Rock residual gas measuring method, gas taking method and experimental device

Abstract

The invention relates to a rock residual gas measuring method, a gas taking method and an experimental device, and relates to the technical field of oil-gas exploration. The measuring method comprises the following steps: putting a rock sample and a grinding ball into a ball milling tank; vacuumizing the ball milling tank to a first air pressure; the ball milling tank is communicated with a first gas taking device, and the first gas taking device and the ball milling tank are sealed; calculating the residual volume of the ball milling tank according to the first air pressure, the second air pressure, the ambient air pressure and the first volume; vacuumizing the ball milling tank to third air pressure; carrying out ball-milling crushing work by utilizing the ball-milling tank, and recording the air pressure in the ball-milling tank as fourth air pressure; calculating the gas production rate of the rock sample according to the residual volume, the third pressure and the fourth pressure. In the measurement process of the gas production rate, liquid does not need to be injected into the ball-milling tank, and saturated saline solution does not need to be injected either, so that the loss of the ball-milling tank is reduced, and the loss of residual gas caused by dissolving the residual gas in the liquid is also avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas exploration, in particular to a rock residual gas measurement method, a rock residual gas collection method and an experimental device. BACKGROUND

[0002] Atoms or ions on the surface of rock pores have residual valence force field, which has the ability to adsorb gas or liquid. During the diffusion and migration of natural gas, it is constantly adsorbed by rocks to form rock adsorbed gas, also known as rock residual gas. The rock adsorbed hydrocarbon gas can strengthen the deep oil and gas information. In natural gas exploration, the information such as gas component and content distribution in rock adsorbed gas can be used to distinguish the type and evolution degree of gas source rock.

[0003] In the related art, the mechanical crushing degassing method is the most commonly used method to study rock residual gas at present. The rock sample is crushed in a vacuum system or a sealed medium of water by mechanical external force, so that the rock residual gas of the rock sample is completely released.

[0004] According to the different methods of crushing the rock sample, the mechanical crushing method is divided into crushing method, cutting method and ball milling method. Among them, the ball milling method can completely crush the rock sample and unify the particle size of the crushed sample. However, since the ball milling method realizes the crushing of the rock sample by the collision of the grinding balls in the ball mill jar with the rock, in order to avoid weakening the impact of the liquid sealing medium, the ball milling method cannot use water as the sealing medium. In order to collect the mixed gas, the crushing is generally carried out in a vacuum system.

[0005] After the rock sample is crushed to obtain the residual gas, the residual gas needs to be collected and the gas production of the rock sample needs to be measured. In the related art, the gas is usually collected by the drainage gas collection method. Saturated brine is generally injected into the ball mill jar containing the product gas to discharge the gas in the ball mill jar to the measuring cylinder, and the volume of the product gas is measured in the measuring cylinder. However, this method for measuring the volume of the gas has low accuracy, it is difficult to avoid the dissolution of the produced rock residual gas into the saturated brine, and the volume measured by the measuring cylinder is often less than the actual produced rock residual gas. Moreover, the saturated brine has certain corrosiveness and can corrode the ball mill jar during the collection of the gas. SUMMARY

[0006] The present application provides a rock residual gas measurement method, a rock residual gas collection method and an experimental device, which are used to reduce the loss of residual gas in the experimental process and avoid the corrosion of the ball mill jar.

[0007] In a first aspect, the present application provides a rock residual gas measurement method, comprising the following steps:

[0008] Put the rock sample and the grinding balls into the ball mill jar and seal the ball mill jar;

[0009] Evacuate the ball mill to the first pressure;

[0010] Connect the ball mill to the first air extraction device, and seal the first air extraction device and the ball mill. After stabilization, the air pressure in the ball mill is recorded as the second air pressure, the volume of the first air extraction device is the first volume, and the air pressure of the first air extraction device is the ambient pressure.

[0011] Calculating a residual volume of the ball mill according to the first air pressure, the second air pressure, the ambient air pressure, and the first volume, wherein the residual volume refers to the available volume of the ball mill after accommodating the rock sample and the grinding balls;

[0012] The ball mill is evacuated to a third pressure and sealed;

[0013] The rock sample is ball-milled using the ball mill, and the air pressure in the ball mill after the ball milling is recorded as the fourth air pressure;

[0014] The gas production of the rock sample is calculated based on the residual volume, the third gas pressure, and the fourth gas pressure.

[0015] In one embodiment, the calculation of the remaining volume of the ball mill according to the first air pressure, the second air pressure, the ambient air pressure, and the first volume comprises the following steps:

[0016] The residual volume is calculated based on a first formula, wherein the first formula includes:

[0017] V1=(P2*V2-Pring*V2) / (P1-P2)

[0018] Among them, V1 represents the remaining volume of the ball mill, P1 represents the first air pressure, P2 represents the second air pressure, P ring represents the ambient air pressure, and V2 represents the first volume.

[0019] In one embodiment, calculating the gas production of the rock gas sample based on the residual volume, the third gas pressure, and the fourth gas pressure comprises the following steps:

[0020] The gas production is calculated based on a second formula, wherein the second formula includes:

[0021] V=(P4-P3)*V1 / 1bar

[0022] Wherein, V represents the gas production, P4 represents the fourth gas pressure, P3 represents the third gas pressure, and V1 represents the remaining volume.

[0023] In one embodiment, the first gas taking device comprises a gas taking cylinder and a communication pipe, a piston block is slidably installed in the gas taking cylinder, the piston block divides the gas taking cylinder into a first chamber and a second chamber which are not communicated with each other, and before the step of communicating the ball mill jar with the closed first gas taking device, the measuring method further comprises the following steps:

[0024] The first chamber is communicated with the outside, and the second chamber is vacuumized to drive the piston block to move to the end of the gas taking cylinder far from the first chamber.

[0025] In one embodiment, before the step of placing the rock sample and the grinding ball in the ball mill jar, the measuring method further comprises the following steps:

[0026] The rock sample is roughly crushed to have an outer diameter less than the first size.

[0027] In a second aspect, embodiments of the present application further provide a gas taking method, which comprises the above-mentioned measuring method, and after the step of calculating the gas production of the rock sample according to the residual volume, the third gas pressure and the fourth gas pressure, the gas taking method further comprises the following steps:

[0028] The first chamber of the gas taking cylinder is vacuumized, and the first chamber is communicated with the ball mill jar to press the produced gas into the first gas taking device.

[0029] In one embodiment, after the step of communicating the vacuumized first gas taking device with the ball mill jar, the gas taking method further comprises the following steps:

[0030] The first chamber is disconnected from the ball mill jar, and the first chamber is sealed by using a second sealing member;

[0031] The second chamber is communicated with the outside air, so that the piston block slidably installed in the gas taking cylinder slides to reduce the space of the first chamber;

[0032] The gas taking needle is pierced into the second sealing member and extends into the first chamber, and the gas taking needle is used to take gas.

[0033] In a third aspect, the present application further provides an experimental device, which comprises:

[0034] a ball mill jar having a ball mill space for accommodating a rock sample and a grinding ball;

[0035] a first gas taking device having a first volume, and the first gas taking device is provided with a first gas taking port for communicating with the ball mill jar;

[0036] a vacuum pump which is detachably communicated with the ball mill jar and is used to vacuumize the ball mill jar; and

[0037] A control module, the first gas taking device, the vacuum pump and the ball mill tank are connected with the control module, and the control module can control the vacuum pump, the ball mill tank and the first gas taking device to execute the measuring method as claimed in any one of claims 1-5.

[0038] In one embodiment, the first gas taking device comprises a gas taking cylinder and a communication pipe, and the volume of the gas taking cylinder and the communication pipe is equal to the first volume.

[0039] One end of the communication pipe is provided with the first gas taking port, and the other end of the communication pipe is connected with the gas taking cylinder.

[0040] A piston block is slidably installed in the gas taking cylinder, and the piston block separates the gas taking cylinder into a first chamber and a second chamber which are not communicated with each other.

[0041] The gas taking cylinder is provided with a first gas outlet and a second gas taking port which are spaced from each other, the first gas outlet is communicated with the first chamber, the second gas taking port is communicated with the second chamber, the first gas outlet and the second gas taking port are both provided with a second gas valve for controlling the opening and closing of the gas outlet, the communication pipe is used for communicating the ball mill tank with the first gas outlet, and the second gas taking port is structurally matched with the vacuum port of the vacuum pump.

[0042] In one embodiment, a tapered hole communicated with the first gas outlet is formed in the side wall of the gas taking cylinder, and a tapered protrusion is arranged at one end of the piston block close to the first gas outlet, and the tapered protrusion is tightly fitted with the tapered hole by sliding the piston block.

[0043] Compared with the prior art, the gas taking device of the application can calculate the residual volume of the ball mill tank by communicating the gas pressure of the ball mill tank before and after the ball milling, and the occupied space of the solid rock sample and the solid grinding ball in the ball mill tank is excluded from the interference on the gas production rate. In the ball milling process, the gas pressure change in the ball mill tank is only related to the gas production rate, and the gas production rate of the rock sample can be obtained by the gas pressure change of the ball mill tank before and after the ball milling.

[0044] The measuring process of the gas production rate does not need to inject liquid into the ball mill tank to measure the residual volume, so as not to affect the normal ball milling work. Moreover, the saturated brine injection method is not needed to measure the gas production rate, the loss of the ball mill tank is reduced, and the ball mill tank can meet more times of ball milling work. BRIEF DESCRIPTION OF DRAWINGS

[0045] Hereinafter, the application will be described in more detail based on the embodiments and with reference to the drawings.

[0046] Figure 1 is a structural schematic view of an experimental device in the embodiments of the application;

[0047] Figure 2 is a flowchart of a measuring method in an embodiment of the present application;

[0048] Figure 3 is a flowchart of a gas extraction method in an embodiment of the present application;

[0049] Figure 4 is a flowchart of a gas extraction method in an embodiment of the present application.

[0050] Reference signs:

[0051] 1, rock sample;

[0052] 2, grinding ball;

[0053] 3, ball mill jar; 31, jar body; 32, jar cover; 321, first air vent; 322, second air vent; 33, first sealing member; 34, first air valve;

[0054] 4, gas extraction cylinder; 41, cylinder body; 411, first gas outlet; 412, second gas extraction port; 413, conical hole; 42, piston block; 421, conical protrusion; 422, tubular groove; 43, second air valve; 44, second sealing member; 45, extension gas pipe; 46, gas extraction needle; 47, silica gel pad;

[0055] 5, communication pipe; 51, first communication joint; 52, second communication joint;

[0056] 6, vacuum pump;

[0057] 7, vacuum gauge. DETAILED DESCRIPTION

[0058] The present application will be further described below with reference to the accompanying drawings.

[0059] The atoms or ions on the pore surface of the rock have a residual valence field and have the ability to adsorb gas or liquid. During the diffusion and migration process of natural gas, the natural gas is constantly adsorbed by the rock to form rock adsorbed gas, also known as rock residual gas. The rock adsorbed hydrocarbon gas can strengthen the deep oil and gas information. In natural gas exploration, the information such as the gas component and content distribution in the rock adsorbed gas can be used to determine the type and evolution degree of the gas source rock.

[0060] In the related art, the mechanical crushing degassing method is the most commonly used method for studying rock residual gas at present. The rock sample is crushed in a vacuum system or a sealed medium of water by mechanical external force, so that the rock residual gas of the rock sample is completely released.

[0061] According to the different methods of crushing the rock sample, the mechanical crushing method is divided into crushing method, cutting method and ball milling method.

[0062] The ball milling method can completely crush the rock sample and uniformly control the particle size after crushing. However, the ball milling method cannot use water as a sealing medium in order to avoid weakening the impact of the liquid sealing medium. In order to collect the mixed gas, the crushing is generally carried out in a vacuum system.

[0063] After the residual gas of the crushed rock sample is obtained, the residual gas needs to be collected and the gas production of the rock sample needs to be measured. In the related art, the gas is generally collected by the drainage gas collection method, and saturated brine is injected into the ball mill tank containing the product gas to discharge the gas in the ball mill tank to a measuring cylinder to measure the volume of the product gas.

[0064] However, the method for measuring the volume of the gas has low accuracy, and it is difficult to avoid the dissolution of the produced rock residual gas into the saturated brine, and the volume measured by the measuring cylinder is often less than the actual produced rock residual gas. In addition, the saturated brine has certain corrosiveness and can corrode the ball mill tank during the collection of the gas.

[0065] In order to solve the above technical problems, the present application provides a rock residual gas measurement method, a gas collection method and an experimental device. The rock sample 1 can be fully broken, and the complete residual gas can be obtained, and the loss of the residual gas or the corrosion of the ball mill tank during the experiment can be avoided.

[0066] Embodiment one

[0067] Referring to FIGS. 1, 2 and 3, Figure 1 and Figure 2 The present application provides a rock residual gas measurement method, which comprises the following steps:

[0068] S100: placing a rock sample 1 and grinding balls 2 into a ball mill tank 3 and sealing the ball mill tank 3;

[0069] S200: vacuumizing the ball mill tank 3 to a first gas pressure;

[0070] S300: connecting the ball mill tank 3 with a first gas collection device, and recording the gas pressure of the ball mill tank 3 after stabilization as a second gas pressure;

[0071] The volume of the first gas collection device is a first volume, and the gas pressure of the first gas collection device is an ambient gas pressure.

[0072] S400: calculating the remaining volume of the ball mill tank 3 according to the first gas pressure, the second gas pressure, the ambient gas pressure and the first volume.

[0073] The remaining volume refers to the available volume of the ball mill tank 3 after containing the rock sample 1 and the grinding balls 2, that is, the remaining volume is equal to the initial volume of the ball mill tank 3 minus the volume of the rock sample 1 minus the volume of the grinding balls 2.

[0074] S500: Evacuate the ball mill 3 to the third pressure and seal the ball mill 3.

[0075] S600: ball milling the rock sample 1 using the ball mill 3, and recording the air pressure in the ball mill 3 after the ball milling as a fourth air pressure;

[0076] S700: Calculate the gas production of the rock sample 1 according to the remaining volume, the third gas pressure, and the fourth gas pressure.

[0077] This application utilizes a ball mill 3 and grinding balls 2 to perform ball milling on the rock sample 1, which can fully release the residual gas adsorbed by the rock sample 1. At the same time, the drainage method is not used in the process of measuring the gas, which can avoid the residual gas from dissolving in saturated salt water, and the measurement result is more accurate.

[0078] Compared with the method of injecting saturated salt water into the ball mill 3 to measure the gas production of the rock sample 1, the present invention only needs to perform vacuuming several times during the measurement process to obtain the gas production of the rock sample 1, thereby avoiding the corrosion of the ball mill 3 due to contact with saturated salt water, and also avoiding the gas production measurement deviation caused by the gas produced by the rock sample 1 dissolving in the saturated salt water.

[0079] The basic principle of step S400 is that the sum of the gas volume in the ball mill 3 and the gas volume in the first gas extraction device remains unchanged before and after the ball mill 3 and the first gas extraction device are connected.

[0080] That is, V1*P1+V2*Pring=V1*P2+V2*P2. ​​(1)

[0081] Wherein, V1 represents the remaining volume of the ball mill jar 3, P1 represents the first air pressure, P2 represents the second air pressure, P ring represents the ambient air pressure, and V2 represents the first volume.

[0082] In formula (1), there is only an unknown number V1, and the remaining volume of the ball mill jar 3 can be calculated using the first air pressure, the second air pressure, the ambient air pressure, and the first volume.

[0083] In order to simplify the calculation, formula (1) can be transformed to obtain

[0084] V1=(P2*V2-Pring*V2) / (P1-P2) (2)

[0085] Formula (2) can be used to directly calculate the remaining volume of the ball mill 3 after containing the rock sample 1 and the grinding balls 2.

[0086] Compared with measuring the volume of the rock sample 1 by the liquid drainage method and then calculating the residual volume of the ball mill jar 3, the rock sample 1 is not soaked in the liquid, so that the residual gas in the rock sample 1 is not dissolved in the liquid, and the loss of the residual gas in the measuring process is reduced.

[0087] Since the residual volume of the ball mill jar 3 is obtained by the prior measurement and calculation, the amount of substance of the gas in the ball mill jar 3 before the rock sample 1 is crushed can be further obtained according to the residual volume and the third gas pressure, and the amount of substance of the gas in the ball mill jar 3 after the rock sample 1 is crushed can be calculated according to the residual volume and the fourth gas pressure.

[0088] The calculation of the amount of substance of the gas can use the ideal gas state equation.

[0089] pV1=nRT (3)

[0090] Wherein, p is the pressure (Pa), n is the amount of substance of the gas (mol), R is the molar gas constant (J / (mol.K)), and T is the temperature (K).

[0091] The amount of substance of the gas in the ball mill jar 3 before and after crushing is calculated according to formula (3), and the amount of substance of the residual gas generated in the crushing process, i.e. the gas production of the rock sample 1, can be obtained by subtracting the amount of substance of the gas in the ball mill jar 3 before crushing from the amount of substance of the gas in the ball mill jar 3 after crushing.

[0092] The measuring process only needs to measure the gas pressure of the ball mill jar 3 by using the vacuum gauge 7, and does not need to add water or saturated brine to the ball mill jar 3, so that the measuring process is more convenient, and the ball mill jar 3 is not corroded. The service life of the ball mill jar 3 is prolonged.

[0093] In some implementations, step S700 can be calculated based on the following formula:

[0094] V=(P4-P3)*V1 / 1bar (4)

[0095] Wherein, V represents the gas production, P4 represents the fourth gas pressure, P3 represents the third gas pressure, and V1 represents the residual volume.

[0096] The volume V of the produced gas under the standard atmospheric pressure can be calculated by the above formula. Compared with formula (3), the manual calculation is more convenient, and the volume of the gas can be obtained, which saves the step of converting the amount of substance into the volume after the calculation.

[0097] In order to improve the accuracy of the residual volume, before step S300: the ball mill jar 3 is communicated with the first gas taking device, the ball mill jar 3 is vacuumized to the first gas pressure, and the first gas pressure is preferably 10 -4 pa±10 -5Pa. It is much smaller than the ambient pressure of the first gas taking device. When the first gas taking device is connected with the ball mill tank 3, the gas in the first gas taking device will flow into the ball mill tank 3, so that the gas pressure in the ball mill tank 3 rises.

[0098] Wherein the ambient pressure refers to the indoor pressure, which is generally maintained at about 1 bar. In some implementations, the gas pressure of the first gas taking device can also be adjusted to 1 bar by means of air extraction or air injection, so that the ambient pressure Pring=1 bar, to facilitate subsequent calculation.

[0099] In some implementations, in order to accurately measure the gas pressure of the ball mill tank 3 and avoid gas leakage caused by the measurement process, the measurement process uses an experimental device as shown in Figure 1 The ball mill tank 3 includes a tank body 31 and a tank cover 32 installed on the tank body 31, and the tank cover 32 is threadedly and sealingly connected with the tank body 31.

[0100] A first air vent 321 and a second air vent 322 are formed on the tank cover 32, and a first air valve 34 is arranged at the first air vent 321 and the second air vent 322.

[0101] Before the vacuum gauge 7 for measuring the gas pressure is installed on the ball mill tank 3, the first air vent 321 is closed by the first air valve 34, and then the first sealing member 33 for sealing the first air vent 321 is removed. Then the vacuum gauge 7 is installed on the first air vent 321, and the first air vent 321 is sealed by the sealing structure at the joint of the vacuum gauge 7. Finally, the first air valve 34 arranged at the first air vent 321 is opened, so that the vacuum gauge 7 can measure the gas pressure of the ball mill tank 3.

[0102] And, before the ball mill tank 3 is vacuumized to the first gas pressure in step S200, the vacuum gauge 7 is installed at the first air vent 321 of the ball mill tank 3. When the ball mill tank 3 needs to be vacuumized, the first air valve 34 at the second air vent 322 is closed first, and then the first sealing member 33 arranged at the second air vent 322 is removed to unblock the second air vent 322. Then the air extraction port of the vacuum pump 6 is installed at the second air vent 322, and the second air vent 322 is sealed by the sealing structure at the air extraction port of the vacuum pump 6. Finally, the first air valve 34 arranged at the second air vent 322 is opened, so that the vacuum pump 6 can realize the air extraction work of the ball mill tank 3.

[0103] When the vacuum pump 6 is vacuumizing the ball mill tank 3, the gas pressure of the ball mill tank 3 is measured by the vacuum gauge 7 installed at the first air vent 321, so as to facilitate confirmation of whether the vacuumization work is completed.

[0104] In step S300, when the ball mill tank 3 is communicated with the first gas taking device, the first gas taking valve 34 at the second gas vent 322 is closed first, and then the vacuum pump 6 is separated from the second gas vent 322.

[0105] Then the first gas taking device is communicated with the second gas vent 322, and the connection between the first gas taking device and the second gas vent 322 is sealed. This avoids gas leakage in the first gas taking device and avoids external gas entering the first gas taking device or the ball mill tank 3 to affect the measurement accuracy of the remaining volume.

[0106] Preferably, when the gas pressure is measured by the vacuum gauge 7, the value after the vacuum gauge 7 stabilizes is the final measured gas pressure value, so as to reduce the gas pressure fluctuation caused by environmental factors.

[0107] Example Two

[0108] On the basis of the above embodiments, as shown in Figure 1 and Figure 2 .

[0109] The embodiment also provides a rock residual gas measurement method.

[0110] The first gas taking device including the gas taking cylinder 4 and the communication pipe 5 is used to complete step S300, wherein the piston block 42 is slidably installed in the gas taking cylinder 4, and the piston block 42 divides the gas taking cylinder 4 into the first chamber and the second chamber which are not communicated with each other.

[0111] Before step S300, the measurement method further includes the following steps:

[0112] The first chamber is communicated with the outside, and the second chamber is vacuumized, so as to drive the piston block 42 to move to the end of the gas taking cylinder 4 away from the first chamber.

[0113] Specifically, the vacuum pump 6 is communicated with the second gas taking port 412 of the gas taking cylinder 4, wherein the second gas taking port 412 is communicated with the second chamber. Through the vacuumization of the vacuum pump 6, the piston block 42 slides relative to the gas taking cylinder 4 until the piston block 42 moves to the end away from the first chamber.

[0114] Then the second gas taking valve 43 arranged at the second gas taking port 412 is closed, and the vacuum pump 6 is removed, and the second gas taking port 412 is sealed by the second sealing piece 44.

[0115] At this time, the first volume is the sum of the volume of the first chamber and the volume of the communication pipe 5. Since the second chamber is vacuumized by the vacuum pump 6, the piston block 42 can be pressed at the end far away from the first chamber by the air pressure in the first chamber, so as to avoid the piston block 42 from sliding after the first gas taking device is connected with the ball mill jar 3. The volume of the chamber connected with the first gas taking device and the ball mill jar 3 is ensured to be maintained at the first volume. Changes in the first volume caused by changes in pressure are avoided.

[0116] In some implementations, when the second gas taking port 412 is vacuumized by the vacuum pump 6, the first gas taking port connected with the first chamber is connected with the outside atmosphere, so that the air pressure in the first chamber is maintained at the ambient air pressure, and the piston block 42 can slide to the end of the gas taking cylinder 4 far away from the first gas taking port more smoothly.

[0117] In the embodiment, the measuring method can be implemented by providing the second gas taking port 412 with an extended air pipe 45 and providing the piston block 42 with a tubular groove 422 for the extended air pipe 45 to extend into.

[0118] Since the tubular groove 422 is provided, even if the middle part of the piston block 42 is attached to the cylinder wall of the gas taking cylinder 4, the gap between the outside of the piston block 42 and the cylinder wall of the gas taking cylinder 4 can still be connected by the space in the tubular groove 422, so as to extract the gas not extracted from the gap, and the vacuum of the second chamber is better maintained.

[0119] In some implementations, before the step S100 of placing the rock sample 1 and the grinding balls 2 in the ball mill jar 3, the measuring method further includes the following steps:

[0120] The rock sample 1 is roughly crushed to have an outer diameter less than the first size. By roughly crushing the rock sample 1 in advance, the rock sample 1 can be fully crushed in the ball milling process, and the rock sample 1 can be broken without difficulty due to the large volume of the rock sample 1.

[0121] The first size is preferably 1 cm, and in some implementations, the first size can also be set to 1.5 cm or 2 cm.

[0122] Reference Figure 1 As shown, three grinding balls 2 are placed in the ball mill jar 3 in the present application. In other embodiments, other numbers of grinding balls 2 can be placed according to the volume of the rock sample 1. In addition, the grinding balls 2 are preferably made of metal material.

[0123] By the measuring method provided in the embodiment, the rock sample 1 can be fully crushed by the ball mill jar 3 and the grinding balls 2, so that the residual gas in the rock sample 1 is fully released. The gas production of the rock sample 1 can be calculated according to the measurement of the air pressure.

[0124] The process of measuring the gas production does not need to inject liquid into the ball mill tank 3, and does not weaken the crushing effect of the grinding ball 2. Moreover, it avoids the dissolution of the hydrocarbon gas produced by the rock sample 1 in water, reduces the loss of residual gas in the measurement process, and the measured gas production is more accurate.

[0125] Example Three

[0126] As shown in Figure 1 , Figure 3 and Figure 4 , the present application also provides a method for taking rock residual gas, which comprises the following steps:

[0127] S100: Put the rock sample 1 and the grinding ball 2 into the ball mill tank 3, and seal the ball mill tank 3;

[0128] S200: Vacuumize the ball mill tank 3 to a first gas pressure;

[0129] S300: Connect the ball mill tank 3 with the first gas taking device, and record the gas pressure of the stabilized ball mill tank 3 as a second gas pressure;

[0130] Wherein the volume of the first gas taking device is a first volume, and the gas pressure of the first gas taking device is the ambient gas pressure.

[0131] S400: Calculate the residual volume of the ball mill tank 3 according to the first gas pressure, the second gas pressure, the ambient gas pressure and the first volume.

[0132] The residual volume refers to the available volume of the ball mill tank 3 after containing the rock sample 1 and the grinding ball 2, that is, the residual volume is equal to the initial volume of the ball mill tank 3 minus the volume of the rock sample 1 minus the volume of the grinding ball 2.

[0133] S500: Vacuumize the ball mill tank 3 to a third gas pressure, and seal the ball mill tank 3.

[0134] S600: Perform ball milling crushing work on the rock sample 1 by using the ball mill tank 3, and record the gas pressure in the ball mill tank 3 after the ball milling crushing work as a fourth gas pressure;

[0135] S700: Calculate the gas production of the rock sample 1 according to the residual volume, the third gas pressure and the fourth gas pressure.

[0136] S800: Vacuumize the first chamber of the gas taking cylinder 4, and connect the first chamber with the ball mill tank 3 to press the produced gas to the first gas taking device.

[0137] Wherein the specific steps in steps S100-S700 can refer to the measurement method provided in Embodiment I or Embodiment II.

[0138] The application can use the ball mill tank 3 and the grinding ball 2 to fully release the residual gas attached to the rock sample 1, and can also avoid the change of the content and composition of the residual gas due to the dissolution of the residual gas in the saturated brine.

[0139] Meanwhile, since the first chamber of the gas taking cylinder 4 is vacuumized in step S800, and then connected with the ball mill tank 3, the residual gas in the first chamber can be reduced, and the residual gas obtained is more pure.

[0140] Since the ball mill tank 3 is first subjected to the ball milling crushing work before being connected with the first chamber, the residual gas adsorbed by the rock sample 1 is released, and the gas pressure in the ball mill tank 3 rises from the third gas pressure to the fourth gas pressure, which is higher than the first chamber subjected to the vacuumizing treatment. The residual gas can be introduced into the first chamber of the gas taking cylinder 4 by means of the relatively higher gas pressure in the ball mill tank 3, and the gas taking is relatively simple.

[0141] In some implementations, the gas taking cylinder 4 can adopt a gas taking cylinder 4 provided with a piston block 42. The piston block 42 is slidingly installed in the gas taking cylinder 4 and divides the gas taking cylinder 4 into the first chamber and the second chamber which are not connected with each other. Before the first chamber of the gas taking cylinder 4 is vacuumized, the second chamber needs to be vacuumized first, and the piston block 42 is locked at the end away from the first chamber.

[0142] In other implementations, the gas taking cylinder 4 can also adopt a conventional cylinder body 41 structure, and only one chamber structure (the first chamber) is formed in the interior, and the chamber of the gas taking cylinder 4 is directly vacuumized.

[0143] In step S800, the gas pressure in the first chamber is vacuumized to 10 -4 pa±10 -5 Pa. The gas pressure in the first chamber can be measured by means of the vacuum gauge 7 to determine whether the first chamber is vacuumized.

[0144] The step S800 of vacuumizing the first chamber of the gas taking cylinder 4 and connecting the first chamber with the ball mill tank 3 specifically includes the following steps:

[0145] The second chamber is vacuumized to 10 -4 pa±10 -5 Pa, and then the second air valve 43 arranged at the second gas taking port 412 of the gas taking cylinder 4 is closed, the vacuum pump 6 is removed from the second gas taking port 412, and the second gas taking port 412 is sealed by the second sealing member 44. Then the vacuum pump 6 is connected with the first gas taking port, and the vacuum pump 6 is started to vacuumize the first chamber to 10 -4 pa±10 -5Pa, and then the second vent valve 43 arranged at the first gas outlet is closed. Then the vacuum pump 6 connected with the first gas outlet is disconnected, and the first gas outlet is sealed by the second sealing member 44.

[0146] After the ball mill jar 3 finishes the work of crushing the rock sample 1, the second sealing member 44 is removed, then the connecting pipe 5 is connected with the first gas outlet, and the first sealing member 33 used to seal the second vent 322 is removed, and the end of the connecting pipe 5 far away from the first gas outlet is connected with the second vent 322.

[0147] The ball mill jar 3 is connected with the first chamber by switching the first vent valve 34 arranged at the second vent 322 from closed to open, and switching the second vent valve 43 arranged at the first gas outlet from open to closed. At this time, under the action of the gas pressure difference, the residual gas in the ball mill jar 3 generated during the crushing process will flow into the first chamber which has been vacuumized previously. With the flow of the gas, when the gas pressure in the ball mill jar 3 is stable again, the gas pressure in the ball mill jar 3 will be equal to the gas pressure in the first chamber. The gas in the ball mill jar 3 is taken into the first chamber of the gas taking cylinder 4.

[0148] The gas taking work of the ball mill jar 3 is realized by connecting the first gas taking device which has been vacuumized, which can avoid the pollution of the detection gas caused by the residual gas in the gas taking device during the gas taking process. Moreover, the ball mill jar 3 is vacuumized before the rock sample 1 is crushed by the ball mill jar 3 and the grinding balls 2, and the ball mill jar 3 is sealed during the crushing process, which avoids the influence of the interference gas in the ball mill jar 3 on the composition of the residual gas.

[0149] Example Four

[0150] On the basis of the above embodiment, after the step S800 of connecting the first gas taking device which has been vacuumized with the ball mill jar 3, the gas taking method further comprises the following steps:

[0151] The first chamber is disconnected with the ball mill jar 3, and the first chamber is sealed by the second sealing member 44;

[0152] The second chamber is connected with the outside air, so that the piston block 42 slidingly installed in the inside of the gas taking cylinder 4 slides to reduce the space of the first chamber. The piston block 42 divides the gas taking cylinder 4 into the first chamber and the second chamber which are not connected with each other;

[0153] The gas taking needle 46 is inserted into the first sealing member 33 and extends into the first chamber, and the gas taking needle 46 is used to take the gas.

[0154] Since the first chamber is communicated with the outside world before step S800, and the second chamber is vacuumized, the piston block 42 is driven to move to the end of the gas taking cylinder 4 away from the first chamber. Before the implementation of step S800, since the second chamber is in a vacuum environment, the piston block 42 is attached to the end of the gas taking cylinder 4 having the second chamber.

[0155] And after the second chamber is communicated with the outside world, the gas pressure in the second chamber rises, so that the piston block 42 moves, so that the gas pressure in the first chamber is not less than the outside air pressure.

[0156] Wherein, the first chamber is disconnected with the ball mill jar 3, and the first chamber is sealed by the second sealing member 44, which specifically includes the following steps:

[0157] The second gas taking valve arranged at the first gas taking port is closed, the first gas taking valve arranged at the second gas taking port 322 is closed, and the communication pipe 5 communicated with the first gas taking port is separated from the first gas taking port. Then the second sealing member 44 is installed at the first gas taking port to seal the first chamber.

[0158] In the embodiment, the second sealing member 44 arranged at the first gas taking port is made of silica gel pad 47. It not only has excellent sealing performance, but also has relatively soft texture, so that the gas taking needle can be conveniently inserted into the silica gel pad 47 to realize the gas taking work.

[0159] By inserting the gas taking needle 46 into the first chamber, since the above steps avoid the situation that the gas taking needle 46 cannot normally take gas due to the too low gas pressure in the first chamber, the gas taking efficiency of the gas taking needle 46 is improved.

[0160] In some embodiments, the gas pressure in the first chamber can be further increased by pressurizing the second chamber, so as to improve the gas taking efficiency of the gas taking needle 46. At the same time, the piston block 42 can be driven to slide during the gas taking process, so that the residual gas in the first chamber is completely taken out by the gas taking needle 46, compared with the fixed volume gas taking device, the residual gas can be completely taken out, and the damage to the residual gas during the gas taking process is reduced.

[0161] Example Five

[0162] The application also provides an experimental device, which comprises:

[0163] The ball mill jar 3 has a ball milling space for accommodating the rock sample 1 and the grinding balls 2;

[0164] The first gas taking device has a first volume, and the first gas taking device is provided with a first gas taking port for communicating with the ball mill jar 3;

[0165] The vacuum pump 6 is detachably communicated with the ball mill jar 3, and is used for vacuumizing the ball mill jar 3; and

[0166] The control module is connected with the first gas taking device, the vacuum pump 6 and the ball milling tank 3, and the control module can control the vacuum pump 6, the ball milling tank 3 and the first gas taking device to perform the measurement method in the above embodiment.

[0167] The control module can be a control terminal with a data processing chip and a communication chip, and the control terminal is connected with the ball milling tank 3, the vacuum gauge 7, the first gas taking device and the vacuum pump 6 by wire or wireless connection. The control of the ball milling tank 3, the first gas taking device and the vacuum pump 6 is realized.

[0168] The control module can also be a device including a broadcast device. The broadcast device sends voice or light instructions to dispatch on-site staff to perform the above steps.

[0169] In some implementations, the control module can directly control the ball milling tank 3, the first gas taking device and the vacuum pump 6. The control module is used to control the operation of the ball milling tank 3, the first gas taking device and the vacuum pump 6. The experimental device can further include a gas pipe system (not shown in the figure), which includes a valve body and a plurality of gas pipes.

[0170] The first air inlet 321 and the second air inlet 322 of the ball milling tank 3, the first gas inlet and the second gas inlet 412 of the first gas taking device, the measurement port of the vacuum gauge 7 and the vacuum port of the vacuum pump 6 are connected with the gas pipe system.

[0171] Specifically, the gas pipe system includes at least three main pipes, wherein the first main pipe is connected with the first air inlet 321, the second main pipe is connected with the second air inlet 322, and the third main pipe is connected with the outside air. The gas pipe system further includes a gas measurement branch pipe, a gas extraction branch pipe and a gas taking branch pipe.

[0172] One end of the gas measurement branch pipe is connected with the vacuum gauge 7, and the other end is provided with a reversing valve connected with the control module. The reversing valve can switch the gas measurement branch pipe to be connected with one of the first main pipe, the second main pipe and the third main pipe.

[0173] One end of the gas extraction branch pipe is connected with the vacuum pump 6, and the other end is provided with a reversing valve connected with the control module. The reversing valve can switch the gas extraction branch pipe to be connected with one of the first main pipe, the second main pipe and the third main pipe.

[0174] Similarly, one end of the gas taking branch pipe is connected with the first gas inlet of the first gas taking device, and the other end is provided with a reversing valve connected with the control module. The reversing valve can switch the gas taking branch pipe to be connected with one of the first main pipe, the second main pipe and the third main pipe.

[0175] The control module is connected with each valve body, so that the control module controls the timing of the communication between the ball mill tank 3 and the first gas taking device, and the timing of the communication between the ball mill tank 3 and the vacuum pump 6.

[0176] By using the control module to execute the measurement method of the above embodiment, the crushing of the rock sample 1 can be completed by using the ball mill tank 3, and the rock sample 1 is fully crushed, so that the residual gas generated in the ball mill tank 3 is closer to the residual gas adsorbed in the rock sample 1.

[0177] And in the process of measuring the gas, the saturated brine is avoided to be injected into the ball mill tank 3, the risk of corrosion of the ball mill tank 3 is reduced, and the generated residual gas is avoided to be dissolved in the protective brine, and the loss of residual gas in the experimental stage is reduced.

[0178] Specifically, the step S100 executed by the control module specifically includes: placing the rock sample 1 and the grinding ball 2 into the ball mill tank 3, and sealing the ball mill tank 3 by using the control module. The first air valve 34 installed on the ball mill tank 3 can be controlled to be closed by the control device to achieve the sealing of the ball mill tank 3.

[0179] Reference Figure 1 As shown in the figure, three grinding balls 2 are placed in the ball mill tank 3 in the present application. In other embodiments, other numbers of grinding balls 2 can be placed according to the volume of the rock sample 1. In addition, the grinding ball 2 is preferably made of metal material.

[0180] In some implementations, before the step S100 of placing the rock sample 1 and the grinding ball 2 in the ball mill tank 3, the measurement method further includes the following steps:

[0181] The rock sample 1 is roughly crushed to an outer diameter less than the first size. By pre-crushing the rock sample 1, the rock sample 1 can be fully crushed in the ball milling process, and the difficulty of crushing the rock sample 1 due to the large volume of the rock sample 1 can be avoided.

[0182] The first size is preferably 1 cm, and in some implementations, the first size can also be set to 1.5 cm or 2 cm.

[0183] The step S200 executed by the control module specifically includes: switching the gas path pipeline to the first mode by using the control module, and the first mode specifically means that the vacuum pump 6 is connected with the first air port 321 of the ball mill tank 3, and the vacuum gauge 7 is connected with the second air port 322 of the ball mill tank 3.

[0184] The control module sends a control instruction to realize the vacuumizing work of the vacuum pump 6 to the ball mill tank 3. At the same time, the vacuum gauge 7 transmits the real-time data of the collected air pressure to the control module, and the control module controls the vacuum pump 6 to stop vacuumizing when the air pressure of the ball mill tank 3 reaches the first air pressure.

[0185] After the vacuum gauge 7 is stabilized, the control module is used to determine whether the air pressure in the ball mill jar 3 is still maintained at the first air pressure. If yes, step S300 is continued to be executed by the control module. If the air pressure in the ball mill jar 3 is not within the range of the first air pressure (10 -4 pa±10 -5 Pa, the specific value can be adjusted according to actual needs), the vacuum pump 6 is continued to be controlled to perform vacuumizing.

[0186] The execution of step S300 by the control module specifically includes: the control module switches the air pipe system to a second mode, the second mode refers to that the first air inlet of the first air taking device is in communication with the first air vent 321 of the ball mill jar 3, and the second air vent 322 of the ball mill jar 3 is in communication with the vacuum gauge 7. The change of the air pressure in the ball mill jar 3 is measured by the vacuum gauge 7. After the air pressure measured by the vacuum gauge 7 is stabilized, the air pressure measured by the vacuum gauge 7 is recorded as the second air pressure.

[0187] The execution of step S400 by the control module specifically includes that the data processing chip of the control module performs relevant operations to calculate the residual volume of the ball mill jar 3 according to the first air pressure, the second air pressure, the ambient air pressure and the first volume.

[0188] Preferably, the control module can calculate the residual volume based on formula (2). Compared with measuring the volume of the rock sample 1 by the liquid discharge method and then calculating the residual volume of the ball mill jar 3, the rock sample 1 does not need to be soaked in the liquid, so that the residual gas in the rock sample 1 will not be dissolved in the liquid, reducing the loss of residual gas in the measurement process.

[0189] The execution of step S500 by the control module specifically includes that the control module controls the air pipe system to switch to a third mode, the third mode refers to that the vacuum air inlet of the vacuum pump 6 is in communication with the first air vent 321 of the ball mill jar 3, and the vacuum gauge 7 is in communication with the second air vent 322 of the ball mill jar 3.

[0190] At the same time, the control module controls the vacuum pump 6 to perform vacuumizing work, so that the air pressure in the ball mill jar 3 is vacuumized to a third air pressure (10 -4 pa±10 -5 Pa, the specific value can be adjusted according to actual needs).

[0191] Then, the first air valve 34 arranged at the first air vent 321 and the second air vent 322 is closed by the control module, so that the ball mill jar 3 is sealed. Then, the control device sends a ball milling instruction to the ball mill jar 3, so that the ball mill jar 3 performs ball milling work.

[0192] In order to achieve better sealing effect, the control module can control the moving device to move the ball mill jar 3 away from the gas pipe system when the first air valve 34 at the first air port 321 and the second air port 322 is closed, and then improve the sealing effect by installing the first sealing member 33 at the first air port 321 and the second air port 322.

[0193] The step S600 performed by the control module specifically includes that the control device opens the second air valve 43 at the second air port 322, and the vacuum gauge 7 connected to the second air port 322 transmits the third air pressure measured to the control module.

[0194] The step S700 performed by the control module specifically includes that the data processing chip of the control module calculates the gas production of the rock sample 1 according to the residual volume, the third air pressure and the fourth air pressure.

[0195] Preferably, the control module can calculate the gas production based on the formula (4), and the volume V of the gas produced under the standard atmospheric pressure can be calculated by the formula, which is more convenient for manual calculation and can obtain the volume of the gas, thereby avoiding the step of converting the amount of substance into volume.

[0196] The ball mill jar 3 includes a jar body 31 and a jar cover 32, the jar body 31 includes a cylinder 41 with an opening at the top, and the jar cover 32 is installed on the opening of the jar body 31.

[0197] In some implementations, the jar body 31 is provided with a first connecting thread at the opening, the size of the jar cover 32 corresponds to the size of the opening, and the jar cover 32 is provided with a second connecting thread, and the jar cover 32 is threadedly connected with the jar body 31 to seal the opening.

[0198] In the experimental preparation stage, the jar cover 32 can be separated from the jar body 31 by screwing the jar cover 32, so as to place the grinding balls 2 and the rock sample 1 in the internal space formed by the jar body 31. Then, the jar cover 32 is screwed on the jar body 31 to seal the opening.

[0199] In another implementation, a sealing structure is arranged between the jar body 31 and the jar cover 32 to achieve the sealing function, for example, a sealing ring is used to seal the jar body 31 and the jar cover 32.

[0200] In some implementations, the first gas inlet is arranged on the jar cover 32, and in other implementations, the first gas inlet can also be arranged on the jar body 31.

[0201] In this embodiment, the jar cover 32 is protruded upward at the top to form a protruding structure, the protruding structure is provided with a first gas inlet penetrating therethrough, and the first air valve 34 for controlling the opening and closing of the first gas inlet is installed.

[0202] The first air vent valve 34 can be connected with the control module, so that the control module controls the first air vent valve 34, thereby realizing the control of the opening and closing of the first air inlet. The first air vent valve 34 can be a needle valve.

[0203] In this embodiment, a third thread is arranged at the protruding structure, the ball mill jar 3 further comprises a first sealing member 33, the first sealing member 33 is detachably installed at the protruding structure of the jar cover 32, and the first sealing member 33 is provided with a fourth thread, the third thread and the fourth thread are matched, so that the first sealing member 33 is installed at the protruding structure and realizes the sealing function by screwing.

[0204] In this embodiment, two protruding structures are arranged on the jar cover 32, one of the protruding structures is provided with a first air inlet 321, and the other protruding structure is provided with a second air inlet 322, and the ball mill jar 3 comprises a first sealing member 33 corresponding to the number of protruding structures, so as to realize independent sealing of a single air inlet.

[0205] In use, the first air inlet 321 can be used for communication with the air taking device, and the second air inlet 322 can be used for communication with the vacuum gauge 7.

[0206] So that when the first air taking device is connected with the ball mill jar 3, the vacuum gauge 7 arranged at the second air inlet 322 is used for measurement, avoiding the leakage of residual gas in the crushing process caused by the back and forth disassembly of the vacuum gauge 7.

[0207] In some implementations, the first air taking device comprises an air taking cylinder 4 and a communication pipe 5, and the volume of the air taking cylinder 4 and the communication pipe 5 is equal to the first volume.

[0208] One end of the communication pipe 5 is provided with a first air inlet, and the other end of the communication pipe 5 is connected with the air taking cylinder 4.

[0209] The air taking cylinder 4 is slidably installed with a piston block 42, and the piston block 42 divides the air taking cylinder 4 into a first chamber and a second chamber which are not communicated with each other.

[0210] The air taking cylinder 4 is provided with a first air outlet 411 and a second air inlet 412 which are spaced apart from each other, the first air outlet 411 is communicated with the first chamber, the second air inlet 412 is communicated with the second chamber, and the first air outlet 411 and the second air inlet 412 are both provided with a second air vent valve 43 for controlling the opening and closing of the air outlet, the communication pipe 5 is used for connecting the ball mill jar 3 with the first air outlet 411, and the second air inlet 412 is adapted to the structure of the vacuum suction port of the vacuum pump 6.

[0211] Through the air taking cylinder 4 slidably installed with the piston block 42, the air pressure of the first chamber can be adjusted by adjusting the air pressure of the second chamber.

[0212] The connecting pipe 5 includes a pipe body, one end of which is provided with a first connecting joint 51 , and the other end of which is provided with a second connecting joint 55 .

[0213] When in use, the first connecting joint 51 can be installed on the first vent 321 of the ball mill 3 to achieve communication between the connecting pipe 5 and the ball mill 3. The second connecting joint 55 can be installed on the first air outlet 411 of the air extraction cylinder 4 to achieve communication between the connecting pipe 5 and the air extraction cylinder 4.

[0214] like Figure 1 As shown, in some implementations, a conical hole 413 connected to the first air outlet 411 is formed on the side wall of the air cylinder 4, and a conical protrusion 421 is provided at one end of the piston block 42 close to the first air outlet 411. The sliding piston block 42 can fit the conical protrusion 421 tightly into the conical hole 413.

[0215] By providing the tapered hole 413 with a tapered structure, the tapered protrusion 421 can be guided to the tapered hole 413. Moreover, compared to the contact between the top surface of the piston block 42 and the inner wall of the gas extraction cylinder 4, the tapered surface provides a larger contact area, thus achieving a better sealing effect.

[0216] In the present application, an extended air pipe 45 is provided at the second air intake port 412 , and a tubular groove 422 for the extended air pipe 45 to extend into is provided at the piston block 42 .

[0217] Due to the provision of the tubular groove 422, even if the middle part of the piston block 42 is in contact with the wall of the gas extraction cylinder 4, the space at the tubular groove 422 can still connect the gap formed between the outside of the piston block 42 and the wall of the gas extraction cylinder 4, thereby extracting the gas that has not been completely extracted in the gap and better maintaining the vacuum of the second cavity.

[0218] In some implementations, a snap-fit ​​structure may be provided at the end of the extended air pipe 45 , and a snap-fit ​​structure may be opened at a corresponding position of the tubular groove 422 . When the piston block 42 moves into position, the snap-fit ​​structure at the end of the extended air pipe 45 may be released from the snap-fit ​​structure of the tubular groove 422 .

[0219] When step S300 is executed after the second chamber is evacuated, the locking of the clamping structure prevents the piston block 42 from sliding, so that the volume of the first gas extraction device is maintained at the first volume.

[0220] Furthermore, the snap-fitting structure can be set as a sliding structure, and the snap-fitting structure can be separated from the slot structure by sliding, and the snap-fitting structure can be connected to the electric control valve, and the sliding of the snap-fitting structure can be controlled by the electric control valve, thereby achieving controllable timing for unlocking the piston block 42.

[0221] In some implementations, the first gas outlet 411 and the second gas outlet 412 of the gas taking cylinder 4 are respectively arranged at opposite ends of the gas taking cylinder 4, and a connecting thread is arranged at the first gas outlet 411 and the second gas outlet 412, so that the second sealing member 44 is installed on the gas taking cylinder 4 to seal the first gas outlet 411 and the second gas outlet 412.

[0222] The control module can further control the ball milling jar 3, the vacuum pump 6 and the first gas taking device to perform step S800 after step S700, i.e., vacuumizing the first chamber of the gas taking cylinder 4 and connecting the first chamber with the ball milling jar 3 to press the generated gas to the first gas taking device, so as to perform the gas taking work by using the first gas taking device.

[0223] Vacuumizing the first chamber of the gas taking cylinder 4 and then connecting the first chamber with the ball milling jar 3 can reduce the residual gas amount in the first chamber, obtain purer residual gas and reduce the influence on the composition of the residual gas.

[0224] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the present application and equivalent components can be substituted therefor. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method of measuring rock residual gas, characterized by, It includes the following steps: Place the rock sample and grinding balls into a ball mill and seal the ball mill; Evacuate the ball mill to the first pressure; Connect the ball mill to the first air extraction device, and seal the first air extraction device and the ball mill. After stabilization, the air pressure in the ball mill is recorded as the second air pressure, the volume of the first air extraction device is the first volume, and the air pressure of the first air extraction device is the ambient pressure. Calculating a residual volume of the ball mill according to the first air pressure, the second air pressure, the ambient air pressure, and the first volume, wherein the residual volume refers to the available volume of the ball mill after accommodating the rock sample and the grinding balls; The ball mill is evacuated to a third pressure and sealed; The rock sample is ball-milled using the ball mill, and the air pressure in the ball mill after the ball milling is recorded as the fourth air pressure; The gas production of the rock sample is calculated based on the residual volume, the third gas pressure, and the fourth gas pressure.

2. The measurement method according to claim 1, characterized in that, The method of calculating the remaining volume of the ball mill according to the first air pressure, the second air pressure, the ambient air pressure, and the first volume comprises the following steps: The residual volume is calculated based on a first formula, wherein the first formula includes: V1=(P2*V2-Pring*V2) / (P1-P2) Among them, V1 represents the remaining volume of the ball mill, P1 represents the first air pressure, P2 represents the second air pressure, P ring represents the ambient air pressure, and V2 represents the first volume.

3. The measurement method according to claim 1, characterized in that, Calculating the gas production of the rock gas sample according to the residual volume, the third gas pressure, and the fourth gas pressure comprises the following steps: The gas production is calculated based on a second formula, wherein the second formula includes: V=(P4-P3)*V1 / 1bar Wherein, V represents the gas production, P4 represents the fourth gas pressure, P3 represents the third gas pressure, and V1 represents the remaining volume.

4. The measurement method according to claim 1, characterized by, The first gas extraction device includes a gas extraction cylinder and a connecting pipe. A piston block is slidably installed in the gas extraction cylinder. The piston block divides the gas extraction cylinder into a first chamber and a second chamber that are not connected to each other. Before the step of connecting the ball mill to the closed first gas extraction device, the measurement method further includes the following steps: The first chamber is connected to the outside, and the second chamber is evacuated to drive the piston block to move to the end of the gas extraction cylinder away from the first chamber.

5. The measurement method according to claim 1, characterized by, Before placing the rock sample and the grinding balls in the ball mill, the measuring method further comprises the following steps: The rock sample is coarsely crushed to an outer diameter smaller than a first size.

6. A method of taking gas, characterized by, It includes the measurement method according to any one of claims 1 to 5, and after calculating the gas production of the rock sample according to the residual volume, the third gas pressure and the fourth gas pressure, the gas extraction method further includes the following steps: The first chamber of the gas extraction cylinder is evacuated, and the first chamber is connected to the ball mill to pressurize the produced gas to the first gas extraction device.

7. The method of claim 6, wherein, After the vacuuming first gas extraction device is connected to the ball mill, the gas extraction method further comprises the following steps: Disconnecting the first chamber from the ball mill jar, and sealing the first chamber with a second sealing member; The second chamber is connected to the outside air, so that the piston block slidably mounted inside the air extraction cylinder slides to reduce the space in the first chamber; A gas extraction needle is inserted into the second seal and into the first chamber, and gas is extracted using the gas extraction needle.

8. An experimental apparatus characterized by, It comprises: a ball mill tank having a ball milling space for accommodating a rock sample and grinding balls; a first gas extraction device having a first volume, and the first gas extraction device is provided with a first gas extraction port for communicating with the ball mill tank; a vacuum pump detachably communicating with the ball mill tank for vacuumizing the ball mill tank; and a control module, the first gas extraction device, the vacuum pump and the ball mill tank being connected to the control module, and the control module is capable of controlling the vacuum pump, the ball mill tank and the first gas extraction device to perform the measurement method as claimed in any one of claims 1-5.

9. The experimental device according to claim 8, characterized in that: the first gas extraction device comprises a gas extraction cylinder and a communicating pipe, and the volume of the gas extraction cylinder and the communicating pipe is equal to the first volume; one end of the communicating pipe is provided with the first gas extraction port, and the other end of the communicating pipe is connected to the gas extraction cylinder; a piston block is slidingly installed in the gas extraction cylinder, and the piston block separates the gas extraction cylinder into a first chamber and a second chamber which are not communicated with each other; the gas extraction cylinder is provided with a first gas outlet and a second gas extraction port which are spaced apart from each other, the first gas outlet is communicated with the first chamber, the second gas extraction port is communicated with the second chamber, and the first gas outlet and the second gas extraction port are both provided with a second air valve for controlling the opening and closing of the gas outlet, the communicating pipe is used for communicating the ball mill tank with the first gas outlet, and the second gas extraction port is structurally matched with the vacuumizing port of the vacuum pump.

10. The experimental setup of claim 9, wherein, a tapered hole communicated with the first gas outlet is formed in the side wall of the gas extraction cylinder, and a tapered protrusion is arranged on one end of the piston block close to the first gas outlet, and sliding the piston block can tightly fit the tapered protrusion to the tapered hole.

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