Apparatus for capturing high-speed images during capillary pressure measurement in a porous sample

Description

1 / 12 “APPARATUS FOR CAPTURING HIGH-SPEED IMAGES DURING CAPILLARY PRESSURE MEASUREMENT IN A POROUS SAMPLE” Cross-reference to Related Orders

[0001] This request is a priority claim of the Request for U.S. Patent Serial No. 18 / 129,266, filed March 31, 2023, and U.S. Patent Application Serial No. 18 / 427,032, filed January 30, 2024, the contents of which are incorporated herein by reference in full. Technical Field

[0002] The present subject matter relates to an apparatus and method for determining the capillary pressure of porous media formations. Background

[0003] Capillary pressure is an inherent property of porous media formations. To determine capillary pressure, samples of porous media are contained in a holder, and the holder is connected to a rotating apparatus inside a centrifuge. The centrifuge spins the samples at high speed, and the centrifugal force displaces the fluid from the sample, which is captured in a measuring cup. The amount of fluid captured over time is measured and directly correlated to the capillary pressure. Conventional centrifuges apply increasing centrifugal force to displace liquid from saturated samples, developing pressure differences at the interface of two immiscible fluids. The amount of fluid captured over time can be measured by capturing images of the liquid interface position in the measuring cup using a computer-controlled high-speed camera.

[0004] As an example, US patent document 2022 / 0168754 describes a centrifuge for analyzing core samples. The centrifuge includes a rotating arm and a support attached to one end. Petition 870250078466, dated 03 / 09 / 2025, page 8 / 41 2 / 12 of the rotating arm, where the support is configured to rotate independently of the rotating arm to analyze the fluid-rock interaction within the support. However, no means for measuring the saturation of samples in porous media is described.

[0005] As another example, US patent 7,352,179 describes a device for measuring capillary pressure in a sample, including a centrifuge in which the sample is mounted so that different portions of the sample are spaced at different distances from the centrifuge axis. As the sample is rotated around the centrifuge axis, a first parameter (e.g., relative saturation) is measured in different parts of the sample, and a value of a second parameter (e.g., capillary pressure) is determined, which is related to the force to which each portion is subjected due to the rotation of the sample. The capillary pressure curve obtained with air and water is converted into a capillary pressure curve under mercury intrusion and is also measured using the magnetic resonance centrifuge. Brief Description of the Drawings

[0006] The illustrated figures represent one or more implementations, only as examples, and not as a limitation. In the figures, similar reference numbers refer to the same elements or to similar elements. The characteristics of the various implementations revealed will be easily understood from the detailed description below, which refers to the attached illustrated figures. A reference number is used with each element in the description and throughout the various views of the drawing. When a plurality of similar elements is present, a single reference number may be assigned to similar elements, with an additional letter referring to a specific element.

[0007] The various elements shown in the figures are not drawn to scale unless otherwise indicated. The di Petition 870250078466, dated 03 / 09 / 2025, p. 9 / 41 3 / 12 Dimensions of the various elements can be enlarged or reduced for greater clarity. The various figures represent one or more implementations and are presented only as examples and should not be interpreted as limiting. The following figures are included in the drawing:

[0008] FIG. 1A is a side sectional view of a sample configuration of an apparatus for measuring capillary pressure in a porous medium sample.

[0009] FIG. 1B is a top view of the rotary apparatus of the configuration of FIG. 1A, better illustrating the arms for a configuration with 4 arms.

[0010] FIG. 2A is a side sectional view of a sample holder in an embedding configuration.

[0011] FIG. 2B is a side cutaway view of the sample holder of FIG. 2A in drainage configuration.

[0012] FIG. 3A illustrates a side view of the flow distribution plug adjacent to the measuring cup.

[0013] FIG. 3B illustrates a side view of the flow distribution plug adjacent to the sample.

[0014] FIG. 4 illustrates the modification of a single measuring cup to include solid spacers to reduce the volumetric capacity as needed to accommodate samples of different sizes or configurations.

[0015] FIG. 5 illustrates a top view of the rotating apparatus of the configuration of FIG. 1A, which has been adapted to include a shield to prevent the light source from reaching the camera, except during measurements. Detailed Description

[0016] A capillary pressure measuring device includes a centrifuge with a rotating apparatus adapted to retain a sample. Petition 870250078466, dated 03 / 09 / 2025, page 10 / 41 4 / 12 of porous medium and test the sample under centrifugal motion during rotation of the rotating apparatus. A fluid capture device, positioned adjacent to the porous medium sample, receives the fluid displaced from the sample due to the centrifugal motion applied to the porous medium sample during rotation. A measuring system measures the amount of fluid displaced from the porous medium sample, obtaining an image of a fluid meniscus on the fluid capture device. A position sensor determines the position of the fluid capture device and triggers a camera to capture the image of the fluid meniscus when it is in the camera's field of view. To prevent a false image from a lighting assembly illuminating the fluid capture device from appearing in the captured image, a shield prevents light from the lighting assembly from reaching the camera when the meniscus is not in the camera's field of view.The fluid meniscus image is processed to determine a fluid volume correlated to the capillary pressure of the porous medium sample.

[0017] The objectives, advantages, and additional innovative features of the examples will be presented in part in the following description and will partly become apparent to those skilled in the art by examining the following drawings and appendices, or may be understood by producing or operating the examples. The objectives and advantages of the present subject matter can be achieved by means of the methodologies, instruments, and combinations particularly indicated in the appended claims.

[0018] In the detailed description that follows, several specific details are presented by way of examples to provide a complete understanding of the relevant teachings. However, it should be evident to those skilled in the art that the present teachings can be practiced without such details. In other cases, well-known methods, procedures, components, and circuits have been used. Petition 870250078466, dated 03 / 09 / 2025, page 11 / 41 5 / 12 described at a relatively high level, without detail, to avoid unnecessarily obscuring aspects of the present teachings.

[0019] Conventional centrifuges also use a camera system to monitor the fluid volume in the fluid capture device. However, a stroboscope is conventionally used to fix the position of the sample holder in time within a viewing window so that an image can be captured with the camera. The stroboscope needs to be manually adjusted to position each sample holder within the viewing window so that an image of the fluid meniscus in the fluid capture device (e.g., measuring cup) can be captured for each sample holder. Furthermore, the stroboscope experiences frequent malfunctions due to the high cycle rate of the lamps, which can result in data loss during a test.In the sample configurations described here, the strobe light is eliminated in favor of a position sensor that detects the location of the rotating device and signals the high-speed camera for time-lapse image capture, thus automating the image capture process and eliminating the strobe light.

[0020] It is also desirable to have measuring cups with different volume capacities. It is also desirable to maximize the size and number of samples tested simultaneously to maximize test results. However, the number and size of samples tested simultaneously are limited by the size of the centrifuge. Furthermore, due to the different properties of the samples, various configurations of fluid capture containers are normally used for drainage and imbibition tests. Conventionally, different measuring cups with different volumetric capacities are used. The sample holders described here accommodate samples Petition 870250078466, dated 03 / 09 / 2025, page 12 / 41 6 / 12 different sizes and configurations in the same measuring cups, for example, by adding solid spacers to the measuring cup to reduce the volumetric capacity.

[0021] The configurations described in the examples illustrated in the attached drawings and discussed below address these limitations of the technique.

[0022] FIG. 1A is a side cutaway view of a sample configuration of an apparatus 100 for measuring capillary pressure in a porous medium sample. As illustrated in FIG. 1A, the main components of the apparatus 100 include a centrifuge 110, a rotary apparatus 120, including a sample holder 130, and a camera system 140. The rotary apparatus 120 has one or more arms 135 adapted to hold a porous medium sample (e.g., cylindrical in shape) in one or more sample holders 130. FIG. Figure 1B is a top view of the rotary apparatus 120, which better illustrates the arms 135 for a configuration with 4 arms 135. Typically, the sample is placed in the sample holder 130, which is on an arm 135 of the rotary apparatus 120. The sample holder 130 with the porous medium sample is fixed to the rotary apparatus 120 of the centrifuge 110 and rotated at a specified high speed.Over time, the fluid is displaced from the sample in the porous medium and collected in a fluid capture device, such as a measuring cup 230 (FIG. 2A) of the sample holder 130.

[0023] The sample holder 130 is attached to the rotor 125 of the rotary apparatus 120, which rotates the sample holder 130 at a specified speed. A position sensor 150 detects the location of the sample holder 130 and signals the camera 140 to capture an image of the sample holder 130. Heaters 160 can be used to heat the sample holder 130. In sample settings, the images from the camera 140 are processed by a pro device. Petition 870250078466, dated 03 / 09 / 2025, page 13 / 41 7 / 12 image shutdown 170 for display on an optional 180 viewfinder.

[0024] FIG. 2A is a side cutaway view of the sample holder 130 in an imbibition configuration. As illustrated, the sample holder 130 consists of a housing 200, a porous medium sample 210, a flow distribution plug 220, and a measuring cup 230. In the imbibition configuration of FIG. 2A, the porous medium sample 210 is placed in the housing 200 at the position furthest from the center of rotation of the rotor 125. The flow distribution plug 220 is placed close to the porous medium sample 210, and then the measuring cup 230 is placed close to the flow distribution plug 220, as illustrated.In the imbibition configuration, the porous medium sample 210 is saturated with a fluid of known density (typically an oil), and the measuring cup 230 is placed in front of the sample 210 (i.e., in a circumferentially inward position) and filled with a fluid of known density (typically brine), which has a higher fluid density than the porous medium sample 210. As the sample holder 130 rotates in the centrifuge 110, centrifugal force creates a pressure imbalance in the porous medium sample 210. The fluid in the measuring cup 230 begins to displace the fluid in the sample 210, and the fluid in the sample 210 accumulates in the measuring cup 230. In a sample configuration, the flow distribution plug 220 is designed to direct the fluid flow from the measuring cup 230 to the ends of the porous medium sample 210, and the fluid from the interior of the porous medium sample... 210 for the measuring cup 230.

[0025] As shown in FIGS 3A and 3B, the flow distribution plug 220 is designed with a configuration of channels 300 and 310 and orifices 320 for flow management. As illustrated in FIG. 3A, the channels 300 on the side of the flow distribution plug 220 adjacent to the measuring cup 230 function to guide the fluid from Petition 870250078466, dated 03 / 09 / 2025, page 14 / 41 8 / 12 side of the flow distribution plug 220 on the side of the measuring cup to the holes 320 for flow in the channels 310 on the side of the flow distribution plug 220 adjacent to the side sample 210 for flow around the periphery of the flow distribution plug 220.

[0026] The camera system 140 in FIG. 1A is used to monitor the amount of fluid collected in the measuring cup 230 from the porous medium sample 210 over time. To monitor the collected fluid, the centrifuge housing 110 contains a groove 190 machined into the side of the centrifuge housing 110, and the measuring cup 230 is opaque to allow visualization of the fluid in the measuring cup 230. In addition, an illumination assembly 195 is provided to illuminate the measuring cup 230 for image generation by the camera system 140. During the test, it is also desirable to heat the apparatus using heaters 160 to simulate the effects of temperature on the measurement.

[0027] FIG. 2B is a side cutaway view of the sample holder 130 in the drain configuration. In the drain configuration, the positions of the porous medium sample 210 and the measuring cup 230 are reversed. In this case, the measuring cup 230 is farther from the center of rotation of the rotor 125, and the porous medium sample 210 is closer to the center of rotation. The porous medium sample 210 is saturated with the denser fluid, and the measuring cup 230 contains the less dense fluid (typically air). As the sample holder 130 rotates, fluid is drawn from the porous medium sample 210, passes through the flow distribution buffer 220, and accumulates in the measuring cup 230 due to centrifugal force.

[0028] Conventional centrifuges use different sample holder designs to conduct soaking and draining tests. In the configuration of FIG. 1A, the rotary apparatus 120 is configured to allow the use of the same sample holder 130 in all test configurations, simplifying the complexity of the centrifuge 110. In Petition 870250078466, dated 03 / 09 / 2025, page 15 / 41 9 / 12 In particular, the rotary apparatus 120 is adapted to simultaneously receive samples of porous media of varying sizes and configurations. For example, in one sample configuration, a single measuring cup 230 can be used by adding solid spacers 240 and 250 to the measuring cup 230, as shown in FIG. 4, to reduce the volumetric capacity as needed to accommodate samples of different sizes or configurations. This simplified construction of the centrifuge 110 allows for an increase in the number and size of samples that can be tested simultaneously, thus improving efficiency.

[0029] Furthermore, in a first sample configuration, the position sensor 150 detects the location of the rotating apparatus 120 and signals the camera system (e.g., digital camera) 140 to capture the image at the appropriate time, thus eliminating the need for a strobe light. In particular, the position sensor 150 detects when the measuring cup 230 passes over or under the position sensor 150 and triggers the camera system 140 to immediately capture an image of a fluid meniscus in the measuring cup 230 when the fluid meniscus is within the camera system's field of view. The position sensor 150 can be connected to the camera system 140 via wired or wireless connection. The image processing device 170 processes the captured images to determine the fluid volume in the measuring cup 230.The image processing device 170 can also calculate capillary pressure as a function of the measured fluid volume and, optionally, display the calculated capillary pressure on a display 180.

[0030] On the other hand, in a second sample configuration, the position sensor 150 can detect a specific indication from the rotating device 120 and trigger the camera system 140 to capture an image at a later time, which is a function of the speed. Petition 870250078466, dated 03 / 09 / 2025, page 16 / 41 10 / 12 rotation speed of the rotary apparatus 120 and distance from the indication to the fluid meniscus on the sample holder 230. The image processing device 170 processes the images and determines the capillary pressure in the same way as in the first sample configuration.

[0031] Skilled individuals will understand that the quality of the image captured by camera system 140 is directly affected by the illumination. For example, during image capture by camera system 140, it was observed that a false image of the illumination set 195 illuminating the measuring cup 230 may appear in the actual captured image of the measuring cup 230. This occurs due to the use of camera system 140, where sensor 150 is exposed to the illumination set 195 at times when camera system 140 is idle. This exposure to the illumination set 195 creates a lasting image of the illumination set 195, which is then superimposed on the image when camera system 140 takes the picture. The false image of the illumination set 195 superimposed on the image of the measuring cup 230 leads to difficulties and errors in image processing for detecting the fluid meniscus.

[0032] To eliminate false imaging, the illumination assembly can be blocked from the camera system 140 and the sensor 150 during the times when the camera system 140 is idle. This can be achieved, for example, by using a shield 500, as shown in FIG. 5, which blocks the illumination assembly 195 during the rotation intervals where the camera system 140 is exposed. In a sample configuration, the shield 500 rotates with the arms 135 and is fixed to the rotor 125. The shield 500 has grooves in the location of the arms 135 to allow light to pass through and illuminate the fluid meniscus in the sample holder 230. As illustrated, the light shield 500 includes grooves 510 in the areas where it is desired that the Petition 870250078466, dated 03 / 09 / 2025, page 17 / 41 11 / 12 lighting matrix light 195 illuminates the sample holder 230, so that the image can be captured.

[0033] In an alternative configuration, the false image can be eliminated by activating the lighting set 195 only when the image is captured by the camera system 140, i.e., by strobing. However, as noted above, strobing the light leads to a decrease in the lifespan of the light source, which is undesirable.

[0034] It should be understood that the terms and expressions used herein have the common meaning attributed to such terms and expressions in relation to their respective areas of research and study, except where specific meanings have been established otherwise. Relational terms such as first and second and the like may be used only to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order between such entities or actions. The terms “comprises”, “comprising”, “includes”, “including” or any other variation thereof, are intended to encompass a non-exclusive inclusion, so that a process, method, article or apparatus that comprises or includes a list of elements or steps does not include only those elements or steps, but may include other elements or steps not expressly listed or inherent in such process, method, article or apparatus.An element preceded by "a" or "an" does not exclude, without further restrictions, the existence of additional identical elements in the process, method, article, or apparatus that comprises it.

[0035] Unless otherwise indicated, all measurements, values, classifications, positions, magnitudes, sizes, and other specifications set forth in this descriptive report, including the following claims, are approximate, not exact. Such quantities should have a reasonable range consistent with the functions to Petition 870250078466, dated 03 / 09 / 2025, p. 18 / 41 12 / 12 which they refer to and what is usual in the technique to which they belong. For example, unless expressly stated otherwise, a parameter value or similar, qualified or not by a degree term (e.g., approximate, substantially, or about), may vary by up to ± 10% of the recited value.

[0036] The examples illustrated here are described in sufficient detail to enable those skilled in the art to practice the teachings revealed. Other examples may be used and derived from them, so that substitutions and structural and logical changes may be made without departing from the scope of this description. The Detailed Description, therefore, should not be taken in a limiting sense, and the scope of the various examples is defined only by the appended claims, together with the full range of equivalents to which such claims are entitled. Petition 870250078466, dated 03 / 09 / 2025, p. 19 / 41

Claims

1 / 5 CLAIMS 1. Capillary pressure measuring device, characterized in that it comprises: a centrifuge comprising a rotating apparatus adapted to hold a plurality of samples of porous media and configured to test the samples of porous media under centrifugal motion during the rotation of the rotating apparatus; a fluid capture device disposed adjacent to each of the samples of porous media during rotation to receive fluid displaced from the respective samples of porous media due to the centrifugal motion applied to the respective samples of porous media by the rotation of the rotating apparatus;A measurement system that measures the amount of fluid displaced from each of the porous media samples, the measurement system including a camera that takes an image of a fluid meniscus in the respective fluid capture devices and a position sensor that determines the position of the respective fluid capture devices and triggers the camera to take an image of each fluid meniscus when the fluid meniscus is within the camera's field of view; wherein each fluid meniscus represents a volume of fluid that is correlated to the capillary pressure of a corresponding porous media sample.

2. A capillary pressure measuring device, according to claim 1, characterized in that the measuring system further includes a light source that illuminates the respective fluid capture devices, and further comprises a shield configured to block light from the light source from reaching the camera, except when the meniscus is in the camera's field of view.

3. Capillary pressure measuring device, according to Petition 870250078466, dated 03 / 09 / 2025, page 20 / 41 2 / 5 with claim 2, characterized in that the shielding comprises a groove adjacent to each fluid capture device adapted to expose the camera to the light source when the meniscus is in the camera's field of view.

4. A capillary pressure measuring device, according to claim 3, characterized in that the rotating apparatus comprises at least two arms and the shield is fixed to the rotating apparatus to rotate with the arms, and wherein the shield comprises grooves adjacent to each arm of the rotating apparatus that allow light to pass through and illuminate the fluid meniscus when the fluid meniscus is in the camera's field of view.

5. A capillary pressure measuring device, according to claim 3, characterized in that the position sensor detects when the respective fluid capture devices and the groove adjacent to the respective fluid capture devices pass over or under the position sensor and triggers the camera to immediately capture the image of the corresponding fluid meniscus.

6. Capillary pressure measuring device, according to claim 1, characterized in that the position sensor detects an indication from the rotating apparatus and triggers the camera to capture the image of the fluid meniscus from each fluid capture device at a later time that is a function of the rotational speed of the rotating apparatus and the distance from the fluid meniscus indication.

7. A capillary pressure measuring device according to claim 1, characterized in that at least one fluid capture device includes one or more solid spacers to reduce the volume of at least one fluid capture device for different porous media sample configurations.

8. Capillary pressure measuring device, according to Petition 870250078466, dated 03 / 09 / 2025, page 21 / 41 3 / 5 with claim 1, characterized in that it further comprises an image processing device that processes images captured by the camera to determine the fluid volume in the respective fluid capture devices.

9. A capillary pressure measuring device, according to claim 8, characterized in that the image processing device further calculates the capillary pressures of the respective porous media samples as a function of the determined fluid volumes and displays the respective calculated capillary pressures on a display.

10. A method for measuring capillary pressure, characterized by comprising: placing a plurality of samples of porous media in a rotating centrifuge apparatus, wherein the rotating apparatus is configured to test the respective samples of porous media under centrifugal motion during the rotation of the rotating apparatus; receiving, in a fluid capture device disposed adjacent to each of the samples of porous media during rotation, the fluid displaced from each sample of porous media due to the centrifugal motion applied to the respective samples of porous media by the rotation of the rotating apparatus; determining the position of the respective fluid capture devices using a position sensor; activating a camera to capture an image of a fluid meniscus in the respective fluid capture devices when each fluid meniscus is in a field of view of the camera;and determine the amount of fluid displaced from each of the porous media samples from the images of each respective fluid meniscus, where each respective fluid meniscus represents a fluid volume that is correlated to the capillary pressure of the respective porous media samples.

11. A capillary pressure measurement method according to claim 10, characterized in that it further comprises blocking the light from a light source illuminating the respective fluid capture devices, preventing them from reaching the camera by using a shield other than that in which the meniscus is in the camera's field of view.

12. A method for measuring capillary pressure, according to claim 11, characterized in that it further comprises providing light from the light source through slots in the shielding adjacent to each fluid capture device to expose the camera to the light source when the meniscus is in the camera's field of view.

13. A method for measuring capillary pressure, according to claim 12, characterized in that the rotating apparatus comprises at least two arms, further comprising the rotation of the shield with the arms, such that the grooves in the shield adjacent to each arm of the rotating apparatus allow light to pass through and illuminate the fluid meniscus when the fluid meniscus is in the camera's field of view.

14. A capillary pressure measurement method according to claim 12, characterized in that determining the position of the respective fluid capture devices comprises the position sensor detecting when the respective fluid capture devices and grooves adjacent to the respective fluid capture devices pass over or under the position sensor, and triggering the camera comprises triggering the camera to immediately capture the image of each fluid meniscus when the respective fluid capture devices and grooves adjacent to the respective fluid capture devices pass over or under the position sensor.

15. Capillary pressure measurement method, according to claim 10, characterized in that determining the position of the respective fluid capture devices comprises the position sensor detecting an indication from the rotating apparatus and triggering the camera comprises triggering the camera to capture the image of each fluid meniscus at a time after detecting the indication which is a function of a rotational speed of the rotating apparatus and a distance from the indication of the respective fluid meniscus.

16. A capillary pressure measurement method according to claim 10, characterized in that determining the amount of fluid displaced from the respective porous media samples from fluid meniscus images comprises processing images captured by the camera to determine the fluid volume in the respective fluid capture devices.

17. A method for measuring capillary pressure, according to claim 10, characterized in that the placement of porous media samples in the rotating apparatus comprises the simultaneous placement of porous media samples of varying sizes and configurations in the rotating apparatus.

18. A method for measuring capillary pressure, according to claim 17, characterized in that the simultaneous placement of samples of porous media of varying sizes and configurations in the rotating apparatus comprises reducing the volume of a corresponding fluid capture device by adding one or more solid spacers to the corresponding fluid capture device for different configurations of porous media samples.

19. A method for measuring capillary pressure, according to claim 10, characterized in that it further comprises calculating the capillary pressures of each of the porous media samples as a function of the respective fluid volumes determined and outputting the respective calculated capillary pressures to a display. Petition 870250078466, dated 03 / 09 / 2025, p. 24 / 41

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