A pressure-holding coring device for on-site gas content testing

Abstract

This invention discloses a pressure-holding coring device for on-site gas content testing, comprising a pressure-holding outer cylinder, a spacer cylinder, a spacer plate, a sealing slip ring, an adjusting mechanism, a sealing mechanism, and a push plate. The spacer cylinder is fixedly disposed within the pressure-holding outer cylinder. A push plate is slidably disposed within the spacer cylinder via a hydraulic rod, dividing the interior of the spacer cylinder into two parts and forming a coring cavity in the lower part of the spacer cylinder. A spacer plate is fixedly disposed on the pressure-holding outer cylinder, dividing the annular space formed by the pressure-holding outer cylinder and the spacer cylinder into two parts and forming a measuring cavity in the upper part of the pressure-holding outer cylinder. A sealing slip ring is slidably disposed within the measuring cavity. An adjusting mechanism is also slidably disposed within the measuring cavity, and the sealing slip ring can push the adjusting mechanism to slide. A sealing mechanism is fixedly disposed at the bottom of the pressure-holding outer cylinder. Multiple support ears are fixedly disposed circumferentially on the outer side of the coring cavity.

Description

Technical Field

[0001] This invention relates to the field of shale gas exploration and development technology, specifically a pressure-maintaining coring field gas content testing device. Background Technology

[0002] In shale gas exploration and development, accurately measuring the gas content of shale is crucial for assessing reservoir potential and formulating development plans. Traditional shale gas content testing typically involves obtaining core samples using pressure-controlled coring equipment, followed by desorption of the core samples to determine the gas content, which is then used to extrapolate the gas content of the entire shale layer. The gas content of the core sample consists of three parts: desorbed gas content, lost gas content, and residual gas content. Calculating the desorbed and residual gas content is relatively simple, while measuring the lost gas content is more challenging.

[0003] Currently, the loss gas content is usually calculated using the USBM method (US Bureau of Mines direct method) linear regression. This method is based on diffusion simulation. In the early stage of desorption, the total amount of desorbed gas changes linearly with the square root of time. The loss gas content is directly calculated by fitting a straight line. However, in the actual coring process, the amount of gas desorbed in the core changes due to the change in the environment of the core, which leads to errors between the calculated and actual values, making it impossible to obtain an accurate gas content. In addition, two gas venting lines can be connected to the pressure-holding coring cylinder and a water tank. A measuring cylinder can be set in the water tank to measure the amount of gas released in the pressure-holding cylinder. Although this method can effectively measure the loss gas content, it is easily affected by the coring depth and has a limited scope of application.

[0004] Therefore, it is necessary to provide a pressure-holding coring field gas content testing device to solve the problems mentioned in the background art. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: a pressure-holding coring field gas content testing device, comprising a pressure-holding outer cylinder, a spacer cylinder, a spacer plate, a sealing slip ring, an adjusting mechanism, a sealing mechanism, and a push plate. The spacer cylinder is fixedly disposed within the pressure-holding outer cylinder. A push plate is slidably disposed within the spacer cylinder via a hydraulic rod, dividing the interior of the spacer cylinder into two parts and forming a coring cavity at the lower part of the spacer cylinder. A spacer plate is fixedly disposed on the pressure-holding outer cylinder, dividing the annular space formed by the pressure-holding outer cylinder and the spacer cylinder into two parts and forming a measuring cavity at the upper part of the pressure-holding outer cylinder. A scale line is provided at one end of the pressure-holding outer cylinder located in the measuring cavity. A sealing slip ring is slidably disposed in the measuring cavity, embedding a distance sensor within the sealing slip ring. An adjusting mechanism is also slidably disposed in the measuring cavity, and the sealing slip ring can push the adjusting mechanism to slide. A sealing mechanism is fixedly disposed at the bottom of the pressure-holding outer cylinder. Multiple support ears are fixedly disposed circumferentially on the outer side of the coring cavity.

[0006] Furthermore, as a preferred embodiment, the adjustment mechanism includes a slide bar, a connecting ring, an adjustment plate one, and an adjustment plate two, wherein there are two connecting rings, and multiple adjustment plates one and adjustment plates two are fixedly arranged in a circular pattern on the two connecting rings respectively, and the two connecting rings are fixedly connected by multiple slide bars;

[0007] Furthermore, the spacer cylinder is provided with multiple circumferentially shaped sliding grooves for the sliding rod to be sealed and slid.

[0008] Furthermore, as a preferred embodiment, the spacer plate has a plurality of sealing grooves circumferentially formed on the side near the measuring cavity, and the adjusting plate slides along the sealing grooves in a sealing manner.

[0009] The pressure-holding outer cylinder has multiple sealing grooves on its circumference near the measuring cavity, and the adjusting plate slides along the sealing grooves.

[0010] Furthermore, as a preferred embodiment, the measuring cavity is provided with multiple air outlets and air inlets in a circular pattern at its upper and lower ends;

[0011] The regulating plate has an L-shaped air inlet and an air outlet that are staggered. The air inlet and the air outlet can be connected to the air inlet and the air outlet located at the lower end of the measuring cavity, respectively.

[0012] The second adjustment plate has an L-shaped air inlet and an air outlet that are staggered. The second air inlet and the second air outlet can be connected to the air inlet and air outlet located at the upper end of the measuring cavity, respectively.

[0013] Furthermore, preferably, the core extraction cavity is provided with multiple through holes;

[0014] The spacer cylinder has multiple air passages, which are connected to multiple through holes and air inlets.

[0015] Furthermore, as a preferred embodiment, the sealing mechanism includes a sealing seat, a sealing plate, and a drive plate, wherein the sealing seat is fixedly disposed at the bottom of the pressure-holding outer cylinder, a sealing groove is provided on the sealing seat, six sealing plates are circumferentially and rotatably disposed in the sealing groove, and a drive plate is circumferentially and rotatably disposed in the sealing groove.

[0016] A guide rod is fixedly mounted on the sealing plate, and six drive grooves are circumferentially formed on the drive plate, with the guide rod sliding along the drive grooves.

[0017] Furthermore, as a preferred embodiment, the sealing plate is a triangular arc-shaped plate, and an arc-shaped rotating block is fixedly provided at the bottom of the sealing plate. The circle of the arc-shaped rotating block is located on one of the vertical sides of the sealing plate, and upward and downward inclined pushing surfaces are respectively provided on the two arc-shaped sides of the sealing plate near the inner side of the core extraction cavity.

[0018] The sealing groove has six arc-shaped grooves circumferentially formed, and the arc-shaped rotating block rotates along the arc-shaped grooves.

[0019] Furthermore, as a preferred embodiment, the sealing groove is provided with an arc-shaped groove, and the arc-shaped groove is provided with an annular hydraulic cavity;

[0020] An arc-shaped block is fixedly mounted on the drive plate, and an annular hydraulic rod is fixedly mounted on the arc-shaped block. The arc-shaped block slides along the arc-shaped groove, and the annular hydraulic rod slides along the annular hydraulic cavity.

[0021] Compared with the prior art, the present invention provides a device for on-site gas content testing in pressure-holding coring, which has the following beneficial effects:

[0022] In this invention, the free gas content of the core sample before it is transported to the desorption tank can be accurately measured by the setting of the measuring chamber, the adjusting mechanism and the sealing slip ring. This makes the value of the total gas content of the core sample more accurate. The pressure-holding outer cylinder can be transported to any depth for coring and the content of lost gas can be accurately measured for any core sample. This makes the pressure-holding outer cylinder and the device as a whole more applicable and the measured gas content data more accurate. In addition, the sealing mechanism can effectively seal the coring chamber. The two arc-shaped edges of the sealing plate are respectively set with upward and downward slopes. The two adjacent sealing plates can use these upward and downward slopes to cut the core sample and push the cut core sample. This effectively prevents the core sample from getting stuck on the sealing plate while it is taken out in its original state. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 This is a schematic cross-sectional view of the overall structure of the present invention;

[0025] Figure 3 for Figure 1 Enlarged schematic diagram of section A in the middle;

[0026] Figure 4 for Figure 1 Enlarged schematic diagram of section B in the middle;

[0027] Figure 5 for Figure 1 Enlarged schematic diagram of the C-section structure;

[0028] Figure 6 This is a schematic diagram of the adjustment mechanism in this invention;

[0029] Figure 7 This is a schematic diagram of the sealing mechanism in this invention;

[0030] In the diagram: 1. Pressure-holding outer cylinder; 11. Measuring chamber; 111. Air outlet; 112. Air inlet; 12. Sealing groove II; 2. Spacer cylinder; 21. Core-taking chamber; 211. Through hole; 22. Support ear; 23. Slide groove; 24. Air passage; 3. Spacer plate; 31. Sealing groove I; 4. Sealing slip ring; 5. Adjusting mechanism; 51. Slide rod; 52. Connecting ring; 53. Adjusting plate I; 531. Air inlet I; 532. Air outlet I; 54. Adjusting plate II; 541. Air inlet II; 542. Air outlet II; 6. Sealing mechanism; 61. Sealing seat; 7. Sealing rotating groove; 612. Arc groove; 62. Sealing plate; 621. Guide rod; 622. Arc rotating block; 631. Drive groove; 632. Arc block; 633. Annular hydraulic rod; 7. Push plate. Detailed Implementation

[0031] Please see Figures 1 to 7In this embodiment of the invention, a pressure-holding coring field gas content testing device includes a pressure-holding outer cylinder 1, a spacer cylinder 2, a spacer plate 3, a sealing slip ring 4, an adjusting mechanism 5, a sealing mechanism 6, and a push plate 7. The spacer cylinder 2 is fixedly disposed within the pressure-holding outer cylinder 1. The push plate 7 is slidably disposed within the spacer cylinder 2 via a hydraulic rod. The push plate 7 divides the interior of the spacer cylinder 2 into two parts and forms a coring cavity 21 at the lower part of the spacer cylinder 2. The spacer plate 3 is fixedly disposed on the pressure-holding outer cylinder 1, separating the pressure-holding outer cylinder 1 from the spacer cylinder 2. The formed annular space is divided into two parts and a measuring cavity 11 is formed on the upper part of the pressure-holding outer cylinder 1. The pressure-holding outer cylinder 1 is provided with a scale line at one end of the measuring cavity 11. A sealing slip ring 4 is slidably disposed in the measuring cavity 11. A distance sensor is embedded in the sealing slip ring 4. An adjustment mechanism 5 is also slidably disposed in the measuring cavity 11, and the sealing slip ring 4 can push the adjustment mechanism 5 to slide. A sealing mechanism 6 is fixedly disposed at the bottom of the pressure-holding outer cylinder 1. Multiple support ears 22 are fixedly disposed in a circular shape on the outer side of the core-taking cavity 21.

[0032] The adjustment mechanism 5 includes a slide bar 51, a connecting ring 52, an adjustment plate 1 53, and an adjustment plate 2 54. There are two connecting rings 52, and multiple adjustment plates 1 53 and adjustment plates 2 54 are fixedly arranged on the two connecting rings 52 in a circular manner. The two connecting rings 52 are fixedly connected by multiple slide bars 51.

[0033] Furthermore, the spacer cylinder 2 is provided with a plurality of circumferentially formed sliding grooves 23 for sealing and sliding of the slide rod 51;

[0034] The spacer plate 3 has multiple sealing grooves 31 circumferentially formed on the side near the measuring cavity 11, and the adjusting plate 53 slides along the sealing grooves 31 in a sealed manner.

[0035] The pressure-holding outer cylinder 1 has multiple sealing grooves 12 circumferentially formed on the side near the measuring cavity 11, and the adjusting plate 54 slides along the sealing grooves 12 in a sealing manner.

[0036] The measuring cavity 11 has multiple air outlets 111 and air inlets 112 circumferentially opened at its upper and lower ends, respectively.

[0037] The regulating plate 53 has an L-shaped air inlet 531 and an air outlet 532 that are staggered. The air inlet 531 and the air outlet 532 can be connected to the air inlet 112 and the air outlet 111 located at the lower end of the measuring cavity 11, respectively.

[0038] The adjustment plate 54 has an L-shaped air inlet 541 and an air outlet 542 that are staggered. The air inlet 541 and the air outlet 542 can be connected to the air inlet 112 and the air outlet 111 located at the upper end of the measuring cavity 11, respectively.

[0039] The core extraction cavity 21 is provided with multiple through holes 211;

[0040] The spacer cylinder 2 has multiple air passages 24, which are connected to multiple through holes 211 and air inlets 112.

[0041] During implementation, the core is extracted through the core extraction chamber 21. After the core enters the core extraction chamber 21, the core extraction chamber 21 is sealed by the sealing mechanism 6. Then, the pressure-holding outer cylinder 1 is transported to the ground to test the gas content of the core. During this process, before and after the core enters the core extraction chamber 21, the free gas emitted from the core can enter the gas passage 24 through multiple through holes 211, and then enter the measuring chamber 11 through the gas passage 24. During entry into the measuring chamber 11, the gas can selectively enter through the air inlet 531 or the air inlet 541 via the sealing slip ring 4 and the adjusting mechanism 5. In the initial state, the sealing slip ring 4 is located at... At the bottom of the measuring chamber 11, the adjusting plate 53 is fully inserted into the sealing groove 31, and the air inlet 531 is connected to the air inlet 112 at the bottom of the measuring chamber 11. The air outlet 542 is connected to the air outlet 111 at the top of the measuring chamber 11, and the air inlet 541 and the air outlet 532 are in a closed state. Then, free air enters the measuring chamber 11 from the air inlet 531 and pushes the sealing slip ring 4 to slide upward along the measuring chamber 11. When the sealing slip ring 4 slides upward and presses against the adjusting plate 54, it can push the entire adjusting mechanism 5 to slide upward synchronously. During this process, the adjusting plate 53 slides along the sealing groove 31 and the air outlet 532 is fully inserted into the sealing groove 31. Adjusting plate 53 can block the air inlet 112 at the bottom of the measuring chamber 11, and make the air outlet 532 communicate with the air outlet 111 at the bottom of the measuring chamber 11. Adjusting plate 54 can slide along the sealing groove 12 and block the air outlet 111 at the top of the measuring chamber 11, and make the air inlet 541 communicate with the air inlet 112 at the top of the measuring chamber 11. Then, free air enters from the air inlet 112 at the top of the measuring chamber 11 and pushes the sealing slip ring 4 to slide downward. Similarly, when the sealing slip ring 4 is against the adjusting plate 53, it also drives the entire adjusting mechanism 5 to slide downward. At this time, free air enters again from the air inlet 112 at the bottom of the measuring chamber 11. The vent 112 enters and pushes the sealing slip ring 4 upward, repeating this cycle until the core is transferred to the desorption tank. During the back-and-forth sliding of the sealing slip ring 4 along the measuring chamber 11, the distance sensor embedded in the sealing slip ring 4 can monitor the distance between the sealing slip ring 4 and the spacer 3 in real time. Based on the distance change pattern, the number of times the sealing slip ring 4 slides up and down is calculated. Then, the scale value of the last sliding position of the sealing slip ring 4 after the core is transferred to the desorption tank is read, thereby accurately measuring the lost gas content. Then, the desorbed gas content and the residual gas content are added together to obtain the total gas content of the core, making the measured core gas content value more accurate and providing experimental basis for subsequent mining work.

[0042] In this embodiment, as Figure 7 The sealing mechanism 6 includes a sealing seat 61, a sealing plate 62, and a drive plate. The sealing seat 61 is fixedly disposed at the bottom of the pressure-holding outer cylinder 1. A sealing groove is provided on the sealing seat 61. Six sealing plates 62 are circumferentially and rotatably disposed in the sealing groove. A drive plate is circumferentially disposed in the sealing groove.

[0043] A guide rod 621 is fixedly installed on the sealing plate 62, and six drive grooves 631 are circumferentially opened on the drive plate. The guide rod 621 slides along the drive grooves 631.

[0044] The sealing plate 62 is a triangular arc plate. An arc-shaped rotating block 622 is fixedly provided at the bottom of the sealing plate 62, and the circle of the arc-shaped rotating block 622 is located on one of the vertical sides of the sealing plate 62. The two arc-shaped sides of the sealing plate 62 near the inner side of the core extraction cavity 21 are respectively provided with upward and downward inclined pushing surfaces.

[0045] Specifically, upward and downward inclined surfaces are respectively provided on the two arc-shaped sides of the sealing plate 62 so that when the sealing plate 62 rotates to seal the core cavity 21, two adjacent sealing plates 62 can cut the core through an upper inclined surface and a lower inclined surface, and push the core after cutting, thereby ensuring that the core is taken out in its original state while preventing the core from getting stuck on the sealing plate 62, that is, ensuring that the sealing plate 62 can effectively block the core cavity 21;

[0046] The sealing groove has six arc-shaped grooves circumferentially formed, and the arc-shaped rotating block 622 rotates along the arc-shaped grooves;

[0047] The sealing groove is provided with an arc-shaped groove 612, and the arc-shaped groove 612 is provided with an annular hydraulic chamber;

[0048] An arc-shaped block 632 is fixedly mounted on the drive plate, and an annular hydraulic rod 633 is fixedly mounted on the arc-shaped block 632. The arc-shaped block 632 slides along the arc-shaped groove 612, and the annular hydraulic rod 633 slides along the annular hydraulic cavity.

[0049] In particular, the drive plate is rotated by hydraulic pressure, which makes the rotation of the sealing plate 62 more stable and convenient, and has a strong driving force, ensuring that the sealing plate 62 can cut the rock core.

[0050] In summary, when implemented, this invention, through the setting of the measuring chamber 11, the adjusting mechanism 5, and the sealing slip ring 4, enables the free gas content of the core sample to be accurately measured before it is transported to the desorption tank. This results in a more accurate value for the total gas content of the core sample in the final test. Furthermore, the pressure-holding outer cylinder 1 can be transported to any depth for coring, and the content of lost gas can be accurately measured for any core sample. Consequently, the pressure-holding outer cylinder 1 and the entire device have a wider range of applications and the measured gas content data is more accurate.

[0051] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A device for on-site gas content testing during pressure-holding coring, characterized in that: The system includes a pressure-holding outer cylinder (1), a spacer cylinder (2), a spacer plate (3), a sealing slip ring (4), an adjusting mechanism (5), a sealing mechanism (6), and a push plate (7). The pressure-holding outer cylinder (1) has a spacer cylinder (2) fixedly installed inside. The spacer cylinder (2) has a push plate (7) slidably installed inside the spacer cylinder (2) via a hydraulic rod. The push plate (7) divides the interior of the spacer cylinder (2) into two parts and forms a core-taking cavity (21) at the lower part of the spacer cylinder (2). The pressure-holding outer cylinder (1) has a spacer plate (3) fixedly installed on it. The spacer plate (3) separates the annular space formed by the pressure-holding outer cylinder (1) and the spacer cylinder (2). The pressure-holding outer cylinder (1) is divided into two parts and a measuring cavity (11) is formed on the upper part of the pressure-holding outer cylinder (1). The pressure-holding outer cylinder (1) is provided with a scale line at one end of the measuring cavity (11). A sealing slip ring (4) is provided in the measuring cavity (11) and a distance sensor is embedded in the sealing slip ring (4). An adjustment mechanism (5) is also provided in the measuring cavity (11) and the sealing slip ring (4) can push the adjustment mechanism (5) to slide. A sealing mechanism (6) is fixedly provided at the bottom of the pressure-holding outer cylinder (1). Multiple support ears (22) are fixedly provided in a circular shape on the outer side of the core-taking cavity (21). The adjustment mechanism (5) includes a slide rod (51), a connecting ring (52), an adjustment plate one (53), and an adjustment plate two (54). There are two connecting rings (52), and multiple adjustment plates one (53) and adjustment plates two (54) are fixedly arranged in a circle on the two connecting rings (52). The two connecting rings (52) are fixedly connected by multiple slide rods (51). Furthermore, the spacer cylinder (2) is provided with a plurality of circumferentially formed sliding grooves (23) for sealing and sliding of the slide rod (51); The spacer plate (3) has multiple sealing grooves (31) circumferentially formed on the side near the measuring cavity (11), and the adjusting plate (53) slides along the sealing grooves (31) in a sealed manner. The pressure-holding outer cylinder (1) has multiple sealing grooves (12) circumferentially formed on the side near the measuring chamber (11), and the adjusting plate (54) slides along the sealing grooves (12) in a sealed manner. The measuring cavity (11) has multiple air outlets (111) and air inlets (112) circumferentially opened at its upper and lower ends, respectively; The regulating plate (53) is provided with an L-shaped and staggered air inlet (531) and an air outlet (532). The air inlet (531) and the air outlet (532) can be connected to the air inlet (112) and the air outlet (111) located at the lower end of the measuring cavity (11), respectively. The adjustment plate 2 (54) is provided with an L-shaped and staggered air inlet 2 (541) and an air outlet 2 (542). The air inlet 2 (541) and the air outlet 2 (542) can be connected to the air inlet hole (112) and the air outlet hole (111) located at the upper end of the measuring cavity (11), respectively. The core extraction cavity (21) is provided with multiple through holes (211); The spacer cylinder (2) is provided with multiple air passages (24), which are connected to multiple through holes (211) and air inlets (112).

2. The pressure-holding coring field gas content testing device according to claim 1, characterized in that: The sealing mechanism (6) includes a sealing seat (61), a sealing plate (62) and a drive plate. The sealing seat (61) is fixedly installed at the bottom of the pressure-holding outer cylinder (1). A sealing groove is provided on the sealing seat (61). Six sealing plates (62) are arranged in a circular sealing rotation in the sealing groove. A drive plate is arranged in a ring rotation in the sealing groove. A guide rod (621) is fixedly installed on the sealing plate (62), and six drive grooves (631) are opened in a circle on the drive plate. The guide rod (621) slides along the drive grooves (631).

3. The pressure-holding coring field gas content testing device according to claim 2, characterized in that: The sealing plate (62) is a triangular arc plate. An arc-shaped rotating block (622) is fixedly provided at the bottom of the sealing plate (62), and the circle of the arc-shaped rotating block (622) is located on one of the vertical sides of the sealing plate (62). The two arc-shaped sides of the sealing plate (62) near the inner side of the core extraction cavity (21) are respectively provided with upward and downward inclined pushing surfaces. The sealing groove has six arc-shaped grooves in a circular pattern, and the arc-shaped rotating block (622) rotates along the arc-shaped grooves.

4. The pressure-holding coring field gas content testing device according to claim 2, characterized in that: The sealing groove is provided with an arc-shaped groove (612), and the arc-shaped groove (612) is provided with an annular hydraulic cavity; An arc-shaped block (632) is fixedly mounted on the drive plate, and an annular hydraulic rod (633) is fixedly mounted on the arc-shaped block (632). The arc-shaped block (632) slides along the arc-shaped groove (612), and the annular hydraulic rod (633) slides along the annular hydraulic cavity.

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