflected wave will cause multiple small peaks. By extracting the envelope curve of the signal, the energy of the main wave can be concentrated on one peak, which is convenient for identification and analysis. The envelope of the signal is calculated using the envelope detection algorithm (Hilbert transform). Extract the maximum value and main peak interval of the envelope curve, which usually corresponds to the arrival time of the direct wave. Ignore other small peaks to reduce the interference of scattering and reflection.

[0069] S3 signal averaging: By measuring the signal multiple times and taking the average value, accidental interference is eliminated and the stable characteristics of the direct wave are extracted. In multiple measurements, the signal arrival time of the direct wave will be relatively stable, while the interference signals of the reflected wave and the scattered wave may be different in each measurement. Through superposition and averaging processing, the direct wave signal can be enhanced and random noise can be weakened. Perform multiple signal acquisitions, each time collecting the complete signal of the ultrasonic wave from transmission to reception. Align the multiple acquired signals in time, superimpose them, and calculate the average value. The obtained average signal can better characterize the direct wave and reduce the influence of interference signals.

[0070] S4 Short-time Fourier Transform: Helps distinguish signal components of different time periods and frequencies, identify the main frequency components of direct waves and eliminate interference. The frequency of ultrasonic direct waves is relatively stable, while reflected and scattered waves often cause frequency changes. Through time-frequency analysis, the main frequency components within the direct wave arrival time window can be distinguished. Apply STFT to the collected signal to generate a time-frequency distribution diagram. Extract the main frequency components in the predetermined direct wave arrival time period. Determine which signals are direct waves through frequency analysis, and ignore interference signals with abnormal frequency components.

[0071] S5 obtains the time when the first direct peak of the ultrasonic signal appears through comparative analysis of the above four steps.

[0072] Step five, open the air bottle 101 or the oxygen-reduced air bottle 102 and the connected gas bottle control valve 104 according to the experimental needs, turn on the pressure pump 105 to pressurize the low-pressure gas in the gas bottle and input it into the high-pressure gas storage tank 107, use the pressure pump 105 to provide power for the gas to enter the high-temperature and high-pressure reactor and simulate the formation pressure, when the value of the pressure gauge of the high-pressure gas storage tank is stable and reaches the pressure required for the experiment, open the pressure regulating valve 108 to allow the gas to enter the gas heating chamber 206 in the high-temperature and high-pressure reactor.

[0073] Step 6: Open the gas heating chamber 206 of the segmented control annular heating element 202, set the heating rate, heating temperature and insulation time through the data collection processor, and when the first temperature sensor 215 shows that the temperature reaches the preset temperature, insulation is performed to preheat the fluid medium to simulate the injection of high-temperature fluid medium during the in-situ conversion of shale oil. When the gas in the gas heating chamber 206 is preheated, open the gas volume regulating valve 216, introduce nitrogen into the closed core placement chamber 222, adjust the gas volume according to the second temperature sensor 219, and keep the temperature at 60°C to simulate the temperature environment of the core under formation conditions.

[0074] Step seven, open the connecting valve 207 and the exhaust valve 220, close the gas volume regulating valve 216, vent for 1 minute to exhaust the nitrogen in the closed core placement chamber 222, close the exhaust valve 220, open the closed core placement chamber 222 part of the segmented control annular heating element 202, set the heating rate, heating temperature and insulation time through the data collection processor, and when the pressure gauge 205 shows that the required formation pressure is reached, close the connecting valve 207.

[0075] Step 8: Using the data collection processor, control the ultrasonic transmitter 213 and the ultrasonic receiver 214 to work and process the ultrasonic signal according to S1-S5 in the above step 4, test the ultrasonic longitudinal wave velocity of the shale sample in the shale oil in-situ conversion process under different conditions, and calculate the damage degree of the sample according to the following formula:

[0076]

[0077] Among them, D Vp is the sample damage factor when the temperature is T, Vp is the ultrasonic longitudinal wave velocity of the rock sample after the reaction at the temperature T, and Vp0 is the ultrasonic longitudinal wave velocity of the rock sample in the original state.

[0078] The present application provides a rock damage detection device for a shale oil production process, comprising a gas injection device 100, a high-temperature reaction device and a testing device; the high-temperature reaction device has a reaction chamber 221, and the reaction chamber 221 is configured to place and heat a shale sample; the gas injection device 100 is connected to the reaction chamber 221, and the gas injection device 100 is configured to introduce high-pressure gas into the reaction chamber 221; the testing device comprises an acoustic wave transmitting unit and an acoustic wave receiving unit, and both the acoustic wave transmitting unit and the acoustic wave receiving unit have partial structures inserted into the reaction chamber 221; the acoustic wave transmitting unit and the acoustic wave receiving unit are in contact with two ends of the shale sample respectively to detect the acoustic wave conduction rate of the shale sample at different temperatures and air pressures. The present application adds a gas injection device 100 and a high-temperature reaction device to a conventional ultrasonic detection device, which can simulate the high temperature and high pressure environment in the actual in-situ shale oil exploitation process, while allowing the rock to be heated more evenly, avoiding the influence of interference waves on the detection results, and using a data processing device to reflect the degree of damage to the shale sample in real time, which can better avoid errors, quantify damage factors, and evaluate changes in the mechanical properties of shale during pyrolysis. It has guiding significance for optimizing the pyrolysis process and conditions during shale oil exploitation and predicting possible geological risks and damage.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A rock damage detection device for shale oil mining process, characterized in that: The detection device comprises a gas injection device (100), a high-temperature reaction device and a testing device (200); the high-temperature reaction device has a reaction chamber (221), and the reaction chamber (221) is configured to place and heat a shale sample; the gas injection device (100) is connected to the reaction chamber (221), and the gas injection device (100) is configured to pass high-pressure gas into the reaction chamber (221); The testing device comprises a sound wave transmitting unit and a sound wave receiving unit, wherein at least a part of the structure of the sound wave transmitting unit and the sound wave receiving unit is inserted into the reaction chamber (221); the sound wave transmitting unit and the sound wave receiving unit are respectively in contact with two ends of the shale sample to detect the sound wave conduction rate of the shale sample at different temperatures and air pressures.

2. The rock damage detection device for shale oil production process according to claim 1 is characterized in that: The high-temperature reaction device comprises a reaction shell (203), a heating element (202), a fixing element (208) and a heat insulating element (201); the reaction shell (203) is used to surround and form the reaction chamber (221); the heating element (202) is connected to the outer wall of the reaction shell (203); the heat insulating element (201) is attached to a side of the heating element (202) away from the reaction shell (203); the fixing element (208) is connected to the inner wall of the reaction shell (203); the fixing element (208) is configured to fix the shale sample; A gas heating chamber (206) is provided in the reaction chamber (221), the gas injection device (100) is in communication with the gas heating chamber (206), and the high-pressure gas heated in the gas heating chamber (206) is configured to flow toward the shale sample.

3. The rock damage detection device for shale oil production process according to claim 2 is characterized in that: The heating element (202) is arranged around the circumferential outer wall of the reaction shell (203); the heat insulating element (201) is arranged around the circumferential outer side of the heating element (202), and the heat insulating element (201) covers the surface of the heating element (202) on a side facing away from the reaction shell (203); The fixing member (208) has a ventilation cavity (223), and the inner wall of the fixing member (208) is provided with a plurality of air outlet holes (224) connected to the ventilation cavity (223), and the plurality of air outlet holes (224) are distributed in an axial spiral along the fixing member (208); the detection device also includes a nitrogen bottle (218), and the nitrogen bottle (218) is connected to the ventilation cavity (223).

4. The rock damage detection device for shale oil production process according to claim 2 is characterized in that: The high temperature reaction device further comprises a sound insulation layer (209), wherein the sound insulation layer (209) is arranged on the surface of the fixing member (208), and the sound insulation layer (209) is located between the fixing member (208) and the shale sample; Wherein, the sound insulation layer (209) comprises a glass fiber layer and a calcium silicate layer.

5. The rock damage detection device for shale oil production process according to claim 2 is characterized in that: The reaction shell (203) comprises a shell body and two end plates (204); the shell body has a cavity with two ends passing through; the two end plates (204) are respectively connected to two axial ends of the shell body and are sealed to the shell body to enclose and form the reaction chamber (221); The heating element (202) is arranged around the outside of the shell body; the end plate (204) is provided with an air inlet, and the gas injection device (100) is connected to the air inlet.

6. The rock damage detection device for shale oil production process according to claim 1 is characterized in that: The gas injection device (100) comprises a gas cylinder, a pressure pump (105), a gas tank (107) and a pressure regulating valve (108); the gas cylinder is connected to the pressure pump (105); the pressure pump (105) is connected to the gas tank (107); the gas tank (107) is in communication with the reaction chamber (221); the pressure regulating valve (108) is arranged between the gas tank (107) and the reaction chamber (221); and the pressure regulating valve (108) is configured to control the gas pressure of the gas tank (107) entering the reaction chamber (221).

7. The rock damage detection device for shale oil production process according to claim 6 is characterized in that: The gas storage cylinder comprises an air cylinder (101) and an oxygen-reduced air cylinder (102); the air cylinder (101) and the oxygen-reduced air cylinder (102) are respectively connected to the booster pump (105); and control valves (104) are respectively provided between the air cylinder (101) and the oxygen-reduced air cylinder (102) and the booster pump (105); The detection device further comprises a first pressure sensor (103), a second pressure sensor (106) and a third pressure sensor (109); the first pressure sensor (103) is respectively arranged at the outlets of the air bottle (101) and the oxygen-reduced air bottle (102); the second pressure sensor (106) is arranged between the booster pump (105) and the gas storage tank (107); and the third pressure sensor (109) is arranged at the air inlet of the reaction chamber (221).

8. The rock damage detection device for shale oil production process according to claim 3 is characterized in that: The sound wave transmitting unit comprises an ultrasonic transmitter (213) and a first ceramic fiber waveguide tube (211); the sound wave receiving unit comprises an ultrasonic receiver (214) and a second ceramic fiber waveguide tube (212); the ultrasonic transmitter (213) and the ultrasonic receiver (214) are both arranged outside the reaction chamber (221); One end of the first ceramic fiber waveguide (211) is connected to the ultrasonic transmitter (213), and the other end of the first ceramic fiber waveguide (211) is inserted into the reaction chamber (221) and contacts the first end of the shale sample; one end of the second ceramic fiber waveguide (212) is connected to the ultrasonic receiver (214), and the other end of the second ceramic fiber waveguide (212) is inserted into the reaction chamber (221) and contacts the second end of the shale sample.

9. The rock damage detection device for shale oil production process according to claim 8, characterized in that: The detection device further comprises a first temperature sensor (215), a second temperature sensor (219) and a controller (300); the first temperature sensor (215) is arranged in the gas heating chamber (206), and the first temperature sensor (215) is configured to detect the temperature in the gas heating chamber (206); the second temperature sensor (219) is arranged in the ventilation cavity (223), and the second temperature sensor (219) is configured to detect the temperature in the ventilation cavity (223); the first temperature sensor (215), the second temperature sensor (219), the ultrasonic transmitter (213), and the ultrasonic receiver (214) are all electrically connected to the controller (300).

10. The rock damage detection device for shale oil production process according to any one of claims 1 to 9, characterized in that: The detection device further comprises a collection bin (400) and a discharge valve (220), wherein the collection bin (400) is connected to an end of the reaction chamber (221) facing away from the gas injection device (100), and the discharge valve (220) is connected to the collection bin (400) and one end of the reaction chamber (221).

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