Ultrahigh-pressure fracturing petroleum drilling and production flexible pipeline

Abstract

The invention belongs to the technical field of petroleum pipelines, and particularly relates to an ultrahigh-pressure fracturing petroleum drilling and production flexible pipeline which sequentially comprises a lining layer, an inner rubber layer, a pressure bearing layer and an outer rubber layer from inside to outside in the pipe diameter direction. The main net is formed by interweaving spiral transverse fibers and longitudinal fibers, the pressure-bearing layer further comprises reinforcing fibers, and the reinforcing fibers are bound with an upper-stage interweaving point of the main net and extend to a lower-stage interweaving point in the diagonal direction of the grid to be bound. The reinforcing fibers are additionally arranged on the basis of the main net of the pressure bearing layer and arranged in the diagonal direction of the grid, the structure can effectively disperse concentrated stress at interweaving points, and the problem that the interweaving points are loosened or broken due to stress concentration of a traditional grid structure is solved; meanwhile, the reinforcing fibers extending diagonally can restrain radial and axial displacement of transverse and longitudinal fibers of the main net, and fiber drawing or deviation under the high-pressure load is prevented.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum pipelines, and in particular relates to an ultra-high pressure fracturing petroleum drilling and production flexible pipeline. Background Art

[0002] Ultra-high-pressure fracturing (UHPF) oil drilling and production technology involves injecting high-pressure fluid into underground rock formations, creating fractures. Proppants are then used to stabilize and propping up the fractures, thereby releasing oil and gas from unconventional reservoirs such as shale and tight sandstone. The drilling process typically involves first drilling vertically into the underground rock formation and then drilling horizontally within it, creating an L-shaped channel. Therefore, flexible pipes are typically used to inject the high-pressure fluid.

[0003] The pressure-bearing layer of existing flexible pipes typically utilizes a mesh-like structure formed by interwoven fibers to withstand the radial and axial loads imposed by high-pressure fluids. However, under conditions of long-term high pressure, high-frequency vibration, and complex stresses, traditional pressure-bearing layer structures are prone to loosening or breaking at the mesh interweaving points due to stress concentration, resulting in a decrease in the overall structural stability of the pressure-bearing layer. Furthermore, the transverse and longitudinal fibers in the mesh structure are simply interwoven and fixed, lacking an effective limiting constraint mechanism. Under high-pressure loads, the fibers are prone to axial or radial displacement, leading to wire pulling and overall damage to the mesh structure. This can cause a sudden drop in the strength of the pressure-bearing layer and even pipeline rupture. Summary of the Invention

[0004] In order to solve the problems existing in the above-mentioned prior art, the present invention provides an ultra-high pressure fracturing flexible pipeline for oil drilling and production. Reinforcing fibers are added to the main grid of the pressure-bearing layer, and the reinforcing fibers are arranged along the diagonal direction of the grid. This structure can effectively disperse the concentrated stress at the interweaving points, avoiding the loosening or breakage of the interweaving points caused by stress concentration in the traditional grid structure; at the same time, the diagonally extending reinforcing fibers can constrain the radial and axial displacement of the transverse and longitudinal fibers of the main grid, preventing the fibers from pulling out or deviating under high pressure loads.

[0005] The specific technical solution adopted in the present invention is:

[0006] A flexible pipeline for ultra-high pressure fracturing oil drilling and production, comprising an inner lining layer, an inner rubber layer, a pressure-bearing layer, and an outer rubber layer from the inside out along the pipe diameter direction. The pressure-bearing layer comprises a main mesh with a cage-like structure, which is formed by interweaving spiral transverse fibers and longitudinal fibers. The pressure-bearing layer also comprises reinforcing fibers, which are tied to the upper-level interweaving point of the main mesh and extend along the diagonal direction of the mesh to the next-level interweaving point for binding.

[0007] The transverse fibers include first transverse fibers and second transverse fibers, and the longitudinal fibers include first longitudinal fibers and second longitudinal fibers. The first transverse fibers, first longitudinal fibers, second transverse fibers, and second longitudinal fibers are overlapped in sequence, and the first transverse fibers and second transverse fibers as well as the first longitudinal fibers and second longitudinal fibers are twisted to form a double-strand helical structure.

[0008] The first transverse fibers and the second transverse fibers are twisted in a clockwise direction, and the first longitudinal fibers and the second longitudinal fibers are twisted in a counterclockwise direction.

[0009] The pressure-bearing layer further includes limiting fibers, which are overlapped between the first longitudinal fibers and the second transverse fibers. The limiting fibers extend along the diagonal direction of the grid and are arranged in an X-shaped cross with the reinforcing fibers.

[0010] The reinforcing fibers are wound around the interweaving points in an S shape. The reinforcing fibers start to wind along the bottom of the previous interweaving point and are led out along the bottom of the previous interweaving point. The reinforcing fibers led out from the previous interweaving point start to wind along the top of the next interweaving point and are led out along the top of the next interweaving point.

[0011] The outer side of the pressure-bearing layer is further wound with steel wire to form a winding layer.

[0012] The pressure-bearing layer further comprises a resin layer. After the main mesh and the reinforcing fibers are woven together, they are soaked in heated liquid resin. The resin adheres to and solidifies on the surfaces of the main mesh and the reinforcing fibers to form a resin layer.

[0013] The beneficial effects of the present invention are:

[0014] The present invention adds reinforcing fibers to the main mesh of the pressure-bearing layer. These fibers are tied diagonally to the interweaving points of the previous and next levels of the mesh, forming a diagonal support structure. This structure effectively disperses concentrated stress at the interweaving points, avoiding the loosening or breakage problems associated with traditional mesh structures caused by stress concentration. Furthermore, the diagonally extending reinforcing fibers constrain the radial and axial displacement of the main mesh's transverse and longitudinal fibers, preventing fiber pullout or displacement under high-pressure loads. This improves the stability and fatigue resistance of the overall pressure-bearing layer structure, extending the service life of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural diagram of a flexible pipe;

[0016] Figure 2 A top view schematic diagram of the joint position between the main net and the limiting fiber;

[0017] Figure 3 A side view schematic diagram of the overlap position of the main net and the limiting fiber;

[0018] Figure 4 This is a schematic diagram of the plane structure after the pressure-bearing layer is flattened;

[0019] In the accompanying drawings, 1, inner lining layer, 2, inner rubber layer, 3, pressure-bearing layer, 4, outer rubber layer, 5, transverse fibers, 6, longitudinal fibers, 7, reinforcing fibers, 8, limiting fibers, 9, winding layer, 501, first transverse fibers, 502, second transverse fibers, 601, first longitudinal fibers, 602, second longitudinal fibers. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0021] Specific embodiments, such as Figure 1-4 As shown, a flexible pipeline for ultra-high pressure fracturing oil drilling and production comprises, from the inside to the outside along the pipe diameter direction, an inner lining layer 1, an inner rubber layer 2, a pressure-bearing layer 3, and an outer rubber layer 4. The pressure-bearing layer 3 comprises a main mesh with a cage-like structure, which is formed by interweaving spiral transverse fibers 5 and longitudinal fibers 6. The pressure-bearing layer 3 also includes reinforcing fibers 7, which are tied to the upper interweaving point of the main mesh and extend along the diagonal direction of the mesh to the next interweaving point for tying.

[0022] The pressure-bearing layer (3) of existing flexible pipes typically utilizes a mesh-like structure formed by interwoven fibers to withstand the radial and axial loads imposed by high-pressure fluids. However, under conditions of long-term high pressure, high-frequency vibration, and complex stresses, the mesh interweaving points of the conventional pressure-bearing layer (3) are susceptible to loosening or breaking due to stress concentration, resulting in a decrease in the overall structural stability of the pressure-bearing layer (3). Furthermore, the transverse fibers (5) and longitudinal fibers (6) in the mesh structure are simply interwoven and fixed, lacking an effective position-limiting constraint mechanism. Under high-pressure loads, the fibers are prone to axial or radial displacement, leading to fiber pullout and overall damage to the mesh structure. This can cause a sudden drop in the strength of the pressure-bearing layer (3) and even pipeline rupture.

[0023] Therefore, the present invention adds reinforcing fibers 7 on the basis of the main mesh of the pressure-bearing layer 3, and the reinforcing fibers 7 are tied along the diagonal direction of the grid to the interweaving points of the upper and lower levels to form a supporting structure in the diagonal direction. Figure 2 and Figure 4 It is a planar structure obtained by cutting off a local area of the cage-shaped main net. This structure can effectively disperse the concentrated stress at the interweaving points, avoiding the loosening or breakage of the interweaving points caused by stress concentration in traditional grid structures; at the same time, the diagonally extending reinforcement fibers 7 can constrain the radial and axial displacement of the transverse and longitudinal fibers 6 of the main net, preventing the fibers from pulling out or shifting under high-pressure loads, thereby improving the stability and fatigue resistance of the overall structure of the pressure-bearing layer 3 and extending the service life of the pipeline.

[0024] like Figure 2As shown, the transverse fibers 5 include a first transverse fiber 501 and a second transverse fiber 502, and the longitudinal fibers 6 include a first longitudinal fiber 601 and a second longitudinal fiber 602. The first transverse fibers 501, the first longitudinal fibers 601, the second transverse fibers 502, and the second longitudinal fibers 602 are overlapped in sequence, and the first transverse fibers 501 and the second transverse fibers 502 as well as the first longitudinal fibers 601 and the second longitudinal fibers 602 are twisted to form a double-strand helical structure.

[0025] The transverse fibers 5 (transverse first fibers 501, transverse second fibers 502) and the longitudinal fibers 6 (longitudinal first fibers 601, longitudinal second fibers 602) are twisted into a double helical structure, and four layers of fibers are alternately overlapped to significantly enhance interfiber friction and winding tightness. The double helical structure evenly distributes the load of a single fiber to another fiber through the twisting force, preventing the single fiber from breaking due to uneven force. At the same time, the structure has an interlocking effect. The double helical structure formed by the transverse fibers 5 tightly clamps the longitudinal first fibers 601 at the interweaving point, and the double helical structure formed by the longitudinal fibers 6 tightly clamps the transverse second fibers 502 at the interweaving point, thereby forming a limit node at the interweaving point, restricting the movement of the individual transverse and longitudinal fibers. In addition, the double helical structure increases the contact area and friction coefficient between the fibers, allowing the transverse fibers 5 and the longitudinal fibers 6 to form a tight mechanical engagement under the action of the twisting torque, thereby limiting the deviation of the transverse and longitudinal fibers, avoiding the phenomenon of pulling out, and improving the ability of the pressure-bearing layer 3 to resist the impact of high-pressure fluid.

[0026] The first transverse fibers 501 and the second transverse fibers 502 are twisted in a clockwise direction, and the first longitudinal fibers 601 and the second longitudinal fibers 602 are twisted in a counterclockwise direction.

[0027] The reverse twisting design of twisting the transverse fibers 5 clockwise and the longitudinal fibers 6 counterclockwise can form a tighter bite relationship between the transverse and longitudinal fibers 6 at the interweaving points, further enhance the connection strength of the interweaving points, and improve the structural stability of the pressure-bearing layer 3.

[0028] like Figure 2-4 As shown, the pressure-bearing layer 3 further includes limiting fibers 8, which are overlapped between the longitudinal first fibers 601 and the transverse second fibers 502. The limiting fibers 8 extend along the diagonal direction of the grid and are arranged in an X-shaped cross with the reinforcing fibers 7.

[0029] The limiting fibers are multiple fibers with a spiral structure. This design forms a bidirectional constraint network with the reinforcing fibers 7 through the support of the limiting fibers 8 in the diagonal direction. On the one hand, the X-shaped cross structure can form multiple triangular support units in the grid plane, and use the stability of the triangle to enhance the ability of the pressure-bearing layer 3 to resist shear stress; on the other hand, the cross setting of the limiting fibers 8 and the reinforcing fibers 7 can further limit the displacement of the main network fibers in the diagonal direction, preventing the grid from undergoing diamond deformation due to high-pressure loads, thereby improving the overall stiffness and deformation resistance of the pressure-bearing layer 3.

[0030] like Figure 4 As shown, the reinforcing fiber 7 is wound around the interweaving point in an S shape. The reinforcing fiber 7 starts to wind along the bottom of the previous interweaving point and is led out along the bottom of the previous interweaving point. The reinforcing fiber 7 led out from the previous interweaving point starts to wind along the top of the next interweaving point and is led out along the top of the next interweaving point.

[0031] The reinforcing fiber 7 adopts an S-shaped winding method, which can evenly distribute the load of the reinforcing fiber 7 on the upper and lower sides of the interweaving point. This winding method avoids the local stress concentration that may be caused by the traditional binding method, and makes the constraint force on the interweaving point more balanced through the upper and lower bidirectional fixation; at the same time, the S-shaped wound reinforcing fiber 7 has a higher fit with the main net, ensuring that the reinforcing fiber 7 is not easy to loosen or fall off under high-pressure vibration environment, thereby continuously and stably improving the connection strength of the interweaving point and the fatigue resistance of the pressure-bearing layer 3.

[0032] like Figure 1 As shown, the outer side of the pressure-bearing layer 3 is further wound with steel wire to form a wound layer 9 .

[0033] Steel wire is wound around the outside of the main mesh to form a wound layer 9. Leveraging the high strength of the steel wire, the radial load-bearing capacity of the pressure-bearing layer 3 is significantly increased. The steel wire wound layer 9 directly withstands the expansion stress generated by the high-pressure fluid, sharing the load of the main mesh fibers. Furthermore, the rigid structure of the steel wire restrains deformation of the main mesh, preventing structural relaxation of the pressure-bearing layer 3 during high-frequency vibrations and loosening of the double helix structure of the transverse and longitudinal fibers 6.

[0034] The pressure-bearing layer 3 also includes a resin layer. After the main mesh and the reinforcing fibers 7 are woven, they are soaked in heated liquid resin. The resin adheres to and solidifies on the surface of the main mesh and the reinforcing fibers 7 to form a resin layer.

[0035] After the pressure-bearing layer 3 is woven, it is soaked in heated liquid resin to form a resin layer. The resin solidifies, bonding the main mesh and reinforcing fibers 7 together. The resin layer fills the spaces between the fibers, reducing wear caused by relative friction. The resin's bonding strength also strengthens the fiber structure, preventing breakage caused by individual fibers being subjected to stress.

Claims

1. An ultra-high pressure fracturing oil drilling flexible pipeline, characterized in that: The flexible pipe comprises an inner lining layer (1), an inner rubber layer (2), a pressure-bearing layer (3), and an outer rubber layer (4) from the inside to the outside along the pipe diameter direction. The pressure-bearing layer (3) comprises a main net with a cage-like structure. The main net is formed by interweaving spiral transverse fibers (5) and longitudinal fibers (6). The characteristic is that the pressure-bearing layer (3) also includes reinforcing fibers (7). The reinforcing fibers (7) are tied to the upper-level interweaving point of the main net and extend along the diagonal direction of the grid to the next-level interweaving point for tying.

2. The ultra-high pressure fracturing oil drilling flexible pipeline according to claim 1, characterized in that: The transverse fibers (5) include first transverse fibers (501) and second transverse fibers (502), and the longitudinal fibers (6) include first longitudinal fibers (601) and second longitudinal fibers (602). The first transverse fibers (501), the first longitudinal fibers (601), the second transverse fibers (502), and the second longitudinal fibers (602) are sequentially overlapped up and down, and the first transverse fibers (501) and the second transverse fibers (502), as well as the first longitudinal fibers (601) and the second longitudinal fibers (602) are respectively twisted to form a double-strand helical structure.

3. The ultra-high pressure fracturing oil drilling flexible pipeline according to claim 2, characterized in that: The first transverse fibers (501) and the second transverse fibers (502) are twisted in a clockwise direction, and the first longitudinal fibers (601) and the second longitudinal fibers (602) are twisted in a counterclockwise direction.

4. The ultra-high pressure fracturing oil drilling flexible pipeline according to claim 2, characterized in that: The pressure-bearing layer (3) further comprises limiting fibers (8), wherein the limiting fibers (8) are overlapped between the longitudinal first fibers (601) and the transverse second fibers (502), and the limiting fibers (8) extend along the diagonal direction of the grid and are arranged in an X-shaped cross with the reinforcing fibers (7).

5. The ultra-high pressure fracturing oil drilling flexible pipeline according to claim 2, characterized in that: The reinforcing fibers (7) are wound around the interweaving points in an S-shape. The reinforcing fibers (7) are wound along the lower side of the previous interweaving point and are led out along the lower side of the previous interweaving point. The reinforcing fibers (7) led out from the previous interweaving point are wound along the upper side of the next interweaving point and are led out along the upper side of the next interweaving point.

6. The ultra-high pressure fracturing oil drilling flexible pipeline according to claim 1, characterized in that: The outer side of the pressure-bearing layer (3) is further wound with steel wire to form a winding layer (9).

7. The ultra-high pressure fracturing oil drilling flexible pipeline according to claim 1, characterized in that: The pressure-bearing layer (3) also includes a resin layer. After the main mesh and the reinforcing fibers (7) are woven together, they are soaked in heated liquid resin, and the resin adheres to and solidifies on the surfaces of the main mesh and the reinforcing fibers (7) to form a resin layer.

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