Method and device for observing water content of rock sample

Abstract

The application provides a rock sample water content observation method and device. The rock sample water content observation method comprises the following steps: contacting a rock sample with a water sensitive test paper; collecting an image of a contact area of the rock sample and the water sensitive test paper, and calculating a total area S of the contact area; collecting an image of a color developing area of the water sensitive test paper, and calculating an area S1 of the color developing area; calculating a percentage of the area S1 of the color developing area to the total area S of the contact area, and analyzing water content of the rock sample according to the percentage. Compared with the prior art, the application utilizes sensitivity of the water sensitive test paper and convenience of image collection and processing, establishes a rock sample water content observation method suitable for a field, and has the advantages of simple operation, short observation period and intuitive observation result display, thereby providing a new means and method for reservoir fluid identification and evaluation. The method obtains a relative water content, and can be used for fluid saturation sample screening, comparison and analysis of water content of different rock samples and different layers, and provides a basis for formation fluid property evaluation.

Description

Technical Field

[0001] This invention relates to the field of rock sample water content detection technology, and more particularly to a method and apparatus for observing rock sample water content. Background Technology

[0002] Reservoir fluid saturation analysis is a fundamental task in the field of petroleum geology, and it is of great significance for determining and evaluating formation fluid production. Reservoir fluids mainly include three types: oil, gas, and water. Water, as an important fluid in formations, has been the subject of numerous experimental methods for testing water content in rock samples. These methods primarily include distillation, chromatography, microwave methods, and closed-loop thermal extraction-chromatography with ethanol.

[0003] The distillation method involves heating toluene to vaporize the water in the rock sample, which is then continuously cooled by cooling water and collected in a collection tube. Distillation is stopped when the volume of water in the collection tube no longer increases, and the volume of water is recorded (Evaluation of Reservoir Oil-Water Saturation Analysis Method and Study on Factors Affecting Analysis Results, Huang Futang et al., Petroleum Exploration and Development, Vol. 19, No. 3, 1992).

[0004] Chromatography is based on the property that ethanol is mutually soluble with water in any proportion. A rock sample of known weight is placed in a 250 ml glass ground glass bottle containing 50 ml of ethanol and soaked for 72 h. Under the selected chromatographic analysis conditions, 1 μL of ethanol aqueous solution is taken for chromatographic analysis. The peak heights of water and ethanol are recorded by a recorder. Then, a standard curve is plotted between the water peak height and the water volume of a standard sample with known water content. Based on the measured water peak height of the sample, the water volume of the sample can be determined from the standard curve.

[0005] The microwave method utilizes the characteristic that water strongly absorbs microwaves, generating a thermal effect. The heating power and time are selected according to different lithologies to remove water from the rock core. The water content in the core is then determined based on the weight difference before and after microwave heating.

[0006] The closed thermal extraction-chromatographic method for ethanol involves placing a known amount of rock sample into a stainless steel cylinder containing 40 ml of ethanol and sealing it. The cylinder is then gradually heated to 140°C in an oven and held at that temperature for 4 hours to accelerate the mutual dissolution of ethanol molecules with water in the pores of the rock core. After cooling to room temperature, the solution is taken and analyzed under selected chromatographic conditions to determine the water content of the rock sample.

[0007] In addition, Li Zhifeng et al. (On Several Issues of Determining Core Water Saturation by Dissolution Method, Electronic Measurement Technology, No. 3, 1982) used the fact that the attenuation of microwaves by ethanol aqueous solution increases sharply with the increase of water content and has a good linear relationship to measure the core water saturation.

[0008] Zhou Hua et al. (Application of Portable NMR Technology in Non-destructive Analysis of Moisture Content in Masonry Materials, Building Materials and Decoration, No. 5, February 2018) obtained the intensity of hydrogen signals in the original sample or saturated water sample by NMR, calculated the absolute moisture content of the sample by correlation curve fitting, and obtained the mass moisture content of the sample by knowing the sample mass.

[0009] Wu Xiaopeng et al. (Application of Karl Fischer Coulometric Method in Rock Water Saturation, Petrochemical Technology, Vol. 25, No. 6, June 2018) used the Karl Fischer coulometric method. Based on the redox reaction between Karl Fischer reagent and water in the electrolytic cell of the instrument, the sample to be analyzed was electrolyzed using a coulometric micro-water analyzer. The water volume results were recorded and then compared with the standard curve to obtain the final water volume.

[0010] Huang Heting et al. (Determination of water content in rock samples by gas chromatography, Analytical Instruments, Vol. 2, April 2021) extracted water from rock samples by closed heating and ultrasonication with anhydrous ethanol, separated the mixture by capillary chromatography, detected it in a TCD detector, and quantified it using the external standard method.

[0011] Patents 2020105664447 (An Accurate Method for Measuring Oil-Water Saturation in Shale Oil and Gas Reservoirs) and 2016110271827 (Ethanol Extraction Analysis Method for Oil-Water Saturation in Core Samples) use distillation and extraction methods, respectively, to determine the water content of samples. Patent 2013101052723 (Accurate Test Method for Oil-Water Saturation in Shale) uses anhydrous ethanol with a purity of 99.7% to extract water from the sample, determines the water content in the test liquid using a micro-water analyzer, and calculates the water content of the core sample by combining it with the water content of a standard liquid. Water volume; Patent 2017210594217 (Oil-water saturation tester for tight oil and gas reservoirs) discloses a device that can accurately measure the oil-water saturation of tight oil and gas reservoirs. The oil and water stored in the pores of tight rocks are vaporized under high temperature and then turned into liquid through condensation. The volume of oil and water in the pores is obtained by collecting it through a metering tube; Patent 2017101461507 (Core water saturation measurement system) discloses a core water saturation measurement system that can accelerate the diffusion of ions in the pore water of the core, with high efficiency and more uniform heating of the core.

[0012] Existing technologies have played a vital role in past laboratory testing practices, but they still have certain shortcomings compared to the needs. Distillation, chromatography, and ethanol-sealed thermal extraction-chromatography all have long testing cycles; microwave and nuclear magnetic resonance methods are affected by many factors. Coulometric methods are cumbersome to operate and use highly toxic reagents (Karl Fischer reagent).

[0013] Oil, gas and water in reservoirs share a similar characteristic: volatility. This objectively requires that tests be completed as soon as possible after obtaining rock samples, or that appropriate technical measures be taken to avoid the loss of fluids in the rock samples in order to obtain more accurate data. Summary of the Invention

[0014] The rock sample water content observation method involves selecting representative rock samples. After the rock samples are cut or broken into granules, the surface fluids are not yet lost or contaminated. If the rock sample pores contain water, its surface will bear moisture. When a granular rock sample with moisture is placed on water-sensitive test paper, the test paper will show a specific color. A rock sample without moisture will not show a color change when in contact with the test paper. Utilizing this phenomenon, when rock sample particles are spread evenly on a certain area of ​​test paper, the larger the proportion of the colored area, the more water the rock sample contains, and vice versa. The proportion of the colored area is identified through imaging and image processing.

[0015] Based on the above-mentioned approach to rock sample water content observation and addressing the shortcomings of existing technologies, the present invention aims to provide a method and apparatus for rock sample water content observation. By utilizing the sensitivity of water-sensitive test paper and the convenience of image acquisition and processing, a method for rock sample water content observation suitable for field use has been established. It has the advantages of simple operation, short observation cycle, and intuitive display of observation results, providing a new means and method for reservoir fluid identification and evaluation.

[0016] This invention provides a method for observing the water content of rock samples, comprising the following steps:

[0017] Make the rock sample come into contact with the water-sensitive test paper;

[0018] Acquire images of the contact area between the rock sample and the water-sensitive test paper, and calculate the total area S of the contact area;

[0019] Acquire an image of the color-developing area of ​​the water-sensitive test strip and calculate the area S1 of the color-developing area;

[0020] Calculate the percentage of the area S1 of the colored region to the total area S of the contact region, and use this percentage to analyze the water content of the rock sample.

[0021] By leveraging the sensitivity of water-sensitive test strips and the ease of image acquisition and processing, a method for observing water content in rock samples suitable for field application was established. This method has the advantages of simple operation, short observation cycle, and intuitive display of observation results, providing new means and methods for reservoir fluid identification and evaluation.

[0022] Preferably, the rock sample is a blocky rock sample. A water-sensitive test paper is laid on the fresh surface of the rock sample, ensuring that the water-sensitive test paper is completely attached to the surface. The edge of the contact between the rock sample and the water-sensitive test paper is determined and marked. After the water-sensitive test paper is laid flat, an image of the area enclosed by the marks is acquired, and the total area of ​​the area enclosed by the marks is calculated. The area enclosed by the marks is the contact area between the rock sample and the water-sensitive test paper, and the total area of ​​the area enclosed by the marks is the total area S of the contact area.

[0023] The advantage of this observation method is that it does not damage the rock sample and can observe the location of the colored part in the rock sample, which facilitates the analysis of the relationship between water content and rock lithology and structure, and provides information for fluid evaluation research.

[0024] Preferably, the method further includes the step of crushing the rock sample into millimeter-sized particles; densely placing the granular rock sample on a water-sensitive test paper to make contact between the two; acquiring images of the water-sensitive test paper and the rock sample covering the water-sensitive test paper, and calculating the area covered by the rock sample on the water-sensitive test paper; the area covered by the rock sample on the water-sensitive test paper is the contact area between the rock sample and the water-sensitive test paper, and the area covered by the rock sample on the water-sensitive test paper is the total area S of the contact area.

[0025] After the rock sample is crushed, the water content is observed. The water content of the rock sample is not limited to a single fresh surface of the rock sample, so it can better reflect the water content of the entire rock sample.

[0026] Preferably, the particle size of the granular rock sample is 2-5 mm. This particle size is beneficial for improving the accuracy of water content observation. If the particle size is too large, it is not conducive to sufficient contact between the rock sample particle surface and the water-sensitive test paper; if the particle size is too small, the processing time is long, and the loss of fluid from the fresh surface of the rock sample particles is also increased.

[0027] Preferably, an image of the colored area of ​​the water-sensitive test paper is acquired after the colorimetric range of the water-sensitive test paper no longer changes. When the displayed range no longer changes, it indicates that the water-sensitive test paper has completely absorbed the water at the contact surface with the rock sample. Acquiring an image of the colored area at this time can improve the accuracy of the observation.

[0028] Preferably, the percentage of the color-developing area S1 corresponding to multiple rock samples to the total area S of the contact area is calculated. The larger the percentage, the greater the water content of the corresponding rock sample.

[0029] This method for observing the water content of rock samples yields a relative water content, which can be used for screening fluid saturation samples, as well as for comparing and analyzing the water content of different rock samples and formations, providing a basis for evaluating formation fluid properties.

[0030] The present invention also provides a rock sample water content observation device, including a rock processing unit and an analysis unit;

[0031] The rock sample processing unit includes a rock sample crusher and water-sensitive test paper. The rock sample crusher is used to crush the rock sample into millimeter-sized particles, and the water-sensitive test paper is used to hold the crushed rock sample, absorb the moisture on the surface of the rock sample, and develop color.

[0032] The analysis unit includes an image acquisition device and an image processing system. The image acquisition device is used to acquire images of the contact area between the rock sample and the water-sensitive test paper and images of the color-developing area of ​​the water-sensitive test paper. The image processing system is used to calculate the total area S of the contact area based on the image of the contact area, and to calculate the area S1 of the color-developing area based on the image of the color-developing area.

[0033] The relative water content of rock samples can be obtained by using a rock sample water content observation device. This device has the advantages of simple structure, easy operation, short observation cycle and intuitive display of observation results, providing a new device for reservoir fluid identification and evaluation.

[0034] To improve the accuracy of observation, it is preferable to acquire an image of the colored area of ​​the water-sensitive test paper after the color development range has stopped changing. However, since the rock sample covers the water-sensitive test paper, the color development cannot be observed from above.

[0035] To facilitate observation of the color development of the water-sensitive test strip, preferably, a support platform for supporting the water-sensitive test strip is also included. The support platform is made of a transparent material to facilitate observation of the color development of the water-sensitive test strip from the bottom.

[0036] Because the fluid on the fresh surface of the rock sample is easily lost after it is broken into particles, in order to reduce the loss of fluid from the rock sample surface, it is preferable to include a sealable box, in which the water-sensitive test paper is placed. After the rock sample is placed on the water-sensitive test paper, the rock sample and the water-sensitive test paper are sealed in the box.

[0037] The box is preferably made of transparent material to facilitate observation of the color development of the water-sensitive test strip, which helps determine the timing for collecting images of the color development area.

[0038] Preferably, the image acquisition device is a camera, which is positioned directly above the water-sensitive test strip.

[0039] Compared with existing technologies, the rock sample water content observation method and device provided by this invention utilizes the sensitivity of water-sensitive test paper and the convenience of image acquisition and processing to establish a rock sample water content observation method suitable for field use. It has the advantages of simple operation, short observation cycle and intuitive display of observation results, providing new means and methods for reservoir fluid identification and evaluation.

[0040] This method yields the relative water content, which can be used for screening fluid saturation samples, as well as for comparing and analyzing the water content of different rock samples and formations, providing a basis for evaluating formation fluid properties.

[0041] The above-mentioned technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved. Attached Figure Description

[0042] The invention will now be described in more detail based on embodiments that are merely non-limiting and with reference to the accompanying drawings. Wherein:

[0043] Figure 1 This is a flowchart of a rock sample water content observation method provided in an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of a granular rock sample placed on water-sensitive paper according to an embodiment of the present invention.

[0045] Figure 3 This is a schematic diagram of the structure of a rock sample water content observation device provided in an embodiment of the present invention.

[0046] Explanation of reference numerals in the attached figures:

[0047] 1. Support platform;

[0048] 2. Water-sensitive test strips;

[0049] 3. Rock samples;

[0050] 4. Image acquisition device;

[0051] 5. Image processing system. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Based on the specific embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0053] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0054] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0055] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0056] like Figure 1 As shown, the method for observing water content in rock samples includes the following steps:

[0057] Step a1: Bring the rock sample into contact with the water-sensitive test paper;

[0058] Step a2: Collect images of the contact area between the rock sample and the water-sensitive test paper, and calculate the total area S of the contact area;

[0059] Step a3: Acquire an image of the color-developing area of ​​the water-sensitive test strip and calculate the area S1 of the color-developing area;

[0060] Step a4: Calculate the percentage of the colored area S1 to the total area S of the contact area, and use this to analyze the water content of the rock sample.

[0061] This rock sample water content observation method obtains the relative water content of the rock sample, which can be used for fluid saturation sample screening, as well as for comparison and analysis of water content of different rock samples and different formations, providing a basis for evaluating formation fluid properties.

[0062] This method has the advantages of being easy to operate, having a short observation period, and displaying observation results intuitively. It is suitable for on-site observation and provides a new means and method for reservoir fluid identification and evaluation.

[0063] Through steps a1 to a4, the percentage of the color-developing area S1 corresponding to multiple rock samples and the total area S of the contact area are obtained respectively. The larger the percentage, the greater the water content of the corresponding rock sample.

[0064] Images of the contact area and the colored area can be acquired using an image acquisition device (such as a camera); the acquired image information can be analyzed by an image processing system to calculate the total area S of the contact area, the area S1 of the colored area, and the percentage of the colored area S1 to the total area S of the contact area.

[0065] To improve the accuracy of observation, it is preferable to acquire images of the colored area of ​​the water-sensitive test paper only after the color development range of the test paper has stopped changing.

[0066] When using this rock sample water content observation method, representative rock samples should be selected.

[0067] Example 1

[0068] The rock sample water content observation method can be directly applied to the observation of water content in massive rock samples.

[0069] Specifically, firstly, a representative blocky rock sample is selected, and water-sensitive test paper is laid on its fresh surface (with short exposure time to air), ensuring complete adhesion between the test paper and the fresh surface of the rock sample. After a short wait, the edge of the contact area between the rock sample and the test paper is identified and marked. This mark serves as the basis for calculating the total contact area S between the blocky rock sample and the test paper. Next, the test paper is laid flat under a camera (CCD) to capture image information of the test paper. This image information includes the marks previously made on the test paper; the area enclosed by these marks is the contact area between the rock sample and the test paper. The image processing system is used to analyze the image information, calculating the total contact area S, the area S1 of the colored region, and the percentage of the colored region S1 in the total contact area S. Finally, the water content of the rock sample is analyzed based on the proportion of the colored area (i.e., the aforementioned percentage).

[0070] The advantage of this observation method is that it does not damage the rock sample and can observe the location of the colored part in the rock sample, which facilitates the analysis of the relationship between water content and rock lithology and structure, and provides information for fluid evaluation research.

[0071] Because fluids on the fresh surface of a rock sample are easily lost, water-sensitive test paper should be applied as soon as the fresh surface of the rock sample is exposed to avoid fluid loss affecting the accuracy of the observation.

[0072] In addition, the rock sample water content observation method provided by the present invention can also observe the water content of the rock sample by breaking the rock sample into millimeter-sized particles and placing the granular rock sample on water-sensitive test paper.

[0073] Example 2

[0074] Rock sample A was broken into 2-5mm particles, and the granular rock sample was densely placed on water-sensitive test paper. The image acquisition device and image processing system were turned on. The image acquisition device acquired images of the water-sensitive test paper and the rock sample covering it, and the image processing system calculated the total contact area S between the rock sample and the water-sensitive test paper to be 36cm². 2Later, the granular rock sample is removed from the water-sensitive test paper to expose the colored area. An image is then captured using an image acquisition device after the rock sample has been removed from the water-sensitive test paper, and the image processing system calculates the area S1 of the colored area on the water-sensitive test paper to be 6 cm². 2 The percentage of the area S1 of the color-developing region of the water-sensitive test strip to the total area S of the contact region is calculated to be 16.7%.

[0075] Rock sample B was broken into 2-5 mm particles, and the granular rock sample was densely placed on water-sensitive test paper. The image acquisition device and image processing system were turned on. The image acquisition device acquired images of the water-sensitive test paper and the rock sample covering it, and the image processing system calculated the total contact area S between the rock sample and the water-sensitive test paper to be 33 cm². 2 Later, the granular rock sample is removed from the water-sensitive test paper to expose the colored area. An image is then captured using an image acquisition device after the rock sample has been removed from the water-sensitive test paper, and the image processing system calculates the area S1 of the colored area on the water-sensitive test paper to be 11 cm². 2 The percentage of the area S1 of the color-developing region of the water-sensitive test strip to the total area S of the contact region is calculated to be 33.3%.

[0076] Based on the above calculations, the water content of rock sample B is greater than that of rock sample A.

[0077] In the above method, since the fluid on the fresh surface of the rock sample is easily lost after it is broken into particles, the rock sample should be placed on water-sensitive paper as soon as the fresh surface of the rock sample is exposed in order to avoid the loss of fluid and affect the accuracy of the observation.

[0078] like Figure 2 As shown, the present invention also provides a rock sample water content observation device, which includes a rock processing unit and an analysis unit. The rock sample processing unit includes a rock sample crusher (not shown) and water-sensitive test paper 2. The rock sample crusher is used to crush the rock sample 3 into millimeter-sized particles. The water-sensitive test paper 2 is used to hold the crushed rock sample 3 particles, absorb moisture from the surface of the rock sample 3, and develop color. The analysis unit includes an image acquisition device 4 and an image processing system 5. The image acquisition device 4 is used to acquire images of the contact area between the rock sample 3 and the water-sensitive test paper 2, and images of the colored area of ​​the water-sensitive test paper 2. Preferably, the image acquisition device 4 uses a camera. When acquiring images, the camera is preferably positioned directly above the water-sensitive test paper 2 to obtain the orthographic projection of the rock sample 3 onto the water-sensitive test paper 2. This orthographic projection is used as the basis for determining the contact area between the rock sample 3 and the water-sensitive test paper 2. The image processing system 5 is used to calculate the total area S of the contact area based on the image of the contact area, and to calculate the area S1 of the colored area based on the image of the colored area. Calculate the percentage of the colored area S1 to the total area S of the contact area, and use this percentage to analyze the water content of rock sample 3.

[0079] The rock sample water content observation device can be used to implement the rock sample water content observation method, as in Example 2, which requires the rock sample 3 to be crushed first.

[0080] When using this rock sample water content observation device, a representative rock sample 3 is selected, and the rock sample 3 is broken into millimeter-sized particles. The granular rock sample 3 is then densely placed on the water-sensitive test paper 2. The image acquisition device 4 and the image processing system 5 are turned on. The image acquisition device 4 acquires images of the water-sensitive test paper 2 and the rock sample 3 covering the water-sensitive test paper 2, and the image processing system 5 calculates the total area S of the contact area between the rock sample 3 and the water-sensitive test paper 2. Later, the granular rock sample 3 is removed from the water-sensitive test paper 2. The image acquisition device 4 acquires images of the water-sensitive test paper 2 after the rock sample 3 is removed, and the image processing system 5 calculates the area S1 of the colored area of ​​the water-sensitive test paper 2. The percentage of the colored area S1 of the water-sensitive test paper 2 to the total area S of the contact area is calculated, and the water content of the rock sample 3 is analyzed based on this percentage.

[0081] This device has the advantages of simple structure, easy operation, short observation cycle, and intuitive display of observation results, providing new means and methods for reservoir fluid identification and evaluation.

[0082] To improve the accuracy of observation, it is preferable to acquire images of the colored area of ​​the water-sensitive test paper 2 only after the color development range of the test paper 2 has stopped changing. Since the rock sample 3 covers the water-sensitive test paper 2, its color development cannot be observed from above. To facilitate observation of the color development of the water-sensitive test paper 2, it is preferable to add a support platform 1 made of transparent material to support the water-sensitive test paper 2. In use, the water-sensitive test paper 2 is placed on the support platform 1, and its color development can then be observed from below through the support platform 1.

[0083] Since the fluid on the fresh surface of rock sample 3 is easily lost after it is broken into particles, it is preferable to add a sealable box. The water-sensitive test paper 2 is placed inside the box. When observing the water content of rock sample 3, sealing rock sample 3 and water-sensitive test paper 2 inside the box can reduce the influence of the external environment on the loss of fluid from the surface of rock sample 3, thereby improving the accuracy of the observation. The box is preferably made of transparent material to facilitate observation of the color development of water-sensitive test paper 2, which is helpful in determining the timing of collecting images of the color development area.

[0084] Finally, it should be noted that the above embodiments and examples are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments and examples, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments or examples, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments or examples of the present invention.

Claims

1. A method for observing the water content of rock samples, characterized in that, Includes the following steps: Make the rock sample come into contact with the water-sensitive test paper; Acquire images of the contact area between the rock sample and the water-sensitive test paper, and calculate the total area S of the contact area; Acquire an image of the color-developing area of ​​the water-sensitive test strip and calculate the area S1 of the color-developing area; Calculate the percentage of the area S1 of the colored region to the total area S of the contact region, and use this percentage to analyze the water content of the rock sample.

2. The method for observing water content in rock samples according to claim 1, characterized in that, The rock sample is a blocky rock sample. A water-sensitive test paper is laid on the fresh surface of the rock sample, ensuring that the water-sensitive test paper is completely attached to the surface. The edge of the contact between the rock sample and the water-sensitive test paper is identified and marked. After the water-sensitive test paper is laid flat, an image of the area enclosed by the marks is acquired, and the total area of ​​the area enclosed by the marks is calculated. The area enclosed by the markings is the contact area between the rock sample and the water-sensitive test paper, and the total area of ​​the area enclosed by the markings is the total area S of the contact area.

3. The method for observing water content in rock samples according to claim 1, characterized in that, It also includes the steps of crushing the rock sample into millimeter-sized particles; densely placing the granular rock sample on a water-sensitive test paper to make them contact each other; acquiring images of the water-sensitive test paper and the rock sample covering the water-sensitive test paper, and calculating the area covered by the rock sample on the water-sensitive test paper; The area covered by the rock sample on the water-sensitive test paper is the contact area between the rock sample and the water-sensitive test paper, and the area covered by the rock sample on the water-sensitive test paper is the total area S of the contact area.

4. The method for observing water content in rock samples according to claim 3, characterized in that, The granular rock sample has a particle size of 2-5 mm.

5. The method for observing the water content of rock samples according to any one of claims 1-4, characterized in that, Once the color development range of the water-sensitive test strip no longer changes, an image of the color development area of ​​the water-sensitive test strip is acquired.

6. The method for observing water content in rock samples according to any one of claims 1-4, characterized in that, Calculate the percentage of the colorimetric area S1 corresponding to multiple rock samples to the total area S of the contact area. The larger the percentage, the greater the water content of the corresponding rock sample.

7. A rock sample water content observation device, characterized in that, Includes rock sample processing and analysis units; The rock sample processing unit includes a rock sample crusher and water-sensitive test paper. The rock sample crusher is used to crush the rock sample into millimeter-sized particles, and the water-sensitive test paper is used to hold the crushed rock sample, absorb the moisture on the surface of the rock sample, and develop color. The analysis unit includes an image acquisition device and an image processing system. The image acquisition device is used to acquire images of the contact area between the rock sample and the water-sensitive test paper and images of the colored area of ​​the water-sensitive test paper. The image processing system is used to calculate the total area S of the contact area based on the image of the contact area, and to calculate the area S1 of the colored area based on the image of the colored area. The system calculates the percentage of the colored area S1 to the total area S of the contact area, and uses this to analyze the water content of the rock sample.

8. The rock sample water content observation device according to claim 7, characterized in that, It also includes a support platform for holding the water-sensitive test strip, the support platform being made of a transparent material to facilitate observation of the color development of the water-sensitive test strip from the bottom.

9. The rock sample water content observation device according to claim 7 or 8, characterized in that, It also includes a sealable housing in which the water-sensitive test strip is placed.

10. The rock sample water content observation device according to claim 7, characterized in that, The image acquisition device is a camera, which is positioned directly above the water-sensitive test strip.

Images