Packer device for use downhole and method of plugging for use downhole

Abstract

The application belongs to the technical field of drilling and completion, and particularly discloses a packer device used in a well. The packer device comprises an inner cylinder, a center passage formed in the inner cylinder for fluid to pass through, and a sealing mechanism comprising a sealing member, a first end head arranged downstream of the sealing member, and a second end head arranged upstream of the sealing member. The first end head and the second end head are both sealingly attached to the inner cylinder and a well wall. The sealing member is configured to form a liquid state after being heated, to fill into the well wall, and to expand to form a fixed connection with the well wall after being cooled. The application replaces the rubber material with a low-melting-point metal material, so that the sealing member still has a stable structure in an oil, gas or acidic environment, thereby ensuring that the packer device used in the well can have a long-term sealing effect in the well. In addition, a sealing method used in the well is also provided.

Description

Technical Field

[0001] This invention relates to the field of drilling and completion technology, and more specifically to a packer device for downhole applications and a plugging method for downhole applications. Background Technology

[0002] One of the most critical technical challenges in gas well cementing is preventing gas channeling. Gas channeling can significantly impact downhole operations, causing annular pressure buildup, casing corrosion, and reduced production and recovery rates. Furthermore, it can severely affect subsequent acidizing and fracturing operations and stratified production, even leading to the abandonment of the entire well. The primary cause of gas channeling is the deformation or aging of cementing cement due to prolonged exposure to downhole temperature and pressure, resulting in a loss of its sealing function and ultimately, gas channeling.

[0003] In recent years, integrating packers onto the casing string has been proposed for cementing. Because the packer contains rubber seals, an elastic seal is formed during cementing through the deformation of the rubber material, thus preventing gas channeling. This method provides good sealing in the initial stages; however, the rubber material rapidly ages and deteriorates due to long-term exposure to downhole oil, gas, water, and acidic annular gases, significantly reducing its sealing effectiveness and exacerbating gas channeling. Even conventional remedial methods such as cementing, gelling, milling, or casing patching are insufficient to control gas channeling.

[0004] However, there is currently no device that can solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a packer device for downhole applications, which replaces rubber materials with low-melting-point metal materials. This ensures that the seal maintains a stable structure in oil, gas, or acidic environments, thereby guaranteeing a long-term sealing effect downhole. Furthermore, because the metal material is remeltable, if the seal fails, the sealing function of the downhole packer device can be restored by reheating and re-solidifying the seal. In addition, a downhole plugging method is also proposed.

[0006] According to a first aspect of the invention, a packer device for downhole applications is provided, comprising an inner cylinder having a central channel through which fluid passes; and a plugging mechanism fitted over the inner cylinder, the plugging mechanism comprising a plugging member, a first end cap disposed downstream of the plugging member, and a second end cap disposed upstream of the plugging member, wherein both the first end cap and the second end cap are in a sealing fit with the inner cylinder and the well wall; wherein the plugging member is configured to form a liquid state upon heating to fill the well wall, and to expand upon cooling to form a fixed connection with the well wall.

[0007] In one embodiment, the sealing element is configured as a hollow columnar structure and has a plurality of first through holes for guiding the fluid.

[0008] In one embodiment, the sealing element is made of a metal material with a melting point lower than that of the first end cap, the second end cap, and the inner cylinder.

[0009] In one embodiment, the liquid density of the metal material is greater than the density of the liquid inside the well.

[0010] In one embodiment, both the first end cap and the second end cap are constructed as hollow bowl-shaped structures.

[0011] In one embodiment, the first end cap is provided with a plurality of second through holes for receiving the cement slurry from the inner cylinder, and the second end cap is provided with a plurality of third through holes, wherein the first through holes, the second through holes, and the third through holes are aligned in the axial direction and interconnected with each other.

[0012] In one embodiment, the packer device further includes a heating mechanism that can be inserted into the central channel, the heating mechanism being configured to heat the packing member so that the packing member becomes liquid under the action of the heating mechanism.

[0013] In one embodiment, the packer device further includes a cementing plug capable of being inserted into the central channel of the inner cylinder.

[0014] According to a second aspect of the present invention, a plugging method for downhole is provided, the method being performed by a packer device for downhole as described above, comprising the following steps: S1, lowering the inner cylinder equipped with the plugging mechanism to a predetermined position downhole, pumping cement slurry into the inner cylinder, the cement slurry sequentially passing through the central channel, the second through hole, the first through hole, and the third through hole to reach the upstream of the second end cap; S2, after stopping the injection of cement slurry, placing the cement plug into the inner cylinder, and pumping displacement fluid into the inner cylinder to perform a displacement operation; S3, waiting for the cement slurry to solidify; S4, lowering a heating mechanism into the inner cylinder for heating, so that the plugging component, after being heated, forms a liquid state to fill the well wall, and expands after cooling to form a fixed connection with the well wall.

[0015] In one embodiment, the method further includes the step of repeating step S4 after the fixed connection formed in step S4 fails. Attached Figure Description

[0016] The invention will now be described in detail with reference to the accompanying drawings, in which:

[0017] Figure 1 The schematic diagram illustrates the structure of a packer device for downhole applications according to the present invention;

[0018] Figure 2 A cross-sectional view of a packer device for downhole applications according to the present invention;

[0019] Figure 3 This is a schematic diagram of the first state of the packer device for downhole applications according to the present invention;

[0020] Figure 4 This is a schematic diagram of the second state of the packer device for downhole applications according to the present invention;

[0021] Figure 5 This is a schematic diagram of the plugging element in a packer device for downhole applications according to the present invention.

[0022] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not drawn to scale. Detailed Implementation

[0023] The invention will now be further described with reference to the accompanying drawings. The directional term "upstream" or similar terms refers to the direction closer to the wellhead, i.e. Figure 1 The direction from the top of the well; the directional term "downstream" or similar terms refer to the direction away from the wellhead, i.e. Figure 1 The direction of the middle and bottom ends.

[0024] Figure 1The schematic diagram illustrates the structure of a packer device 100 for downhole applications according to the present invention. (As shown) Figure 1 As shown, according to a first aspect of the present invention, a packer device 100 for downhole applications is disclosed, mainly comprising an inner cylinder 10 and a plugging mechanism 20. The plugging mechanism 20 is sleeved on the outside of the inner cylinder 10, and the inner wall of the plugging mechanism 20 is in a sealing fit with the outer wall of the inner cylinder 10. Furthermore, the plugging mechanism 20 and the inner cylinder 10 are assembled and then deployed downhole together to achieve a sealing effect within the well. The details are described below.

[0025] According to the present invention, such as Figure 1 As shown, a central channel 11 is formed in the inner cylinder 10. The central channel 11 provides a passage for fluid to be delivered downhole, thereby facilitating the subsequent initial fixation of the packer device 100 for downhole use. In one embodiment of the invention, the fluid includes cement slurry 2 and displacement fluid.

[0026] According to the present invention, such as Figure 1 As shown, the sealing mechanism 20 includes a sealing element 30, a first end cap 40, and a second end cap 50. Both the first end cap 40 and the second end cap 50 are constructed as hollow, bowl-shaped structures, allowing for easier installation on the outer periphery of the inner cylinder 10. Furthermore, the first end cap 40 is positioned downstream of the sealing element 30, with its upstream end sealingly fitted to the first end of the sealing element 30, thus preventing leakage during fluid injection. The second end cap 50 is positioned upstream of the sealing element 30, with its downstream end sealingly fitted to the second end of the sealing element 30, again preventing leakage during fluid injection. In one embodiment of the invention, both the first end cap 40 and the second end cap 50 are made of an elastic material, such as rubber. This facilitates a more secure seal with the inner cylinder 10 and the well wall 1, effectively preventing leakage of the cement slurry 2.

[0027] Figure 5 This is a schematic diagram of the sealing element 30 in a packer device 100 for downhole applications according to the present invention. Figure 5 As shown, the sealing element 30 is constructed as a hollow cylindrical structure, which makes it easier to install the sealing element 30 on the outer periphery of the inner cylinder 10.

[0028] According to one embodiment of the present invention, the plugging element 30 is made of a metal material and is configured to liquefy upon heating, thereby filling the irregular well wall 1, and expand upon cooling, further strengthening the fixed connection with the well wall 1, so that the packer device 100 used downhole can achieve a good sealing effect downhole. In one embodiment of the present invention, the metal material used for the plugging element 30 has a low melting point, and the metal material has good fluidity, stable properties, and does not react with oil, gas, or acids after melting.

[0029] According to one embodiment of the present invention, the melting point of the metal material used in the plugging component 30 is lower than that of the first end cap 40, the second end cap 50, and the inner cylinder 10. Thus, during the process of the plugging component 30 forming a liquid state after being heated, the first end cap 40, the second end cap 50, and the inner cylinder 10 will not deform due to temperature changes, thereby effectively improving the sealing performance of the packer device 100 used downhole.

[0030] In one embodiment of the invention, the liquid density of the metal material used in the plugging member 30 is greater than the density of the liquid accumulated inside the well wall 1. This gives the liquid plugging member 30 better fluidity, allowing it to displace the liquid accumulated in holes, crevices, or fissures in the well wall 1 and completely fill the well wall 1. Consequently, after the plugging member 30 cools and expands, it further strengthens its connection with the well wall 1, enabling the packer device 100 used downhole to achieve a good sealing effect downhole.

[0031] Figure 2 This is a cross-sectional view of a packer device 100 for downhole applications according to the present invention. According to the present invention, as... Figure 2 As shown, the sealing member 30 is provided with a plurality of first through holes 31. The sealing member 30 can guide the cement slurry 2 to move upstream through the first through holes 31.

[0032] According to the present invention, such as Figure 2 As shown, a plurality of second through holes 41 are provided on the first end cap 40. The first end cap 40 can receive cement slurry 2 transported to the well by the central channel 11 through the second through holes 41.

[0033] According to the present invention, such as Figure 2 As shown, several third through holes 51 are provided on the second end cap 50. The second end cap 50 can guide the cement slurry 2 to move upstream through the third through holes 51.

[0034] According to one embodiment of the present invention, the first through hole 31, the second through hole 41, and the third through hole 51 are all aligned axially and interconnected. Specifically, the cement slurry 2 from the central channel 11 can flow sequentially through the second through hole 41, the first through hole 31, and the third through hole 51, and finally flow through the third through hole 51 to the upstream of the second end cap 50. Furthermore, since both the first end cap 40 and the second end cap 50 are in a sealed fit with the inner cylinder 10 and the well wall 1, when the cement slurry 2 flows into the first end cap 40 through the second through hole 41 and flows upstream of the second end cap 50 through the third through hole 51, it is possible to effectively prevent the cement slurry 2 from seeping between the sealing member 30 and the well wall 1. Since the upstream end of the first end cap 40 is in a sealed fit with the first end of the sealing member 30 and the downstream end of the second end cap 50 is in a sealed fit with the second end of the sealing member 30, it is possible to effectively prevent the cement slurry 2 from seeping between the sealing member 30 and the well wall 1 during its upward movement.

[0035] Figure 3 This is a schematic diagram of a first state of a packer device 100 for downhole applications according to the present invention. In one embodiment of the invention, as... Figure 3 As shown, the downhole packer device 100 also includes a cementing plug 60. The cementing plug 60 can be inserted into the central channel 11, thereby separating the cement slurry 2 from the displacement fluid, thus ensuring that the cement slurry 2 can flow completely into the well.

[0036] Figure 4 This is a schematic diagram of a second state of the packer device 100 for downhole applications according to the present invention. In one embodiment of the invention, as... Figure 4 As shown, the downhole packer device 100 also includes a heating mechanism 71. The heating mechanism 71 is constructed as a cylindrical structure and is capable of releasing a large amount of heat in a short time downhole using electrical, chemical, or nuclear energy. Thus, when the heating mechanism 71 is inserted into the central channel 11, it can fully heat the plugging element 30, causing it to melt into a liquid state and further fill the irregular well wall 1.

[0037] In one embodiment of the present invention, the upstream and downstream ends of the inner cylinder 10 are provided with threads, and multiple sections of the inner cylinder 10 can be connected by threads to form a casing string, thereby making it easier to deliver the packer device 100 for downhole use to the designated location.

[0038] In a second aspect of the invention, a downhole plugging method is disclosed, which is performed using the downhole packer device 100 as described above, and includes the following steps:

[0039] First, the sealing element 30, the first end cap 40, and the second end cap 50 are installed on the outside of the inner cylinder 10, and then the assembled downhole packer device 100 is lowered into the predetermined position downhole.

[0040] Then, cement slurry 2 is pumped into the inner cylinder 10. At this time, cement slurry 2 passes through the second through hole 41, the first through hole 31 and the third through hole 51 in sequence, and finally flows to the upstream of the second end cap 50 through the third through hole 51.

[0041] After the cement slurry 2 is stopped, cement plug 60 is inserted into the inner cylinder 10, and displacement fluid is pumped into the inner cylinder 10 to perform a displacement operation, thereby completely discharging the cement slurry 2 from the inner cylinder 10.

[0042] Finally, after the cement slurry 2 solidifies, the heating mechanism 71 is put into the inner cylinder 10 to heat the sealing component 30. The sealing component 30 becomes liquid after being heated, thereby replacing the accumulated liquid in the irregular well wall 1. After the sealing component 30 cools down, it expands, further forming a fixed connection between the sealing component 30 and the well wall 1 to achieve a sealing effect.

[0043] In one embodiment of the present invention, when the fixed connection between the sealing component 30 and the well wall 1 fails during the above process, the heating mechanism 71 can be put back into the inner cylinder 10 and the sealing component 30 can be reheated, so that the sealing component 30 becomes liquid after being heated again, thereby replacing the accumulated liquid in the irregular well wall 1. Furthermore, the sealing component 30 expands after cooling, so that the sealing component 30 and the well wall 1 form a fixed connection again, thereby further achieving the sealing effect.

[0044] The packer device 100 for downhole applications according to the present invention replaces the rubber material with a low-melting-point metal material, ensuring that the sealing element 30 maintains a stable structure in oil, gas, or acidic environments, thereby guaranteeing a long-term sealing effect for the packer device 100 downhole. Furthermore, because the metal material is remeltable, when the sealing effect fails, the sealing effect of the downhole packer device 100 can be restored by reheating and resolidifying the sealing element 30.

[0045] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can easily make changes or modifications within the scope of the present invention, and such changes or modifications should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A packer device (100) for downhole applications, comprising: Inner cylinder (10), wherein a central channel (11) for fluid to pass through is formed. as well as A plugging mechanism (20) is fitted outside the inner cylinder (10). The plugging mechanism (20) includes a plugging component (30), a first end cap (40) disposed downstream of the plugging component (30), and a second end cap (50) disposed upstream of the plugging component (30). The first end cap (40) and the second end cap (50) are both in a sealed fit with the inner cylinder (10) and the well wall. The sealing element (30) is configured to form a liquid state upon heating to fill the well wall, and to expand upon cooling to form a fixed connection with the well wall. The plugging member (30) is provided with a plurality of first through holes (31), the first end cap (40) is provided with a plurality of second through holes (41), and the second end cap (50) is provided with a plurality of third through holes (51). The first through holes (31), the second through holes (41), and the third through holes (51) are aligned in the axial direction and interconnected with each other. The packer device (100) also includes a heating mechanism (71) that can be inserted into the central channel (11). The heating mechanism (71) is configured to heat the plugging member (30) so that the plugging member (30) forms a liquid under the action of the heating mechanism (71). The packer device (100) also includes a cementing plug (60) that can be inserted into the central channel (11) of the inner cylinder (10).

2. The packer device for downhole applications according to claim 1, characterized in that, The sealing element (30) is constructed as a hollow columnar structure.

3. The packer device for downhole applications according to claim 2, characterized in that, The sealing element (30) is made of metal, and the melting point of the metal is lower than that of the first end cap (40), the second end cap (50) and the inner cylinder (10).

4. The packer device for downhole applications according to claim 3, characterized in that, The density of the liquid metal is greater than that of the liquid inside the well.

5. The packer device for downhole applications according to claim 4, characterized in that, Both the first end cap (40) and the second end cap (50) are constructed as hollow bowl-shaped structures.

6. A method for plugging in wells, characterized in that, The method is carried out using a packer device (100) for downhole applications according to any one of claims 1 to 5, and includes the following steps: S1. The inner cylinder (10) equipped with the sealing mechanism (20) is lowered into the predetermined position in the well, and cement slurry is pumped into the inner cylinder (10). The cement slurry passes through the central channel (11), the second through hole (41), the first through hole (31) and the third through hole (51) in sequence to reach the upstream of the second end cap (50). S2. After the cement slurry injection is stopped, place the cementing plug (60) into the inner cylinder (10) and pump the displacement fluid into the inner cylinder (10) to perform the displacement operation. S3. Wait for the cement grout to solidify; S4. The heating mechanism (71) is lowered into the inner cylinder (10) for heating, so that the sealing component (30) is heated to form a liquid state to fill the well wall, and expands after cooling to form a fixed connection with the well wall.

7. The plugging method for downhole applications according to claim 6, characterized in that, The method further includes the following steps: If the fixed connection formed in step S4 fails, repeat step S4.

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