Stratum plugging device and method

Abstract

The invention belongs to the technical field of well drilling, and discloses a stratum plugging device and method.The stratum plugging device comprises an expansion pipe, a bottom plug, an expansion cone and a bottom plug. The bottom plug is installed at the bottom end of the expansion pipe and abuts against the inner wall of the expansion pipe. The expansion cone is arranged in the expansion pipe in a sleeved mode, a hydraulic cavity is formed between the expansion cone and the bottom plug, the expansion cone comprises a cone body and a plurality of sliding assemblies, the diameter of the cone body is gradually increased from the bottom end of the expansion pipe to the top end of the expansion pipe, and the sliding assemblies are arranged on the outer wall of the cone body and make rolling contact with the inner wall of the expansion pipe; the central pipe is installed in the expansion pipe, one end of the central pipe penetrates through the cone to be located in the hydraulic cavity, through the structure, the inner diameter of the expansion pipe is expanded, the expanded inner diameter of the expansion pipe is consistent in full length, and when follow-up drilling encounters a complex stratum, the stratum plugging device can be repeatedly used for deeper-layer plugging operation; no cement is needed for auxiliary sealing, and the construction process is simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling, and in particular to a formation plugging device and method. Background Art

[0002] As oil and gas exploration and development continue to advance into deep, complex formations and the ocean, the construction quality of oil and gas wells has become an effective guarantee for the smooth progress of subsequent oil and gas extraction work. When constructing oil and gas wells in deep and complex formations, abnormal formations such as high pressure, well leakage, water production, and collapse are often encountered. These situations seriously affect the construction quality and progress of oil and gas wells. Therefore, countermeasures and technical means are urgently needed to effectively solve the above problems and ensure the safety and smooth progress of subsequent drilling operations. The conventional way to solve the above problems is generally to isolate the next layer of casing. However, when encountering multiple complex formations, the casing has many layers, high costs, long construction cycles, and small completion sizes, making it difficult to drill to the target layer. As a result, the expansion tube open hole plugging technology was introduced.

[0003] The expansion tube is a metal steel tube with good properties. It expands in the well and fits tightly to the well wall to achieve the purpose of isolating complex formations. The operation process is as follows: place the expansion cone in the expansion tube, push the expansion cone from bottom to top in the expansion tube by hydraulic or mechanical force, expand the expansion tube and fit it tightly to the well wall, and cooperate with the cement on the outside of the expansion tube to seal the formation. However, when the formation is currently blocked by the expansion tube open hole blocking technology, the expansion cone has a large resistance when moving from bottom to top in the expansion tube, the expansion process of the expansion tube is not smooth, the process is cumbersome, and after the construction of the existing expansion tube open hole blocking technology is completed, the inner diameter of the expansion tube is inconsistent from top to bottom, and the blocking effect is poor. If the subsequent drilling encounters complex formations again, the expansion tube cannot be lowered and secondary blocking cannot be performed.

[0004] Therefore, there is an urgent need for a formation plugging device and method to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a formation plugging device and method to solve the problem that when plugging complex formations by expansion tube technology, the expansion process of the expansion tube is not smooth, the process is cumbersome, and the inner diameter of the expansion tube after the construction is completed is inconsistent up and down, the plugging effect is poor, and the subsequent plugging operation cannot be carried out.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In one aspect, a formation plugging device is provided, comprising:

[0008] Expansion tube;

[0009] A bottom plug, installed at the bottom end of the expansion pipe and abutting against the inner wall of the expansion pipe;

[0010] An expansion cone, wherein the expansion cone is sleeved in the expansion tube and a hydraulic cavity is formed between the expansion cone and the bottom plug, the expansion cone comprises a cone body and a plurality of sliding components, the diameter of the cone body gradually increases from the bottom end of the expansion tube to the top end of the expansion tube, and the plurality of sliding components are arranged on the outer wall of the cone body and in rolling contact with the inner wall of the expansion tube;

[0011] A central tube is installed in the expansion tube, and one end of the central tube passes through the vertebral body and is located in the hydraulic cavity.

[0012] Preferably, the plurality of sliding components include rotating shafts and rollers, the outer wall of the vertebral body is provided with a plurality of grooves, the plurality of rotating shafts are installed in the grooves one by one, and the plurality of rollers are sleeved on the rotating shafts one by one.

[0013] Preferably, the formation plugging device also includes a safety joint, and the safety joint is connected to the central pipe.

[0014] Preferably, the formation plugging device also includes a sand filter short section, and the sand filter short section is arranged on the central pipe.

[0015] On the other hand, a formation plugging method is provided, which is applied to the formation plugging device mentioned above, and comprises the following steps:

[0016] Step S1: lowering the formation plugging device into the wellbore;

[0017] Step S2: Continuously inject clean water into the central tube on the ground, so that the clean water is injected into the hydraulic cavity through one end of the central tube, and the clean water pushes the expansion cone to move toward the top of the expansion tube, and squeezes the expansion tube to expand it, while crushing and compacting the external strata that are prone to collapse and leakage, until the expansion cone reaches the top of the expansion tube;

[0018] Step S3: lift out the expansion cone and salvage the bottom plug at the bottom end of the expansion tube;

[0019] Step S4: After the bottom plug (2) at the bottom end of the expansion tube (1) is salvaged, the drilling process can be carried out. If a complex formation is drilled again, steps S1-S3 are repeated.

[0020] Preferably, in step S1, before lowering the formation plugging device into the wellbore, the wellbore is drilled to 20 to 50 m below the complex formation.

[0021] Beneficial effects of the present invention:

[0022] The formation plugging device provided by the present invention lowers the expansion tube into the complex formation, and continuously injects clean water into the hydraulic chamber through the center tube. The clean water in the hydraulic chamber generates hydraulic pressure to push the expansion cone to move toward the top of the expansion tube, squeeze the expansion tube, and expand the inner diameter of the expansion tube. The inner diameter of the expanded expansion tube is consistent throughout the length. When the subsequent drilling encounters a complex formation again, the formation plugging device can be reused to perform deeper plugging operations. By arranging multiple sliding components on the outer wall of the cone and in rolling contact with the inner wall of the expansion tube, the friction between the expansion cone and the inner wall of the expansion tube can be reduced, thereby effectively reducing the construction pressure, and there is no need to use cement to assist in sealing, which reduces the cementing process, greatly reduces the risk of premature solidification of cement, and simplifies the construction process.

[0023] The formation plugging method provided by the present invention is to lower the formation plugging device into the wellbore, and then continuously inject clean water into the center tube on the ground, so that the clean water is injected into the hydraulic cavity through one end of the center tube, and the clean water pushes the expansion cone to move toward the top of the expansion tube, and squeezes the expansion tube to expand it, until the expansion cone reaches the top of the expansion tube, and then the expansion cone is lifted out, and the bottom plug at the bottom of the expansion tube is salvaged. In this process, the sliding assembly on the outer wall of the vertebral body is pushed toward the top of the expansion cone by hydraulic pressure, and the expansion tube is pushed out radially by the roller in the sliding assembly, so that the expansion tube expands. Since the complex formation in this embodiment is a formation that is easy to collapse and leak, this method can also be used to crack and compact the formation rock outside the expansion tube, so that it fits tightly with the expansion tube, thereby effectively plugging the complex formation, and the plugging effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The overall structure of the formation plugging device provided by the embodiment of the present invention is shown in FIG. Figure 1 ;

[0025] Figure 2 The overall structure of the formation plugging device provided by the embodiment of the present invention is shown in FIG. Figure 2 ;

[0026] Figure 3 is a schematic structural diagram of an expansion cone provided by an embodiment of the present invention;

[0027] Figure 4 It is a front view of the expansion cone provided by an embodiment of the present invention.

[0028] In the figure:

[0029] 1. Expansion tube; 11. Hydraulic chamber;

[0030] 2. Bottom blocking;

[0031] 3. expansion cone; 31. cone; 311. groove; 32. sliding assembly; 321. rotating shaft; 322. roller;

[0032] 4. Center pipe; 5. Safety joint; 6. Sand filter short section. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0036] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0037] like Figures 1 to 4As shown, this embodiment provides a formation plugging device, including an expansion tube 1, a bottom plug 2, an expansion cone 3 and a center tube 4. The bottom plug 2 is installed at the bottom end of the expansion tube 1 and is in contact with the inner wall of the expansion tube 1; the expansion cone 3 is sleeved in the expansion tube 1 and a hydraulic chamber 11 is formed between the expansion cone 3 and the bottom plug 2; the expansion cone 3 includes a cone 31 and a plurality of sliding components 32, the diameter of the cone 31 gradually increases from the bottom end of the expansion tube 1 to the top end of the expansion tube 1, and the plurality of sliding components 32 are arranged on the outer wall of the cone 31 and are in rolling contact with the inner wall of the expansion tube 1; the center tube 4 is installed in the expansion tube 1, and one end of the center tube 4 passes through the cone 31 and is located in the hydraulic chamber 11.

[0038] The formation plugging device provided in the present embodiment lowers the expansion tube 1 into the complex formation, and continuously injects clean water into the hydraulic chamber 11 through the central tube 4. The clean water in the hydraulic chamber 11 generates hydraulic pressure to push the expansion cone 3 to move toward the top of the expansion tube 1, squeeze the expansion tube 1, and expand the inner diameter of the expansion tube 1. The inner diameter of the expanded expansion tube 1 is consistent throughout the length. When the subsequent drilling encounters a complex formation again, the formation plugging device can be reused to perform deeper plugging operations. By arranging multiple sliding components 32 on the outer wall of the vertebral body 31 and in rolling contact with the inner wall of the expansion tube 1, the friction between the expansion cone 3 and the inner wall of the expansion tube 1 can be reduced, thereby effectively reducing the construction pressure, and there is no need to use cement to assist in sealing, which reduces the cementing process, greatly reduces the risk of premature solidification of cement, and simplifies the construction process.

[0039] Specifically, the cone angle of the cone 31 in this embodiment is 3-6° to meet engineering needs. In other embodiments, the cone angle of the cone 31 can also be less than 3° or more than 6°. Specifically, the cone angle can meet actual engineering needs, and the cone angle size is not specifically limited here.

[0040] Alternatively, if Figure 1 , Figure 3 and Figure 4 As shown, the plurality of sliding components 32 include a rotating shaft 321 and a roller 322, a plurality of grooves 311 are provided on the outer wall of the vertebral body 31, a plurality of rotating shafts 321 are installed in the grooves 311 in a one-to-one correspondence, and a plurality of rollers 322 are sleeved on the rotating shaft 321 in a one-to-one correspondence. In this embodiment, along the axial direction of the vertebral body 31, three rows of grooves 311 are circumferentially provided on the outer wall of the vertebral body 31, a rotating shaft 321 is installed in each groove 311, and a roller 322 is sleeved on the rotating shaft 321, so that when the vertebral body 31 moves toward the top end of the expansion tube 1, the plurality of rollers 322 roll in contact with the inner wall of the expansion tube 1, which can effectively reduce the friction between the vertebral body 31 and the expansion tube 1, effectively reduce the construction pressure, make the expansion tube 1 easier to expand, and reduce the construction difficulty.

[0041] Alternatively, if Figure 1 and Figure 2 As shown, the formation plugging device also includes a safety joint 5, which is connected to the central pipe 4. Specifically, the central pipe 4 in this embodiment includes multiple central pipe sections, which are connected by the safety joint 5. It can be understood that the safety joint 5 in this embodiment is a safety tool that is easy to release and lock. It is installed at the position where the central pipe 4 needs to be released, and can transmit torque and withstand various composite stresses together with the central pipe 4. When the formation plugging device fails, the release and lock of the central pipe 4 can be completed through the connection between the wellbore and the ground, providing a guarantee tool for preventing and resolving accidents in the wellbore.

[0042] Alternatively, if Figure 1 and Figure 2 As shown, the formation plugging device also includes a sand filter short section 6, which is arranged on the central tube 4. Since the wellbore in this embodiment is used for drilling oil and gas wells, the wellbore is deep. During the ground construction process, water mixes with the mud and sand into the wellbore, causing the expansion cone 3 to move toward the top of the expansion tube 1. The resistance increases, affecting the construction progress, and even causing the expansion cone 3 to be unable to move. Therefore, the sand filter short section 6 plays a role in blocking the mud and sand, ensuring that the expansion cone 3 can smoothly reach the top of the expansion tube 1. Specifically, the sand filter short section 6 in this embodiment is circumferentially arranged on the outer wall of the central tube 4 to play a role in blocking and containing mud and sand.

[0043] In addition, this embodiment also provides a formation plugging method, which is applied to the above-mentioned formation plugging device, and includes the following steps:

[0044] Step S1: lowering the formation plugging device into the wellbore.

[0045] Step S2: Clean water is continuously injected into the central tube 4 on the ground, so that the clean water is injected into the hydraulic chamber 11 through one end of the central tube 4. The clean water pushes the expansion cone 3 to move toward the top of the expansion tube 1, and squeezes the expansion tube 1 to expand it, while crushing and compacting the external strata that are prone to collapse and leakage, until the expansion cone 3 reaches the top of the expansion tube 1.

[0046] Step S3: lift out the expansion cone 3 and salvage the bottom plug 2 at the bottom end of the expansion tube 1;

[0047] Step S4: After the bottom plug at the bottom end of the expansion tube is fished out, the drilling process can be carried out. If a complex formation is drilled again, steps S1-S3 are repeated.

[0048] The formation plugging method provided in this embodiment continuously injects clean water into the center tube 4 on the ground, so that the clean water is injected into the hydraulic chamber 11 through one end of the center tube 4, and the clean water pushes the expansion cone 3 to move toward the top of the expansion tube 1, and squeezes the expansion tube 1 to expand it, and at the same time crushes and compacts the external formation that is easy to collapse and leak, until the expansion cone 3 reaches the top of the expansion tube 1. In this process, the sliding assembly 32 on the outer wall of the vertebral body 31 is pushed toward the top of the expansion cone 3 by hydraulic pressure, and the roller 322 in the sliding assembly 32 is pushed out along the radial direction of the expansion tube 1, so that the expansion tube 1 expands. Since the complex formation in this embodiment is a formation that is easy to collapse and leak, this method can also be used to crack and compact the formation rock outside the expansion tube 1, so that it fits tightly with the expansion tube 1, thereby effectively plugging the complex formation, with good plugging effect, and the inner diameter of the expanded expansion tube is consistent throughout, and the plugging device can be reused to plug deeper complex formations.

[0049] Optionally, in step S1, before lowering the formation plugging device into the wellbore, the wellbore is pre-drilled to 20 to 50 meters below the complex formation, thereby ensuring that the formation plugging device can completely plug the complex formation within the entire thickness range, ensuring the smooth and safe subsequent operation.

[0050] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A formation plugging device, characterized in that: include: Expansion tube (1); A bottom plug (2) is installed at the bottom end of the expansion pipe (1) and is in contact with the inner wall of the expansion pipe (1); An expansion cone (3), wherein the expansion cone (3) is sleeved in the expansion tube (1) and a hydraulic chamber (11) is formed between the expansion cone (3) and the bottom plug (2); the expansion cone (3) comprises a cone body (31) and a plurality of sliding components (32); the diameter of the cone body (31) gradually increases from the bottom end of the expansion tube (1) to the top end of the expansion tube (1); and the plurality of sliding components (32) are arranged on the outer wall of the cone body (31) and are in rolling contact with the inner wall of the expansion tube (1); A central tube (4), wherein the central tube (4) is installed in the expansion tube (1), and one end of the central tube (4) passes through the vertebral body (31) and is located in the hydraulic chamber (11).

2. The formation plugging device according to claim 1, characterized in that: The plurality of sliding components (32) include a rotating shaft (321) and a roller (322); a plurality of grooves (311) are provided on the outer wall of the vertebral body (31); the plurality of rotating shafts (321) are installed in the grooves (311) in a one-to-one correspondence; and the plurality of rollers (322) are sleeved on the rotating shafts (321) in a one-to-one correspondence.

3. The formation plugging device according to claim 1, characterized in that: The formation plugging device also includes a safety joint (5), and the safety joint (5) is connected to the central pipe (4).

4. The formation plugging device according to claim 1, characterized in that: The formation plugging device also includes a sand filter short section (6), and the sand filter short section (6) is arranged on the central pipe (4).

5. A formation plugging method, characterized in that: The formation plugging device according to any one of claims 1 to 4 comprises the following steps: Step S1: lowering the formation plugging device into the wellbore; Step S2: Clean water is continuously injected into the central tube (4) on the ground, so that the clean water is injected into the hydraulic chamber (11) through one end of the central tube (4), and the clean water pushes the expansion cone (3) to move toward the top of the expansion tube (1), and squeezes the expansion tube (1) to expand it, while crushing and compacting the external strata that are prone to collapse and leakage, until the expansion cone (3) reaches the top of the expansion tube (1); Step S3: lift out the expansion cone (3) and salvage the bottom plug (2) at the bottom end of the expansion tube (1); Step S4: After the bottom plug (2) at the bottom end of the expansion tube (1) is salvaged, the drilling process can be carried out. If a complex formation is drilled again, steps S1-S3 are repeated.

6. The formation plugging method according to claim 5, characterized in that: In step S1, before lowering the formation plugging device into the wellbore, the wellbore is drilled to 20 to 50 meters below the complex formation.

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