Packer for open hole well

Abstract

The invention relates to the field of petroleum and natural gas extraction downhole tools, in particular to a packer for an open hole well, a fixing assembly used for being clamped on the wall of the open hole well is movably connected to a first connecting assembly, and a second connecting assembly used for being communicated with a center pipe is arranged on the left side of a driving assembly; the sealing device comprises an arc-shaped metal sheet arranged on the driving assembly, and a sealing assembly used for sealing the open hole well is arranged on the outer side of the arc-shaped metal sheet. When the self-adaptive profiling rubber sleeve is in contact with an irregular well wall, the bulges with high contact pressure reversely press the local rubber sleeve; the pressure is transmitted to the elastic capsule through the rubber barrel, so that the pressure of fluid in the capsule is increased; as the fluid in the storage cavity is incompressible and communicated, the high pressure can drive the fluid to flow to the corresponding area of the recess with lower pressure; therefore, at the sunken part of the well wall, the fluid pressure can push the elastic capsule and the self-adaptive profiling rubber barrel to continue to expand outwards until the pit is tightly filled with the elastic capsule and the self-adaptive profiling rubber barrel.

Description

Technical Field

[0001] This invention relates to the field of downhole tools for oil and gas extraction, specifically a packer for open-hole wells. Background Technology

[0002] In oil and gas field development, it is often necessary to carry out stratified fracturing, stratified testing, or stratified production in open-hole sections; packers are key tools for achieving inter-layer separation. However, the open-hole wall is composed of natural rock, which has a rough, uneven, and irregular surface, and the rock hardness varies greatly between different strata.

[0003] Currently, common open-hole packers mainly rely on large, high-hardness rubber cylinders that expand under strong mechanical or hydraulic forces to forcibly deform and conform to the well wall.

[0004] However, when using a packer with a rubber sleeve to seal the well wall in an open hole, the well wall is not entirely smooth. Therefore, for irregular well walls, the rigid rubber sleeve cannot completely fill all the gaps, easily creating localized leakage channels and leading to seal failure. Simultaneously, the enormous expansion force may crush weaker rock formations, causing well wall instability, debris generation, and even stuck pipe accidents. Therefore, to address these problems, a packer for open holes is proposed. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art and solve at least one of the technical problems mentioned in the background art, the present invention proposes a packer for open-hole wells.

[0006] The technical solution adopted by the present invention to solve its technical problem is as follows: a packer for open-hole wells, comprising a central tube, a fixing device for locking onto the wall of the open-hole well is fitted on the body of the central tube, a driving device for left and right movement is fitted on the body of the central tube, and a sealing device for sealing the open-hole well is fitted on the driving device, the fixing device includes a connecting component one fitted on the central tube, and a fixing component for locking onto the wall of the open-hole well is movably connected to the connecting component one, the driving device includes a driving component fitted on the central tube for driving the fixing component to open, a connecting component two for communicating with the central tube is provided on the left side of the driving component, and the sealing device includes an arc-shaped metal plate provided on the driving component, and a sealing component for sealing the open-hole well is provided on the outer side of the arc-shaped metal plate.

[0007] Preferably, the connecting component includes a connecting ring fitted onto the central tube, which is typically fixed to the central tube by a pin or interference fit; the connecting ring has four slots for hinged connection with the fixing component; the sides of these slots are designed with hinge holes for forming a movable connection with the fixing component.

[0008] Preferably, the fixing assembly includes a slip for rotation disposed within a slot, the inner end of which is hinged to the slot by a pin, allowing the slip to open outward or retract inward around the hinge point like a door panel; the outer wall of the slip is machined with hard teeth with transverse grooves to increase friction with irregular rock walls; a ring is provided on the outer wall of the slip; for easy driving, the inner sides of the slip are connected by a common ring that can slide axially to synchronously push or pull all the slips, causing them to rotate around the hinge point.

[0009] Preferably, the drive assembly includes a front pressure cylinder fitted onto the central tube, and a conical platform for driving the slot to unfold is fixedly installed at the right end of the front pressure cylinder; the right end of the front pressure cylinder is integrally formed or fixedly connected to a conical platform whose outer radial direction gradually increases to the right; the conical surface of the conical platform mates with the inner inclined surface of the slip; during operation, when the front pressure cylinder moves to the right relative to the connecting ring, the conical platform squeezes into the inner side of the slip, forcing the slip to open radially outward around its hinge point until its outer wall teeth bite into the open hole wall, thus achieving anchoring.

[0010] Preferably, the second connecting component includes a rear pressure cylinder disposed at the left end of the front pressure cylinder. The rear pressure cylinder is also fitted onto the central tube, and its right end is fixedly connected to the left end of the front pressure cylinder by means of threads, thereby forming a whole during operation. The tube body of the rear pressure cylinder has four through holes for communicating with the central tube. These through holes communicate with the internal flow channel of the central tube, and their function is to maintain the communication of the annular fluid in the wellbore above and below the packer before or after the packer is set; or, after setting, to serve as a channel for injecting fluid into the wellbore below the packer.

[0011] Preferably, the sealing assembly includes an adaptive conforming rubber sleeve fitted onto a conical platform for sealing the open hole well, and the outer working surface of the adaptive conforming rubber sleeve is inlaid with several micro-hard wear-resistant particles; the adaptive conforming rubber sleeve is the outermost sealing body, made of super-elastic, oil-resistant and high-temperature resistant rubber; its inner wall is firmly bonded or tightly fitted to the outer wall of the elastic capsule; its outer working surface is inlaid with several micro-hard wear-resistant particles; these particles protrude slightly from the surface of the rubber sleeve, which can provide a certain anti-slip anchoring force during setting and effectively protect the adaptive conforming rubber sleeve from scratches by sharp rocks on the well wall.

[0012] Preferably, the inner side of the adaptive contoured rubber tube is provided with an elastic capsule for protecting the adaptive contoured rubber tube, and the elastic capsule is wrapped around the outer side of the arc-shaped metal sheet; the elastic capsule is made of high-strength, high-elasticity rubber material.

[0013] Preferably, the elastic capsule has a storage cavity for filling with an incompressible fluid; the cavity is pre-filled with an incompressible fluid, such as silicone oil or special hydraulic oil; the elastic capsule, the incompressible fluid inside, and the external adaptive contouring sleeve together constitute an adaptive contouring unit; when the unit is subjected to radial compression, the pressure of the internal fluid will be instantly and evenly distributed throughout the storage cavity.

[0014] Preferably, there are several arc-shaped metal sheets, which are arranged in a circumferential array on the tube of the conical platform. These arc-shaped metal sheets are closely arranged along the circumferential direction and are installed on the outer surface of the conical platform through the sliding groove or limiting mechanism on their inner side, forming a radially expandable bamboo curtain-like flexible skeleton. Each arc-shaped metal sheet can independently undergo a small-amplitude elastic bending.

[0015] The advantages of this invention are:

[0016] This invention utilizes an adaptive contoured rubber sleeve that, when in contact with an irregular wellbore, experiences high-pressure protrusions that reverse-pressure the sleeve. This pressure is transmitted through the sleeve to the elastic capsule, causing an increase in fluid pressure within the capsule. Since the fluid within the storage chamber is incompressible and interconnected, the high pressure drives the fluid towards the corresponding area of ​​lower pressure depression. Therefore, at the depression in the wellbore, the fluid pressure pushes the elastic capsule and the adaptive contoured rubber sleeve to continue expanding outwards until they completely fill the depression. This achieves a result where the shape of the adaptive contoured rubber sleeve closely matches the actual contour of the open-hole wellbore, forming a large-area surface contact seal and effectively sealing the annulus. This solves the problem that, because wellbore walls are not entirely smooth, rigid rubber sleeves cannot completely fill all gaps on irregular wellbore walls, easily creating local leakage channels and leading to seal failure. Furthermore, the enormous expansion force can crush weaker rock formations, causing wellbore instability, debris generation, and even stuck drill bit accidents. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the central tube structure of the present invention;

[0020] Figure 3 This is a schematic diagram of the fixing device structure of the present invention;

[0021] Figure 4 For the present invention Figure 3 Enlarged view of point A in the middle;

[0022] Figure 5 This is a schematic diagram of the drive device structure of the present invention;

[0023] Figure 6 This is a schematic diagram of the sealing device structure of the present invention;

[0024] Figure 7 For the present invention Figure 6 Enlarged view of section B in the middle.

[0025] In the diagram: 100, central tube; 200, fixing device; 210, connecting component one; 211, connecting ring; 212, slot; 220, fixing component; 221, slip; 222, ring; 300, driving device; 310, driving component; 311, front pressure cylinder; 312, conical platform; 320, connecting component two; 321, rear pressure cylinder; 322, through hole; 400, sealing device; 410, sealing component; 411, self-adaptive contoured rubber sleeve; 412, elastic capsule; 413, storage cavity; 420, arc-shaped metal sheet. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The following is in conjunction with the appendix Figures 1-7 This application will be described in further detail.

[0028] This application discloses a packer for open-hole wells, including a central tube 100. A fixing device 200 for locking onto the wall of the open-hole well is fitted onto the body of the central tube 100. A driving device 300 for left-right movement is fitted onto the body of the central tube 100. A sealing device 400 for sealing the open-hole well is fitted onto the driving device 300. The fixing device 200 includes a connecting assembly 210 fitted onto the central tube 100, and a device for locking onto the wall of the open-hole well is movably connected to the connecting assembly 210. The fixed assembly 220 and the driving device 300 include a driving assembly 310 mounted on the central tube 100 for driving the fixed assembly 220 to open. A connecting assembly 320 communicating with the central tube 100 is provided on the left side of the driving assembly 310. The sealing device 400 includes an arc-shaped metal plate 420 mounted on the driving assembly 310. A sealing assembly 410 for sealing the open hole is provided on the outer side of the arc-shaped metal plate 420. The packer is connected to the lower end of the tubing string and lowered to the designed position in the open hole section. At this time, the slips 221 retract, and the sealing device 400 is in an unexpanded state with its outer diameter at its minimum. Then, a ball is dropped or pressurized into the tubing string from the wellhead. Hydraulic pressure pushes the setting ball or piston inside the central tube 100 downwards, generating force. The force drives the central tube 100 to move upward relative to the front pressure cylinder 311 and the rear pressure cylinder 321; the front pressure cylinder 311 drives the conical platform 312 downward, and its conical surface presses against the inner inclined surface of the slip 221, forcing the four slips 221 to open outward synchronously and be firmly anchored to the well wall; at the same time, the downward movement of the conical platform 312 also drives the arc-shaped metal plate 420, the elastic capsule 412 and the adaptive contoured rubber sleeve 411 on it to move to the right as a whole and be subjected to axial compression through the structure of its outer surface; since the slip 221 has been anchored, the conical platform 312 can not continue to move downward, causing the sealing device 400 to be compressed axially, forcing the arc-shaped metal plate 420 to bend and expand outward, thereby squeezing the elastic capsule 412 and the adaptive contoured rubber sleeve 411 to expand radially and initially contact the well wall; when the adaptive contoured rubber sleeve 411 contacts the irregular well wall, the protrusion with high contact pressure will press against the local rubber sleeve; this pressure is transmitted to the elastic capsule 412 through the rubber sleeve, causing the fluid pressure inside the capsule to increase at that point.Because the fluid within the storage chamber 413 is incompressible and interconnected, high pressure will drive the fluid to flow towards the corresponding area of ​​the lower-pressure depression. Therefore, at the depression in the well wall, the fluid pressure will push the elastic capsule 412 and the adaptive contoured rubber sleeve 411 to continue to expand outward until they tightly fill the depression. Finally, when the overall fluid pressure reaches equilibrium, the shape of the adaptive contoured rubber sleeve 411 will closely conform to the actual contour of the open-hole well wall, forming a large-area surface contact seal, effectively sealing the annulus. After setting, the seal can be closed by using a post-pressure sleeve. The through-hole 322 on 321 is used for fluid injection and other operations; after the operation is completed, the tubing string is lifted; the upward force of the central tube 100 is released through the unlocking mechanism, which drives the conical platform 312 and the sealing device 400 to move upward and get rid of the squeezing of the slip 221; the slip 221 retracts under its own elasticity or the action of the return spring and gets rid of the well wall; at the same time, the axial compression of the sealing device 400 is released, and the elastic restoring force of the arc-shaped metal sheet 420 and the contraction force of the rubber sleeve work together to restore the sealing device 400 to its original shape, thereby achieving smooth unsealing and removal.

[0029] Reference Figure 2 , Figure 3 and Figure 4 The connecting component 210 includes a connecting ring 211 fitted onto the central tube 100. The connecting ring 211 is usually fixed relative to the central tube 100 by a pin or interference fit. The ring body of the connecting ring 211 has slots 212 for hinged connection with the fixing component 220, and there are four slots 212. The sides of these slots 212 are designed with hinge holes for forming a movable connection with the fixing component 220.

[0030] The fixing assembly 220 includes a slip 221 for rotation disposed in a slot 212. The inner end of the slip 221 is hinged to the slot 212 by a pin, so that the slip 221 can open outward or close inward around the hinge point like a door panel. The outer wall of the slip 221 is machined with hard teeth with transverse grooves to increase the friction with the irregular rock well wall. The outer wall of the slip 221 is provided with a ring 222. For easy driving, the inner sides of the slip 221 are connected by a common ring 222, which can slide axially to synchronously push or pull all the slips 221 to rotate around the hinge point.

[0031] Reference Figure 2 and Figure 3The drive assembly 310 includes a front pressure cylinder 311 fitted onto the central tube 100. A conical platform 312 for driving the slot 212 to unfold is fixedly installed at the right end of the front pressure cylinder 311. The right end of the front pressure cylinder 311 is integrally formed or fixedly connected to a conical platform 312 whose outer radial direction gradually increases to the right. The conical surface of the conical platform 312 mates with the inner inclined surface of the slip 221. During operation, when the front pressure cylinder 311 moves to the right relative to the connecting ring 211, the conical platform 312 squeezes into the inner side of the slip 221, forcing the slip 221 to open outward radially around its hinge point until its outer wall teeth bite into the open hole wall, thus achieving anchoring.

[0032] The second connecting component 320 includes a rear pressure cylinder 321 located at the left end of the front pressure cylinder 311. The body of the rear pressure cylinder 321 has four through holes 322 for communicating with the central tube 100. The second connecting component 320 is located at the left end of the front pressure cylinder 311 and is a rear pressure cylinder 321. The rear pressure cylinder 321 is also fitted onto the central tube 100, and its right end is fixedly connected to the left end of the front pressure cylinder 311 by means of threads, so that it forms a whole when in operation. The cylinder wall of the rear pressure cylinder 321 has four through holes 322 evenly provided circumferentially. These through holes 322 communicate with the internal flow channel of the central tube 100. Their function is to maintain the communication of the annular fluid in the wellbore above and below the packer before or after the packer is set; or after setting, to serve as a channel for injecting fluid into the wellbore below the packer.

[0033] Reference Figure 2 , Figure 6 and Figure 7 The sealing assembly 410 includes an adaptive contoured rubber sleeve 411 fitted on a conical platform 312 for sealing the open hole well. The outer working surface of the adaptive contoured rubber sleeve 411 is inlaid with several micro-hard wear-resistant particles. The adaptive contoured rubber sleeve 411 is the outermost sealing body, made of super-elastic, oil-resistant and high-temperature resistant rubber. Its inner wall is firmly bonded or tightly fitted to the outer wall of the elastic capsule 412. Its outer working surface is inlaid with several micro-hard wear-resistant particles. These particles protrude from the surface of the rubber sleeve, which can provide a certain anti-slip anchoring force during setting and effectively protect the adaptive contoured rubber sleeve 411 from scratches by sharp rocks on the well wall.

[0034] Furthermore, an elastic capsule 412 is provided inside the adaptive contouring rubber sleeve 411 to protect it, and the elastic capsule 412 is wrapped around the outside of the arc-shaped metal sheet 420. The elastic capsule 412 is made of high-strength, high-elasticity rubber material. The elastic capsule 412 has a complete storage cavity 413 inside, which is pre-filled with an incompressible fluid, such as silicone oil or special hydraulic oil. The elastic capsule 412, together with the incompressible fluid inside and the adaptive contouring rubber sleeve 411 outside, constitute an adaptive contouring unit. When the unit is subjected to radial compression, the pressure of the internal fluid will be instantly and evenly distributed throughout the storage cavity 413.

[0035] Furthermore, there are several arc-shaped metal sheets 420, which are arranged in a circumferential array on the tube body of the conical platform 312. These arc-shaped metal sheets 420 are closely arranged along the circumferential direction and are installed on the outer surface of the conical platform 312 through the inner groove or limiting mechanism to form a radially expandable bamboo curtain-like flexible skeleton. Each arc-shaped metal sheet 420 can independently undergo a small-amplitude elastic bending.

[0036] Working principle: The packer is connected to the lower end of the tubing string and lowered to the designed position in the open hole section. At this time, the slip 221 retracts, and the sealing device 400 is in an unexpanded state with its outer diameter at its minimum. Then, a ball is dropped or pressurized into the tubing string from the wellhead; hydraulic pressure pushes the setting ball or piston inside the central tube 100 downward, generating force. The force drives the central tube 100 to move upward relative to the front pressure cylinder 311 and the rear pressure cylinder 321; the front pressure cylinder 311 drives the conical platform 312 downward, and its conical surface presses against the inner inclined surface of the slip 221, forcing the four slips 221 to open outward synchronously and be firmly anchored to the well wall; at the same time, the downward movement of the conical platform 312 also drives the arc-shaped metal plate 420, the elastic capsule 412 and the adaptive contoured rubber sleeve 411 on it to move to the right as a whole and be subjected to axial compression through the structure of its outer surface; since the slip 221 has been anchored, the conical platform 312 can not continue to move downward, causing the sealing device 400 to be compressed axially, forcing the arc-shaped metal plate 420 to bend and expand outward, thereby squeezing the elastic capsule 412 and the adaptive contoured rubber sleeve 411 to expand radially and initially contact the well wall; when the adaptive contoured rubber sleeve 411 contacts the irregular well wall, the protrusion with high contact pressure will press against the local rubber sleeve; this pressure is transmitted to the elastic capsule 412 through the rubber sleeve, causing the fluid pressure inside the capsule to increase at that point. Because the fluid within the storage chamber 413 is incompressible and interconnected, high pressure will drive the fluid to flow towards the corresponding area of ​​the lower-pressure depression. Therefore, at the depression in the well wall, the fluid pressure will push the elastic capsule 412 and the adaptive contoured rubber sleeve 411 to continue to expand outward until they tightly fill the depression. Finally, when the overall fluid pressure reaches equilibrium, the shape of the adaptive contoured rubber sleeve 411 will closely conform to the actual contour of the open-hole well wall, forming a large-area surface contact seal, effectively sealing the annulus. After setting, the seal can be closed by using a post-pressure sleeve. The through-hole 322 on 321 is used for fluid injection and other operations; after the operation is completed, the tubing string is lifted; the upward force of the central tube 100 is released through the unlocking mechanism, which drives the conical platform 312 and the sealing device 400 to move upward and get rid of the squeezing of the slip 221; the slip 221 retracts under its own elasticity or the action of the return spring and gets rid of the well wall; at the same time, the axial compression of the sealing device 400 is released, and the elastic restoring force of the arc-shaped metal sheet 420 and the contraction force of the rubber sleeve work together to restore the sealing device 400 to its original shape, thereby achieving smooth unsealing and removal.

[0037] In summary, this invention achieves reliable anchoring through the mechanical linkage of the fixing device and the driving device, and utilizes an adaptive sealing device based on the principle of fluid pressure balance to achieve efficient and user-friendly sealing of irregular open hole well walls. It has the advantages of reliable sealing, minimal damage to the well wall, and easy unsealing.

[0038] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A packer for open-hole wells, comprising a central tube (100), characterized in that: The central tube (100) is fitted with a fixing device (200) for locking onto the wall of the open hole. The central tube (100) is also fitted with a drive device (300) for left and right movement. The drive device (300) is fitted with a sealing device (400) for sealing the open hole. The fixing device (200) includes a connecting assembly (210) fitted onto the central tube (100). The connecting assembly (210) is movably connected to a fixing assembly for locking onto the wall of the open hole. The drive device (300) includes a drive assembly (310) mounted on the central tube (100) for driving the fixed assembly (220) to open. A connecting assembly (320) for communicating with the central tube (100) is provided on the left side of the drive assembly (310). The sealing device (400) includes an arc-shaped metal sheet (420) provided on the drive assembly (310). A sealing assembly (410) for sealing the open hole well is provided on the outer side of the arc-shaped metal sheet (420).

2. A packer for open-hole wells according to claim 1, characterized in that: The first connecting component (210) includes a connecting ring (211) fitted on the central tube (100). The connecting ring (211) has four slots (212) for hinged connection with the fixing component (220).

3. A packer for open-hole wells according to claim 2, characterized in that: The fixing component (220) includes a locating pad (221) disposed in a locating groove (212) for rotation, and the outer side wall of the locating pad (221) is provided with a ring (222).

4. A packer for open-hole wells according to claim 3, characterized in that: The drive assembly (310) includes a front pressure cylinder (311) fitted on the central tube (100), and a conical platform (312) for driving the card slot (212) to unfold is fixedly installed at the right end of the front pressure cylinder (311).

5. A packer for open-hole wells according to claim 4, characterized in that: The second connecting component (320) includes a rear pressure cylinder (321) located at the left end of the front pressure cylinder (311). The body of the rear pressure cylinder (321) has four through holes (322) for communicating with the central tube (100).

6. A packer for open-hole wells according to claim 4, characterized in that: The sealing assembly (410) includes an adaptive contoured rubber sleeve (411) fitted on a conical platform (312) for sealing the open hole well, and the outer working surface of the adaptive contoured rubber sleeve (411) is inlaid with a number of micro hard wear-resistant particles.

7. A packer for open-hole wells according to claim 6, characterized in that: The inner side of the adaptive contoured rubber tube (411) is provided with an elastic capsule (412) for protecting the adaptive contoured rubber tube (411), and the elastic capsule (412) is wrapped around the outer side of the arc-shaped metal sheet (420).

8. A packer for open-hole wells according to claim 7, characterized in that: The elastic capsule (412) has a storage cavity (413) for filling with an incompressible fluid.

9. A packer for open-hole wells according to claim 1, characterized in that: There are several arc-shaped metal sheets (420), and these arc-shaped metal sheets (420) are arranged in a circular array on the tube body of the conical platform (312).

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