Horizontal well casing bottom hydraulic rotary telescopic tripping-in device and construction method

Abstract

The invention discloses a horizontal well casing bottom hydraulic rotary telescopic tripping-in device and a construction method. The problems that drilling, pigging and borehole cleaning are needed before casing running in existing horizontal well drilling construction, and casing running is difficult are mainly solved. The device is characterized in that the front end of the sleeve (1) is connected with a first back pressure valve (3) and a second back pressure valve (4), the front end of the second back pressure valve (4) is connected with a hydraulic rotary expansion piece (6) through a release pup joint (5), and the front end of the hydraulic rotary expansion piece (6) is connected with a guide head (7). According to the construction method, the borehole cleaning procedure before casing running is omitted, and the casing can be safely run.

Description

Technical Field

[0001] The invention relates to the technical field of oil field production engineering, in particular to a horizontal well drilling device and a construction method. Background Art

[0002] The existing horizontal well drilling construction technology requires, after the well reaches the designed well depth, to pull out the drilling tools in the well, lower the wellbore drilling tools to the bottom of the well, circulate the drilling fluid to clean the wellbore (clean the wellbore before lowering the casing, mainly to ensure the smooth lowering of the casing), pull out the wellbore drilling tools in the well, lower the casing to the bottom of the well, circulate the drilling fluid to clean the wellbore (clean the wellbore after lowering the casing, mainly to improve the cementing quality), and inject cement slurry for cementing.

[0003] The above process requires one trip to drill through the well before casing is lowered, and two cycles of drilling fluid circulation to clean the wellbore before and after casing is lowered. During the casing lowering process, the drilling fluid in the wellbore is basically static, and solids such as barite in the drilling fluid will gradually settle in the horizontal section. At the same time, the casing and its attached centralizer will touch the well wall during the lowering process, causing varying degrees of rock debris peeling and accumulation. Especially for shale horizontal wells, affected by the lithology of the formation, the friction resistance at the bottom of the well is large. Especially as the casing is lowered to an increasing depth, the rock debris will accumulate more and more, making it difficult or even impossible to lower the casing. Summary of the invention

[0004] In order to overcome the problems that the existing horizontal well drilling construction needs to drill through the well and clean the wellbore before casing is lowered, and casing lowering is difficult, the present invention provides a horizontal well casing bottom hydraulic rotary telescopic running device and a construction method, the construction method reduces the wellbore cleaning procedure before casing lowering and allows the casing to be lowered safely.

[0005] The technical solution of the present invention is: a hydraulic rotary telescopic running device at the bottom of a horizontal well casing, comprising a casing, the front end of the casing is connected to a first back-pressure valve and a second back-pressure valve, the front end of the second back-pressure valve is connected to a hydraulic rotary telescopic device through a hand-release short circuit, and the front end of the hydraulic rotary telescopic device is connected to a guide head.

[0006] The hydraulic rotary telescope comprises a stator, a rotor is arranged inside the stator, the front end of the rotor is connected to the flexible shaft, the front end of the flexible shaft is connected to the telescopic shaft through a push cylinder, and the guide head is connected to the telescopic shaft.

[0007] A stator outer cylinder is arranged outside the stator, a front end of the stator outer cylinder is connected to an upper shell, a front end of the upper shell is connected to a lower shell, and the telescopic shaft is located inside the lower shell.

[0008] The outer surface of the telescopic shaft is provided with a groove in the circumferential direction, and an axially arranged spring is arranged in the groove. When the spring is in a free state, the telescopic shaft retracts backward.

[0009] During horizontal well drilling, casing is lowered. When the casing encounters resistance, the drilling fluid is circulated to drive the hydraulic rotary telescopic device to rotate and drive the guide head forward, while the casing is lowered from the wellhead. This process is repeated until the casing reaches the designed well depth. A ball is dropped into the casing to build up pressure, and the hand release short circuit is disengaged. The drilling fluid is then circulated and cement is injected to solidify the well.

[0010] The drilling fluid drives the rotor of the hydraulic rotary telescope to rotate, and the rotor drives the flexible shaft to rotate. The flexible shaft rotates and drives the telescopic shaft to move forward and backward.

[0011] The present invention has the following beneficial effects: due to the adoption of the above scheme, the construction method of the horizontal well casing bottom hydraulic rotation and telescopic lowering eliminates the wellbore cleaning procedure before casing lowering, and circulates drilling fluid to clean the wellbore while casing lowering, so that the casing can be lowered smoothly, avoiding the peeling of well wall rock debris when casing lowering, making the operation safer and improving the construction efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 It is a structural schematic diagram of a hydraulic rotary expansion joint.

[0013] In the figure, 1-drill rod, 2-elastic stabilizer, 3-first back pressure valve, 4-second back pressure valve, 5-hand-release short circuit, 6-hydraulic rotary telescopic device, 7-guide head, 61-stator outer cylinder, 62-stator, 63-rotor, 64-upper shell, 65-flexible shaft, 66-push cylinder, 67-lower shell, 68-spring, 69-telescopic shaft. Implementation

[0014] The present invention will be further described below in conjunction with the accompanying drawings: Depend on Figure 1 , Figure 2 As shown, a hydraulic rotary telescopic lowering device for the bottom of a horizontal well casing comprises a casing 1, and a plurality of elastic stabilizers 2 are arranged on the outside of the casing 1. The number and placement position of the elastic stabilizers 2 are determined according to the well conditions. The front end of the casing 1 is connected to a first back pressure valve 3 and a second back pressure valve 4. The back pressure valve can prevent cement slurry from flowing back into the casing. Two back pressure valves are used. When the pipe string is detached from the second back pressure valve 4, the first back pressure valve 3 can still work, making the prevention of back pressure more reliable. The front end of the second back pressure valve 4 is connected to a hand release short circuit 5, and the front end of the hand release short circuit 5 is connected to a hydraulic rotary telescopic device 6, and the front end of the hydraulic rotary telescopic device 6 is connected to a guide head 7. The outer dimensions of the guide head 7 are basically the same as those of the wellbore drilling bit, and an old drill bit when drilling is completed can also be used.

[0015] The hydraulic rotary telescopic device 6 includes a stator 62, and a stator outer tube 61 is provided outside the stator 62. One end of the stator outer tube 61 is connected to the hand-release short circuit 5, and the other end is connected to the upper shell 64. The front end of the upper shell 64 is connected to the lower shell 67. A rotor 63 is provided inside the stator 62. The rotor 63 can rotate inside the stator 62 after being subjected to force. The front end of the rotor 63 is connected to the flexible shaft 65. The front end of the flexible shaft 65 is connected to the telescopic shaft 69 through the push cylinder 66, wherein the flexible shaft 65 is located in the upper shell 64, and the telescopic shaft 69 is located in the lower shell 67. The flexible shaft 65 is made of flexible material, so that the flexible shaft 65 will be displaced in the axial direction while rotating under the drive of the rotor 63. The push cylinder 66 is provided with a liquid hole for discharging liquid when the pipe column moves forward. The guide head 7 is connected to the telescopic shaft 69. The outer surface of the telescopic shaft 69 is circumferentially provided with a groove, in which an axially arranged spring 68 is provided. The front end of the spring 68 is limited by a boss fixed inside the lower shell 67, so that the telescopic shaft 69 retracts backward when the spring 68 is in a free state.

[0016] When the rotor 63 rotates, the flexible shaft 65 is driven to rotate. Since the flexible shaft 65 is made of flexible material, the flexible shaft 65 will also be displaced in the axial direction while rotating, thereby driving the telescopic shaft 69 to extend and retract forward and backward while rotating. When the flexible shaft 65 moves forward, the push cylinder 66 drives the telescopic shaft 69 to move forward while rotating, compressing the spring 68, driving the guide head 7 to rotate and move forward; when the flexible shaft 65 moves backward, the telescopic shaft 69 loses the force to push forward, and retracts backward under the elastic force of the spring 68, thereby driving the guide head 7 to retract backward. The hydraulic rotary telescopic device 6 moves forward a stroke under the push of the drilling fluid, just like the piston rod of the oil cylinder extends, and this is repeated, driving the guide head 7 to rotate and stir the silted rock cuttings to return to the wellhead with the drilling fluid, so that the wellbore is clean.

[0017] The device can save the procedure of cleaning the wellbore before lowering the casing. The drilling fluid can be circulated to clean the wellbore while lowering the casing, so that the casing can be lowered smoothly, and the rock debris from the wellbore wall can be avoided during the casing lowering, making the operation safer and improving the construction efficiency.

[0018] A construction method for hydraulically rotating and telescoping the bottom of a horizontal well casing comprises the following steps: S1. After drilling to the designed well depth, the drilling tool in the well is pulled out, and the hydraulic rotary expansion joint 6 is connected to the bottom of the pipe string. The front end of the hydraulic rotary expansion joint 6 is connected to the guide head 7, and the rear end of the hydraulic rotary expansion joint 6 is connected to the hand release short circuit 5. The rear end of the hand release short circuit 5 is connected to two back pressure valves. The outer side of the casing 1 is provided with an elastic centralizer 2. The casing 1 is lowered to the predetermined position by using the top drive device of the drilling rig at the wellhead. When lowering the casing, the top drive device is used at the wellhead. The top drive does not rotate during the casing lowering process to prevent damage to the elastic centralizer 2 and damage to the well wall.

[0019] S2. When the casing 1 encounters resistance when being lowered, the pump is turned on to circulate the drilling fluid. The drilling fluid drives the hydraulic rotary expander 6 to rotate and drives the guide head 7 to move forward, stirring the accumulated rock cuttings to be discharged with the circulation of the drilling fluid to clean the wellbore, so that the casing can be smoothly lowered into the clean wellbore for one stroke, and the casing is lowered at the wellhead for one stroke at the same time. This process is repeated and the casing is continuously lowered until the casing reaches the designed well depth, and the circulation of the drilling fluid is stopped.

[0020] S3. After the casing is lowered to the designed position, a small ball is dropped into the casing 1 at the wellhead. The small ball goes down with the drilling fluid to the release short circuit 5. After the pressure is pressed to the set pressure, the release short circuit 5 is disengaged, so that the hydraulic rotary expansion joint 6 and the guide head 7 are separated from the second back pressure valve 4, but the first back pressure valve 3 is still in effect.

[0021] S4, the hydraulic rotary expansion joint 6 and the guide head 7 remain in the well, and the drilling fluid circulates normally from the back pressure valve 4 to prepare for subsequent conventional cementing.

Claims

1. A hydraulic rotary telescopic running device for a horizontal well casing bottom, comprising a casing (1), characterized in that: The front end of the sleeve (1) is connected to a first back-pressure valve (3) and a second back-pressure valve (4); the front end of the second back-pressure valve (4) is connected to a hydraulic rotary expansion joint (6) via a hand-release short circuit (5); and the front end of the hydraulic rotary expansion joint (6) is connected to a guide head (7).

2. The horizontal well casing bottom hydraulic rotary telescopic running device according to claim 1, characterized in that: The hydraulic rotary telescopic device (6) comprises a stator (62), a rotor (63) is arranged inside the stator (62), the front end of the rotor (63) is connected to a flexible shaft (65), the front end of the flexible shaft (65) is connected to a telescopic shaft (69) via a push cylinder (66), and the guide head (7) is connected to the telescopic shaft (69).

3. The horizontal well casing bottom hydraulic rotary telescopic running device according to claim 2, characterized in that: A stator outer cylinder (61) is provided outside the stator (62); the front end of the stator outer cylinder (61) is connected to an upper shell (64); the front end of the upper shell (64) is connected to a lower shell (67); and the telescopic shaft (69) is located inside the lower shell (67).

4. The horizontal well casing bottom hydraulic rotary telescopic running device according to claim 3, characterized in that: The outer surface of the telescopic shaft (69) is provided with a groove in the circumferential direction, and an axially arranged spring (68) is provided in the groove. When the spring (68) is in a free state, the telescopic shaft (69) retracts backwards.

5. A construction method for hydraulically rotating and telescoping the bottom of a horizontal well casing, characterized in that: During horizontal well drilling construction, casing (1) is lowered. When the casing (1) encounters resistance during lowering, drilling fluid is circulated to drive the hydraulic rotary expansion joint (6) to rotate and drive the guide head (7) forward, while the casing is lowered from the wellhead. This process is repeated to continuously lower the casing until the casing reaches the designed well depth. A ball is inserted into the casing to build up pressure, and the hand release short circuit (5) is disengaged, and the drilling fluid is continued to be circulated to inject cement for well cementing.

6. The construction method for hydraulically rotating and telescoping the bottom of a horizontal well casing according to claim 5 is characterized in that: The drilling fluid drives the rotor (63) of the hydraulic rotary telescopic device (6) to rotate, and the rotor (63) drives the flexible shaft (65) to rotate. The flexible shaft (65) rotates and drives the telescopic shaft (69) to move forward and backward.

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