A rock sample residual gas tester and testing method

Abstract

The application discloses a rock sample residual gas tester and a testing method, which comprise a crushing and grinding module, a sealing cover module, a sealing tank main body, an air inlet and outlet module and a sample clamping module; the crushing and grinding module is arranged on the top of the sealing tank main body and adopts a rotary grinding mode to crush and grind a rock sample in the sealing tank main body; the sample clamping module is arranged on the bottom of the sealing tank main body and is used for clamping and fixing the rock sample to be ground; and the air inlet and outlet module is arranged on the side wall of the sealing tank main body and is used for measuring the residual gas content of the rock sample after crushing and grinding. Compared with the prior art, the rock sample crushing and grinding mode disclosed by the application has more advantages. The rock sample crushing in the prior art usually adopts an impact crushing mode, and the rotary crushing and grinding mode adopted by the application has the characteristics of small noise, small dust, small volume and high efficiency, and is more suitable for installation and use in a laboratory and a closed space.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas exploration and development technology, specifically relating to a residual gas tester and test method for rock samples. Background Technology

[0002] In the exploration of oil and gas resources such as shale gas and coalbed methane, the evaluation of resource quantity is a very important issue, both in terms of theoretical understanding and actual production. Among them, the accurate measurement of residual gas quantity has always been a difficult problem in resource quantity evaluation.

[0003] In shale gas and coalbed methane exploration, the gas content of shale gas and coalbed methane in formations is a crucial parameter for evaluating the natural gas resources of a region. Geologists have long sought accurate data on the gas content in formations to calculate natural gas reserves and provide a reliable basis for exploration. Gas content data mainly includes three parts: lost gas, desorbed gas, and residual gas. To obtain accurate gas content data, the residual gas content in the formation is an indispensable factor. Currently, existing invention patents describe the acquisition of parameters for lost gas (ZL201310338001.2) and desorbed gas (ZL201120465348.X), but technologies for accurately acquiring residual gas parameters are still lacking. This invention is specifically designed for the collection and measurement of residual gas, filling the gaps in shale gas content measurement and enabling the measurement of all stages of the entire process of shale gas loss, desorbing, and residual gas.

[0004] With the rapid development of shale gas exploration in China in recent years, new technologies for evaluating shale gas resources are gradually emerging. Patented technologies for measuring lost gas and desorbed gas content in shale gas content parameters have appeared and are being applied in shale gas evaluation. Currently, the applicable standard for residual gas in China is the standard "Method for Determination of Coalbed Methane Content - GB / T19559-2021," promulgated and implemented in 2021. This standard is based on the national standard promulgated and implemented in 2004, and has been revised twice in 2008 and 2021 before being officially promulgated and used in 2021. In the latest version of the national standard, the method for collecting residual gas is to first put the coal sample, after the desorbed gas test, into a ball mill for crushing, and then put the crushed sample into a measuring container for measurement. This method in the national standard consists of two steps: the first step is crushing and grinding in the ball mill, and the second step is to remove the crushed sample and put it into the measuring container for residual gas measurement. During the second step of sampling and placing the sample into the measuring container, the gas that escaped during the crushing and grinding process will be lost, resulting in the measured data being lower than the actual gas content.

[0005] The commonly used methods for crushing rocks are ball mills or impact crushing. While these methods achieve the goal of crushing rocks, they also have obvious drawbacks, such as high noise, high dust, and low efficiency. Therefore, it is necessary to further innovate and improve the methods for crushing rocks to make them more suitable for experimental testing requirements and improve measurement accuracy and efficiency.

[0006] (1) Insufficiency of rock sample crushing methods

[0007] Current methods for crushing rocks mainly involve ball milling or impact crushing. Essentially, both methods force the rock to break by external force. While these methods can achieve the goal of crushing rock samples, they suffer from drawbacks such as high vibration, discontinuous testing processes, and difficulty in ensuring a tight seal. They also generate a lot of noise, dust, and create a poor working environment for both the operator and the machine.

[0008] Ball mills are widely used in industries such as mineral processing, chemicals, and building materials. They are essential equipment for crushing large, blocky ores and are also widely used in the mineral product processing industry. Simply put, the grinding media in a ball mill are carried to a certain height by the rotation of the cylinder. Due to their own weight, the grinding media fall back down, subjecting the ore inside the cylinder to a powerful impact. On the other hand, the revolution and rotation of the grinding media around the cylinder's axis generate squeezing and abrasive forces on the ore in the contact areas between the grinding media and the cylinder, thus grinding the ore. [1] A brief analysis of the grinding mechanism reveals that rock samples inside the mill are primarily ground by abrasive, impact, and compressive forces. This method of rock crushing dictates that the tank cannot be sealed during the crushing process, inevitably resulting in noise and dust. This leads to a poor working environment for both operators and the machine, a significant drawback of this crushing method, necessitating a new approach to address the noise and dust issues caused by rock crushing. In mining operations, where the working environment is relatively open, the noise and dust issues of this crushing method are not particularly prominent. However, for experiments requiring continuous measurements in enclosed spaces such as laboratories to obtain more accurate data, the limitations of ball mills are unacceptable.

[0009] (2) Deficiencies in the measurement method

[0010] After a rock sample is crushed in a ball mill, it needs to be removed from the mill and placed into a testing instrument for residual gas analysis. During this process, residual gas released during crushing is lost, resulting in measured data that is lower than the actual gas content, making it impossible to obtain accurate gas content data. The key to overcoming this deficiency is to integrate the rock sample crushing and residual gas measurement processes into a continuous measurement procedure.

[0011] (3) Low measurement efficiency

[0012] The method of crushing samples using a ball mill and then measuring residual gas is problematic. First, the sample crushing time is relatively long. Second, after crushing, the sample must be collected again, placed in the residual gas measuring device, and then reheated to the formation temperature and allowed to stand for a period of time before the residual gas content of a single sample can be measured. This process involves many steps and is time-consuming. Although it can determine the residual gas content of a sample, the long time required makes it unsuitable for rapid testing of residual gas content in samples.

[0013] (4) Insufficient compatibility with other instruments

[0014] Because the crushing method uses impact crushing, the process generates significant vibration, noise, and dust, which may affect other testing equipment. Therefore, it is not suitable to form a testing group with other equipment. However, if the noise and vibration can be reduced sufficiently to meet the operating conditions of other instruments, it becomes easier to form a testing group with them, improving testing efficiency and accuracy, thereby achieving the goal of increasing both testing efficiency and experimental precision.

[0015] References:

[0016] [1] Yin Zixin, Wang Nan. Study on the distribution behavior of ball mill media motion state under different rotation speeds [J]. Nonferrous Metals (Mineral Processing Section), 2022; 3(19):118~123. Summary of the Invention

[0017] Purpose of the invention: The technical problem to be solved by the present invention is to provide a rock sample residual gas tester with high testing accuracy and higher efficiency, which addresses the shortcomings of the existing technology.

[0018] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0019] A residual gas tester for rock samples includes a crushing and grinding module, a sealing cover module, a sealing container body, an inlet and outlet module, and a sample clamping module.

[0020] The crushing and grinding module is installed on the top of the sealed tank body and uses a rotary grinding method to crush and grind the rock sample located inside the sealed tank body.

[0021] The sealing cap module covers the top of the main body of the sealing container;

[0022] The sample clamping module is installed at the bottom of the sealed container body and is used to clamp and fix the rock sample to be ground.

[0023] The air inlet and outlet modules are installed on the side wall of the sealed tank body and are used to measure the residual gas content of the rock sample after crushing and grinding.

[0024] Specifically, the crushing and grinding module includes a crushing and grinding power component, a rotating lifting rod, and a crushing and grinding head. The rotating lifting rod extends longitudinally through the sealing cover module. The outer end of the rotating lifting rod located at the top of the sealing cover module is connected to the crushing and grinding power component, and the inner end of the rotating lifting rod located in the main body of the sealing container is connected to the crushing and grinding head. The crushing and grinding power component drives the rotating lifting rod to rotate the crushing and grinding head, and it can move up and down to achieve crushing and grinding of the rock sample fixed in the sample clamping module.

[0025] Alternatively, the crushing and grinding power component includes a rotary motor and a lifting power assembly; the output shaft of the rotary motor is connected to the rotary lifting rod, and the rotary motor drives the rotary lifting rod to rotate; the lifting power assembly includes a lifting slide rail and a lifting power component, and the lifting power component drives the rotary lifting rod to move up and down.

[0026] Alternatively, the crushing and grinding power component is a rotary wrench that works in conjunction with the rotary lifting rod. The rotary lifting rod is driven to rotate and lift simultaneously by manually turning the rotary wrench.

[0027] Specifically, the sealing cover module includes a sealing cover, a rotating shaft dynamic seal, and a sealing ring; the sealing cover is fitted onto the top of the sealing tank body; the rotating shaft dynamic seal is used to dynamically seal the rotating shaft of the crushing and grinding module, and the rotating shaft dynamic seal has a V-shaped groove at the center of the sealing cover for filling with lubricating sealing oil.

[0028] The sealing ring is set in the sealing groove inside the sealing cover to achieve a static seal at the joint between the tank body and the sealing cover.

[0029] Specifically, the main body of the sealed container includes a container body, a heating strip, a support bracket, and a sealing cap fastening buckle;

[0030] The tank is a circular metal container, which is sealed by a top-mounted sealing cap fastening buckle and sealing cap module.

[0031] The heating strips are built into the bottom of the tank and are distributed in a ring shape;

[0032] The support bracket is installed at the bottom of the tank, and the support bracket is provided with fixing screw holes for fixing the tank to the plane.

[0033] The sealing cap fastening buckle is divided into upper and lower parts, which are fastened by bolts. The upper part is on the outer wall of the sealing cap, and the lower part is on the outer wall of the sealing container.

[0034] The outer wall of the tank is pre-insulated.

[0035] Specifically, the air inlet and outlet module includes an air inlet pipe and an air outlet pipe; the end of the air inlet pipe is connected to a carrier gas storage bottle outside the tank body, and the air inlet pipe is equipped with an air inlet control valve and an air inlet metering valve. The experimental carrier gas is injected into the sealed tank body through the air inlet pipe; the density of the selected carrier gas must be greater than the density of the gas to be tested, and its composition must be clearly distinguishable from that of the gas to be tested.

[0036] The end of the vent pipe is connected to a gas detection device outside the tank. The vent pipe is equipped with a vent control valve, a pressure gauge and a vent metering valve. The carrier gas and residual gas are discharged from the sealed tank through the vent pipe.

[0037] Specifically, the sample clamping module includes a hydraulic oil inlet line, an oil inlet control hydraulic valve, a jaw connecting line and a jaw oil inlet line, a jaw telescopic component and a sample clamping jaw;

[0038] The sample clamping claws are a set used to clamp rock samples; each sample clamping claw is set on a corresponding claw telescopic component, and the clamping and releasing actions are realized by the telescopic movement of the claw telescopic component.

[0039] The claw telescopic components are connected to the claw communication pipeline through their respective claw oil inlet pipelines. Each claw oil inlet pipeline is equipped with a hydraulic control valve, which controls the independent telescopic movement of the corresponding claw telescopic component.

[0040] The claw connecting pipeline is connected to an external hydraulic oil inlet pipeline, and hydraulic oil is injected into the claw connecting pipeline through the hydraulic oil inlet pipeline; the hydraulic oil inlet pipeline is equipped with an oil inlet control hydraulic valve.

[0041] Furthermore, the present invention also provides a method for determining residual gas in rock samples using the above-mentioned testing instrument, comprising the following steps:

[0042] S1: Weigh the rock sample to be tested and clamp it in place using the sample clamping module;

[0043] S2: Seal the main body of the sealed container and measure the pressure value in the experimental container;

[0044] S3: Open the air inlet and outlet modules, keep the pressure in the test tank stable, fill the test tank with carrier gas, and record the injected carrier gas volume V1 and pressure value P1 at the same time; the density of the selected carrier gas should be greater than the density of the gas to be tested, and the composition should be clearly distinguishable from the gas to be tested.

[0045] S4: Turn on the crushing and grinding module to grind the rock sample in the tank into powder, so that the free gas remaining in the sample pores and the adsorbed gas adsorbed on the sample can escape and enter the tank.

[0046] S5: After crushing and grinding, heat the sealed container to the formation temperature of the rock sample layer, let it stand for a period of time, and wait for all the free gas and adsorbed gas remaining in the powder to dissipate into the sealed pressure container.

[0047] S6: Collect and measure the residual gas in the tank.

[0048] Specifically, in step S6, the collection and measurement of residual gas is divided into two steps:

[0049] First, after the free gas and adsorbed gas remaining in the rock sample have completely escaped into the sealed pressure vessel, open the vent valve and record the vent data; at the same time, measure the quantity and composition of the discharged residual gas. Since the carrier gas density is greater than the residual gas density, the escaped residual gas is concentrated at the top of the sealed vessel. At this time, when the vent valve is opened, the residual gas comes out first. The vent data measured in this step is the first part of the residual gas quantity C1.

[0050] When the discharged gas is entirely carrier gas and the pressure inside the tank is consistent with the pressure P1 in the sealed pressure tank before crushing and grinding, it indicates that the first part of the residual gas has been discharged from the sealed tank. Then the gas outlet valve is closed. During this process, the gas data measured from the gas outlet is the first part of the residual gas in the rock sample.

[0051] The second step is to open the exhaust valve again, and then open the intake valve to inject carrier gas. After injecting the same amount of carrier gas as before the grinding step (V1), close the intake valve. During the injection of carrier gas, collect and observe the gas discharged from the exhaust port and record the change in the amount of gas discharged. When the gas discharge from the exhaust port stabilizes and no more gas is discharged, close the exhaust valve. The data recorded at this time is the total amount of residual gas and carrier gas in the second part (C2).

[0052] The residual gas in rock sample (6) was obtained by the following calculation formula:

[0053] C = C1 + (C2 - V1)

[0054] Where C is the residual gas content;

[0055] C1 is the amount of residual gas measured from the outlet in the first step.

[0056] C2 is the total amount of residual gas and carrier gas measured from the outlet in the second step.

[0057] V1 is the amount of carrier gas injected in the first step.

[0058] Beneficial effects:

[0059] (1) Compared with the prior art, the rock sample crushing and grinding method of the present invention has more advantages. The prior art rock sample crushing usually adopts impact crushing method, which is discontinuous in the testing process and difficult to guarantee the sealing. The present invention adopts rotary crushing and grinding, which has the characteristics of good sealing, low noise, low dust, small size, high efficiency and good continuity, and is more suitable for installation and use in laboratories and enclosed spaces.

[0060] (2) The residual gas collection and measurement are more accurate. The present invention realizes the continuous and uninterrupted process of transporting carrier gas, grinding samples, discharging residual gas, and collecting and measuring residual gas. This reduces the possibility of residual gas escaping and becoming unmeasurable when the sealed container is opened during the experimental process, and makes the measured data more accurate.

[0061] (3) Residual gas collection and measurement are more convenient. The present invention can realize the automated measurement of the entire process from conveying carrier gas, grinding samples, heating to formation temperature, heat preservation, exhausting residual gas to finally collecting and measuring residual gas, which improves the automatic measurement of experiments, reduces labor intensity and improves efficiency.

[0062] (4) The present invention has better adaptability and compatibility with other existing instruments and equipment. The present invention has the advantages of low noise, low vibration, low dust, small size and high efficiency. The intake and exhaust can be connected to other existing instruments and equipment through small diameter pipelines. Moreover, since the noise and vibration are relatively small, they have almost no significant impact on existing equipment. It can be well compatible with existing equipment and realize the requirements of continuous measurement.

[0063] (5) The device of the present invention can realize segmented measurement of residual gas content in the longitudinal direction, thereby observing the characteristics of heterogeneous gas content in shale. Shale gas content has the characteristic of heterogeneity. By segmented crushing and grinding and segmented measurement, the residual gas content of each segment can be measured (grind one segment, measure one segment, then grind the second segment and measure the second segment), thereby observing the change of gas content in each segment and evaluating the heterogeneity of gas content. Attached Figure Description

[0064] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0065] Figure 1 This is a multi-view view of the residual gas analyzer used to test the rock sample.

[0066] Figure 2 This is a right-hand view of the residual gas analyzer used to test the rock sample.

[0067] Figure 3 This is a front perspective view (main view) of the residual gas tester for the rock sample.

[0068] Figure 4 This is the left view of the residual gas analyzer for the rock sample and the BB′ cross-section.

[0069] Figure 5 This is a schematic diagram and CC' cross-sectional view of the sealing cover module of the residual gas tester for rock samples.

[0070] Figure 6 This is a top view of the residual gas analyzer used to test the rock sample.

[0071] Figure 7 This is a schematic diagram (AA′ cross-sectional view) of the internal sample clamping module of the residual gas tester for rock samples.

[0072] The reference numerals in the attached figures represent:

[0073] 1. Crushing and grinding module; 1-1 Crushing and grinding power component; 1-2 Rotary lifting rod; 1-3 Crushing and grinding head;

[0074] 2. Sealing cover module; 2-1 Rotary shaft moving seal; 2-2 Sealing ring; 2-3 Sealing cover;

[0075] 3. Sealed tank body; 3-1 Tank body; 3-2 Heating strip; 3-3 Support legs; 3-4 Sealing cap fastener; 3-5 Insulation layer;

[0076] 4. Inlet / Outlet Module; 4-1 Inlet Pipe; 4-2 Inlet Control Valve; 4-3 Outlet Control Valve; 4-4 Outlet Pipe; 4-5 Pressure Gauge

[0077] 5 Sample clamping module; 5-1 Hydraulic oil inlet line; 5-2 Oil inlet control hydraulic valve; 5-3 Claw connecting line; 5-4 Claw oil inlet line; 5-5 Claw telescopic component; 5-6 Sample clamping claw.

[0078] 6 rock samples. Detailed Implementation

[0079] The present invention can be better understood from the following embodiments.

[0080] like Figures 1 to 4 As shown, the rock sample residual gas tester of the present invention mainly consists of 5 large modules, totaling about 20 parts, namely, crushing and grinding module 1, sealing cover module 2, sealing tank body 3, gas inlet and outlet module 4, and sample clamping module 5.

[0081] The crushing and grinding module 1 is installed on the top of the sealed tank body 3 and uses a rotary grinding method to crush and grind the rock sample 6 located inside the sealed tank body 3.

[0082] The sample clamping module 5 is installed at the bottom of the sealed container body 3 and is used to clamp and fix the rock sample 6 to be ground.

[0083] The air inlet and outlet module 4 is installed on the side wall of the sealed tank body 3 and is used to measure the residual gas content of the rock sample 6 after crushing and grinding.

[0084] Combination Figure 3 and Figure 4 The crushing and grinding module 1 consists of three parts: a crushing and grinding power unit 1-1, a rotating lifting rod 1-2, and a crushing and grinding head 1-3. These three parts work together to complete the grinding action. Its main function is to use an electric motor to provide power and generate a rotating cutting force, which is used to repeatedly grind the rock sample 6 into powder that meets the test requirements through repeated grinding by the crushing and grinding head 1-3.

[0085] Specifically, the rotating lifting rod 1-2 extends longitudinally through the sealing cover module 2. The outer end of the rotating lifting rod 1-2 located at the upper part of the sealing cover module 2 is connected to the crushing and grinding power component 1-1. The inner end of the rotating lifting rod 1-2 located in the sealing tank body 3 is connected to the crushing and grinding head 1-3. The crushing and grinding power component 1-1 drives the rotating lifting rod 1-2 to rotate the crushing and grinding head 1-3 and can move up and down to crush and grind the rock sample 6 fixed in the sample clamping module 5.

[0086] Alternatively, the crushing and grinding power unit 1-1 includes a rotary motor and a lifting power assembly; the output shaft of the rotary motor is connected to the rotary lifting rod 1-2, driving the rotary lifting rod 1-2 to rotate; the lifting power assembly includes a lifting slide rail and a lifting power component, driving the rotary lifting rod 1-2 to move up and down. In this alternative scheme, the rotational power is provided by the electric motor, providing power for the crushing and grinding. Alternatively, another motor is designed to provide power for the lifting of the crushing and grinding component. The lifting speed is set according to the hardness difference of the rock sample, and the lifting distance is set according to the length of the rock sample. The grinding power unit has an internal slide rail, along which the crushing and grinding component moves up and down. A computer controls the speed and lifting action of both motors. The speed of the two motors and the lifting speed and distance are set separately by the computer. After the relevant programs are set, the crushing and grinding component can automatically rise and fall according to the preset program, reducing the workload of the experimenter.

[0087] Alternatively, the crushing and grinding power component 1-1 is a rotary wrench that works in conjunction with the rotary lifting rod 1-2. The rotary wrench is manually rotated to drive the rotary lifting rod 1-2 to rotate and lift simultaneously. In this alternative, the top of the rotary lifting rod 1-2 is designed with a square or hexagonal nut, allowing a square or hexagonal wrench to fit over it. A dedicated square or hexagonal wrench with appropriate torque is then used to provide power for grinding, crushing the rock sample into powder suitable for the release of residual gas, thus facilitating subsequent experimental work.

[0088] In this invention, the surfaces of the rotating lifting rods 1-2 are treated to be smooth, and the hardness and strength of the lifting rods must meet the requirements for crushing and grinding rock samples.

[0089] In this invention, the hardness and strength of the crushing and grinding head 1-3 must meet the requirements for crushing and grinding rock samples, and its diameter is slightly smaller than the diameter of the rock sample 6 to be ground. The rock sample powder ground by the crushing and grinding head 1-3 must meet the requirement that both free and adsorbed natural gas can escape from the rock sample powder. To ensure that the rock sample powder particles are small enough, the rotation speed of the power unit should be matched with the requirements that the ground rock sample powder particles must meet. A reasonable configuration should be formed between slow and uniform rotation and short-term rapid rotation to ensure that the ground rock sample powder meets the experimental requirements. The crushing and grinding head 1-3 uses a fine-grained diamond grinding drill bit with a cylindrical design. The diameter of the cylinder matches the diameter of the core sample commonly used in well drilling and is slightly smaller than the diameter of the rock sample to ensure that the grinding particles can allow gas to escape.

[0090] Combination Figure 5 The sealing cover module 2 includes a sealing cover 2-3, a rotating shaft dynamic seal 2-1, and a sealing ring 2-2. The sealing cover 2-3 covers the top of the sealing tank body 3. The rotating shaft dynamic seal 2-1 is used to dynamically seal the rotating shaft of the crushing and grinding module 1. The rotating shaft dynamic seal is an important sealing measure for the sealing tank. Currently, mature rotating shaft dynamic seals in the industry can achieve dynamic sealing requirements of over 0.5 MPa, which can meet the experimental requirements of this invention. The rotating dynamic seal is the main sealing method for the top of the sealing tank.

[0091] The rotating shaft dynamic seal 2-1 is installed at the center of the sealing cover and has a V-shaped groove for filling with lubricating sealing oil. During operation, lubricating sealing oil needs to be added to the groove. The lubricating sealing oil serves three purposes: first, it lubricates the rotating shaft, keeping its surface smooth; second, it forms an oil film between the lifting rod and the sealing ring, also sealing the sealing tank; and third, if gas leakage occurs in the dynamic seal, bubbles will appear on the oil surface, making it easy to observe the gas leakage.

[0092] The sealing ring 2-2 is installed in the sealing groove inside the sealing cap to achieve a static seal at the joint between the tank body and the sealing cap. An O-ring sealing groove is provided inside the sealing cap 2-3, where an O-ring is used to statically seal the joint between the tank body and the sealing cap. The sealing cap is the main component for opening or closing the sealed tank, playing a crucial role in creating a completely sealed environment. A snap-fit ​​is provided at the interface between the sealing cap and the tank body, which matches the snap-fit ​​on the sealing tank. After the sealing cap and the main body of the sealing tank are aligned, they are locked together using the snap-fit, achieving a seal. At this point, the main body of the sealing tank and the sealing cap are in a relatively static state, and this static seal meets the requirement of preventing gas escape.

[0093] Combination Figure 3 The main body 3 of the sealed container includes a container body 3-1, a heating strip 3-2, a support bracket 3-3, and a sealing cover fastening buckle 3-4.

[0094] The tank body 3-1 is a circular metal container whose height is sufficient to meet the requirements for measuring rock samples. The bottom of the tank body is completely sealed to prevent gas from entering. A buckle is provided at the interface between the tank body and the sealing cap, which matches the buckle on the sealing cap. The sealing cap is secured by buckle 3-4 at the top, which closes and seals the sealing cap module 2.

[0095] The heating strip 3-2 is built into the bottom of the tank 3-1 and is arranged in a ring; its main function is to heat the sealed tank. After the rock sample is ground into powder, the temperature inside the tank is heated to the formation temperature, causing the adsorbed and free shale gas to escape. The heating strip converts electricity into heat energy to heat the sealed tank.

[0096] The support bracket 3-3 is located at the bottom of the tank body 3-1. The support bracket 3-3 is provided with fixing screw holes for fixing the tank body 3-1 to the plane. The support bracket 3-3 mainly supports and stabilizes the tank body. The support bracket has fixing screw holes, which can be used to fix the tank body to the plane with bolts to fix the sealed tank.

[0097] The sealing cap fastening buckle is divided into upper and lower parts, which are fastened by bolts. The upper part of the buckle is on the outer wall of the sealing cap, and the lower part of the buckle is on the outer wall of the sealed container. After the sealing cap is fastened to the container, the bolts are used to tighten the sealing cap fastening buckle to achieve the function of fixing and sealing.

[0098] The outer wall of tank 3-1 is pre-insulated with a layer 3-5. This insulation layer 3-5 serves two basic functions: first, it provides insulation against electrical leakage. Although the heating strips at the bottom of the tank have insulation, there is still a possibility of leakage; therefore, adding an insulation layer protects the operator. Second, it maintains the internal temperature of the tank. Once the internal temperature reaches the ground temperature, heating is stopped. Because of the insulation layer, the internal temperature can be maintained at the ground temperature for a longer period, thus saving energy consumption while ensuring experimental conditions.

[0099] Combination Figure 6 The air inlet and outlet module 4 includes an inlet pipe 4-1 and an outlet pipe 4-4. The end of the inlet pipe 4-1 is connected to a carrier gas storage bottle outside the tank body. The inlet pipe 4-1 is equipped with an inlet control valve 4-2 and an inlet metering valve. Experimental carrier gas is introduced into the sealed tank body 3 through the inlet pipe 4-1. The selected carrier gas density must be greater than the density of the gas to be tested, and its composition must be clearly distinguishable from the gas to be tested.

[0100] The end of the vent pipe 4-4 is connected to a gas detection device outside the tank, allowing the carrier gas and residual gas to be connected to other measuring instruments. The vent pipe 4-4 is equipped with a vent control valve 4-3, a pressure gauge 4-5, and a vent metering valve, through which the carrier gas and residual gas are discharged from the sealed tank.

[0101] Combination Figure 3 and Figure 7 The sample clamping module 5 includes a hydraulic oil inlet line 5-1, an oil inlet control hydraulic valve 5-2, a claw connecting line 5-3 and a claw oil inlet line 5-4, a claw telescopic component 5-5 and a sample clamping claw 5-6; its main function is to clamp the rock sample and fix the rock sample at the bottom of the sealed container, preparing it for crushing and grinding.

[0102] The sample clamping jaws 5-6 are arranged in a group (3-6 pieces) to clamp the rock sample 6. Each sample clamping jaw 5-6 is mounted on a corresponding jaw telescopic component 5-5. The clamping and releasing actions are achieved by the telescopic movement of the jaw telescopic component 5-5. The jaw telescopic components 5-5 are connected to the jaw connecting pipeline 5-3 through their respective jaw oil inlet pipelines 5-4. Each jaw oil inlet pipeline 5-4 is equipped with a hydraulic control valve, which controls the independent telescopic movement of the corresponding jaw telescopic component 5-5. The jaw connecting pipeline 5-3 is connected to an external hydraulic oil inlet pipeline 5-1, through which hydraulic oil is injected into the jaw connecting pipeline 5-3. The hydraulic oil inlet pipeline 5-1 is equipped with an oil inlet control hydraulic valve 5-2.

[0103] The hydraulic inlet line 5-1 is mainly used to transmit hydraulic power, thereby enabling the jaws to move back and forth and clamp the rock sample. One end of the inlet line is connected to the hydraulic pump, and the other end is connected to the jaw connecting line 5-3, with the hydraulic pump providing the total power for the jaws to clamp.

[0104] The hydraulic inlet control valve 5-2 has the function of opening and closing the oil inlet line. When the jaws need to move back and forth, the oil inlet control valve is opened, allowing the jaws to move back and forth as needed. Once the jaws have clamped the rock sample, the oil inlet line is closed, keeping the jaws in the clamped state, thereby fixing the rock sample.

[0105] The chuck connecting line 5-3 connects the oil inlet line of each chuck, connecting all the chucks to provide power to each chuck, and ultimately achieving the purpose of multiple chucks moving back and forth and clamping the rock sample.

[0106] The hydraulic inlet lines 5-4 transmit hydraulic power to each jaw, ensuring that each jaw firmly grips the sample and secures it at the bottom of the sealed container. The jaw inlet lines are divided into three pressure points (upper, middle, and lower) inside the jaws. This design avoids uneven clamping force, ensuring the clamping force is evenly distributed across the three jaws, resulting in a more stable and continuous clamping of the rock sample.

[0107] The jaw telescopic component 5-5 is a part that enables the jaw to move back and forth, and is used to clamp and release rock samples. Each telescopic component is independently controlled by a hydraulic control valve. This design avoids the situation where failure of a single hydraulic valve would affect the overall crushing and grinding operation. This component can be made using a mature product.

[0108] The sample clamping claws 5-6 are a component for clamping rock samples. Depending on the work requirements, 3-6 claws are provided. The outermost layer of each claw has an anti-slip design so that the claw can firmly hold and hold the rock sample.

[0109] The method for determining residual gas in rock samples using the aforementioned testing instrument specifically includes the following steps:

[0110] (1) Weigh the rock sample to be measured and record the weight data. Adjust the clamping mechanism and clamp the prepared rock sample in the clamping mechanism.

[0111] (2) Adjust the grinding mechanism to prepare for crushing and grinding the rock sample.

[0112] (3) Prepare the test carrier gas and ensure that the carrier gas inlet and outlet channels are kept unobstructed.

[0113] (4) To ensure the accuracy of the test, the density of the carrier gas should be greater than that of the gas to be tested, and the composition should be clearly distinguishable from that of the gas to be tested.

[0114] (5) Seal the pressure vessel and prepare for testing.

[0115] (6) After sealing the experimental test container, test the pressure value in the experimental container.

[0116] (7) Keep the pressure in the test tank stable, inject carrier gas through the air inlet pipe, and record the quantity parameter V1 of the injected carrier gas and the pressure value P1 in the tank.

[0117] (8) After injecting the carrier gas, test and record the gas data discharged from the outlet pipe through the measuring instrument on the outlet pipe until the gas content in the outlet pipe is all carrier gas, then stop the input of carrier gas and close the outlet.

[0118] (9) Start the rock sample crushing and grinding process. Use the grinding equipment in the tank to grind the rock sample into powder, so that the free gas remaining in the sample pores and the adsorbed gas adsorbed on the sample can escape and enter the tank.

[0119] (10) After the rock sample is crushed and ground, the sealed container is heated to the formation temperature of the rock sample layer. After standing for a period of time, the free gas and adsorbed gas remaining in the powder are completely dissipated into the sealed pressure container. At this time, the pressure inside the container will change.

[0120] (11) Collection and measurement of residual gas

[0121] The collection and measurement of residual gas is divided into two steps. The first step is to open the gas outlet valve after the free gas and adsorbed gas remaining in the rock sample have completely escaped into the sealed pressure vessel, and record the gas data at the outlet. At the same time, the quantity and composition of the discharged residual gas are measured. Since the carrier gas density is greater than the residual gas density, the escaped residual gas is concentrated at the top of the sealed vessel. At this time, the gas outlet valve is opened, and the residual gas comes out first. The gas volume data measured in this step is the first part of the residual gas quantity C1.

[0122] When the discharged gas is entirely carrier gas and the pressure inside the tank is consistent with the pressure P1 in the sealed pressure tank before crushing and grinding, it indicates that the first part of the residual gas has been discharged from the sealed tank. Then the gas outlet valve is closed. During this process, the gas data measured from the gas outlet is the first part of the residual gas in the rock sample.

[0123] The second step is to reopen the exhaust valve after completing the first step, then open the intake valve to inject carrier gas. Inject the same amount of carrier gas as before the grinding step (V1), then close the intake valve. During the carrier gas injection process, collect and observe the gas discharged from the exhaust port, and record the changes in the gas discharge volume. When the gas discharge from the exhaust port stabilizes and no more gas is discharged, close the exhaust valve. The data recorded at this time is the total quantity C2 of the second part of residual gas and carrier gas. Subtract the amount of injected carrier gas from this data to obtain the quantity of the second part of residual gas.

[0124] (12) Add the first part of residual gas and the second part of residual gas together. The total amount is the gas content data of the sample.

[0125] The residual gas in the rock sample is obtained by the following calculation formula:

[0126] C = C1 + (C2 - V1)

[0127] Where C is the residual gas content;

[0128] C1 is the amount of residual gas measured from the outlet in the first step.

[0129] C2 is the total amount of residual gas and carrier gas measured from the outlet in the second step.

[0130] V1 is the amount of carrier gas injected in the first step.

[0131] The residual gas analyzer for rock samples of this invention can be used to measure the heterogeneous distribution of residual gas content along depth in rock samples, specifically:

[0132] ① When measuring residual gas, the measurement process can be divided into multiple rounds according to the research objective. The grinding depth of each round can be set to 1-3 cm according to the research accuracy (the grinding depth can be increased or decreased according to the research accuracy).

[0133] ②After grinding the rock sample in the first round, measure the residual gas in the first round according to steps (7)-(12) of the residual gas determination method.

[0134] ③ After the first round of measurement is completed, the sample is crushed and ground in the second round according to the research purpose, and the residual gas is measured in the second round. Steps (7) to (12) of the residual gas determination method are repeated to measure the residual gas in the second round.

[0135] By performing multiple rounds of crushing and grinding, and measuring residual gas, the heterogeneous distribution characteristics of residual gas content along depth in rock samples can be evaluated.

[0136] This invention provides a concept and method for a residual gas analyzer and testing method for rock samples. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method of determining residual gas in a rock sample, characterized by, The determination is carried out by using a tester comprising a crushing and grinding module (1), a sealing cover module (2), a sealing tank main body (3), an air inlet and outlet module (4) and a sample clamping module (5); The crushing and grinding module (1) is installed on the top of the sealing tank main body (3) and adopts a rotary grinding mode to crush and grind the rock sample (6) in the sealing tank main body (3); The sealing cover module (2) is covered on the top of the sealing tank main body (3); The sample clamping module (5) is installed on the bottom of the sealing tank main body (3) and is used for clamping and fixing the rock sample (6) to be ground; The air inlet and outlet module (4) is installed on the side wall of the sealing tank main body (3) and is used for measuring the residual gas content of the crushed and ground rock sample (6); The crushing and grinding module (1) comprises a crushing and grinding power component (1-1), a rotary lifting rod (1-2) and a crushing and grinding head (1-3); the rotary lifting rod (1-2) longitudinally penetrates the sealing cover module (2), the outer end of the rotary lifting rod (1-2) located at the upper part of the sealing cover module (2) is connected with the crushing and grinding power component (1-1), the inner end of the rotary lifting rod (1-2) located in the sealing tank main body (3) is connected with the crushing and grinding head (1-3), the rotary lifting rod (1-2) is driven by the crushing and grinding power component (1-1) to drive the crushing and grinding head (1-3) to rotate and can be lifted up and down, so as to crush and grind the rock sample (6) fixed in the sample clamping module (5); The method for determining the residual gas of the rock sample comprises the following steps: S1: weighing the rock sample (6) to be measured and clamping and fixing the rock sample (6) by the sample clamping module (5); S2: closing the sealing tank main body (3) to measure the pressure value in the experimental tank; S3: opening the air inlet and outlet module (4), keeping the pressure in the experimental tank stable, filling the experimental tank with carrier gas, recording the injected carrier gas amount V1 and the pressure value P1 at the same time; the selected carrier gas density is greater than the density of the gas to be tested, and the composition can be obviously distinguished from the gas to be tested; S4: starting the crushing and grinding module (1), grinding the rock sample (6) in the tank to powder, so that the free gas remaining in the sample pores and the adsorbed gas adsorbed on the sample can escape into the tank; S5: after the crushing and grinding is completed, heating the sealing tank, heating the temperature to the formation temperature of the layer where the rock sample is located, standing for a period of time, and waiting for the residual free gas and adsorbed gas in the powder to completely escape into the sealing pressure tank; S6: collecting and measuring the residual gas in the tank; Through multiple rounds of crushing and grinding, the residual gas measurement can evaluate the heterogeneous distribution characteristics of the residual gas content in the rock sample along the depth; In step S6, the collection and measurement of the residual gas are divided into two steps: The first step, when the free gas and adsorbed gas in the rock sample completely escapes into the sealed pressure tank, the gas outlet valve is opened, and the gas data of the gas outlet is recorded; at the same time, the amount and composition of the discharged residual gas are measured, because the density of the carrier gas is greater than that of the residual gas, the escaped residual gas is concentrated at the top of the sealed tank, at this time the gas outlet valve is opened, the first to come out is the residual gas, the gas amount data measured in this step is the first part of the residual gas quantity C1; When the composition of the discharged gas is completely carrier gas, and the pressure in the tank is consistent with the pressure P1 in the sealed pressure tank before crushing and grinding, it indicates that the first part of the residual gas has been discharged from the sealed tank, then the gas outlet valve is closed, and the gas data tested from the gas outlet in this process is the first part of the residual gas in the sample; The second step, the gas inlet valve is opened again, then the carrier gas is injected, the same amount of carrier gas as the amount of gas injected before the grinding step V1 is injected, and then the gas inlet valve is closed; in the process of injecting the carrier gas, the gas discharged from the gas outlet is collected and observed at the same time, the change of the gas amount is recorded, when the gas outlet is stable and no gas is discharged, the gas outlet valve is closed, the data recorded at this time is the total amount of the second part of the residual gas and the carrier gas C2; The residual gas in the rock sample (6) is obtained by the following calculation formula: C=C1+(C2-V1) Wherein, C is the residual gas content; C1 is the first part of the residual gas quantity measured from the gas outlet in the first step; C2 is the total quantity of the second part of the residual gas and the carrier gas measured from the gas outlet in the second step; V1 is the quantity of the carrier gas injected for the first time.

2. The method of residual gas measurement of a rock sample according to claim 1, characterized in that, The crushing and grinding power component (1-1) includes a rotating motor and a lifting power assembly; the output shaft of the rotating motor is connected with the rotating lifting rod (1-2), and the rotating lifting rod (1-2) is driven to rotate by the rotating motor; the lifting power assembly includes a lifting slide rail and a lifting power piece, and the rotating lifting rod (1-2) is driven to move up and down by the lifting power piece.

3. The method of residual gas analysis of a rock sample according to claim 1, wherein, The crushing and grinding power component (1-1) is a rotating wrench cooperating with the rotating lifting rod (1-2), and the rotating wrench is manually rotated to drive the rotating lifting rod (1-2) to rotate and lift at the same time.

4. The method of residual gas analysis of a rock sample according to claim 1, wherein, The sealing cover module (2) includes a sealing cover (2-3), a rotating shaft dynamic sealing piece (2-1) and a sealing ring (2-2); the sealing cover (2-3) is covered on the top of the sealing tank body (3); the rotating shaft dynamic sealing piece (2-1) is used for dynamically sealing the rotating shaft of the crushing and grinding module (1), and the rotating shaft dynamic sealing piece (2-1) is arranged at the center position of the sealing cover and is provided with a V-shaped groove for filling lubricating sealing oil; The sealing ring (2-2) is arranged in the sealing groove on the inner side of the sealing cover, and realizes the static sealing of the joint part of the tank body and the sealing cover.

5. The method of residual gas analysis of a rock sample according to claim 1, wherein, The sealing tank body (3) includes a tank body (3-1), a heating strip (3-2), a support foot (3-3) and a sealing cover fastening buckle (3-4); The tank body (3-1) is a circular metal container, which is sealed by the sealing cover fastening buckle (3-4) arranged on the top and the sealing cover module (2); The heating strip (3-2) is arranged in the bottom of the tank body (3-1) and is distributed in a ring shape; The support foot (3-3) is installed at the bottom of the tank body (3-1), and the support foot (3-3) is provided with a fixing screw hole for fixing the tank body (3-1) on a plane; The sealing cover fastening buckle (3-4) is divided into upper and lower two part buckles, and the two part buckles are fastened by bolts, the upper half part buckle is on the outer wall of the sealing cover, and the lower half part buckle is on the outer wall of the sealing tank; The outer wall of the tank body (3-1) is provided with an insulating and heat insulating layer (3-5).

6. The method of residual gas analysis of a rock sample according to claim 1, wherein, The gas inlet and outlet module (4) comprises a gas inlet pipe (4-1) and a gas outlet pipe (4-4); the end of the gas inlet pipe (4-1) is connected with a carrier gas storage bottle outside the tank body, the gas inlet pipe (4-1) is provided with a gas inlet control valve (4-2) and a gas inlet metering valve, and the experimental carrier gas is injected into the sealing tank body (3) through the gas inlet pipe (4-1); The end of the gas outlet pipe (4-4) is connected with a gas detection device outside the tank body, the gas outlet pipe (4-4) is provided with a gas outlet control valve (4-3), a pressure gauge (4-5) and a gas outlet metering valve, and the carrier gas and residual gas are discharged from the sealing tank through the gas outlet pipe (4-4).

7. The method of residual gas analysis of a rock sample according to claim 1, wherein, The sample clamping module (5) comprises a hydraulic oil inlet pipeline (5-1), an oil inlet control hydraulic valve (5-2), a jaw communication pipeline (5-3) and a jaw oil inlet pipeline (5-4), a jaw telescopic component (5-5) and a sample clamping jaw (5-6); The sample clamping jaw (5-6) is a group of jaws for clamping the rock sample (6); each sample clamping jaw (5-6) is arranged on the corresponding jaw telescopic component (5-5), and the clamping and releasing actions are realized by the telescopic movement of the jaw telescopic component (5-5); The jaw telescopic component (5-5) is connected to the jaw communication pipeline (5-3) through the respective jaw oil inlet pipeline (5-4), and each jaw oil inlet pipeline (5-4) is respectively provided with a hydraulic control valve, and the corresponding jaw telescopic component (5-5) is independently telescoped by the respective hydraulic control valve; The jaw communication pipeline (5-3) is connected with the external hydraulic oil inlet pipeline (5-1), and the hydraulic oil is injected into the jaw communication pipeline (5-3) through the hydraulic oil inlet pipeline (5-1); the hydraulic oil inlet pipeline (5-1) is provided with an oil inlet control hydraulic valve (5-2).

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