CN-116793914-B - Rock sample skeleton volume measuring device and method

CN116793914BCN 116793914 BCN116793914 BCN 116793914BCN-116793914-B

Abstract

The invention relates to the technical field of geology, in particular to a rock sample skeleton volume measuring device and method. The rock sample skeleton volume measuring device comprises a first gas circuit for measuring standard rock samples with known skeleton volumes and a second gas circuit for measuring the rock samples to be measured with the skeleton volumes, wherein a first measuring chamber of the first gas circuit comprises a first cup body and a first top cover, the first cup body and the first top cover are sealed through a first sealing ring, a second measuring chamber of the second gas circuit comprises a second cup body and a second top cover, the second cup body and the second top cover are sealed through a second sealing ring, the first sealing ring and the second sealing ring are both charging-discharging sealing rings, and the first sealing ring and the second sealing ring are mutually communicated. According to the invention, through the design of the double air paths, the automatic judgment of the device state in the skeleton volume measurement process is realized, and a novel means and method are provided for rapid and accurate measurement of the rock sample volume and porosity.

Inventors

BAO YUNJIE
YANG ZHENHENG
JIA MENGYAO
Li chuxiong
SUN ZHONGLIANG
LI ZHIMING
MA XIAOXIAO

Assignees

中国石油化工股份有限公司
中国石油化工股份有限公司石油勘探开发研究院

Dates

Publication Date: 20260505
Application Date: 20220315

Claims (8)

1. A rock sample skeleton volume measuring method is characterized in that the rock sample skeleton volume measuring method adopts a rock sample skeleton volume measuring device to measure the rock sample skeleton volume, the rock sample skeleton volume measuring device comprises a first gas path for measuring a standard rock sample with a known skeleton volume and a second gas path for measuring the rock sample to be measured with the skeleton volume to be measured, The first gas path comprises a first measuring chamber for setting the standard rock sample, the first measuring chamber comprises a first cup body and a first top cover, the first cup body and the first top cover are sealed through a first sealing ring, the second gas path comprises a second measuring chamber for setting the rock sample to be measured, the second measuring chamber comprises a second cup body and a second top cover, and the second cup body and the second top cover are sealed through a second sealing ring; The first sealing ring and the second sealing ring are both charge-discharge sealing rings, and the first sealing ring and the second sealing ring are communicated with each other; The rock sample skeleton volume measuring method comprises the following steps: step 1, measuring the skeleton volume of a standard rock sample through a first gas circuit, and measuring the skeleton volume of the rock sample to be measured through a second gas circuit; Step 2, comparing the measured value and the nominal value of the skeleton volume of the standard rock sample, if the measured value and the nominal value of the skeleton volume of the standard rock sample are within the accuracy allowable error range, judging that the tightness of the skeleton volume measuring device of the rock sample is good, and the measured value of the skeleton volume of the rock sample to be measured is accurate and reliable; Wherein step 1 comprises the following sub-steps: Step 11, placing a standard rock sample with a known skeleton volume into a first measuring chamber, and placing a rock sample to be measured with a skeleton volume to be measured into a second measuring chamber; Step 12, filling media into the first sealing ring and the second sealing ring simultaneously through a filling device so as to seal the first measuring chamber and the second measuring chamber; Step 13, injecting measurement gas with preset pressure into the first standard chamber and the second standard chamber through gas sources respectively; Step 14, introducing the measurement gas in the first standard chamber into the first measurement chamber, and introducing the measurement gas in the second standard chamber into the second measurement chamber until the pressures of the first gas path and the second gas path reach balance, and respectively acquiring balance pressure data of the first gas path and the second gas path; and 15, respectively calculating the skeleton volume of the standard rock sample and the skeleton volume of the rock sample to be measured according to the acquired balance pressure data of the first gas path and the second gas path.
2. The rock sample skeleton volume measurement method of claim 1, wherein the first seal ring and the second seal ring are seal rings of the same material and specification; The first measuring chamber and the second measuring chamber are air chambers with the same material and specification.
3. The method for determining the volume of a rock sample framework according to claim 2, wherein the charge-discharge type sealing ring is an inflatable sealing ring or a liquid-filled sealing ring.
4. A rock sample skeleton volume measurement method according to any one of claims 1-3, further comprising a filling device connected to the filling port of the first seal ring and the filling port of the second seal ring, respectively, by a transfer line, the transfer line being provided with a transfer valve.
5. A rock sample skeleton volume measurement method according to any one of claims 1 to 3, wherein the first gas circuit further comprises a first standard chamber, the outlet end of the first standard chamber is connected with the first measurement chamber through a pipeline, and a first valve is arranged on the pipeline between the first standard chamber and the first measurement chamber; the second gas circuit further comprises a second standard chamber, the outlet end of the second standard chamber is connected with the second measuring chamber through a pipeline, and a second valve is arranged on the pipeline between the second standard chamber and the second measuring chamber; The first standard chamber and the second standard chamber are air chambers with the same materials and specifications, the first standard chamber and the second standard chamber are connected through a pipeline, and a third valve is arranged on the pipeline between the first standard chamber and the second standard chamber.
6. The rock sample skeleton volume measuring method of claim 5, further comprising a gas source for providing a measuring gas, wherein the gas outlet end of the gas source is provided with a gas source valve, and the gas source valve is connected with the gas inlet end of the first standard chamber and the gas inlet end of the second standard chamber through corresponding pipelines, respectively.
7. The method of claim 6, wherein the measurement gas is helium, nitrogen or air.
8. The method of determining the volume of a rock sample framework according to claim 6, further comprising a detection system, wherein the detection system comprises a control computing system and a first pressure sensor, a second pressure sensor, a third pressure sensor and a fourth pressure sensor connected to the control computing system, The first pressure sensor is connected to a pipeline between the air source valve and the first standard chamber, the second pressure sensor is connected to a pipeline between the air source valve and the second standard chamber, the third pressure sensor is connected to a pipeline between the first valve and the first measuring chamber, and the fourth pressure sensor is connected to a pipeline between the second valve and the second measuring chamber.

Description

Rock sample skeleton volume measuring device and method Technical Field The invention relates to the technical field of geology, in particular to a rock sample skeleton volume measuring device and method. Background In the process of measuring the porosity of a rock sample, a gas method is a more mature method for measuring the skeleton volume of the rock sample. The principle is that according to Boyle's law, the ideal gas with certain mass has its pressure inversely proportional to volume under the condition of constant temperature. The standard chamber and the measuring chamber are connected through a pipeline, a gas pressure sensor (or a pressure gauge) and a valve are arranged on the pipeline, after gas (air or nitrogen, etc.) with a certain pressure (initial pressure P 1) is filled in the standard chamber, the gas is conveyed into the measuring chamber under isothermal condition, the gas pressure gradually drops until the pressure is stable and balanced, and the pressure at the moment is called as balanced pressure (P 2). At this time, the following formula holds: P1*V1＝P2*(V2+V1)-------------------------------------------(1) Wherein V 1 is the sum of the volumes of the standard chamber and the pipeline between the standard chamber and the valve; V 2 is the sum of the measurement chamber and the line volume between the measurement chamber and the valve; When a rock sample with a skeleton volume of V 3 is placed in the measuring chamber, the above procedure is repeated, and the following formula holds: P1*V1＝P2*(V2+V1－V3) V3＝V2+V1-P1*V1/P2------------------------------------------(2) It can be seen that, since V 2、V1 and P 1 are both known, the rock sample skeleton volume can be calculated by equation (2) as long as the equilibrium pressure P 2 of the gas after loading the rock sample is measured, and the equilibrium pressure P 2 is a key parameter for accurately calculating the rock sample skeleton volume. The operation process of the measuring method is as follows: (1) And placing the rock sample into the measuring chamber, and screwing a top cover of the measuring chamber to enable a sealing ring on the top cover of the measuring chamber to be pressed and deformed to form a closed space. (2) The valve is opened so that the gas with a certain pressure in the standard chamber enters the closed space of the measuring chamber. (3) At this time, the gas continuously enters into the pores of the rock sample, the pressure of the gas is reduced, the pressure is stable after a period of time without gas leakage, and the balance is achieved, and the measured pressure is the balance pressure. From the principle and operation process, the method has the advantages of simple instrument structure and simple and convenient operation. But also presents certain drawbacks and risks. The sealing ring is one of key components for keeping tightness of the sealed space of the measuring chamber, and the time required for the pressure to reach stable balance is greatly different according to the rock sample in the process that the gas of the standard chamber enters the measuring chamber and enters the pore of the rock sample, and the pressure can reach balance only for a few minutes and a few tens of minutes. What is the leakage of gas at the seal ring during the gradual pressure drop process or the normal pressure balancing process. Chinese patent (application number 201210273356.3) provides a rock sample volume test system and a gas leakage monitoring method, which are used for monitoring gas leakage in real time in the process of measuring the rock sample skeleton volume by a gas method. The method comprises the following steps of firstly placing a standard chamber, a measuring chamber, a pipeline, a valve and the like which are involved in gas sealing in a relatively sealed box body, wherein the box body can be a relatively sealed machine box, the front surface of the box body is provided with a door, rock samples can be conveniently put in and taken out, secondly mixing a certain amount of trace gas into a measuring gas medium, the trace gas is low in content in the atmosphere and easy to detect, thirdly, installing a trace gas detection device in the box body or outside the box body, monitoring and displaying the concentration change of the trace gas in the box body in real time, fourthly, setting an alarm value of the concentration change amount of the trace gas, and once the concentration change amount of the trace gas reaches the lower limit of the alarm value, indicating that the gas leaks, and stopping rock sample testing, checking the pipeline, determining the leakage position and performing sealing treatment by a computer. When the pressure of the gas is reduced and the computer does not alarm, the gas is slowly introduced into the micro-pores of the rock sample, the instrument is in a normal working state, and the pressure change condition can be observed with ease until the pressure is stable and balanced. H