A self-expanding packer with a water-permeable interlayer

Abstract

The present invention relates to a self-expanding seal with a water-permeable interlayer, comprising a base pipe and a self-expanding rubber sleeve, wherein couplings are respectively provided at both ends of the base pipe, and retaining rings are respectively provided at both ends of the rubber sleeve, for fixing the rubber sleeve on the outer surface of the base pipe; a circle of water-permeable interlayer is provided in the side wall of the base pipe corresponding to the rubber sleeve, and either end of the water-permeable interlayer is connected to the external space of the seal through a water-permeable groove, so that external water is introduced into the water-permeable interlayer; a plurality of through holes are provided on the side of the water-permeable interlayer facing the rubber sleeve, so that water in the water-permeable interlayer can flow to the rubber sleeve, thereby promoting the rubber sleeve to absorb water and expand; the water inlet of the water-permeable groove is located between a pair of couplings and retaining rings close to each other, the water inlet is arranged around the base pipe, and a circle of concave storage tank is provided on the inner wall of the water-permeable groove near the water inlet, and a self-expanding rubber ring is provided in the storage tank, and a circle of detachable baffle is provided at the opening of the storage tank. When the baffle is removed, the rubber ring in the reservoir absorbs water and expands, thereby blocking the water inlet of the water-permeable groove and preventing the water-permeable interlayer from continuing to inlet water.

Description

Technical Field

[0001] The invention belongs to the technical field of self-expanding packers, and in particular relates to a self-expanding packer with a water-permeable interlayer. Background Art

[0002] A packer is a tool connected to the downhole tubing string and used to isolate the annular space between the oil pipe and the oil and gas well casing or the wall of the open hole. A self-expanding packer is a conventional packer. The outer side of the middle part of the pipe is equipped with a layer of water-swellable rubber tube. The top and bottom of the rubber tube are respectively fixed to the outer wall of the packer's base pipe by a retaining ring. One part of the retaining ring is connected to the base pipe, and the other part is connected to the rubber tube. When encountering oil and water from downhole, the rubber tube spontaneously expands, sealing the space between the packer and the inner wall of the well, blocking the passage outside the packer, so that the oil and water below the packer can only flow through the base pipe inside the packer. When the well needs to be sealed, it is only necessary to control the sealing of the base pipe.

[0003] At present, when the self-expanding packer is used, oil and water surge from the bottom of the rubber tube. Due to the shielding effect of the retaining ring at the bottom of the rubber tube, the oil and water need to penetrate into the retaining ring and then expand the rubber tube. Therefore, the expansion speed of the rubber tube part covered by the retaining ring is not fast. The lower part of the rubber tube is first exposed to a large amount of oil and water, and the expansion speed of the lower part is faster than that of other parts. When the lower part of the rubber tube expands to completely block the passage of oil and water, the expansion of the upper and top parts of the rubber tube is not sufficient, but is almost out of contact with a large amount of oil and water, and cannot expand normally. This causes the expansion speed of various parts of the rubber tube to be uneven. Ultimately, the rubber tube that plays the role of sealing may not be the entire length of the rubber tube, resulting in waste of the rubber tube, and uneven force on the rubber tube when blocking water, and ultimately the water blocking effect is relatively weak. Summary of the Invention

[0004] To address the above problems, the present invention provides a self-expanding packer with a water-permeable interlayer, comprising a base pipe and a self-expanding rubber sleeve, wherein couplings are provided at both ends of the base pipe, and retaining rings are provided at both ends of the rubber sleeve for fixing the rubber sleeve on the outer surface of the base pipe;

[0005] A water-permeable interlayer is provided inside the side wall of the base pipe corresponding to the rubber sleeve. Either end of the water-permeable interlayer is connected to the external space of the packer through a water groove, allowing external water to be introduced into the water-permeable interlayer. A plurality of through holes are provided on the side of the water-permeable interlayer facing the rubber sleeve, allowing water in the water-permeable interlayer to flow to the rubber sleeve, promoting the rubber sleeve to absorb water and expand.

[0006] The water inlet of the water trough is located between a pair of couplings and retaining rings close to each other. The water inlet is arranged around the base pipe. A circle of recessed storage tank is provided on the inner wall of the water trough near the water inlet. A self-expanding rubber ring is provided in the storage tank. A circle of detachable baffles is provided at the opening of the storage tank. When the baffle is removed, the rubber ring in the reservoir absorbs water and expands, blocking the water inlet of the water trough and preventing water from continuing to enter the water interlayer.

[0007] When a traditional packer is used, it is vertically inserted into the wellbore. When the oil and water rising from the wellbore contacts the rubber sleeve, the rubber sleeve absorbs water and expands, increasing its volume and sealing the space between the base pipe and the inner wall of the wellbore, thereby sealing the oil and water below. In actual use, the inventors found that the lower part of the rubber sleeve contacts the oil and water first and expands first, and the expansion degree is also the greatest. The upper part of the rubber sleeve contacts the oil and water later and expands subsequently. In most cases, the expansion degree and speed of the upper part of the rubber sleeve are not as good as those of the lower part of the rubber sleeve. In extreme cases, the lower part of the rubber sleeve expands to the point where it can seal the oil and water. The oil and water can only be transferred to the upper part of the rubber sleeve within the rubber sleeve material, allowing the upper part of the rubber sleeve to absorb water and expand. Finally, it slowly expands, and even when the upper part or top part can no longer absorb water, the expansion degree of this part is less than that of the lower part of the rubber sleeve. Ultimately, the sealing effect is mainly performed by the middle and lower part of the rubber sleeve, rather than the entire length of the rubber sleeve. This results in waste of rubber sleeves and uneven force on the rubber sleeve when blocking water, resulting in a relatively weak water blocking effect.

[0008] In view of the situation that a vertical rubber cylinder of a certain length encounters water unevenly, the present invention designs a water-permeable interlayer. The water-permeable interlayer is located inside the side wall of the base pipe and corresponds to the entire length range of the rubber cylinder. A plurality of through holes are provided on the outer side of the water-permeable interlayer, and the water inside the water directly reaches the inner side of the rubber cylinder through the through holes. That is, the water-permeable interlayer serves as a water transmission channel, and directly transports water to various parts of the rubber cylinder along the length direction of the rubber cylinder. By rationally designing the through hole area on the outer side of the water-permeable interlayer, it is ensured that the rubber cylinder can be evenly exposed to water and expand evenly.

[0009] A water channel is located below the water-passing interlayer to guide upwelling water into the interlayer. The interlayer cannot be continuously permeable to water; once the rubber cylinder has expanded to its full potential, it should block water flow from the channel. The present invention incorporates a reservoir at the water inlet of the water channel. A pre-installed rubber ring is placed within the reservoir. The rubber ring is made of the same material as the rubber cylinder and expands upon contact with water, thereby blocking the water inlet and preventing water from entering the interlayer. A removable baffle is provided at the reservoir opening. Removal of the baffle exposes the internal rubber ring, which expands upon contact with water, achieving automatic water blocking.

[0010] Optionally, the cross section of the water-permeable interlayer is annular, the inner side of the water-permeable interlayer is the outer side of the base pipe, the outer side of the water-permeable interlayer faces the rubber sleeve, and the length of the water-permeable interlayer is not less than the length of the rubber sleeve;

[0011] The outer side surface of the water-permeable interlayer is divided into a non-porous area, a first porous area, a second porous area and a third porous area along its own length direction. No through holes are set in the non-porous area, and through holes are set in the other three porous areas, and the through holes have the same aperture to control the different water permeability of the water-permeable interlayer to different parts of the rubber cylinder. The non-porous area is closest to the water groove.

[0012] The thickness of the water-permeable interlayer is reasonably set according to the material, expansion performance and diameter of the actual rubber sleeve, and the thickness of the water-permeable interlayer is uniform along the length of the base pipe.

[0013] Further optionally, the length of the non-porous area accounts for 30-40% of the total length of the water-permeable interlayer, the first porous area and the second porous area have the same length, and the third porous area corresponds to the part of the rubber cylinder covered by a retaining ring away from the water groove.

[0014] Further optionally, in the first porous area, the total area of the through holes accounts for 20-25% of the total surface area of the first porous area; in the second porous area, the total area of the through holes accounts for 30-40% of the total surface area of the second porous area; in the third porous area, the total area of the through holes accounts for 35-45% of the total surface area of the third porous area.

[0015] Optionally, the water trough is provided in the side of the base pipe, the water trough is annular and surrounds the base pipe, one end of the water trough is connected to the water interlayer, and the other end of the water trough is the water inlet for connecting to the environment outside the base pipe, the water trough is concentrically arranged with the base pipe, and the length direction of the water trough is parallel to the length direction of the base pipe;

[0016] The water inlet is circular and is an empty side surface formed by hollowing out the outer side wall of the base pipe.

[0017] Further optionally, a storage tank is provided on the inner wall of the water trough close to the inside of the base pipe, the storage tank is circular and surrounds the base pipe, and the storage tank protrudes toward the inside of the base pipe; the rubber ring is circular, the rubber ring is arranged inside the storage tank and arranged in a circle along the storage tank; the opening of the storage tank faces the water inlet and is closed by the baffle to protect the internal rubber ring.

[0018] Further optionally, the baffle is divided into a plurality of curved sub-plates, which are connected together to form a complete circle. The baffle can tightly seal the storage tank opening and protect the internal rubber ring from expanding.

[0019] Optionally, the packer further comprises a plurality of drawstrings and a plurality of support plates, wherein the drawstrings extend along the length of the packer, within the water groove and the water-permeable interlayer, and are parallel to the central axis of the base pipe; one end of the drawstrings is connected to the outer side surface of the split plate, and the other end of the drawstrings passes through the outer side wall of the water-permeable interlayer and the rubber sleeve from the second perforated area to connect to the external support plates;

[0020] The support sheet is arranged on the outside of the rubber cylinder and has a curvature so that the support sheet can be attached to the outer surface of the rubber cylinder. Several support sheets are at the same height, and temporary connecting belts are connected between adjacent support sheets. Before the rubber cylinder expands, several support sheets are connected into a circle by the connecting belt and hung on the outside of the rubber cylinder.

[0021] Further optionally, the side of the support sheet away from the rubber cylinder is the outer side surface, and one end of the pull rope passes through the support sheet and is fixedly connected to the outer side surface of the support sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the self-expanding packer with a water-permeable interlayer according to Example 1;

[0023] Figure 2 Schematic diagram of the storage tank and rubber ring;

[0024] Figure 3 Schematic diagram of the baffle.

[0025] In the accompanying drawings, 1-base tube, 2-rubber cylinder, 3-support plate, 4-retaining ring, 5-water interlayer, 6-water trough, 7-water inlet, 8-storage tank, 9-rubber ring, 10-baffle, 11-dividing plate, 12-pull rope. DETAILED DESCRIPTION

[0026] Example 1

[0027] This embodiment provides a self-expanding packer with a water-permeable interlayer, such as Figure 1-Figure 3 As shown, it includes a base pipe 1 and a self-expanding rubber cylinder 2. A coupling is provided at both ends of the base pipe, and a retaining ring 4 is provided at both ends of the rubber cylinder for fixing the rubber cylinder 2 on the outer surface of the base pipe 1.

[0028] A water-permeable interlayer 5 is provided inside the side wall of the base pipe 1 corresponding to the rubber sleeve 2. Either end of the water-permeable interlayer 5 communicates with the external space of the packer through a water groove 6, allowing external water to be introduced into the water-permeable interlayer 5. A plurality of through holes are provided on the side of the water-permeable interlayer 5 facing the rubber sleeve, allowing water in the water-permeable interlayer 5 to flow to the rubber sleeve, promoting its water absorption and expansion.

[0029] The water inlet 7 of the water trough 6 is located between a pair of couplings and retaining rings close to each other. The water inlet 7 is arranged around the base pipe 1. A circle of recessed storage tank 8 is provided on the inner wall of the water trough 6 near the water inlet 7. A self-expanding rubber ring 9 is provided in the storage tank 8. The opening of the storage tank 8 is provided with a circle of detachable baffles 10. When the baffles 10 are removed, the rubber rings 9 in the reservoir absorb water and expand, blocking the water inlet 7 of the water trough 6, thereby preventing the water-passing interlayer 5 from continuing to enter water.

[0030] The cross section of the water-permeable interlayer 5 is annular, the inner side of the water-permeable interlayer 5 is the outer side of the base pipe, the outer side of the water-permeable interlayer 5 faces the rubber sleeve, and the length of the water-permeable interlayer 5 is not less than the length of the rubber sleeve;

[0031] The outer side surface of the water-permeable interlayer 5 is divided into a non-porous area, a first porous area, a second porous area and a third porous area along its own length direction. No through holes are set in the non-porous area, and through holes are set in the other three porous areas, and the through holes have the same aperture to control the different water permeability of the water-permeable interlayer 5 to different parts of the rubber cylinder. The non-porous area is closest to the water groove 6.

[0032] The length of the non-porous area accounts for 30% of the total length of the water-permeable interlayer 5 , the lengths of the first porous area and the second porous area are the same, and the third porous area corresponds to the portion of the rubber cylinder covered by a retaining ring away from the water-permeable groove 6 .

[0033] In the first porous area, the total area of the through holes accounts for 20% of the total surface area of the first porous area; in the second porous area, the total area of the through holes accounts for 30% of the total surface area of the second porous area; in the third porous area, the total area of the through holes accounts for 35% of the total surface area of the third porous area.

[0034] The non-porous area of the water-permeable interlayer 5 corresponds to the lower part of the rubber tube. When in the well, the lower part of the rubber tube can preferentially contact the upwelling oil and water, and there is no need for the water-permeable interlayer 5 to additionally supply water to the lower part of the rubber tube. The middle part of the rubber tube corresponds to the first porous area, the upper part of the rubber tube corresponds to the second porous area, and the top of the rubber tube corresponds to the third porous area. From bottom to top, the difficulty of the rubber tube contacting the water outside the packer gradually increases, so three porous areas with different through-hole areas are set to increase the permeable area from bottom to top, and then combined with the length setting of the three porous areas, water is reasonably supplied to the middle, upper and top parts of the rubber tube, so that the entire rubber tube expands evenly. In particular, the top of the rubber tube corresponds to the retaining ring, and the expansion speed needs to be reasonably controlled. If it expands too quickly, it is easy to damage the retaining ring or the top of the rubber tube is squeezed by the retaining ring.

[0035] The structure and installation of the retaining ring and rubber sleeve are identical to those of conventional packers. The retaining ring is circular, with one portion attached to the outer wall of the base pipe and the other portion pressing against the outer side of the rubber sleeve to secure the ends. The inner side of the rubber sleeve is mechanically or adhesively fixed to the non-porous outer wall of the water-permeable interlayer 5 (the non-porous wall portions of the three perforated areas can be bonded to the rubber sleeve), or the rubber sleeve can be connected to the base pipe using other conventional methods. Conventional couplings are used at both ends of the base pipe to facilitate connection to upstream and downstream pipelines within the wellbore.

[0036] The packer should be erected vertically when in use, with one end of the water channel 6 facing downwards to facilitate receiving the oil and water rising from the bottom of the well.

[0037] The water trough 6 is provided in the side of the base pipe. The water trough 6 is annular and surrounds the base pipe. One end of the water trough 6 is connected to the water interlayer 5. The other end of the water trough 6 is the water inlet 7 for connecting to the environment outside the base pipe. The water trough 6 is concentric with the base pipe, and the length direction of the water trough 6 is parallel to the length direction of the base pipe.

[0038] The water inlet 7 is circular and is an empty side surface formed by hollowing out the outer wall of the base pipe.

[0039] A circular reservoir 8 is provided on the inner wall of the water channel 6, near the base pipe. This reservoir 8 surrounds the base pipe and protrudes toward the interior of the base pipe. A circular rubber ring 9 is positioned within and along the perimeter of the reservoir 8. The opening of the reservoir 8 faces the water inlet 7 and is sealed by a baffle 10, protecting the internal rubber ring 9. The side of the rubber ring 9 facing away from the water inlet 7 is bonded to the inner wall of the reservoir 8 to prevent it from completely falling out of the reservoir 8 when it expands.

[0040] The water inlet is circular, that is, the outer side of the base pipe corresponding to the water inlet is hollowed out, the base pipe wall has a certain thickness, and the other parts of the base pipe wall except the water groove can also play a connecting role, which will not cause the base pipe to fall off.

[0041] The baffle 10 is divided into three curved sub-plates 11, which form a complete circle when connected together. A sealing strip or other sealing component can be set between the sub-plate 11 and the opening of the storage tank 8. A sealing strip is also set at the position where the outer edge of the sub-plate 11 connects to the opening of the storage tank 8. A sealing strip or a sealing strip is set at the joint of two adjacent sub-plates 11, so that the baffle 10 can tightly seal the opening of the storage tank 8 and protect the internal rubber ring 9 from expansion.

[0042] The packer further includes six drawstrings 12 and six support plates 3. The drawstrings 12 extend along the length of the packer, within the water groove 6 and the water-permeable interlayer 5, and are parallel to the central axis of the base pipe. One end of the drawstring 12 is connected to the outer side of the split plate 11, and the other end of the drawstring 12 passes through the outer side wall of the water-permeable interlayer 5 and the rubber sleeve from the second perforated area to connect to the external support plate 3.

[0043] The support sheet 3 is arranged on the outside of the rubber cylinder and has a curvature so that the support sheet 3 can be attached to the outer surface of the rubber cylinder. Several support sheets 3 are at the same height, and temporary connecting belts are connected between adjacent support sheets 3. Before the rubber cylinder expands, several support sheets 3 are connected into a circle by the connecting belt and hung on the outside of the rubber cylinder.

[0044] Each split plate 11 is connected to a pull rope 12 near both ends thereof, so that the two pull ropes 12 can evenly pull up the corresponding split plate 11 to separate from the opening of the storage tank 8 .

[0045] The side of the support sheet 3 away from the rubber cylinder is the outer side surface, and one end of the pull rope 12 passes through the support sheet 3 and is fixedly connected to the outer side surface of the support sheet 3. The support sheet 3 is not directly connected to the rubber cylinder. When the rubber cylinder is not expanded, a section of the pull rope 12 is outside the rubber cylinder, so that the support sheet 3 is suspended outside the rubber cylinder; when the rubber cylinder expands, the connecting belt is broken and the pull rope 12 is driven outward until the pull rope 12 pulls the corresponding split plate 11 away from the opening of the storage tank 8, so that the rubber ring 9 is exposed and can absorb water and expand to block the water inlet 7.

[0046] The support sheet 3 is made of hard plastic, with its edges ground to a smooth, curved surface and its top corners rounded to prevent scratches on the rubber packer. When the rubber packer is not inflated and the pull cord 12 is pre-installed, a section of the top of the pull cord 12 extends beyond the outer surface of the rubber packer. This prevents the pull cord 12 from being pulled upon initial expansion, which could prematurely open the baffle 10. Because a section of the pull cord 12 overhangs the outer surface of the rubber packer, the support sheet 3 also overhangs the outer surface. Simultaneously, the individual support sheets 3 are connected by a connecting tape, temporarily securing them to the outer surface of the rubber packer. This allows the support sheets 3 to adhere to the outer surface of the rubber packer during lowering of the packer down the wellbore to the target depth, preventing them from shaking or striking the wellbore wall. Preferably, the connecting tape also covers the portion of the pull cord 12 overhanging the outer surface of the rubber packer to protect it. The connecting tape is a conventional plastic film and is easily torn by direct external forces.

[0047] After the packer is lowered into position in the well, it is subjected to the upwelling of oil and water. The rubber sleeve expands upon contact with water, and water is also transported through the water channel 6 and the water-permeable interlayer 5, promoting expansion of the upper middle and top portions of the rubber sleeve. The pull rope 12 exits the rubber sleeve above the second perforated area and close to the third perforated area, positioning the overhanging support piece 3 above the second perforated area. The force of the expanding rubber sleeve severing the connecting strap, the support piece 3 being essentially only subjected to the rubber sleeve's thrust (the packer is stable in the well), ensuring that the inner surface of the support piece 3 remains in contact with the outer surface of the rubber sleeve. The rubber cylinder expands, continuously engulfing the originally hanging rope 12 (i.e., the preset surplus). When the expansion of the part of the rubber cylinder corresponding to the rope 12 is about to approach the inner wall of the well, the surplus of the rope 12 is exhausted, the support sheet 3 is pressed against the outside of the rubber cylinder, the rope 12 is tightened, and as the rubber cylinder continues to expand, the rope 12 is further pulled out, and the rope 12 in the water-permeable interlayer 5 is lifted, thereby pulling the corresponding split plate 11, and finally making the split plate 11 separate from the opening of the storage tank 8. The split plates 11 separate from each other, but remain in the water-permeable tank 6. The rubber ring 9 absorbs water and expands, and blocks the water inlet 7. The residual water in the water-permeable interlayer 5 can continue to temporarily supply the upper middle and top parts of the rubber cylinder with expansion until the rubber cylinder is fully expanded.

[0048] The support piece 3 can ensure that one end of the pull rope 12 is always outside the rubber cylinder. If the pull rope 12 is directly fixed on the outer surface of the rubber cylinder, when the rubber cylinder expands, the pull rope 12 may cut the rubber at the connection, causing damage to the rubber cylinder and affecting the sealing effect.

[0049] Comparative Example 1

[0050] This comparative example provides a self-expanding packer with a water-permeable interlayer, which is the same as Example 1, except that no water-permeable interlayer and water-permeable groove are provided on the side wall of the base pipe, that is, a traditional packer.

[0051] Example 2

[0052] This embodiment provides a self-expanding packer with a water-permeable interlayer, which is the same as that of the first embodiment, except that the length of the non-porous area accounts for 40% of the total length of the water-permeable interlayer.

[0053] Example 3

[0054] This embodiment provides a self-expanding packer with a water-permeable interlayer, which is the same as that of Example 1, except that the length of the non-porous area accounts for 41% of the total length of the water-permeable interlayer.

[0055] Example 4

[0056] This embodiment provides a self-expanding packer with a water-permeable interlayer, which is the same as the embodiment 1, except that the total area of the through holes in the first porous area accounts for 25% of the total surface area of the first porous area.

[0057] Example 5

[0058] This embodiment provides a self-expanding packer with a water-permeable interlayer, which is the same as the embodiment 1, except that the total area of the through holes in the first porous area accounts for 19% of the total surface area of the first porous area.

[0059] Example 6

[0060] This embodiment provides a self-expanding packer with a water-permeable interlayer, which is the same as the embodiment 1, except that the total area of the through holes in the second porous area accounts for 40% of the total surface area of the second porous area.

[0061] Example 7

[0062] This embodiment provides a self-expanding packer with a water-permeable interlayer, which is the same as the embodiment 1, except that the total area of the through holes in the second porous area accounts for 29% of the total surface area of the second porous area.

[0063] Example 8

[0064] This embodiment provides a self-expanding packer with a water-permeable interlayer, which is the same as the embodiment 1, except that the total area of the through holes in the third perforated area accounts for 45% of the total surface area of the third perforated area.

[0065] Example 9

[0066] This embodiment provides a self-expanding packer with a water-permeable interlayer, which is the same as the embodiment 1, except that the total area of the through holes in the third perforated area accounts for 34% of the total surface area of the third perforated area.

[0067] In the above embodiments and comparative examples, in order to facilitate the test and save costs, the outer side surface of the water-permeable interlayer is divided into four sections, each of which is a circle with the same diameter. The bottom section is not provided with a through hole (corresponding to the non-porous area), and then the three side walls from bottom to top are respectively the first porous area, the second porous area, and the third porous area. The top coupling is detachable, which is convenient for removing the top coupling and replacing the side walls with different opening areas. The joints of the side walls of adjacent sections are provided with stepped overlapping edges to facilitate the jointing of the upper and lower side walls. A sealing strip is provided at the overlapping edge. By pressing down the upper side wall, the sealing strip at the overlapping edge can be compressed to achieve a sealing effect (or an additional sealing tape is wrapped around the outer wall of the joint, and the sealing tape does not cover the through hole. The sealing tape cooperates with the sealing strip to ensure the sealing effect).

[0068] During the test, a transparent acrylic bucket was used to simulate an underground wellbore to test the expansion performance of the rubber packer. The two couplings at the top and bottom of the packer were removed, and the top and bottom of the base pipe were directly sealed. The packer was then placed upright in the bucket. The bottom of the bucket was connected to a pump and water source to provide an upward flow of water. A water outlet pipe was installed at the top of the bucket. A new rubber packer was used for each test. The old, expanded rubber packer from the previous test was removed and replaced with a sidewall with a different opening area. The sealing of the sidewall joint was tested (to check for leaks). Once the sealing was satisfactory, a new rubber packer was installed for the next test.

[0069] Draw a vertical scale line on the outer wall of the bucket. On the scale line, draw a first horizontal line at the position corresponding to the boundary line between the non-porous area and the first porous area, draw a second horizontal line at the position corresponding to the boundary line between the first porous area and the second porous area, and draw a third horizontal line at the position corresponding to the boundary line between the second porous area and the third porous area.

[0070] During the test, water is pumped into the bottom of the bucket, causing the water level to rise. The liquid level in the water-permeable interlayer also rises, causing the rubber tube to absorb water and expand. The outer surface of the rubber tube gradually adheres to the inner wall of the bucket from bottom to top. The rubber tube is considered fully expanded at that point when it adheres to the inner wall. Timing begins when the water surface outside the packer reaches the bottom of the rubber tube. When the outer surface of the rubber tube adheres to the first horizontal line, the time is recorded once. When the outer surface of the rubber tube adheres to the second horizontal line, the time is recorded twice, which is the difference in expansion time between the portion of the rubber tube corresponding to the first perforated area and the portion corresponding to the non-perforated area. When the outer surface of the rubber tube adheres to the third horizontal line, the time is recorded a third time, which is the difference in expansion time between the portion of the rubber tube corresponding to the second perforated area and the portion corresponding to the first perforated area.

[0071] The top of the bucket can be opened. A circular stopper is lowered from the top and fits over the outer side of the rubber cylinder portion corresponding to the third perforated area (also outside the corresponding retaining ring). This circle corresponds to the mid-height of the rubber cylinder portion, and its inner diameter is designed to be the outer diameter of the retaining ring's midpoint when the rubber cylinder's top expands to the maximum extent the retaining ring can withstand. This circle is concentric with the base pipe. When the retaining ring is pushed out by the expanding rubber cylinder until it contacts the circle, the fourth time is recorded, representing the difference in expansion time between the rubber cylinder portion corresponding to the third perforated area and the rubber cylinder portion corresponding to the second perforated area.

[0072] Before the test, the distance between the outer surface of the rubber sleeve and the inner wall of the water bucket was 20 mm. The thickness of the water-passing interlayer and the water channel was 5 mm. The water inlet was circular and 5 mm high. The outer diameter of the base pipe was 115 mm, and the total length of the rubber sleeve was 1 meter.

[0073] Table 1 Comparison of the expansion of the rubber sleeve corresponding to the non-porous area of Example 1 to Example 3

[0074] .

[0075] Table 1 shows the time between the start of the countdown and the time of recording for each embodiment. This time is the time required for the rubber sleeve corresponding to the non-porous area to expand to the inner wall of the bucket. As can be seen from Table 1, the length of the rubber sleeve portion corresponding to the non-porous area directly affects the expansion speed of this portion of the rubber sleeve.

[0076] Table 2 Comparison of the expansion of the first perforated area corresponding to the rubber sleeve in Examples 1, 4, and 5

[0077] .

[0078] Table 2 shows the time between the first and second time recordings for each embodiment. This time represents the difference in expansion time between the portion of the rubber sleeve corresponding to the first perforated area and the portion corresponding to the non-perforated area. Table 2 shows that the through-hole area (i.e., the opening area) of the first perforated area influences the expansion rate of the corresponding rubber sleeve portion. When the through-hole area is within an appropriate range, the time it takes for this portion of the rubber sleeve to expand to the inner wall of the bucket is shorter, and the expansion gap between this portion and the portion corresponding to the non-perforated area is reduced, resulting in more uniform expansion of the rubber sleeve.

[0079] Table 3 Comparison of the expansion of the second perforated area corresponding to the rubber sleeve of Examples 1, 6, and 7

[0080] .

[0081] Table 3 shows the time between the second and third time recordings for each embodiment. This time period represents the difference in expansion time between the portion of the rubber sleeve corresponding to the second perforated area and the portion corresponding to the first perforated area. Table 3 shows that the through-hole area (i.e., the opening area) of the second perforated area influences the expansion rate of the corresponding rubber sleeve portion. When the through-hole area is within an appropriate range, the time it takes for this portion of the rubber sleeve to expand to the inner wall of the bucket is shorter, the expansion gap between this portion and the portion corresponding to the first perforated area is reduced, and the rubber sleeve expands more evenly.

[0082] Table 4 Comparison of the expansion of the rubber sleeve corresponding to the third hole area of Examples 1, 8, and 9

[0083] .

[0084] Table 4 shows the time between the third and fourth times of recording, for each embodiment. This time period represents the difference in expansion time between the portion of the rubber sleeve corresponding to the third perforated area and the portion corresponding to the second perforated area. Table 4 shows that the through-hole area (i.e., the opening area) of the third perforated area influences the expansion rate of the corresponding rubber sleeve portion. When the through-hole area is within an appropriate range, the time it takes for this portion of the rubber sleeve to expand to the inner wall of the bucket is shorter, the expansion gap between this portion and the portion corresponding to the second perforated area is reduced, and the rubber sleeve expands more evenly.

[0085] The actual total time for the entire rubber cylinder of Example 1 to expand to the inner wall of the bucket is 5 days and 9 hours, and the actual total time for the entire rubber cylinder of Comparative Example 1 to expand to the inner wall of the bucket is 7 days and 17 hours. It can be seen that the seal rubber cylinder provided by the present invention can achieve faster and more uniform expansion.

Claims

1. A self-expanding packer with a water-permeable interlayer, comprising a base pipe and a self-expanding rubber tube, wherein couplings are provided at both ends of the base pipe, and retaining rings are provided at both ends of the rubber tube for fixing the rubber tube to the outer surface of the base pipe, characterized in that: A water-permeable interlayer is provided inside the side wall of the base pipe corresponding to the rubber sleeve. Either end of the water-permeable interlayer is connected to the external space of the packer through a water groove, allowing external water to be introduced into the water-permeable interlayer. A plurality of through holes are provided on the side of the water-permeable interlayer facing the rubber sleeve, allowing water in the water-permeable interlayer to flow to the rubber sleeve, promoting the rubber sleeve to absorb water and expand. The water inlet of the water trough is located between a pair of mutually adjacent couplings and retaining rings. The water inlet is arranged around the base pipe. A concave storage tank is provided on the inner wall of the water trough near the water inlet. A self-expanding rubber ring is provided in the storage tank. A detachable baffle is provided at the opening of the storage tank. When the baffle is removed, the rubber ring in the reservoir absorbs water and expands, thereby blocking the water inlet and preventing water from continuing to enter the water-passing interlayer. The outer side of the water-permeable interlayer is divided into a non-porous area, a first porous area, a second porous area and a third porous area along its length direction; the baffle is divided into several curved sub-plates. The packer further includes a plurality of drawstrings and a plurality of support plates. The drawstrings extend along the length of the packer, within the water groove and the water-permeable interlayer, and are parallel to the central axis of the base pipe. One end of the drawstring is connected to the outer side of the split plate, and the other end of the drawstring passes through the outer side wall of the water-permeable interlayer and the rubber sleeve from the second perforated area to connect to the external support plate. The support sheet is arranged on the outside of the rubber cylinder and has a curvature so that the support sheet can be attached to the outer surface of the rubber cylinder. Several support sheets are at the same height, and temporary connecting belts are connected between adjacent support sheets. Before the rubber cylinder expands, several support sheets are connected into a circle by the connecting belt and hung on the outside of the rubber cylinder.

2. The self-expanding packer with a water-permeable interlayer according to claim 1, characterized in that: The cross section of the water-permeable interlayer is annular, the inner side of the water-permeable interlayer is the outer side of the base pipe, the outer side of the water-permeable interlayer faces the rubber sleeve, and the length of the water-permeable interlayer is not less than the length of the rubber sleeve; No through holes are set in the non-porous area, and through holes are set in the other three porous areas to control the different water permeability of the water-permeable interlayer to different parts of the rubber cylinder.

3. The self-expanding packer with a water-permeable interlayer according to claim 2, characterized in that: The length of the non-porous area accounts for 30-40% of the total length of the water-permeable interlayer. The lengths of the first porous area and the second porous area are the same. The third porous area corresponds to the part of the rubber cylinder covered by a retaining ring away from the water groove.

4. The self-expanding packer with a water-permeable interlayer according to claim 3, characterized in that: In the first porous area, the total area of through holes accounts for 20-25% of the area of the first porous area; in the second porous area, the total area of through holes accounts for 30-40% of the area of the second porous area; in the third porous area, the total area of through holes accounts for 35-45% of the area of the third porous area.

5. The self-expanding packer with a water-permeable interlayer according to claim 1, characterized in that: The water trough is arranged in the side of the base pipe. The water trough is annular and surrounds the base pipe. One end of the water trough is connected to the water interlayer, and the other end of the water trough is the water inlet, which is used to connect to the environment outside the base pipe. The water trough is concentrically arranged with the base pipe; the water inlet is circular and is an empty side formed by hollowing out the outer wall of the base pipe.

6. The self-expanding packer with a water-permeable interlayer according to claim 5, characterized in that: A storage tank is provided on the inner wall of the water trough close to the inside of the base pipe. The storage tank is circular and surrounds the base pipe. The storage tank protrudes toward the inside of the base pipe. The rubber ring is circular and is arranged inside the storage tank and arranged in a circle along the storage tank. The opening of the storage tank faces the water inlet and is closed by the baffle to protect the internal rubber ring.

7. The self-expanding packer with a water-permeable interlayer according to claim 6, characterized in that: When several sub-plates are connected together, a complete circle is formed. The baffle can tightly seal the storage tank opening and protect the internal rubber ring from expanding.

8. The self-expanding packer with a water-permeable interlayer according to claim 7, characterized in that: The side of the support sheet away from the rubber cylinder is the outer side surface, and one end of the drawstring passes through the support sheet and is fixedly connected to the outer side surface of the support sheet.

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