Device and method for measuring rock adsorption strain curve

Abstract

The invention discloses a device and a method for measuring a rock adsorption strain curve. According to the method, a sample cabin, a gas cylinder, a heating jacket, a vacuum pump, an image processing assembly and measuring equipment are included; the sample cabin is used for placing rock samples; a second valve is arranged on the outer wall of the sample cabin; the gas cylinder is connected with one end of the sample cabin, a third valve is arranged between the gas cylinder and the sample cabin, and a pressure reducing valve and a pressure gauge are arranged on the outer wall of the gas cylinder; the vacuum pump is connected with the other end of the sample cabin; a first valve is arranged between the vacuum pump and the sample cabin; the heating sleeve wraps the side wall of the sample cabin; the image processing assembly is used for taking a picture of the rock sample in the sample cabin body and storing the picture of the taken rock sample; the measuring equipment is used for measuring the adsorption strain curve of the rock sample according to the rock sample picture, and the adsorption strain curve of the rock sample is measured through the rock adsorption strain curve measuring device. The operation is simple and convenient, and an adsorption strain curve can be accurately measured.

Description

Technical Field

[0001] The invention relates to the technical field of rock determination, and in particular to a device and method for measuring rock adsorption strain curves. Background Art

[0002] Under different pressure conditions, the dynamic changes of rock deformation and rock permeability are affected by the adsorption strain parameters of the rock. The existing technology mainly uses the method of pasting strain gauges to indirectly test the adsorption strain curve, but this method has the following disadvantages: 1. The test accuracy is significantly affected by temperature, and temperature compensation is required under different temperature conditions to ensure the test accuracy; 2. The pasting method and adhesive have a significant impact on the test results. If the pasting method is inappropriate, the test error is large; 3. When measuring the strain curve of the rock under a high-pressure fluid environment, the wire connected to the strain gauge usually affects the sealing, resulting in great difficulty in testing. Based on this, a high-precision and easy-to-operate method for testing the adsorption strain curve is urgently needed. Summary of the invention

[0003] In view of the above problems, the present invention is proposed to provide a device and method for rock adsorption strain curve that overcomes the above problems or at least partially solves the above problems.

[0004] In a first aspect, an embodiment of the present invention provides a device for measuring rock adsorption strain curves, including: a sample chamber, a gas cylinder, a heating jacket, a vacuum pump, an image processing component, and a measuring device;

[0005] The sample chamber is used to place rock samples; a second valve is provided on the outer wall of the sample chamber;

[0006] The gas cylinder is connected to one end of the sample chamber and is used to fill the sample chamber with gas. A pressure reducing valve and a pressure gauge are provided between the gas cylinder and the sample chamber.

[0007] The vacuum pump is connected to the other end of the sample chamber, and a first valve is provided between the vacuum pump and the sample chamber for extracting gas from the sample chamber;

[0008] The heating jacket is wrapped around the side wall of the sample chamber, and is used to heat the sample chamber and maintain the temperature inside the chamber;

[0009] The image processing component is used to take photos of the rock samples in the sample chamber and store the photos of the rock samples;

[0010] The measuring device is used to measure the adsorption strain curve of the rock sample based on the rock sample photo.

[0011] In one embodiment, the image processing component includes: a microscope, a camera, and a computer;

[0012] The microscope is used to observe the image of the rock sample in the sample cabin;

[0013] The camera is used to take pictures of the rock sample images observed by the microscope;

[0014] The computer is used to store the rock sample photos taken by the camera.

[0015] In one embodiment, the device further comprises: a light source;

[0016] The light source is placed below the sample chamber.

[0017] In one embodiment, the measuring device is used to measure the adsorption strain curve of the rock sample according to the rock sample photo, including:

[0018] The measuring device is used to determine the length and width of the rock sample corresponding to each rock sample photo, and select and retain multiple measurement photos from the rock sample photos according to the length and width of the rock sample corresponding to each rock sample photo; the measurement photos are photos of the rock samples in a stable state;

[0019] The measuring device is also used to determine the adsorption strain value in the length direction and the adsorption strain value in the width direction of the rock sample corresponding to each measurement photo, and determine the adsorption strain value of the corresponding rock sample according to the adsorption strain value in the length direction and the adsorption strain value in the width direction of the rock sample corresponding to each measurement photo;

[0020] The measuring device is also used to draw the adsorption strain curve of the rock sample according to the adsorption strain value and the corresponding pressure value of the rock sample corresponding to each measurement photo. The pressure value corresponding to the measurement photo is determined by the pressure gauge.

[0021] In a second aspect, an embodiment of the present invention provides a method for measuring a rock adsorption strain curve, wherein the method for measuring a rock adsorption strain curve is implemented by the aforementioned device for measuring a rock adsorption strain curve, and comprises:

[0022] Obtaining a rock sample, and placing the rock sample in a sample chamber;

[0023] Using a heating jacket to heat the sample chamber and keep the temperature inside the sample chamber within a preset temperature range;

[0024] Check whether the air tightness of the device for measuring the rock adsorption strain curve is good;

[0025] If so, within a preset pressure range, the adsorbed gas is filled into the sample chamber body by using a gas cylinder, the rock sample is photographed by using an image processing component and the corresponding rock sample photograph is stored, and based on the rock sample photograph, a measuring device is used to determine whether the rock sample has reached a preset stable state, and if so, the measured photograph in the stable state and the corresponding pressure value in the sample chamber body are determined, and the step of filling the sample chamber body with the gas cylinder is performed several times, and after each filling with the adsorbed gas, the rock sample is photographed by using the image processing component and the corresponding rock sample photograph is stored, and the measuring device is used to determine the measured photograph in the stable state after each filling with the adsorbed gas, and the corresponding pressure value in the sample chamber body; the pressure of the adsorbed gas filled each time is higher than the pressure of the previous filling with the adsorbed gas;

[0026] According to each measurement photograph and the corresponding pressure value in the sample chamber, the adsorption strain curve of the rock sample is measured by using the measurement equipment.

[0027] In one embodiment, the stable state is that within a preset first time period, the length change and width change of the rock sample are both less than a preset side length change threshold.

[0028] In one embodiment, the using of an image processing component to take a photo of the rock sample and store the corresponding rock sample photo, and using a measuring device to determine whether the rock sample has reached a preset stable state based on the rock sample photo, includes:

[0029] Taking a preset second time period as a cycle, using an image processing component, taking photos of the rock sample and storing corresponding photos of the rock sample;

[0030] Using the measuring device, determine the length and width of the rock sample in each rock sample photo;

[0031] Judging whether the rock sample has reached the stable state according to the length and width of the rock sample in each rock sample photo;

[0032] Accordingly, determining the measurement photo in the stable state and the corresponding pressure value in the sample chamber includes:

[0033] The last rock sample photo taken by the image processing component during the process of the rock sample reaching the stable state is used as the measurement photo;

[0034] The reading of the pressure gauge in the stable state is the pressure value in the sample chamber.

[0035] In one embodiment, the method of measuring the adsorption strain curve of the rock sample using the measuring device according to each measurement photograph and the corresponding pressure value in the sample chamber includes:

[0036] Using the measuring device, the length and width of the rock sample in each measuring photo are determined; according to the length and width of the rock sample in each measuring photo, the lengthwise adsorption strain value and the widthwise adsorption strain value of the corresponding rock sample in each measuring photo are determined respectively; according to the lengthwise adsorption strain value and the widthwise adsorption strain value of the rock sample, the average adsorption strain value of the corresponding rock sample is determined;

[0037] By using the measuring device, a coordinate system is established with the average adsorption strain value of the rock sample in each measurement photo as the ordinate and the corresponding pressure value in the sample chamber as the abscissa to determine the adsorption strain curve of the rock sample.

[0038] In one embodiment, the air tightness of the measuring device for detecting the rock adsorption strain curve is good, including:

[0039] The gas cylinder is used to fill the sample chamber with non-adsorbent gas to determine whether the pressure change in the sample chamber is less than a preset pressure change threshold within a preset third time period. If so, the measuring device for detecting the rock adsorption strain curve has good air tightness.

[0040] In one embodiment, the method of detecting whether the air tightness of the measuring device for detecting the rock adsorption strain curve is good also includes:

[0041] If so, the non-adsorbent gas in the sample chamber is extracted by a vacuum pump to make the sample chamber meet the vacuum state;

[0042] If not, repair the air tightness of the device for measuring the rock adsorption strain curve.

[0043] In a third aspect, an embodiment of the present invention provides a method for determining a rock adsorption strain curve, comprising:

[0044] Obtain multiple photos of the target rock during the adsorption process and the corresponding pressure values;

[0045] Determine the average adsorption strain value of the target rock in each photo;

[0046] A coordinate system is established with the average adsorption strain value of the target rock in each photo as the ordinate and the corresponding pressure value as the abscissa to determine the adsorption strain curve of the target rock.

[0047] In one embodiment, determining the average adsorption strain value of the target rock in each photo includes:

[0048] For each photo, determine the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock in the photo.

[0049] According to the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock, the average adsorption strain value of the target rock is determined.

[0050] In one embodiment, determining the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock in the photo includes:

[0051] Determine the length and width of the target rock in the photo to obtain a first length and a first width;

[0052] Determine the adsorption strain value of the target rock in the length direction according to the first length and the second length, wherein the second length is the length of the target rock before adsorption;

[0053] The adsorption strain value of the target rock in the width direction is determined according to the first width and the second width, wherein the second width is the width of the target rock before adsorption.

[0054] In one embodiment, determining the length and width of the target rock in the photo includes:

[0055] Binarizing the photo;

[0056] According to the processed photos, the number of pixels along the width direction of the target rock and the number of pixels on the row corresponding to each pixel in the width direction of the target rock are determined, and the length of the target rock in the photo is obtained according to the length of the pixel, the number of pixels along the width direction of the target rock and the number of pixels on the row corresponding to each pixel in the width direction of the target rock;

[0057] Determine the number of pixels along the length direction of the target rock and the number of pixels on the column corresponding to each pixel in the length direction of the target rock. According to the length of the pixel, the number of pixels along the length direction of the target rock and the number of pixels on the column corresponding to each pixel in the width direction of the target rock, the width of the target rock in the photo is obtained.

[0058] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0059] The device for measuring rock adsorption strain curve provided by the embodiment of the present invention comprises a sample cabin, a gas cylinder, a heating sleeve, a vacuum pump, an image processing component and a measuring device. The sample is placed in the sample cabin, and the heating sleeve is wrapped on the side wall of the sample cabin for heating the sample cabin and maintaining the temperature inside the cabin. Compared with the method of using strain gauges to test rock adsorption strain curves, the temperature inside the sample cabin is maintained by the heating sleeve, which overcomes the problem of the prior art that temperature compensation is required under different temperature conditions, so that the test results are not affected by temperature, thereby improving the accuracy of the test. In addition, the device for measuring rock adsorption strain curve provided by the embodiment of the present invention does not require the use of adhesives and is not limited by the pasting method. The vacuum pump and the sample cabin, and the gas cylinder and the sample cabin are connected by valves, thereby ensuring the airtightness of the device and solving the problem that the wires connected to the strain gauges usually affect the sealing when measuring rock strains in a high-pressure fluid environment. The test difficulty is reduced, the sealing is improved, and the accuracy of the test results is ensured.

[0060] The method for measuring the rock adsorption strain curve provided by the embodiment of the present invention is as follows: a rock sample is placed in a sample chamber, the sample chamber is heated by a heating sleeve, and the sample chamber is kept at a constant temperature; when the air tightness test result of the rock adsorption strain curve measuring device is good, an adsorbent gas is filled into the sample chamber through a gas cylinder; an image processing component is used to take a photo of the rock sample and the corresponding rock sample photo is stored; a measuring device is used to determine whether the rock sample has reached a preset stable state; within a preset pressure range, the step of filling the sample chamber with the adsorbent gas using the gas cylinder is repeated several times, and the pressure of each filling of the adsorbent gas is higher than that of the previous filling. The pressure of the adsorbent gas is filled, and the measurement photos under each stable state and the corresponding pressure value in the sample cabin are determined. The adsorption strain curve of the rock sample is measured by the measuring equipment. The adsorption strain curve of the rock is measured by the device of the rock adsorption strain curve. Compared with the method of using sticking strain gauges, it has the following advantages: 1. The ambient temperature of the rock is constant, which avoids the influence of temperature compensation under different temperature conditions and improves the test accuracy; 2. Avoid the use of adhesives, which is not affected by adhesives and bonding methods, and ensures the test accuracy; 3. Under high pressure environment, the airtightness of the device is not affected, which reduces the test difficulty and improves the test accuracy.

[0061] The method for determining the rock adsorption strain curve provided by the embodiment of the present invention determines the average adsorption strain value and the corresponding pressure value of the rock in each photo, establishes a coordinate system, and determines the adsorption strain curve of the target rock.

[0062] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0064] Figure 1 It is a schematic structural diagram of a device for measuring rock adsorption strain curve in an embodiment of the present invention;

[0065] Figure 2 It is a flow chart of the method for determining the rock adsorption strain curve in an embodiment of the present invention;

[0066] Figure 3 is a flow chart of a method for determining a rock adsorption strain curve in an embodiment of the present invention;

[0067] Figure 4-1 is a schematic diagram of the length of the target rock in an embodiment of the present invention;

[0068] Figure 4-2 is a schematic diagram of the width of the target rock in an embodiment of the present invention;

[0069] Figure 5 This is a flow chart of the method for averaging the adsorption strain value of the target rock in an embodiment of the present invention. DETAILED DESCRIPTION

[0070] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0071] In order to solve the problems in the prior art of low accuracy in testing rock adsorption strain curves using strain gauges and great difficulty in testing under high pressure environments, an embodiment of the present invention provides a device and method for measuring rock adsorption strain curves.

[0072] Example

[0073] The embodiment of the present invention provides a device for measuring rock adsorption strain curve, the structure of which is as follows: Figure 1 As shown, it includes: a sample chamber 4, a gas cylinder 5, a heating jacket, a vacuum pump 7, an image processing component and a measuring device (not shown in the figure);

[0074] The sample chamber 4 is used to place rock samples; a second valve 8 is provided on the outer wall of the sample chamber 4;

[0075] The gas cylinder 5 is connected to one end of the sample cabin 4 and is used to fill the sample cabin 4 with gas. A pressure reducing valve 9 and a pressure gauge 11 are provided between the gas cylinder 5 and the sample cabin 4.

[0076] The vacuum pump 7 is connected to the other end of the sample chamber 4, and a first valve 10 is provided between the vacuum pump 7 and the sample chamber 4 for extracting gas from the sample chamber 4;

[0077] The heating jacket is wrapped around the side wall of the sample chamber 4 to heat the sample chamber 4 and maintain the temperature inside the chamber;

[0078] The image processing component is used to take pictures of the rock samples in the sample cabin 4 and store the pictures of the rock samples;

[0079] The measuring equipment is used to measure the adsorption strain curve of the rock sample based on the rock sample photograph.

[0080] In some optional embodiments, the sample cabin 4 is made of temperature-resistant and pressure-resistant materials. Since it is necessary to take photos of the rock samples in the cabin, the sample cabin 4 is a visual sample cabin 4. Optionally, the upper and lower bottom surfaces of the sample cabin 4 are made of sapphire glass that is temperature-resistant, pressure-resistant and transmissive to visible light. The sample cabin 4 is made of temperature-resistant and pressure-resistant stainless steel. A second valve 8 is provided on the outer wall of the sample cabin 4. The second valve 8 is used to control the discharge of gas in the sample cabin 4. Specifically, the second valve 8 is opened to discharge the gas in the sample cabin 4.

[0081] The heating sleeve has a constant temperature control function, and is wrapped around the side of the temperature-resistant and pressure-resistant visualization sample chamber 4 to heat the sample chamber 4 and maintain a constant temperature inside the sample chamber 4 .

[0082] A first valve 10 is provided on the connecting pipeline between the vacuum pump 7 and the sample chamber 4 . By opening the first valve 10 and starting the vacuum pump 7 , the gas in the sample chamber 4 can be extracted, so that the sample chamber 4 reaches a vacuum state.

[0083] The gas cylinder 5 is connected to one end of the sample cabin 4 through a connecting pipeline. A pressure reducing valve 9, a pressure gauge 11 and a first valve 10 are sequentially arranged from the gas cylinder 5 along the direction of the sample cabin 4. The pressure reducing valve 9 is controlled to enable the gas cylinder 5 to fill the sample cabin 4 with gas. Specifically, the first valve 10 and the second valve 8 are closed, and the pressure reducing valve 9 is opened to enable the gas cylinder 5 to fill the sample cabin 4 with gas. Accordingly, after the gas of preset pressure is injected, the pressure reducing valve 9 is closed to stop the gas injection. The pressure inside the sample cabin 4 is measured by the pressure gauge 11.

[0084] In some optional embodiments, the image processing component includes: a microscope 3, a camera 2 and a computer 1;

[0085] Microscope 3 is used to observe the image of rock samples in sample cabin 4;

[0086] The camera 2 is used to take pictures of the rock sample images observed by the microscope 3;

[0087] The computer 1 is used to store the rock sample photos taken by the camera 2.

[0088] The camera 2, the computer 1 and the microscope 3 are connected in sequence. Optionally, the camera 2 is a high-speed camera 2, and the microscope 3 is an ultra-depth-of-field microscope 3. The observation magnification of the ultra-depth-of-field microscope 3 is higher, and the obtained rock sample image is clearer. The high-speed camera 2 has functions such as high resolution, fast response time, wide dynamic range and automatic white balance. Its high-speed continuous shooting function can capture instant photos of rock samples and obtain real-time and high-definition photos of rock samples.

[0089] In some optional embodiments, in order to more clearly observe and photograph the edge of the rock sample, the device for measuring the rock adsorption strain curve further includes: a light source 6;

[0090] The light source 6 is placed below the sample chamber 4 to increase the brightness inside the sample chamber 4 so that the edge of the rock sample is displayed more clearly.

[0091] In some optional embodiments, the measuring device is used to measure the adsorption strain curve of the rock sample based on the rock sample photo, specifically:

[0092] The measuring equipment is used to determine the length and width of the rock sample corresponding to each rock sample photo, and select and retain multiple measuring photos from the rock sample photos according to the length and width of the rock sample corresponding to each rock sample photo; the measuring photos are photos of the rock samples in a stable state;

[0093] The measuring device is also used to determine the adsorption strain value in the length direction and the adsorption strain value in the width direction of the rock sample corresponding to each measured photo, and determine the adsorption strain value of the corresponding rock sample according to the adsorption strain value in the length direction and the adsorption strain value in the width direction of the rock sample corresponding to each measured photo;

[0094] The measuring equipment is also used to draw the adsorption strain curve of the rock sample according to the adsorption strain value and the corresponding pressure value of the rock sample corresponding to each measurement photo. The pressure value corresponding to the measurement photo is determined by the pressure gauge 11.

[0095] Based on the same inventive concept, the embodiment of the present invention also provides a method for measuring a rock adsorption strain curve. The method is implemented by the above-mentioned rock adsorption strain curve measuring device. The process is as follows: Figure 2 As shown, the following steps are included:

[0096] Step S21: Obtain rock samples and place the rock samples in the sample chamber 4;

[0097] Step S22: heating the sample chamber 4 by using the heating jacket, and maintaining the temperature inside the sample chamber 4 within a preset temperature range;

[0098] Step S23: Detect whether the air tightness of the measuring device for the rock adsorption strain curve is good;

[0099] Step S24: If so, within the preset pressure range, the gas cylinder 5 is used to fill the sample chamber 4 with adsorbed gas, the image processing component is used to take photos of the rock samples and the corresponding rock sample photos are stored, and based on the rock sample photos, the measuring equipment is used to determine whether the rock samples have reached a preset stable state, and if so, the measured photos in the stable state and the corresponding pressure value in the sample chamber 4 are determined, and the step of filling the sample chamber 4 with adsorbed gas using the gas cylinder 5 is performed several times, and after each filling with adsorbed gas, the image processing component is used to take photos of the rock samples and the corresponding rock sample photos are stored, and the measuring equipment is used to determine the measured photos in the stable state after each filling with adsorbed gas, and the corresponding pressure value in the sample chamber 4; the pressure of the adsorbed gas filled each time is higher than the pressure of the previous filling with adsorbed gas;

[0100] Step S25: Based on each measurement photograph and the corresponding pressure value in the sample chamber 4, the adsorption strain curve of the rock sample is measured using a measurement device.

[0101] In some optional embodiments, in the above steps S21-S22, the rock sample is a rectangular or cube sample. For example, a wire cutting sample making machine is used to cut the rock sample to be tested into a rectangular sample with a length, width and height of L, W and H respectively. The rectangular sample is placed in the visualized pressure-resistant sample chamber 4. The selection of cutting tools is very wide, and the embodiments of the present invention do not limit this.

[0102] In some optional embodiments, when the temperature in the pressure-resistant sample chamber 4 reaches the test condition, the above step S23 is performed to detect whether the air tightness of the measuring device for the rock adsorption strain curve is good, which can be achieved in the following way:

[0103] Non-adsorbent gas is filled into the sample chamber 4 using the gas cylinder 5 to determine whether the pressure change in the sample chamber 4 is less than a preset pressure change threshold within a preset third time period. If so, the rock adsorption strain curve measuring device has good air tightness.

[0104] Specifically, close the first valve 10 and the second valve 8, open the pressure reducing valve 9, and fill the sample chamber 4 with a non-adsorbent gas. Optionally, the non-adsorbent gas may be helium or argon. After the sample chamber 4 reaches a preset pressure, close the pressure reducing valve 9. After several hours, observe the pressure in the sample chamber 4 through the pressure gauge 11, and observe the pressure in the sample chamber 4 for multiple times according to a preset time period. If, within a preset third time period, the pressure change in the sample chamber 4 is less than a preset pressure change threshold, the air tightness of the rock adsorption strain curve measuring device is good. For example, fill the sample chamber 4 with helium or argon, observe the pressure in the sample chamber 4 after 2 hours, and if, within 3 consecutive hours, the pressure change in the sample chamber 4 is less than 0.005MPa, it is considered that the rock adsorption strain curve measuring device has a good air tightness.

[0105] Correspondingly, if, that is, the air tightness of the measuring device for the rock adsorption strain curve is good, the vacuum pump 7 is used to extract the non-adsorbed gas in the sample cabin 4 so that the sample cabin 4 meets the vacuum state. Specifically, the second valve 8 is opened, the non-adsorbed gas in the sample cabin 4 is discharged, and then the second valve 8 is closed, and then the first valve 10 is opened, and the vacuum pump 7 is turned on. After the sample cabin 4 is vacuumed for several hours, the first valve 10 and the vacuum pump 7 are closed. The vacuuming treatment time is determined according to the actual situation, so that the sample cabin 4 reaches a vacuum state. Optionally, the treatment time is 3 hours, which is not limited to the embodiment of the present invention.

[0106] If not, that is, there is leakage in the measuring device for the rock adsorption strain curve, and the measured result is inaccurate, then the air tightness of the measuring device for the rock adsorption strain curve needs to be repaired.

[0107] In some optional embodiments, after the gas in the sample chamber 4 is extracted to make the sample chamber 4 reach a vacuum state, the image processing component is started, and the rock sample is photographed by the image processing component and the corresponding rock sample photo is stored, and the length and width of the rock sample at this time are determined as the initial length (recorded as L 0 ) and the initial width W 0 , within the preset pressure range, open the pressure reducing valve 9, use the gas cylinder 5 to fill the sample chamber 4 with adsorbent gas, the image processing component continues to take pictures of the rock sample and stores the corresponding rock sample photos, and based on the rock sample photos, use the measuring equipment to determine whether the rock sample has reached the preset stable state, which can be achieved in the following way:

[0108] Using measuring equipment, determine the length and width of the rock sample in each rock sample photograph;

[0109] Whether the rock sample has reached a stable state is determined based on the length and width of the rock sample in each rock sample photo.

[0110] Accordingly, the last rock sample photo taken by the image processing component when the rock sample reaches a stable state is used as the measurement photo; the reading of the pressure gauge 11 in the stable state is the pressure value in the sample chamber 4.

[0111] Among them, the stable state is that within the preset first time period, the length change and width change of the rock sample are both less than the preset edge length change threshold. Specifically, an example is used to illustrate that the adsorptive gas of xMPa is filled into the visualized pressure-resistant sample chamber 4 for the first time, and the pressure value displayed by the pressure gauge 11 is periodically recorded (for example, once every 5 seconds). The image processing component takes photos of the rock samples while recording the pressure values ​​at the same period, and the length and width of the rock samples in each rock sample photo are calculated using the measuring equipment. If within several hours (optional, for example, within 6 hours), the length change and width change of the rock sample are both less than 0.0001, it is considered that the adsorption strain of the rock sample has reached stability, and the photo of the rock sample that has reached stability is used as the measurement photo, and the length of the rock sample in the measurement photo is recorded as L 1 , the width is W 1 At the same time, record the pressure value at this time as P 1 ;

[0112] Continue to perform the step of using the gas cylinder 5 to fill the sample chamber 4 with adsorbed gas for several times. The pressure of each filling of the adsorbed gas is higher than the pressure of the previous filling of the adsorbed gas. After each filling of the adsorbed gas, use the image processing component to take a photo of the rock sample and store the corresponding rock sample photo. Use the measuring equipment to determine the measured photo in the stable state after each filling of the adsorbed gas, as well as the corresponding pressure value in the sample chamber 4. The length of the rock sample in the measured photo obtained by the second filling of the gas is recorded as L 2 , the width is W 2 At the same time, record the pressure value at this time as P 2 , and so on. The length of the rock sample in the measurement photo obtained by filling the gas for the Mth time is recorded as L m , the width is W m At the same time, record the pressure value at this time as P m .

[0113] In some optional embodiments, the above step S25, based on each measurement photo and the corresponding pressure value in the sample chamber 4, uses a measurement device to measure the adsorption strain curve of the rock sample, which can be achieved in the following way:

[0114] (1) Using the measuring equipment, determine the length and width of the rock sample in each measured photo; determine the adsorption strain value in the length direction and the adsorption strain value in the width direction of the corresponding rock sample in each measured photo according to the length and width of the rock sample; and determine the average adsorption strain value of the corresponding rock sample according to the adsorption strain value in the length direction and the adsorption strain value in the width direction of the rock sample;

[0115] Specifically, in chronological order, the adsorption strain values ​​in the length direction and width direction of the rock sample in the first measured photo are recorded as ε L，1 and ε w，1 , accordingly, the average adsorption strain value is recorded as ε s，1 , the adsorption strain values ​​of the rock sample in the length direction and width direction in the second measurement photo are ε L，2 and ε w，2 , accordingly, the average adsorption strain value is recorded as ε s，2 , and so on, the adsorption strain values ​​in the length direction and width direction of the rock sample in the Mth measurement photo are ε L，m and ε W，m , accordingly, the average adsorption strain value is recorded as ε s，m .

[0116] (2) Using the measuring equipment, a coordinate system is established with the average adsorption strain value of the rock sample in each measurement photo as the vertical coordinate and the pressure value in the corresponding sample chamber 4 as the horizontal coordinate to determine the adsorption strain curve of the rock sample.

[0117] The method for determining the rock adsorption strain curve provided by the embodiment of the present invention has higher accuracy than the existing testing method based on strain gauges, and the system has better sealing during the test, higher test success rate, and test accuracy is less affected by temperature, pasting method and adhesive. It overcomes the problem that when strained in a high-pressure fluid environment, the wires connected to the strain gauge usually do not affect the sealing, resulting in great testing difficulty. The method for determining the rock adsorption strain curve provided by the embodiment of the present invention can simply and accurately determine the rock adsorption strain, and can realize direct testing of the rock adsorption strain under high temperature and high pressure conditions.

[0118] Based on the same inventive concept, the embodiment of the present invention also provides a method for determining a rock adsorption strain curve, the process of which is as follows: Figure 3 As shown, the following steps are included:

[0119] Step S31: obtaining multiple photos of the target rock during the adsorption process and the corresponding pressure values;

[0120] Step S32: determining the average adsorption strain value of the target rock in each photo;

[0121] Step S33: A coordinate system is established with the average adsorption strain value of the target rock in each photo as the ordinate and the corresponding pressure value as the abscissa to determine the adsorption strain curve of the target rock.

[0122] In some optional embodiments, the length and width of the target rock can be determined by:

[0123] (1) Binarize the photo;

[0124] Image software such as imageJ is used to convert the captured RGB image into a binary image. There are many ways of binarization processing, which are not limited in the embodiment of the present invention.

[0125] (2) Determine the length of the target rock:

[0126] According to the processed photos, the number of pixels along the width direction of the target rock and the number of pixels on the row corresponding to each pixel in the width direction of the target rock are determined, and the length of the target rock in the photo is obtained according to the length of the pixel, the number of pixels along the width direction of the target rock and the number of pixels on the row corresponding to each pixel in the width direction of the target rock;

[0127] Determine the length of the target rock according to the following formula:

[0128]

[0129] In the above formula, L n represents the length of the target rock in the Nth photo, D x is the pixel distance unit, I means there are I pixels along the width of the target rock, l i Represents the number of pixels on the i-th row.

[0130] To illustrate with a specific example, refer to Figure 4-1 As shown, there are I pixels along the width direction of the target rock, where the number of pixels on the row corresponding to the first pixel, i.e. the number of pixels in the length direction corresponding to the first pixel, is l. 1 , the number of pixels on the row corresponding to the I-th pixel, that is, the number of pixels in the length direction corresponding to the I-th pixel I , the number of pixels on the row corresponding to the i-th pixel, that is, the number of pixels in the length direction corresponding to the i-th pixel l i (0 <i<I);

[0131] (3) Determine the width of the target rock:

[0132] Determine the number of pixels along the length of the target rock and the number of pixels on the column corresponding to each pixel in the length direction of the target rock. According to the length of the pixel, the number of pixels along the length of the target rock and the number of pixels on the column corresponding to each pixel in the width direction of the target rock, the width of the target rock in the photo is obtained.

[0133] Determine the width of the target rock according to the following formula:

[0134]

[0135] In the above formula, W n represents the width of the target rock in the Nth photo, D x is the pixel distance unit, J means there are J pixels along the width of the target rock, w j represents the number of pixels on the jth column;

[0136] To illustrate with a specific example, refer to Figure 4-2 As shown;

[0137] There are J pixels along the length direction of the target rock, where the number of pixels on the column corresponding to the first pixel, that is, the number of pixels on the width direction corresponding to the first pixel, is w. 1 , the number of pixels on the column corresponding to the J-th pixel, that is, the number of pixels in the width direction corresponding to the J-th pixel w J , the number of pixels on the column corresponding to the j-th pixel, that is, the number of pixels in the width direction corresponding to the j-th pixel w j (0 <j<J)。

[0138] In some optional embodiments, determining the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock in the photo can be achieved in the following ways:

[0139] (1) determining the length and width of the target rock in the photo to obtain a first length and a first width;

[0140] (2) Determine the adsorption strain value in the length direction of the target rock

[0141] The adsorption strain value in the longitudinal direction of the target rock is determined according to the first length and the second length. The second length is the length of the target rock before adsorption; that is, the initial length L of the target rock before the adsorbent gas is filled. 0 ;

[0142] According to the following formula, the adsorption strain value of the target rock in the length direction is determined:

[0143]

[0144] In the above formula, ε L,1Indicates the adsorption strain value of the target rock in the length direction in the Nth photo, L n Indicates the length of the target rock in the Nth photo, L 0 Indicates the initial length of the target rock.

[0145] (3) Determine the adsorption strain value in the width direction of the target rock

[0146] The adsorption strain value in the width direction of the target rock is determined according to the first width and the second width. The second width is the width of the target rock before adsorption, that is, the initial width W of the target rock before the adsorbent gas is filled. 0 .

[0147] According to the following formula, the adsorption strain value in the width direction of the target rock is determined:

[0148]

[0149] In the above formula, ε W,n represents the adsorption strain value in the width direction of the target rock in the Nth photo, W n Indicates the width of the target rock in the Nth photo, W 0 Indicates the initial width of the target rock.

[0150] In some optional embodiments, the above step S32 determines the average adsorption strain value of the target rock in each photo, referring to Figure 5 , which can be achieved by the following steps:

[0151] Step S41: for each photo, determining the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock in the photo;

[0152] Step S42: Determine the average adsorption strain value of the target rock according to the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock.

[0153] According to the following formula, the average adsorption strain value of the target rock is determined:

[0154]

[0155] In the above formula, ε s,n It represents the average adsorption strain value of the target rock in the Nth photo. Other parameters have been described in the foregoing and will not be described in detail in the embodiment of the present invention.

[0156] Unless otherwise specifically stated, terms such as processing, computing, calculating, determining, displaying, etc. may refer to the actions and / or processes of one or more processing or computing systems, or similar devices, which operate and convert data represented as physical (e.g., electronic) quantities within registers or memories of a processing system into other data similarly represented as physical quantities within memories, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips mentioned throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0157] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0158] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0159] Those skilled in the art will also appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments herein can all be implemented as electronic hardware, computer 1 software, or a combination thereof. In order to clearly illustrate the interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps are generally described above around their functions. Whether such functions are implemented as hardware or software depends on the specific application and the design constraints imposed on the entire system. A skilled person can implement the described functions in an alternative manner for each specific application, but such implementation decisions should not be interpreted as departing from the scope of protection of the present disclosure.

[0160] The steps of the method or algorithm described in conjunction with the embodiments herein may be directly embodied as hardware, a software module executed by a processor, or a combination thereof. The software module may be located in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a mobile disk, a CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Of course, the storage medium may also be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The ASIC may be located in a user terminal. Of course, the processor and the storage medium may also be present in a user terminal as discrete components.

[0161] For software implementation, the techniques described in this application can be implemented with modules (e.g., procedures, functions, etc.) that perform the functions described in this application. These software codes can be stored in a memory unit and executed by a processor. The memory unit can be implemented within the processor or outside the processor. In the latter case, it is coupled to the processor in a communication manner via various means, which are well known in the art.

[0162] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

Claims

1. A device for measuring rock adsorption strain curve, characterized in that: include: Sample chamber, gas cylinder, heating jacket, vacuum pump, image processing components and measurement equipment; The sample chamber is used to place rock samples; A second valve is provided on the outer wall of the sample chamber; The gas cylinder is connected to one end of the sample chamber and is used to fill the sample chamber with gas. A pressure reducing valve and a pressure gauge are provided between the gas cylinder and the sample chamber. The vacuum pump is connected to the other end of the sample chamber, and a first valve is provided between the vacuum pump and the sample chamber for extracting gas from the sample chamber; The heating jacket is wrapped around the side wall of the sample chamber, and is used to heat the sample chamber and maintain the temperature inside the chamber; The image processing component is used to take photos of the rock samples in the sample chamber and store the photos of the rock samples; The measuring device is used to measure the adsorption strain curve of the rock sample based on the rock sample photo.

2. The device for measuring rock adsorption strain curve according to claim 1, characterized in that: The image processing component includes: a microscope, a camera and a computer; The microscope is used to observe the image of the rock sample in the sample cabin; The camera is used to take pictures of the rock sample images observed by the microscope; The computer is used to store the rock sample photos taken by the camera.

3. The device for measuring rock adsorption strain curve according to claim 1, characterized in that: Also includes: light source; The light source is placed below the sample chamber.

4. The device for measuring rock adsorption strain curve according to claim 1, characterized in that: The measuring device is used to measure the adsorption strain curve of the rock sample according to the rock sample photo, including: The measuring device is used to determine the length and width of the rock sample corresponding to each rock sample photo, and select and retain multiple measurement photos from the rock sample photos according to the length and width of the rock sample corresponding to each rock sample photo; the measurement photos are photos of the rock samples in a stable state; The measuring device is also used to determine the adsorption strain value in the length direction and the adsorption strain value in the width direction of the rock sample corresponding to each measurement photo, and determine the adsorption strain value of the corresponding rock sample according to the adsorption strain value in the length direction and the adsorption strain value in the width direction of the rock sample corresponding to each measurement photo; The measuring device is also used to draw the adsorption strain curve of the rock sample according to the adsorption strain value and the corresponding pressure value of the rock sample corresponding to each measurement photo. The pressure value corresponding to the measurement photo is determined by the pressure gauge.

5. A method for measuring a rock adsorption strain curve, the method for measuring a rock adsorption strain curve being implemented by the rock adsorption strain curve measuring device according to any one of claims 1 to 4, characterized in that: include: Obtaining a rock sample, and placing the rock sample in a sample chamber; Using a heating jacket to heat the sample chamber and keep the temperature inside the sample chamber within a preset temperature range; Check whether the air tightness of the device for measuring the rock adsorption strain curve is good; If so, within a preset pressure range, the adsorbed gas is filled into the sample chamber body by using a gas cylinder, the rock sample is photographed by using an image processing component and the corresponding rock sample photograph is stored, and based on the rock sample photograph, a measuring device is used to determine whether the rock sample has reached a preset stable state, and if so, the measured photograph in the stable state and the corresponding pressure value in the sample chamber body are determined, and the step of filling the sample chamber body with the gas cylinder is performed several times, and after each filling with the adsorbed gas, the rock sample is photographed by using the image processing component and the corresponding rock sample photograph is stored, and the measuring device is used to determine the measured photograph in the stable state after each filling with the adsorbed gas, and the corresponding pressure value in the sample chamber body; the pressure of the adsorbed gas filled each time is higher than the pressure of the previous filling with the adsorbed gas; According to each measurement photograph and the corresponding pressure value in the sample chamber, the adsorption strain curve of the rock sample is measured by using the measurement equipment.

6. The method according to claim 5, characterized in that The stable state is that within a preset first time period, the length change and width change of the rock sample are both less than a preset edge length change threshold.

7. The method according to claim 6, characterized in that The method of taking a photo of the rock sample using an image processing component and storing the corresponding rock sample photo, and judging whether the rock sample has reached a preset stable state using a measuring device according to the rock sample photo, comprises: Taking a preset second time period as a cycle, using an image processing component, taking photos of the rock sample and storing corresponding photos of the rock sample; Using the measuring device, determine the length and width of the rock sample in each rock sample photo; Judging whether the rock sample has reached the stable state according to the length and width of the rock sample in each rock sample photo; Accordingly, determining the measurement photo in the stable state and the corresponding pressure value in the sample chamber, including taking the last rock sample photo taken by the image processing component during the process of the rock sample reaching the stable state as the measurement photo; The reading of the pressure gauge in the stable state is the pressure value in the sample chamber.

8. The method according to claim 7, characterized in that The method of measuring the adsorption strain curve of the rock sample using the measuring device according to each measurement photograph and the corresponding pressure value in the sample chamber includes: Using the measuring device, the length and width of the rock sample in each measuring photo are determined; according to the length and width of the rock sample in each measuring photo, the lengthwise adsorption strain value and the widthwise adsorption strain value of the corresponding rock sample in each measuring photo are determined respectively; according to the lengthwise adsorption strain value and the widthwise adsorption strain value of the rock sample, the average adsorption strain value of the corresponding rock sample is determined; By using the measuring device, a coordinate system is established with the average adsorption strain value of the rock sample in each measurement photo as the ordinate and the corresponding pressure value in the sample chamber as the abscissa to determine the adsorption strain curve of the rock sample.

9. The method according to claim 5, characterized in that The air tightness of the measuring device for detecting the rock adsorption strain curve is good, including: The gas cylinder is used to fill the sample chamber with non-adsorbent gas to determine whether the pressure change in the sample chamber is less than a preset pressure change threshold within a preset third time period. If so, the measuring device for detecting the rock adsorption strain curve has good air tightness.

10. The method according to claim 9, characterized in that The air tightness of the measuring device for detecting the rock adsorption strain curve is good, and also includes: If so, the non-adsorbent gas in the sample chamber is extracted by a vacuum pump to make the sample chamber meet the vacuum state; If not, repair the air tightness of the device for measuring the rock adsorption strain curve.

11. A method for determining a rock adsorption strain curve, characterized in that: include: Obtain multiple photos of the target rock during the adsorption process and the corresponding pressure values; Determine the average adsorption strain value of the target rock in each photo; A coordinate system is established with the average adsorption strain value of the target rock in each photo as the ordinate and the corresponding pressure value as the abscissa to determine the adsorption strain curve of the target rock.

12. The method according to claim 11, characterized in that Determining the average adsorption strain value of the target rock in each photo includes: For each photo, determine the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock in the photo. According to the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock, the average adsorption strain value of the target rock is determined.

13. The method according to claim 12, characterized in that The step of determining the adsorption strain value in the length direction and the adsorption strain value in the width direction of the target rock in the photograph includes: Determine the length and width of the target rock in the photo to obtain a first length and a first width; Determine the adsorption strain value of the target rock in the length direction according to the first length and the second length, wherein the second length is the length of the target rock before adsorption; The adsorption strain value of the target rock in the width direction is determined according to the first width and the second width, wherein the second width is the width of the target rock before adsorption.

14. The method according to claim 13, characterized in that Determining the length and width of the target rock in the photo includes: Binarizing the photo; According to the processed photos, the number of pixels along the width direction of the target rock and the number of pixels on the row corresponding to each pixel in the width direction of the target rock are determined, and the length of the target rock in the photo is obtained according to the length of the pixel, the number of pixels along the width direction of the target rock and the number of pixels on the row corresponding to each pixel in the width direction of the target rock; Determine the number of pixels along the length direction of the target rock and the number of pixels on the column corresponding to each pixel in the length direction of the target rock. According to the length of the pixel, the number of pixels along the length direction of the target rock and the number of pixels on the column corresponding to each pixel in the width direction of the target rock, the width of the target rock in the photo is obtained.

Images