阅读说明：本技术 一种井下更换套管用倒扣装置 (Replacing back-off device for casing in pit ) 是由 于涛 于海丰 于 2019-11-19 设计创作，主要内容包括：本发明公开了一种套管倒扣装置,用于石油油气井井下套管更换,包括一个转动输入轴(20),所述转动输入轴(20)连接了行星齿轮减速器(X)输入转动的太阳轮；所述行星齿轮减速器(X)包括输出转动的行星轮,转动输出的行星轮连接了接箍定位器(Y)和下锚定器(Z)；所述行星齿轮减速器(X)的内齿圈(8)连接了上锚定器(Q)。下锚定器(Z)和上锚定器(Q)分别用于与被倒扣的相邻两节套管相对固定,分别包括用于与被倒扣的相邻两节套管固定的拆卸式锚定结构。本发明在套管损坏处以下1～2根的接箍松开卸扣,起出损坏套管,重新下入新的套管与下端套管对扣上紧。本发明对套管通径没有缩减,更换后的套管具有使用寿命长的优点。(The invention discloses a casing back-off device, which is used for replacing a casing under a petroleum oil and gas well, and comprises a rotation input shaft (20), wherein the rotation input shaft (20) is connected with a sun gear which is input and rotates by a planetary gear reducer (X); the planetary gear reducer (X) comprises a planetary gear for outputting rotation, and the planetary gear for outputting rotation is connected with the coupling positioner (Y) and the lower anchor (Z); the inner gear ring (8) of the planetary gear reducer (X) is connected with an upper anchor (Q). The lower anchor (Z) and the upper anchor (Q) are respectively used for being relatively fixed with two inverted adjacent casing pipes and respectively comprise detachable anchor structures used for being fixed with two inverted adjacent casing pipes. According to the invention, 1-2 couplings below the damaged part of the casing pipe are loosened and broken off, the damaged casing pipe is pulled out, and a new casing pipe is put in again to be fastened with the lower-end casing pipe. The invention has no reduction on the drift diameter of the casing, and the replaced casing has the advantage of long service life.)

1. An underlisting device for downhole casing replacement, comprising a rotary input shaft (20), said rotary input shaft (20) being connected to a sun gear for input rotation of a planetary gear reducer (X);

the planetary gear reducer (X) comprises a planetary gear for outputting rotation, and the planetary gear for outputting rotation is connected with the coupling positioner (Y) and the lower anchor (Z);

the inner gear ring (8) of the planetary gear reducer (X) is connected with an upper anchor (Q);

the lower anchor (Z) and the upper anchor (Q) are respectively used for being relatively fixed with two inverted adjacent casing pipes and respectively comprise detachable anchor structures used for being fixed with two inverted adjacent casing pipes.

2. An apparatus for downhole replacement of a casing string as claimed in claim 1, wherein the collar locator (Y) comprises a tubular locator sub (6) associated with the rotational output of the reducer (X);

a positioning ring (5) fixed by a shearing pin (4) is sleeved outside the positioning joint (6); a plurality of positioning claws (3) are supported on the outer side of the circumference of the positioning ring (5) at intervals, so that gaps exist between the lower ends of the positioning claws (3) and the outer surface of the positioning joint (6);

the positioning claw (3) comprises a plate-shaped connecting part and a claw head, wherein the upper outer surface of the claw head is inclined upwards, and the lower outer surface of the claw head is inclined downwards; the upper parts of the positioning claws (3) are connected into a whole and sleeved outside the positioning joint (6) and are positioned on the positioning ring (5) and the pin (4); one side of the positioning joint (6) positioned at the claw head is also provided with an annular bulge (26) with the outer diameter consistent with that of the positioning ring (5), so that the claw head of the positioning claw (3) is supported by the annular bulge (26) in a positioning state and is clamped at a coupling between an upper casing and a lower casing at the damaged part of the underground casing.

3. The apparatus of claim 1, wherein the lower anchor (Z) and the upper anchor (Q) comprise flukes and cam means; the cam device includes a central tube associated with a rotational input; the outside of the central pipe is provided with the fluke (13);

a friction block (15) radially supported by a spring (25) is embedded outside the central tube (14); the friction blocks (15) are arranged around the central pipe (14) at intervals, and each friction block (15) is supported in a friction block seat by a plurality of springs (25).

4. A reversing device for downhole casing replacement according to any of claims 1-3, wherein the planetary gear reducer (X) comprises a three-stage planetary gear; the inner gear rings of all levels of planetary gears are shared reducer inner gear rings (8); the rotation input shaft (20) is connected with a sun gear (12) of the first-stage planetary gear;

the wheel carrier of the first-stage planetary gear planet wheel (11) is relatively fixed with the sun gear (17) of the second-stage planetary gear, and the wheel carrier of the second-stage planetary gear planet wheel (10) is relatively fixed with the sun gear (18) of the third-stage planetary gear; the third stage planetary gear (9) is associated with a central tube (14) of which the lower anchor (Z) carries out the rotational input.

Technical Field

The invention relates to a device for replacing a casing in a petroleum oil and gas well, in particular to a back-off device for a casing (only limited to a well with a technical casing which is not sealed by cement).

Background

The damage of the underground casing of the petroleum oil and gas well caused by corrosion or external force influences normal production and other engineering operations. Specifically, as shown in fig. 1, the downhole casing comprises a plurality of joints 2 formed by connecting a plurality of couplings 1 in series. In the prior art, when the sleeve is damaged, the sleeve is repaired or cement is injected outside the sleeve to repair the damaged sleeve, the drift diameter of the sleeve after the sleeve is repaired is generally reduced by 15-20 mm compared with the original inner diameter, and other operations in the later period are greatly influenced. Although the casing external pressure cementing is simpler in construction, the repair success rate is lower, and the casing external pressure cementing can be easily damaged in a short time after being repaired.

Therefore, the invention provides an operation method for taking out and replacing a damaged casing, and the operation method has the problems that the positions of the couplings 1 of the casing in the prior art are welded and fixed, and the casing is difficult to take out in a deep well. For this purpose, the invention also adopts the planetary gear principle of the prior art, and as shown in fig. 2, the planetary gear comprises an inner gear ring positioned at the outer part, a sun gear positioned at the middle part and a planetary gear positioned between the inner gear ring and the sun gear.

The invention also selects the prior art of the principle of the planetary gear reducer with more than three levels, and specifically refers to the description of the internal structure of the planetary gear reducer with more than three levels in the prior art, and specifically refers to the following contents of the related articles: when the planetary gear set works, the motor is connected with the input device of the speed reducer through the coupling shaft to drive the first-stage sun gear, the sun gear drives the first-stage planetary gear to drive the first-stage planetary gear to rotate around the axis of the sun gear, so that the second-stage sun gear is driven, the second-stage planetary gear set transmission mechanism and the third-stage planetary gear set transmission mechanism are sequentially driven, and finally, the output device outputs torque. The number of the planet wheels in each stage of the planetary gear train transmission mechanism can be more than four. "

Disclosure of Invention

Aiming at the problem of underground casing pipe replacement, the invention aims to solve the problems of one-time use, difficult repair and the like of the existing underground casing pipe by utilizing the planetary gear principle and the planetary gear reducer principle with more than three stages, and has the characteristics of convenient replacement operation, high efficiency and low cost; and a new sleeve is put into the sleeve again to be fastened with the lower end sleeve, so that the advantages of no reduction of the drift diameter of the sleeve and long service life after replacement are achieved.

In order to achieve the above object, the present invention provides a bushing reversing device, comprising a rotation input shaft connected to a sun gear of a planetary gear reducer for input rotation; the planetary gear reducer comprises a planetary gear for outputting rotation, and the planetary gear for outputting rotation is connected with the coupling positioner and the lower anchor; the inner gear ring of the planetary gear reducer is connected with an upper anchor.

The lower anchor and the upper anchor comprise detachable anchoring structures used for being fixed with the reversed casing pipes, and the lower anchor and the upper anchor are respectively used for being fixed with two adjacent reversed casing pipes relatively. Specifically, the anchoring structure can be a mode of penetrating an anchoring bolt, and other fixing forms such as anchoring or adsorption can be selected according to needs, but according to the use condition of the oil and gas well, the structure of the underground oil extraction screw pump fixer in the Chinese patent CN200610045411.8 is preferably selected.

In a preferred form, the invention provides a further improvement in which the collar locator comprises a tubular locating sub associated with the reducer rotational output; a positioning ring fixed by a shearing pin is sleeved outside the positioning joint; a plurality of positioning claws are supported at intervals on the outer side of the circumference of the positioning ring, so that gaps exist between the lower ends of the positioning claws and the outer surface of the positioning joint; the positioning claw comprises a plate-shaped connecting part and a claw head, wherein the upper outer surface of the claw head is upwards inclined, and the lower outer surface of the claw head is downwards inclined; the upper parts of the positioning claws are connected into a whole and sleeved outside the positioning joint and are positioned on the positioning ring and the upper part of the pin; the positioning joint is also provided with an annular bulge with the outer diameter consistent with that of the positioning ring on one side of the claw head, so that the claw head of the positioning claw is supported by the annular bulge and clamped at a coupling between an upper casing and a lower casing at the damaged part of the underground casing in a positioning state.

In a preferred form, the invention is further developed in that the lower anchor and the upper anchor include flukes and cam means; the cam device includes a central tube associated with a rotational input; the outside of the central pipe is provided with the fluke. A friction block radially supported by a spring is also embedded outside the central tube; the friction blocks are arranged around the central tube at intervals, and each friction block is supported in a friction block seat by a plurality of springs 25.

The planetary gear reducer comprises three-stage planetary gears; the inner gear rings of all stages of planetary gears are shared reducer inner gear rings; the rotation input shaft is connected with a sun gear of the first-stage planetary gear; the wheel carrier of the first-stage planetary gear is relatively fixed with the sun gear of the second-stage planetary gear, and the wheel carrier of the second-stage planetary gear is relatively fixed with the sun gear of the third-stage planetary gear; the third-stage planetary gear is associated with a central pipe of which the lower anchor realizes the rotation input.

The casing pipe back-off device is used for replacing a casing pipe, 1-2 couplings below a damaged part of the casing pipe are loosened and broken off (only limited to a well with a technical casing pipe not sealed by cement), the damaged casing pipe is taken out, and a new casing pipe is put into the damaged casing pipe again to be fastened with the lower end casing pipe. The invention has no reduction on the drift diameter of the casing, and the replaced casing has the advantage of long service life.

Drawings

Figure 1 is a schematic representation of the structure of a prior art downhole casing for a petroleum hydrocarbon well.

Fig. 2 is a schematic structural view of the prior art planetary gear principle.

Fig. 3 is a schematic view of the overall structure of the back-off device of the present invention.

Fig. 4 is a schematic view of the state where the back-off device of the present invention is positioned to the damaged position of the casing.

Fig. 5 is an enlarged schematic view of the left side portion of the overall structure shown in fig. 3.

Fig. 6 is an enlarged structural view of a middle portion of the overall structure shown in fig. 3.

Fig. 7 is an enlarged structural view of a right-side portion of the overall structure shown in fig. 3.

Fig. 8 is a cross-sectional view taken at a-A, B-B in fig. 3.

Fig. 9 is an enlarged schematic view of the structure at C in fig. 4.

Fig. 10 is an enlarged schematic view of fig. 3 at D.

Detailed Description

As shown in fig. 3-7, the cannula reversing device is mainly composed of: the power input part P, the upper anchor Q, the reducer X, the coupling locator Y and the lower anchor Z.

The power input part P is a rotation input shaft 20, and the rotation input shaft 20 drives the sun gear 12 of the first stage planetary gear of the speed reducer X to rotate.

The inner gear rings of the planetary gears at all stages of the speed reducer X are shared speed reducer inner gear rings 8. In the back-off state, the inner gear ring 8 is relatively fixed with the upper casing at the damaged part of the underground casing. So that the planet wheels 11 of the first stage planet gears act under the drive of the sun wheel 12. The carrier of the first stage planetary gear 11 is fixed relative to the sun gear 17 of the second stage planetary gear, so as to drive the second stage sun gear 17; like the above structure, the sun gear 17 drives the planet gears 10 of the second-stage planetary gear; the second stage planets 10 drive the third stage sun 18; the sun gear 18 of the third stage drives the planet gears 9 of the third stage. The above process is consistent with the principle of the planetary gear reducer with more than three stages in the prior art. Therefore, the invention can also adopt a multi-stage or one-stage planetary gear to realize the function of the invention according to the principle, which is determined according to the output torque and the specific design.

The planet wheel 9 of the third stage drives the part of the coupling positioner Y and the lower anchoring device Z to act. Specifically, the planet wheel 9 of the third stage is connected with and drives an output shaft 7 to rotate, and the output shaft 7 is connected with the tubular positioning joint 6 of the coupling positioner Y. The coupling locator Y further comprises a locating ring 5 which is located outside the locating joint 6 and surrounds the locating joint in a circle, and the locating ring 5 is fixed outside the locating joint 6 through a shearing pin 4. The shear pin 4 is a prior art formed product that will break under shear forces. The outer side of the positioning ring 5 supports a plurality of positioning claws 3 at intervals on the circumference so that the lower ends (right side in the drawing) of the positioning claws 3 have an elastic clearance with the outer surface of the positioning nipple 6 (as shown in fig. 10, the collar positioner is in a state before positioning). The positioning claws 3 include plate-like connecting portions and claw heads formed by connecting upper outer surfaces of the connecting portions in an upward inclined manner and lower outer surfaces of the connecting portions in a downward inclined manner. Wherein the lower outer surface of the jaw head is inclined downwards, so that the positioning jaw 3 can more easily enter the downhole casing. And as shown in fig. 9, the claw head formed by connecting the upper outer surface upwards and the lower outer surface downwards is just clamped at the coupling 1 between the upper casing 2 and the lower casing 2 at the damaged part of the downhole casing in a positioning state. In addition, as shown in the figure, the upper parts of a plurality of positioning claws 3 are integrally sleeved outside the positioning joint and are positioned above the positioning ring 5 and the pin 4 (on the left side in the figure); as shown in fig. 9 and 10, an annular protrusion 26 having an outer diameter substantially identical to that of the positioning ring 5 is further provided on one side of the positioning joint 6, so that in a positioning state, the claw head of the positioning claw 3 is supported by the annular protrusion 26 to be clamped at the coupling 1 between the upper casing 2 and the lower casing 2 at the damaged position of the downhole casing.

The positioning process of the positioning claw 3 is that firstly, the state is shown in figure 10 when the positioning claw does not enter the underground casing; after entering the underground casing, the claw head is attached to the positioning joint 6; when the claw head reaches the coupling 1 between the upper casing 2 and the lower casing 2 at the damaged part of the underground casing, the claw head is popped out and clamped at the coupling 1 between the upper casing and the lower casing, at the moment, the back-off device of the invention needs to be lifted, so that under the clamping action of the claw head, the positioning claw 3 generates relative displacement relative to the positioning joint 6 until the state shown in the figure 9 is achieved; the acting force of the pawl head of the reversing device is continuously lifted and applied to the uppermost end of the reversing device through the positioning ring 5 and the pin 4, so that whether the positioning is accurate or not can be judged through the acting force.

The positioning ring 5 and the pin 4 also have the function that after the back-off is finished, an upper casing pipe and a lower casing pipe at the damaged part of the underground casing pipe are separated at a coupling, the back-off is pulled through lifting at the moment, the lifting is continued in the state shown in figure 9, and the shearing pin 4 is cut off under larger shearing force; the positioning pawl 3 continues to displace relative to the positioning nipple 6 so that the head of the positioning pawl moves to the right of the annular projection 26 in fig. 9, and thus can elastically contract towards the surface of the positioning nipple 6, so that the reversing device can be removed from the downhole casing while the anchor Q and the lower anchor Z are reversed to release the anchor.

The upper and lower anchors Q, Z may be selected from prior art anchoring arrangements, as shown in figure 8, comprising flukes 13 and cam means 22. The concrete prior art can refer to the structure of a Chinese patent CN200610045411.8 underground oil extraction screw pump fixer. And the anchoring structure of this patent can also be used in the present invention.

The cam device 22 of the upper anchor Q comprises a central tube 14 sleeved outside the rotation input shaft 20; outside the base pipe 14 there is arranged a fluke 13 in the manner of a prior art anchoring structure. Furthermore, the central tube 14 is also fixedly connected with a reducer ring gear 8, as shown in fig. 6.

Also embedded outside the central tube 14, in fig. 6 above the fluke 13 (to the left in the figure), is a friction block 15 radially supported by a spring 25. After entering the downhole casing, the friction block 15 is supported by the outer side of the spring to abut against the inner wall of the casing, so that the central tube 14 fixed with the friction block 15 and the fluke 13 of the upper anchor Q rotate relatively, and the anchoring function is realized. The flukes, friction blocks and central tube of the lower anchor Z are arranged in the same manner but in the opposite direction.

In which the hatched portions in figures 5, 6 and 7, respectively, correspond to the relatively fixed portions during the back-off operation. Specifically, the shaded portion of fig. 5 is a rotation input portion of the rotation input shaft 20 for bringing the sun gear 12 to the first-stage planetary gear for rotation.

In the back-off operation, the shaded part of fig. 6 is a fixed part relative to the upper casing at the damaged part of the underground casing; it should be noted that the reducer ring gear 8 is relatively fixed with the upper casing at the damaged position of the downhole casing, that is, the fluke 13 is relatively fixed with the upper casing at a-a in fig. 3, and the fluke 13 is relatively fixed with the reducer ring gear 8 through a certain connection.

The shaded part of figure 7 is fixed relative to the lower casing at the damaged part of the downhole casing in the back-off work; namely, the anchor fluke 13 and the upper section sleeve are relatively fixed at the position B-B of the figure 3, and the anchor fluke 13 and the inner gear ring 8 of the speed reducer are relatively fixed through certain connection.

The relative fixation of the parts in the shaded parts in fig. 5, 6, and 7 may be in the connection manner of pins, keys, screws, etc., or in the manner of clamping, embedding, etc., or in the manner of transition connection rings, connection columns, etc., and the connection fixing structure may be designed according to specific requirements. In addition, the device shown in fig. 3 to 7 should be in an upright state with the right side down in an actual use state.

The working principle of the invention is as follows:

the casing back-off device is lowered into the casing at a predetermined location and the collar locator Y is positioned at the casing collar location with the upper anchor Q and the reducer X above the collar. The lower anchor Z is below the collar. The drill rod which is connected with the lower drill rod in a positive rotation mode transmits the input torque of the rotating input shaft 20 to the speed reducer, so that the lower anchor Z rotates in the positive direction, the upper anchor Q rotates in the reverse direction, then the lower anchor Z and the upper anchor Q are successively anchored on the inner wall of the casing, the drill rod (input torque) continuously rotates, the drill rod (input torque) starts to be unscrewed when the torque reaches the torque for loosening the coupling thread and the casing thread, and the torque for rotating the drill rod (input torque) gradually decreases along with the increase of the.

The following provides working examples of the apparatus of the present invention

1. Casing damage positioning and drifting:

accurately measuring the casing damage location, determining an approximate trip location (typically between the first and second pipe below the damaged casing to avoid anchoring the upper anchor to the damaged casing), running a drift pattern (51/2 '-phi 117X 2000, 7' -phi 153X 2000) and moving it 40 meters below the casing damage location, and tripping the drift pattern.

2. Checking before the tool enters the well:

and (4) verifying whether the connection threads of the fed drill rod and the casing pipe back-off device are matched, if not, using a variable buckle joint for transition connection, measuring the drill rod entering the well and accurately recording. The flukes of the upper and lower anchors can be smoothly screwed out and retracted, the locating claws of the coupling locator have no defects such as deletion, crack and serious abrasion, the reducer rotates smoothly without blocking phenomenon, and the connection between tools has no loosening phenomenon.

3. The tool is put into the well:

when the operation equipment lifts the tool tree, the tool needs to be slowly lifted, the anchor fluke of the anchor is withdrawn before the wellhead casing is introduced, the tool is slowly lowered, the collar locator is righted and introduced until the collar locator smoothly enters the casing when the collar locator enters the casing, the tool is lowered to a position 30 meters below the casing damage position by connecting a drill rod, the lowering speed is controlled within 20 meters/min, and the hanging weight of the drill string is recorded. Note that: when connecting each drill rod screw thread, it is ensured that the hydraulic tong back-up tong can not slip and rotate, and the anchor fluke can be screwed out and block the inner wall of the sleeve when the pipe column rotates. If the drill pipe is stuck or has resistance in the running process, the drill pipe can be reversed properly and lifted up and down slightly until the sticking is eliminated.

4. Positioning a coupling:

slowly lifting the casing pipe back-off device, observing the hanging weight of the pipe column, if the hanging weight is increased, slowly lifting the pipe column, confirming that the casing pipe positioning claw is clamped at the position of the coupling when the hanging weight is increased by 4-5 tons, and lowering the drill column to the original hanging weight.

5. And (4) carrying out back-off operation:

the tail of the hydraulic clamp is fixed on a vertical frame of the operation vehicle by a steel wire rope with the length being more than or equal to 16mm, the steel wire rope is ensured to be clamped tightly, an operation handle of the hydraulic clamp is connected by a hemp rope with proper length for operation, and personnel safety is noticed during operation. The drill pipe is rotated in the forward rotation mode to observe torque change, the torque is increased (generally within 10-20 weeks), the upper anchor device and the lower anchor device are anchored, the drill pipe is rotated continuously, whether the wellhead casing pipe has reverse rotation signs or not is observed, if the reverse rotation phenomenon exists, the casing pipe coupling starts to be loosened, the drill pipe is stopped to rotate when the casing pipe is continuously opened backwards for more than 25 weeks after the loosening, and the torque of the drill pipe is gradually reduced in the process. And lifting the casing string to confirm that the casing coupling is completely reversed, and putting down the casing string after confirming that the casing coupling is completely reversed.

6. Pulling out the tool:

the drill string is lifted up to release the positioning claw of the coupling positioner, so that the tool can be lifted out, and the speed of lifting the drilling tool is controlled within 20 m/min so as to prevent the positioning claw from being damaged at an excessive speed and falling off to clamp the tool.

7. Tool maintenance:

the casing back-off device is used for maintaining and maintaining the tool as soon as possible to prevent the tool from being rusted, and each part is detected during maintenance to replace and repair the damaged and seriously abraded parts.

8. Replacing the sleeve:

and (4) pulling out the inverted casing, determining whether to replace the whole casing or partially according to the corrosion and strength damage conditions of the casing, buckling and tightening the inserted new casing, then carrying out internal pressure inspection, and checking and accepting and handing over the casing after the casing is qualified.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.