Well washing anti-pollution process pipe column under perforation interval and well washing method

Abstract

The anti-pollution process pipe column comprises an upper oil pipe, a lower oil pipe and a reversing well washing valve, the reversing well washing valve comprises a valve seat fixedly installed at the lower end of an extension pipe, a valve hole is formed in the center of the valve seat, a valve ball is arranged in the valve hole in a seated mode, and a well washing pressure guiding device is installed between the upper oil pipe and the lower oil pipe. The well washing pressure guiding device comprises an inner pipe, an outer pipe is fixedly installed on the outer circle face of the inner pipe, circulation holes are formed in the pipe wall of the outer pipe, and the inner pipe is installed between the upper oil pipe and the lower oil pipe. The lower oil pipe is sleeved with the sleeve plugging device, the upper connector and the outer pipe are fixedly installed, the extension pipe is fixedly installed on the lower connector, and the reversing well washing valve is fixedly installed at the lower end of the extension pipe through the valve seat. When the inside of an oil pipe is flushed, a perforation section on a casing pipe is sealed and separated, water is prevented from being injected into a stratum, and normal oil extraction operation after flushing is guaranteed.

Description

Technical Field

[0001] The invention relates to oil field production equipment, in particular to a well-washing anti-pollution process pipe column under a perforation section and a well-washing method. Background Art

[0002] During long-term oil production in oil fields, there are blockages such as wax deposition and agglomeration inside the oil pipes. In order to ensure efficient oil production in the oil fields, the inside of the oil pipes must be flushed.

[0003] The traditional way to flush the inside of the oil pipe is to inject water between the oil pipe and the casing outside the oil pipe. The water injected between the oil pipe and the casing enters the inside of the oil pipe through the reversing well flushing valve at the lower end of the oil pipe and finally flows out from the upper end of the oil pipe, thereby flushing the inside of the oil pipe.

[0004] When the oil pump is lowered into a position below the perforation section, because the casing wall is provided with a perforation section, water flows downward through the oil pipe and the casing during well washing, enters the oil pipe through the lowest end of the oil pipe, and is discharged to the ground. At the same time, the water injected between the oil pipe and the casing will also enter the formation through the perforation section. Although this flushing method can flush the inside of the oil pipe, a large amount of water enters the formation at the same time, polluting the formation. When the cleaning is completed and the oil production operation is carried out, the water injected into the formation needs to be discharged before normal oil production can be carried out, which seriously affects the normal oil production operation. Summary of the invention

[0005] The present invention aims to solve the above technical problems and provides a perforation section well washing anti-pollution process pipe string. When flushing the inside of the oil pipe, the perforation section on the casing is sealed to prevent water from being injected into the formation, ensuring normal oil production operations after flushing.

[0006] The technical solution of the present invention is:

[0007] A pipe string for anti-pollution process of well washing under perforation section, comprising an upper oil pipe, a lower oil pipe and a reversing well washing valve, wherein the reversing well washing valve comprises a valve seat fixedly mounted at the lower end of an extension pipe, a valve hole is arranged at the center of the valve seat, and a valve ball is seated in the valve hole, and the special feature thereof is that a well washing pressure guide is installed between the upper oil pipe and the lower oil pipe, the well washing pressure guide comprises an inner pipe, an outer pipe is fixedly mounted on the outer circumferential surface of the inner pipe, a flow hole is arranged on the pipe wall of the outer pipe, and the inner pipe is installed between the upper oil pipe and the lower oil pipe;

[0008] A casing plugger is mounted on the outer side of the lower oil pipe, and the casing plugger includes a center tube, an upper joint and a lower joint are fixedly installed at the upper and lower ends of the center tube, and an upper pressure cap, a rubber cylinder, a lower pressure cap, a cone, a plurality of circumferentially distributed slips, an upper limit sleeve, a straightening body and a lower limit sleeve are slidably installed on the outer cylindrical surface of the center tube from top to bottom in sequence, the lower end of the outer cylindrical surface of the cone is conical, and the upper end of the inner cylindrical surface of each slip is respectively a cone that matches the lower end of the outer cylindrical surface of the cone, a limit ring is clamped on the outer cylindrical surface of the slip, and a connection is made between the outer cylindrical surface of each slip and the inner cylindrical surface of the limit ring. Connect the elastic original component, install multiple circumferentially distributed and radially sliding straightening blocks on the outer circular surface of the straightening body, connect the lower elastic element between the inner circular surface of each straightening block and the outer circular surface of the straightening body, the upper limit sleeve and the lower limit sleeve are fixedly installed at the upper and lower ends of the straightening body, the upper and lower ends of the straightening block are clamped in the upper limit sleeve and the lower limit sleeve, a locking mechanism is installed between the lower limit sleeve and the lower joint, the upper joint is fixedly installed with the outer tube, an extension pipe is fixedly installed on the lower joint, and the reversing well flushing valve is fixedly installed at the lower end of the extension pipe through a valve seat.

[0009] Furthermore, a connector is fixedly installed on the upper end of the inner tube, a coupling is fixedly installed on the lower end of the outer circular surface of the connector, the outer tube is fixedly installed on the lower end of the inner circular surface of the coupling, and the connector is fixedly installed on the upper oil pipe.

[0010] Furthermore, the locking mechanism includes a locking pin fixedly mounted on the outer cylindrical surface of the lower joint, a locking opening arranged on the lower limit sleeve, a side opening arranged on one side of the locking opening and extending toward the lower end of the lower limit sleeve, the locking pin is located in the locking opening, the lower limit sleeve and the lower joint are locked up and down, the locking pin slides out through the side opening, and the lower limit sleeve and the lower joint are unlocked up and down.

[0011] Furthermore, there are multiple rubber cylinders, and a spacer ring is installed on the outer circumferential surface of the central cylinder between two upper and lower adjacent rubber cylinders to improve the sealing effect.

[0012] Furthermore, each slip is provided with corrugations distributed up and down on the outer circumferential surface to improve the friction between the slip and the inner circumferential surface of the casing.

[0013] Furthermore, a connecting tube is slidably installed up and down on the outer circumferential surface of the central tube, and the connecting tube is fixedly installed between the pressing cap and the cone.

[0014] Furthermore, the upper elastic element is an arc-shaped spring sheet.

[0015] Furthermore, the lower elastic element is a spring.

[0016] Furthermore, a mesh plate is fixedly installed on the inner circular surface of the valve seat above the valve ball to prevent the valve ball from being lost.

[0017] The well washing method using the well washing and pollution prevention process string under the perforation section as described above has the following steps:

[0018] Step 1: Place the lock pin in the lock port, lock the lower limit sleeve and the lower joint up and down, and insert the perforating section down-well washing and pollution prevention process pipe string into the casing downward to overcome the friction between the straightening block and the inner surface of the casing, and make the casing plugger located above the perforating section on the casing;

[0019] Step 2: Rotate the upper oil pipe to make the lock pin escape from the lock port through the side opening, and unlock the lower limit sleeve and the lower joint up and down;

[0020] Step 3: Move the upper oil pipe downward, the straightening block expands on the inner surface of the casing due to friction, the upper joint drives the upper pressure cap, rubber cylinder, spacer ring, lower pressure cap connector and cone to move downward, and the slips expand tightly on the inner surface of the casing under the lateral force generated by the cone at the upper end of the outer surface of the cone;

[0021] Step 4: Continue to move the upper oil pipe downward. The rubber cylinder expands and deforms outwards under the action of up and down squeezing, expands and seals on the inner surface of the casing, and rotates the upper oil pipe to lock the lock pin against the lower end surface of the lower limit sleeve;

[0022] Step 5: Inject water between the upper oil pipe and the casing. The injected water enters between the lower oil pipe and the extension pipe through the flow hole on the pressure guide. Under the plugging action of the valve ball of the reversing well flushing valve, the water enters the lower oil pipe, the center pipe and the upper oil pipe from bottom to top in turn to clean the inside of the lower oil pipe, the center pipe and the upper oil pipe.

[0023] The beneficial effects of the present invention are:

[0024] During the well washing operation, firstly, the lower limit sleeve and the lower joint are locked up and down by the locking mechanism, and the anti-pollution process pipe string of the perforating section is inserted into the casing downward to overcome the friction between the straightening block and the inner circular surface of the casing, and the casing plugger is located above the perforating section on the casing. Then, the lower limit sleeve and the lower joint of the locking mechanism are unlocked up and down, and the upper oil pipe is moved down. The straightening block is expanded on the inner circular surface of the casing due to friction, and the upper joint drives the upper pressure cap, the rubber cylinder, the lower pressure cap connector and the cone to move down. The slip is tightly expanded on the inner circular surface of the casing under the lateral component force generated by the cone at the upper end of the outer circular surface of the cone, and the upper oil pipe is continued to be moved down. The rubber cylinder is deformed outward under the action of the upper and lower extrusion, and the expansion hoop is sealed on the inner circular surface of the casing, and the lower limit sleeve and the lower joint are locked up and down again by the locking mechanism. Finally, water is injected between the upper oil pipe and the casing. The injected water enters between the lower oil pipe and the extension pipe through the flow hole on the pressure guide. Under the blocking action of the reversing well flushing valve, it enters the lower oil pipe, the center pipe and the upper oil pipe from bottom to top for flushing. When flushing the inside of the oil pipe, the perforation section on the casing is blocked to prevent water from being injected into the formation and ensure normal oil production operations after flushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of the present invention;

[0026] Figure 2 yes Figure 1 Schematic diagram of the structure of the pressure guide device for well washing;

[0027] Figure 3 yes Figure 1 Schematic diagram of the structure of the middle casing occluder;

[0028] Figure 4 yes Figure 3 Enlarged view of part A in the middle;

[0029] Figure 5 yes Figure 3 Structural schematic diagram of the middle and lower limit sleeves;

[0030] Figure 6 yes Figure 1 Structural diagram of the middle reversing well flushing valve;

[0031] In the figure: 1-upper oil pipe, 2-lower oil pipe, 3-well flushing pressure guide, 4-casing plug, 5-reversing well flushing valve, 6-extension pipe, 301-connector, 302-inner pipe, 303-coupling, 304-outer pipe, 305-flow hole, 401-center pipe, 402-upper joint, 403-lower joint, 404-upper pressure cap, 405-rubber cylinder, 406-lower pressure cap, 407- Connecting cylinder, 408-cone, 409-slip, 410-upper limit sleeve, 411-centering body, 412-lower limit sleeve, 413-spacer ring, 414-limiting ring, 415-spring, 416-centering block, 417-spring, 418-locking pin, 419-locking mouth, 420-side opening, 501-valve seat, 502-valve hole, 503-valve ball, 504-mesh plate. DETAILED DESCRIPTION

[0032] like Figure 1-Figure 6 As shown, a pipe string for anti-pollution process of well washing in a perforation section comprises an upper oil pipe 1 and a lower oil pipe 2, a well washing pressure guide 3 is installed between the upper oil pipe 1 and the lower oil pipe 2, the well washing pressure guide 3 comprises a connector 301 and an inner pipe 302 fixedly installed up and down, a coupling 303 and an outer pipe 304 fixedly installed up and down are sleeved outside the inner pipe 302, a flow hole 305 is provided on the wall of the outer pipe 304, the connector 301 is fixedly installed with the coupling 303, the connector 301 is fixedly installed with the upper oil pipe 1, and the inner pipe 302 is fixedly installed with the lower oil pipe 2;

[0033] A casing plugger 4 is sleeved on the outer side of the lower oil pipe 2, and the casing plugger 4 includes a central tube 401, an upper joint 402 and a lower joint 403 are fixedly installed at the upper and lower ends of the central tube 401, and an upper pressure cap 404, a rubber cylinder 405, a lower pressure cap 406, a connecting tube 407, a cone 408, a plurality of circumferentially distributed slips 409, an upper limit sleeve 410, a straightening body 411 and a lower limit sleeve 412 are slidably installed in sequence from top to bottom on the outer cylindrical surface of the central tube 401, the rubber cylinder 405 is multiple, and a spacer ring 413 is slidably installed up and down between two adjacent rubber cylinders 405 on the outer cylindrical surface of the central tube, the lower end of the outer cylindrical surface of the cone 408 is conical, and the upper end of the inner cylindrical surface of each slip 409 is respectively a cone that matches the lower end of the outer cylindrical surface of the cone 408, and the outer cylindrical surface of each slip 409 is respectively provided with corrugations distributed up and down, and a limit ring 414 is clamped on the outer cylindrical surface of the slip 409, and a spacer ring 413 is clamped on each clamp An arc-shaped spring piece 415 is connected between the outer cylindrical surface of the shoe 409 and the inner cylindrical surface of the limiting ring 414. A plurality of circumferentially distributed and radially sliding straightening blocks 416 are installed on the outer cylindrical surface of the straightening body 411. A spring 417 is connected between the inner cylindrical surface of each straightening block 416 and the outer cylindrical surface of the straightening body 411. The upper limit sleeve 410 and the lower limit sleeve 412 are fixedly installed at the upper and lower ends of the straightening body 411. The upper and lower ends of the straightening block 416 are clamped in the upper limit sleeve 410 and the lower limit sleeve 412. A locking mechanism is installed between the lower limit sleeve 412 and the lower joint 403. The locking mechanism includes a locking pin 418 fixedly installed on the outer cylindrical surface of the lower joint 403, a locking port 419 provided on the lower limit sleeve 412, and a side opening 420 provided on one side of the locking port 419 and extending to the lower end of the lower limit sleeve 412. The upper joint 402 is fixedly installed with the outer tube 304, and an extension tube is fixedly installed on the lower joint 403.

[0034] A reversing well-washing valve 5 is fixedly installed at the lower end of the extension pipe, and the reversing well-washing valve 5 includes a valve seat 501 fixedly installed at the lower end of the extension pipe, a valve hole 502 which is wide at the top and narrow at the bottom is provided in the center of the valve seat 501, a valve ball 503 is seated in the valve hole 502, and a mesh plate 504 is fixedly installed on the inner circular surface of the valve seat 501 and above the valve ball 503.

[0035] The above-mentioned well washing method for the well washing and pollution prevention process pipe string under the perforation section has the following steps:

[0036] Step 1: The locking pin is located in the locking port 419, the lower limit sleeve 412 and the lower joint 403 are locked up and down, and the anti-pollution process string for the perforation section is inserted downward into the casing to overcome the friction between the straightening block 416 and the inner surface of the casing, and the casing plugger 4 is located above the perforation section of the casing;

[0037] Step 2: Rotate the upper oil pipe to make the lock pin 418 escape from the lock port 419 through the side opening 420, and the lower limit sleeve 412 and the lower joint 403 are unlocked up and down;

[0038] Step 3: Move the upper oil pipe 1 downward, the straightening block 416 expands and hoops on the inner surface of the casing due to friction, the upper joint 402 drives the upper pressure cap 404, the rubber cylinder 405, the spacer ring 413, the lower pressure cap 406 connector and the cone 408 to move downward, and the slip 409 is tightly expanded and hooped on the inner surface of the casing under the action of the lateral component force generated by the cone at the upper end of the outer surface of the cone 408;

[0039] Step 4: Continue to move the upper oil pipe 1 downward, the rubber cylinder 405 expands and deforms outward under the action of upper and lower squeezing, expands and seals on the inner surface of the casing, and the upper oil pipe 1 is rotated to press the locking pin 418 against the lower end surface of the lower limit sleeve 412 to lock it;

[0040] Step 5: Inject water between the upper oil pipe 1 and the casing. The injected water enters between the lower oil pipe 2 and the extension pipe 6 through the flow hole 305 on the pressure guide. Under the blocking effect of the valve ball 503 of the reversing well washing valve 5, the water enters the lower oil pipe 2, the center pipe 401 and the upper oil pipe 1 from bottom to top in turn, and cleans the inside of the lower oil pipe 2, the center pipe 401 and the upper oil pipe 1.

[0041] During the oil production operation, the oil in the formation enters between the casing and the extension pipe 6 through the perforation section on the casing, and then pushes the valve ball 503 upward through the valve hole 502 of the reversing well washing valve 5 to enter the extension pipe 6, and then enters the lower oil pipe 2, the central pipe 401 and the upper oil pipe 1 from bottom to top in turn, and finally the oil is produced by the sucker rod pre-inserted into the lower oil pipe 2.

[0042] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pipe string for anti-pollution process of well washing under perforation section, comprising an upper oil pipe, a lower oil pipe and a reversing well washing valve, wherein the reversing well washing valve comprises a valve seat fixedly mounted at the lower end of an extension pipe, a valve hole is arranged at the center of the valve seat, and a valve ball is seated in the valve hole, and the special feature thereof is that a well washing pressure guide is installed between the upper oil pipe and the lower oil pipe, the well washing pressure guide comprises an inner pipe, an outer pipe is fixedly mounted on the outer circumference of the inner pipe, a flow hole is arranged on the pipe wall of the outer pipe, and the inner pipe is installed between the upper oil pipe and the lower oil pipe; A casing plugger is mounted on the outer side of the lower oil pipe, and the casing plugger includes a center tube, an upper joint and a lower joint are fixedly installed at the upper and lower ends of the center tube, and an upper pressure cap, a rubber cylinder, a lower pressure cap, a cone, a plurality of circumferentially distributed slips, an upper limit sleeve, a straightening body and a lower limit sleeve are slidably installed on the outer cylindrical surface of the center tube from top to bottom in sequence, the lower end of the outer cylindrical surface of the cone is conical, and the upper end of the inner cylindrical surface of each slip is respectively a cone that matches the lower end of the outer cylindrical surface of the cone, a limit ring is clamped on the outer cylindrical surface of the slip, and a connection is made between the outer cylindrical surface of each slip and the inner cylindrical surface of the limit ring. Connect the elastic original component, install multiple circumferentially distributed and radially sliding straightening blocks on the outer circular surface of the straightening body, connect the lower elastic element between the inner circular surface of each straightening block and the outer circular surface of the straightening body, the upper limit sleeve and the lower limit sleeve are fixedly installed at the upper and lower ends of the straightening body, the upper and lower ends of the straightening block are clamped in the upper limit sleeve and the lower limit sleeve, a locking mechanism is installed between the lower limit sleeve and the lower joint, the upper joint is fixedly installed with the outer tube, an extension pipe is fixedly installed on the lower joint, and the reversing well flushing valve is fixedly installed at the lower end of the extension pipe through a valve seat.

2. The anti-pollution process string for well washing in the perforation section according to claim 1 is characterized in that: A connector is fixedly installed on the upper end of the inner tube, a coupling is fixedly installed on the lower end of the outer circular surface of the connector, the outer tube is fixedly installed on the lower end of the inner circular surface of the coupling, and the connector is fixedly installed on the upper oil pipe.

3. The anti-pollution process string for well washing in the perforation section according to claim 1 is characterized in that: The locking mechanism comprises a locking pin fixedly mounted on the outer circumferential surface of the lower joint, a locking opening arranged on the lower limiting sleeve, and a side opening arranged on one side of the locking opening and extending toward the lower end of the lower limiting sleeve.

4. The anti-pollution process string for well washing in the perforation section according to claim 1 is characterized in that: There are multiple rubber cylinders, and a spacer ring is installed on the outer circumferential surface of the central cylinder between two upper and lower adjacent rubber cylinders for vertical sliding.

5. The anti-pollution process string for well washing in the perforation section according to claim 1 is characterized in that: The outer circumferential surface of each slip is provided with corrugations distributed up and down.

6. The anti-pollution process string for well washing in the perforation section according to claim 1 is characterized by: A connecting tube is slidably installed on the outer circumferential surface of the central tube, and the connecting tube is fixedly installed between the pressing cap and the cone.

7. The anti-pollution process string for well washing in the perforation section according to claim 1 is characterized by: The upper elastic element is an arc-shaped spring sheet.

8. The anti-pollution process string for well washing in the perforation section according to claim 1 is characterized by: The lower elastic element is a spring.

9. The anti-pollution process string for well washing in the perforation section according to claim 1 is characterized in that: A mesh plate is fixedly installed on the inner circular surface of the valve seat above the valve ball.

10. A method for washing wells with a pipe string for anti-pollution in a perforation section, characterized in that: Here are the steps: Step 1: Place the lock pin in the lock port, lock the lower limit sleeve and the lower joint up and down, and insert the perforating section down-well washing and pollution prevention process pipe string into the casing downward to overcome the friction between the straightening block and the inner surface of the casing, and make the casing plugger located above the perforating section on the casing; Step 2: Rotate the upper oil pipe to make the lock pin escape from the lock port through the side opening, and unlock the lower limit sleeve and the lower joint up and down; Step 3: Move the upper oil pipe downward, the straightening block expands on the inner surface of the casing due to friction, the upper joint drives the upper pressure cap, rubber cylinder, spacer ring, lower pressure cap connector and cone to move downward, and the slips expand tightly on the inner surface of the casing under the lateral force generated by the cone at the upper end of the outer surface of the cone; Step 4: Continue to move the upper oil pipe downward. The rubber cylinder expands and deforms outwards under the action of up and down squeezing, expands and seals on the inner surface of the casing, and rotates the upper oil pipe to lock the lock pin against the lower end surface of the lower limit sleeve; Step 5: Inject water between the upper oil pipe and the casing. The injected water enters between the lower oil pipe and the extension pipe through the flow hole on the pressure guide. Under the plugging action of the valve ball of the reversing well flushing valve, the water enters the lower oil pipe, the center pipe and the upper oil pipe from bottom to top in turn to clean the inside of the lower oil pipe, the center pipe and the upper oil pipe.

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