Oil-string casing upward-moving prevention device for light casing fracturing construction

Abstract

The utility model relates to a device for preventing an oil-string casing from moving upwards for light casing fracturing construction, and belongs to the technical field of light casing fracturing construction. Comprising an upper flange plate abutting against an opening in the upper end of an oil-string casing coupling, a lower flange set movably and detachably arranged on the outer side of a surface casing coupling in a sleeving mode, and a plurality of connecting screw rods used for connecting the upper flange plate and the lower flange set. The upper flange plate abuts against the upper end of the oil-string casing coupling, the lower flange group is fixedly clamped on the outer side of the surface casing coupling, the relative position between the upper flange plate and the lower flange group is kept in a fixed state under the effective fixation of the connecting screw rod, the upper nut and the lower nut, and the upper flange plate and the lower flange group are fixed under the action of the limiting ring. And the lower flange group cannot slide upwards relative to the surface casing coupling, so that the condition that the oil-string casing body moves upwards in the fracturing construction process of the light casing is effectively prevented, and the smooth fracturing construction is ensured. The device is simple in structure, convenient to disassemble and assemble and capable of being repeatedly used, so that the cost is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of bare casing fracturing construction, in particular to an oil-proof casing upward movement device for bare casing fracturing construction. Background Art

[0002] Bare casing fracturing (also known as casingless fracturing) is a technology used for fracturing oil and gas wells, mainly used to improve the production capacity of oil and gas wells, especially in the exploitation of unconventional oil and gas resources (such as coalbed methane, shale gas, tight oil, etc.).

[0003] During the bare casing fracturing construction, the oil layer casing will be pushed up by high pressure (tens of MPa) (tens of tons of pushing force), causing the oil layer casing to jump 10-20 cm during the construction process, thus forcing the fracturing construction to stop.

[0004] At present, in order to prevent the oil layer casing from flowing upward during the bare casing fracturing construction process, construction personnel usually take the following measures, but these methods also have disadvantages to varying degrees: 1. Filling the space between the oil layer casing and the surface casing with cement slurry (full well cementing) until the cement slurry returns to the surface to relatively fix the two, thereby reducing the risk of flowing upward. However, this will increase the cost of each well by 50,000 to 100,000 yuan, and the high liquid column pressure of the cement slurry during cementing will damage the oil layer; 2. Using a permanent casing head with high cost, although it can provide a stable fixation effect, the device cannot be reused, which further increases the overall mining cost; 3. Using a circular steel plate originally welded to the surface casing coupling to weld it to the oil layer casing coupling, thereby indirectly fixing the oil layer casing coupling to the surface casing coupling. Although it can effectively prevent the oil layer casing from flowing upward, welding will cause the strength of the oil layer casing coupling to decrease, and this operation has a great safety hazard. Utility Model Content

[0005] In order to solve the above technical problems, the present invention provides a device for preventing oil layer casing from moving up during bare casing fracturing construction. The technical solution of the present invention is as follows:

[0006] The cam is secured to the outer wall of the oil wellbore by a secure connection to the flange, and the cam is secured to the outer wall of the oil wellbore by a secure connection to the flange. The cam is secured to the outside of the casing by a spring which is secured to the cam face by a spring which is secured to the outside of the casing by a spring which is secured to the cam face by a spring which is secured to the cam face by a spring which is secured to the cam face by a spring

[0007] Optionally, a plurality of groups of reinforcing ribs are fixedly provided in a circular array at the connection between the lower surface of the upper flange and the sleeve.

[0008] Optionally, the through hole is configured as an arc-shaped long groove.

[0009] Optionally, the front and rear sides of the main C-shaped buckle seat are fixedly connected with a main ear plate, and the front and rear sides of the secondary C-shaped buckle seat are fixedly connected with a secondary ear plate, and the main ear plate and the secondary ear plate located on the same side are fixed by bolts.

[0010] Optionally, a plurality of sets of reinforcing rib blocks 2 are equidistantly and fixedly connected to the connection between the upper surface of the C-shaped plate and the main C-shaped buckle seat.

[0011] Optionally, positioning blocks are fixedly connected to the middle positions of the upper surfaces of the main C-shaped buckle seat and the auxiliary C-shaped buckle seat, and positioning grooves that cooperate with the positioning blocks are provided on the left and right sides of the lower surface of the limiting ring.

[0012] All the above optional technical solutions can be combined arbitrarily, and the present utility model does not provide detailed descriptions of the structures after the combinations.

[0013] By means of the above solution, the beneficial effects of the present invention are as follows:

[0014] 1. The utility model fixes and clamps the lower flange group on the outside of the surface casing coupling by contacting the upper flange plate with the upper end of the oil layer casing coupling. Under the effective fixation of the connecting screw, the upper nut and the lower nut, the relative position between the upper flange plate and the lower flange group is maintained in a fixed state, and under the action of the limit ring, the lower flange group cannot slide upward relative to the surface casing coupling, thereby preventing the oil layer casing coupling from sliding upward relative to the surface casing coupling, thereby effectively preventing the oil layer casing body and the oil layer casing coupling from moving upward during the bare casing fracturing construction process, thereby ensuring the smooth progress of the fracturing construction.

[0015] 2. The device has a simple structure, is easy to assemble and disassemble, and is reusable, significantly reducing costs. Compared to cement slurry injection, this device does not require large amounts of cement slurry, thus avoiding potential damage to the oil reservoir and reducing the construction cost per well. Compared to permanent casing heads, this device not only provides a stable fixation but is also reusable, effectively reducing maintenance costs. Compared to welding, this device avoids the strength loss and safety risks associated with welding, significantly improving the safety and reliability of construction.

[0016] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the overall appearance and structure of the oil-proof casing upper device for bare casing fracturing construction provided by the utility model;

[0018] Figure 2 This is a right side view of the oil-proof casing upper device for bare casing fracturing construction provided by the utility model;

[0019] Figure 3 This is a front cross-sectional view of the oil-proof casing upper device for bare casing fracturing construction provided by the utility model;

[0020] Figure 4 Schematic diagram of the exploded structure of the oil-proof casing upper device for bare casing fracturing construction provided by the utility model Figure 1 ;

[0021] Figure 5 Schematic diagram of the exploded structure of the oil-proof casing upper device for bare casing fracturing construction provided by the utility model Figure 2 ;

[0022] Figure 6 This is a schematic structural diagram of the upper flange in the utility model;

[0023] Figure 7 This is a schematic diagram of the exploded structure of the upper flange in the utility model;

[0024] Figure 8 This is a schematic diagram of the exploded structure of the lower flange group in the utility model.

[0025] Numbers in the figure: 1. Oil layer casing coupling; 11. Oil layer casing body; 12. Fracturing wellhead assembly; 2. Surface casing coupling; 21. Surface casing body; 22. Annular steel plate; 3. Upper flange; 31. Center hole; 32. Through hole; 33. Sleeve; 34. Reinforcement rib block 1; 4. Lower flange assembly; 41. Main C-type buckle seat; 411. Main ear plate; 42. Secondary C-type buckle seat; 421. Secondary ear plate; 43. C-type plate; 431. Fixing hole; 432. Reinforcement rib block 2; 44. Positioning block; 5. Connecting screw; 51. Upper nut; 52. Lower nut; 6. Limiting ring; 61. Positioning groove. DETAILED DESCRIPTION

[0026] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] See also Figure 1-8The utility model provides an anti-oil layer casing upper device for bare casing fracturing construction, comprising an upper flange 3 abutting against the upper end opening of the oil layer casing coupling 1, a lower flange group 4 movably and detachably sleeved on the outer side of the surface casing coupling 2, and a plurality of connecting screws 5 for connecting the upper flange 3 and the lower flange group 4. The oil layer casing coupling 1 is fixedly sleeved on the upper end of the oil layer casing body 11, and the upper end of the oil layer casing coupling 1 is fixedly connected to a fracturing wellhead assembly 12. The surface casing coupling 2 The fixed sleeve is arranged on the upper end of the surface casing body 21, and the upper surface of the surface casing coupling 2 is fixedly connected with an annular steel plate 22. The oil layer casing coupling 1 abuts against the upper surface of the annular steel plate 22. The oil layer casing body 11 is located on the inner side of the annular steel plate 22 and the surface casing body 21. A center hole 31 is opened through the center of the upper flange 3. The diameter of the center hole 31 is the same as the inner diameter of the oil layer casing coupling 1. A plurality of through holes 32 are opened in an annular array on the surface of the upper flange 3. The lower surface of the flange 3 is fixedly connected to a sleeve 33 below the center hole 31. The sleeve 33 is sleeved on the outer side of the upper end of the oil layer casing coupling 1. The lower flange group 4 includes a main C-shaped buckle seat 41 and a sub-C-shaped buckle seat 42. The main C-shaped buckle seat 41 and the sub-C-shaped buckle seat 42 are symmetrically buckled on the outer side of the surface casing coupling 2 and the two are fixed by bolts. The main C-shaped buckle seat 41 and the sub-C-shaped buckle seat 42 are fixedly connected to a C-shaped plate 43 on the side away from the surface casing coupling 2. The C-shaped plate 43 is fixedly connected to the C-shaped plate 43 on the side away from the surface casing coupling 2. 3 is provided with a fixing hole 431, the upper end of the connecting screw 5 passes through the through hole 32 and is threadedly sleeved with an upper nut 51, the upper nut 51 abuts against the upper surface of the upper flange 3, the lower end of the connecting screw 5 passes through the fixing hole 431 and is threadedly sleeved with a lower nut 52, the lower nut 52 abuts against the lower surface of the C-shaped plate 43, the outer upper end of the surface casing coupling 2 is fixedly connected to a limit ring 6 for limiting the upward movement of the lower flange group 4, and the lower flange group 4 abuts against the lower surface of the limit ring 6.

[0028] The present invention fixes the lower flange assembly 4 on the outside of the surface casing coupling 2 by placing the upper flange 3 against the upper end of the oil layer casing coupling 1. Under the effective fixation of the connecting screw 5, the upper nut 51 and the lower nut 52, the relative position between the upper flange 3 and the lower flange assembly 4 is maintained in a fixed state, and under the action of the limit ring 6, the lower flange assembly 4 cannot slide upward relative to the surface casing coupling 2, thereby preventing the oil layer casing coupling 1 from sliding upward relative to the surface casing coupling 2, thereby effectively preventing the oil layer casing body 11 and the oil layer casing coupling 1 from moving upward during the bare casing fracturing construction process, ensuring that the fracturing construction proceeds smoothly. The device has a simple structure, is easy to disassemble and assemble, and is reusable, which greatly reduces costs. Compared with the method of pouring cement slurry, the present invention does not require a large amount of cement slurry, thereby avoiding potential damage to the oil layer and reducing the construction cost of each well. Compared with permanent casing heads, the present invention not only has a stable fixing effect, but is also reusable, effectively reducing maintenance costs. Compared with welding, the utility model avoids the strength loss and safety risks caused by welding, and significantly improves the safety and reliability of construction.

[0029] Specific operation method: First weld the limiting ring 6 to the upper end of the outer side of the surface casing coupling 2 to ensure that its position is stable and firm. Then use bolts (bolts, nuts) to fasten the main C-type buckle seat 41 and the auxiliary C-type buckle seat 42 to the outer side of the surface casing coupling 2, and abut against the lower surface of the limiting ring 6. Then put the sleeve 33 on the outer side of the upper end of the oil layer casing coupling 1. At this time, the upper flange 3 and the upper end of the oil layer casing coupling 1 form a reliable abutment structure. Then insert the connecting screw 5 into the through hole 32 and the fixing hole 431 in turn, and then thread the upper nut 51 on the outer side of the connecting screw 5 and abut against the upper surface of the upper flange 3, and thread the lower nut 52 on the outer side of the connecting screw 5 and abut against the lower surface of the C-type plate 43. Finally, fix the fracturing wellhead assembly 12 to the upper end of the oil layer casing coupling 1. During the fracturing operation, since the relative distance between the upper flange 3 and the lower flange assembly 4 cannot be increased, the upward movement of the oil layer casing body 11 is effectively avoided.

[0030] Specifically, spring washers may be installed between the upper nut 51 and the upper flange 3 and between the lower nut 52 and the C-shaped plate 43 to ensure a better compression effect during the connection process.

[0031] Specifically, the material of the connecting screw 5, the upper nut 51 and the lower nut 52 can be high-strength 42CrMoA alloy structural steel. This material has excellent tensile strength, corrosion resistance and good toughness, and can effectively withstand high-intensity fracturing operation pressure and mechanical load. The preferred diameter of the connecting screw 5 is 2 cm, and the preferred number of screws is 6. In this device, in order to prevent the oil layer casing body 11 from moving upward, the connecting screw 5 plays a key role as the main load-bearing member. The tensile strength of 42CrMoA alloy structural steel reaches 1080 MPa, that is, 10.8 tons per square centimeter. Taking a connecting screw 5 with a diameter of 2 cm as an example, the tensile strength of a single connecting screw 5 is 33.9 tons, and 6 screws can withstand 203.6 tons. When using 5"1 / 2" casing for bare casing fracturing operations, the maximum operating pressure can reach 100 MPa, corresponding to a top force of 94 tons. The device, with the combined support of the six connecting screws 5, is fully capable of withstanding such high-intensity fracturing operation pressures.

[0032] Furthermore, a plurality of groups of reinforcing ribs 34 are fixedly provided in a circular array at the connection between the lower surface of the upper flange 3 and the sleeve 33 .

[0033] Specifically, the reinforcing rib 1 34 is fixedly connected to the connection between the upper flange 3 and the sleeve 33, thereby enhancing the overall strength of the upper flange 3. During the fracturing operation, the oil layer casing body 11 is subjected to high pressure uplift. The reinforcing rib 1 34 can effectively prevent the upper flange 3 from tearing or deforming under the action of the high pressure uplift force.

[0034] Furthermore, the through hole 32 is configured as an arc-shaped long slot.

[0035] Specifically, the provision of the arc-shaped long groove is intended to improve the installation efficiency when the connecting screw 5 is docked with the fixing hole 431. Since the connecting screw 5 needs to pass through the through hole 32 and the fixing hole 431, when installing the upper flange 3 and the lower flange group 4, it is necessary to ensure that the through hole 32 and the fixing hole 431 remain vertically aligned, which requires a long time to position. Through the provision of the arc-shaped long groove, the utility model allows the connecting screw 5 to be fine-tuned within the through hole 32, thereby avoiding the difficulty of precise alignment required in traditional methods. The connecting screw 5 can move freely within a certain range within the arc-shaped long groove and adjust its position, so that it can more easily dock with the fixing hole 431, reducing the time required for positioning and greatly improving installation efficiency.

[0036] Furthermore, the front and rear sides of the main C-shaped buckle seat 41 are fixedly connected with the main ear plate 411, and the front and rear sides of the auxiliary C-shaped buckle seat 42 are fixedly connected with the auxiliary ear plate 421. The main ear plate 411 and the auxiliary ear plate 421 on the same side are fixed by bolts.

[0037] Specifically, the lower flange assembly 4 utilizes a split structure. During installation, simply interlock the primary C-shaped buckle 41 with the secondary C-shaped buckle 42 and secure with bolts. This split structure not only simplifies installation but also facilitates subsequent disassembly and maintenance. When the equipment is no longer in use, the split structure allows for easy disassembly and reuse, reducing component consumption and lowering maintenance costs.

[0038] Furthermore, a plurality of sets of reinforcing rib blocks 432 are fixedly connected at equal intervals between the upper surface of the C-shaped plate 43 and the connection between the main C-shaped buckle seat 41 .

[0039] Specifically, the second reinforcement rib 432 is fixedly connected to the connection between the C-shaped plate 43 and the primary C-shaped buckle 41, thereby enhancing its overall strength. During the fracturing operation, the second reinforcement rib 432 prevents the C-shaped plate 43 from tearing under the high-pressure upward force. Similarly, multiple sets of second reinforcement ribs 432 are fixedly connected at equal intervals at the connection between the upper surface of the C-shaped plate 43 and the secondary C-shaped buckle 42.

[0040] Furthermore, positioning blocks 44 are fixedly connected to the middle positions of the upper surfaces of the main C-shaped buckle seat 41 and the auxiliary C-shaped buckle seat 42, and positioning grooves 61 that cooperate with the positioning blocks 44 are provided on both left and right sides of the lower surface of the limiting ring 6.

[0041] Specifically, when installing the lower flange group 4, it is only necessary to insert the positioning block 44 into the positioning groove 61. By utilizing the precise fit between the positioning groove 61 and the positioning block 44, the relative positioning of the main C-shaped buckle seat 41 and the auxiliary C-shaped buckle seat 42 can be easily completed, making installation more convenient.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A device for preventing oil layer casing from sliding up for bare casing fracturing construction, characterized by: The invention comprises an upper flange (3) abutting against the upper opening of an oil layer casing coupling (1), a lower flange group (4) movably and detachably sleeved on the outside of a surface casing coupling (2), and a plurality of connecting screws (5) for connecting the upper flange (3) and the lower flange group (4); the oil layer casing coupling (1) is fixedly sleeved on the upper end of an oil layer casing body (11); the upper end of the oil layer casing coupling (1) is fixedly connected to a fracturing wellhead assembly (12); the surface casing coupling (2) is fixedly sleeved on the upper end of a surface casing body (21); the surface casing coupling (2) is fixedly sleeved on the upper end of a surface casing body (21); The upper surface is fixedly connected with an annular steel plate (22), the oil layer casing coupling (1) is in contact with the upper surface of the annular steel plate (22), the oil layer casing body (11) is located inside the annular steel plate (22) and the surface casing body (21), a center hole (31) is opened through the center of the upper flange (3), the diameter of the center hole (31) is the same as the inner diameter of the oil layer casing coupling (1), the surface of the upper flange (3) is provided with a plurality of through holes (32) in an annular array, and the lower surface of the upper flange (3) is located below the center hole (31). A sleeve (33) is fixedly connected, and the sleeve (33) is sleeved on the outer side of the upper end of the oil layer casing coupling (1). The lower flange group (4) includes a main C-shaped buckle seat (41) and a secondary C-shaped buckle seat (42). The main C-shaped buckle seat (41) and the secondary C-shaped buckle seat (42) are symmetrically buckled on the outer side of the surface casing coupling (2) and the two are fixed by bolts. The main C-shaped buckle seat (41) and the secondary C-shaped buckle seat (42) are fixedly connected to a C-shaped plate (43) on the side away from the surface casing coupling (2). The upper surface of the C-shaped plate (43) is provided with a fixing hole ( 431), the upper end of the connecting screw (5) passes through the through hole (32) and is threadedly sleeved with an upper nut (51), and the upper nut (51) abuts against the upper surface of the upper flange (3), the lower end of the connecting screw (5) passes through the fixing hole (431) and is threadedly sleeved with a lower nut (52), and the lower nut (52) abuts against the lower surface of the C-shaped plate (43), and the upper end of the outer side of the surface casing coupling (2) is fixedly connected with a limiting ring (6) for limiting the upward movement of the lower flange group (4), and the lower flange group (4) abuts against the lower surface of the limiting ring (6).

2. The oil-proof casing upper device for bare casing fracturing construction according to claim 1, characterized in that: A plurality of groups of reinforcing ribs (34) are fixedly provided in an annular array at the connection between the lower surface of the upper flange (3) and the sleeve (33).

3. The oil-proof casing upper device for bare casing fracturing construction according to claim 1 or 2, characterized in that: The through hole (32) is configured as an arc-shaped long slot.

4. The oil-proof casing upper device for bare casing fracturing construction according to claim 1, characterized in that: The front and rear sides of the main C-shaped buckle seat (41) are fixedly connected to a main ear plate (411), and the front and rear sides of the auxiliary C-shaped buckle seat (42) are fixedly connected to an auxiliary ear plate (421), and the main ear plate (411) and the auxiliary ear plate (421) located on the same side are fixed by bolts.

5. The oil-proof casing upper device for bare casing fracturing construction according to claim 1 or 4, characterized in that: A plurality of sets of reinforcing rib blocks (432) are fixedly connected at equal intervals to the connection between the upper surface of the C-shaped plate (43) and the main C-shaped buckle seat (41).

6. The oil-proof casing upper device for bare casing fracturing construction according to claim 1, characterized in that: A positioning block (44) is fixedly connected to the middle position of the upper surface of the main C-shaped buckle seat (41) and the auxiliary C-shaped buckle seat (42), and a positioning groove (61) matching the positioning block (44) is provided on both the left and right sides of the lower surface of the limiting ring (6).

Images