CN108915629B

CN108915629B - Hydraulic cutting knife device for cutting multilayer sleeves

Info

Publication number: CN108915629B
Application number: CN201810884909.6A
Authority: CN
Inventors: 肖仕红; 唐鹏; 廖贵鹏; 唐松; 李大洋; 张靖柯; 蹇宝锐
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2018-08-06
Filing date: 2018-08-06
Publication date: 2020-11-03
Anticipated expiration: 2038-08-06
Also published as: CN108915629A

Abstract

The utility model provides a water conservancy cutting knife device for cutting multilayer sheathed tube for the well operation is abandoned to the deep water well head, cuts well head sleeve pipe with the help of this device, and the well head device of being convenient for is retrieved. The technical scheme is as follows: the drilling fluid pushes the piston to move downwards, and then the piston drives the cutting knife to rotate around the pin, so that the cutting knife cuts the sleeve; when the cutting knife finishes cutting, the circumferential through hole of the piston is communicated with the radial through hole of the limiting rod, and the pressure of the drilling fluid has obvious pressure difference, so that the completion of cutting the sleeve can be judged according to the fluctuation of the pressure of the drilling fluid; and a blade supporting structure is added at the end part of the cutting knife, so that the blade can be smoothly recovered. The method is simple to operate, can effectively judge the completion of the cutting of the sleeve, and can realize the cutting of the multi-layer sleeves with different diameters by adjusting the relative distance of the pressure relief holes.

Description

Hydraulic cutting knife device for cutting multilayer sleeves

Technical Field

The invention relates to a hydraulic cutting knife device for cutting a multilayer sleeve, and belongs to the field of cutting of offshore oil and natural gas wellhead sleeves.

Background

With the continuous development of ocean oil gas, more and more oil gas wells are close to the service life, lose the value of continuous use, for preventing oil gas pollution, to reaching the underwater oil gas well head of operation life, if there is not other usage, need to abandon the well operation to it according to the national regulation, however the key technology in abandoning the well operation process is the casing cutting. The cutting of present underwater wellhead casing has the following problems: (1) whether the cutting of the sleeve is finished or not cannot be effectively judged; (2) after the sleeve is cut, the cutting knife cannot be smoothly retracted; (3) it is impossible to continuously cut multi-layer sleeves of different diameters.

In order to solve the problems, underwater wellhead casing cutting devices are researched and developed at home and abroad. The hydraulic cutters developed by foreign Logan Oil Tools and Pioneer Oil Tools Limited companies can complete multilayer casing cutting at one time by driving the cutters to cut by means of pressure generated by drilling fluid, and obvious pressure reduction occurs when cutting is completed, which indicates that the cutting is completed, but the cutting blades of the two companies cannot be actively recycled into the cutter bodies. And domestic patent No. CN201679464U a hydraulic internal cutting knife for cutting expansion pipes has added centering device thereby effectively prevented the problem of cutting knife skew, and adopts the change of drilling rod moment of torsion to judge whether the sleeve pipe cutting is accomplished, utilizes the form of adding the spring leaf outside the cutting knife body to retrieve the cutting knife and get into inside the cutting knife body, and the shortcoming of the device is: the torque change judgment is not obvious, and the external spring piece has no safety: the spring leaf may be deformed too much to lose its resiliency when the drill rod is lowered. The pressure relief type hydraulic cutter of patent No. CN107288566A for completing multi-layer cutting at a time determines whether the cutting of the casing is completed by using the pressure reduction inside the drill rod, but does not have the cutter recovery function.

Disclosure of Invention

The purpose of the invention is as follows: in order to effectively judge whether the cutting of the casing is finished or not, the pressure relief function is added in the cutter device, when the cutting of the cutter is finished, the drilling pump generates obvious pressure drop, and the completion of the cutting of the casing can be judged. In order to realize the cutting of different multilayer sleeves, different limiting sleeves can be replaced, so that the relative distance between the limiting rod and the piston pressure relief hole is adjusted. In order to retract the opened cutting knife into the cutting knife body, the invention adds a cutting knife supporting device to realize the retraction function of the cutting knife.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

the utility model provides a water conservancy cutting knife device for cutting multilayer sheathed tube, includes connecting rod, nozzle, gag lever post, stop collar, piston, sealing plug, spring I, spring II, cutting knife, pin, limit baffle, retrieves baffle and cutting knife body, its characterized in that: the connecting rod is in threaded connection with the cutting knife body, knife grooves are uniformly distributed in the circumferential direction of the cutting knife body, the cutting knife is fixed in the knife grooves through pins, and the cutting knife can rotate by taking the pins as axes; a limiting rod, a limiting sleeve and a piston are sequentially arranged in the cutting knife body; one end of the limiting rod is in threaded connection with the cutting knife body, the other end of the limiting rod stretches into the piston axial through hole, and the end part of the limiting rod is in threaded connection with a nozzle in the direction close to the connecting rod; the limiting sleeve is in threaded connection with the cutting knife body, and the end part of the limiting sleeve is in contact with the end part of the limiting rod; an annular space is arranged between the piston and the cutting knife body, a spring I is arranged between the piston and the cutting knife body, and the upper end and the lower end of the spring I are limited by the shoulder of the piston and the shoulder of the cutting knife body respectively; the piston has recovery baffle and limit baffle in proper order in the one end of keeping away from the gag lever post, retrieves the baffle nestification in the piston surface and with piston relative slip, limit baffle and piston threaded connection are provided with spring II between recovery baffle and the limit baffle, retrieve the baffle and contact with the cutting knife tip all the time under the spring force effect.

Furthermore, one end of the piston is provided with an axial through hole and an axial bypass blind hole, a radial bypass hole is arranged in the circumferential direction and is communicated with the axial bypass blind hole and the piston axial through hole, and the piston axial through hole is oval; and a sealing ring I is arranged at the contact part of the piston and the cutting knife body.

Furthermore, the limiting rod is T-shaped, an axial through hole is formed in the center of the large-diameter end of the limiting rod, eccentric through holes are evenly distributed on the periphery of the large-diameter end of the limiting rod, the small-diameter end of the limiting rod slides relative to the axial through hole of the piston, and circumferential through holes are evenly distributed on the small-diameter end of the limiting rod in the circumferential direction; when the limiting rod circumferential through hole is communicated with the piston radial bypass hole, fluid enters the limiting rod axial through hole through the limiting rod eccentric through hole, the piston axial bypass blind hole, the piston radial bypass hole and the limiting rod circumferential through hole, so that the pressure drop is reduced, and the completion of sleeve cutting is judged; the cross section of the small-diameter section of the limiting rod is oval, and a sealing ring II is arranged on the sliding contact part of the limiting rod and the piston.

Furthermore, the outer end of the piston radial bypass hole is provided with a sealing plug which cannot extend into the piston axial bypass blind hole.

Furthermore, a convex structure is arranged on the radial direction of the circular bead of the cutting knife body, a groove matched with the convex structure of the cutting knife body is arranged on the piston, and the piston can move up and down along the circular bead of the cutting knife body.

Compared with the prior art, the invention has the beneficial effects that: 1) the underwater cutting knife device adopts the mutual communication between the pressure relief hole of the limiting rod and the radial bypass hole of the piston to realize the pressure reduction of the drilling pump, and the ground device can judge whether the cutting of the sleeve is finished or not through obvious pressure reduction; 2) a cutting knife recovery device is added in the cutting knife body, when the cutting knife finishes cutting, the cutting knife can be successfully retracted, and the cutting knife is prevented from scratching the sleeve; 3) the supporting structure of the cutting knives is added, so that the knife tips of the cutting knives are on the same horizontal line during rotary cutting, the elliptical cutting is reduced, the cutting stability is improved, the vibration is reduced, and the safe and high-speed cutting is facilitated. 4) Can change the stop collar of co-altitude not to adjust the relative distance in the pressure release hole of gag lever post and piston, be applicable to not unidimensional multilayer sleeve pipe cutting operation, improved the operating efficiency, practice thrift the cost.

Drawings

FIG. 1 is a drawing showing the opening of a hydraulic cutter according to the present invention

FIG. 2 is a cross-sectional view taken along the direction A in FIG. 1 according to the present invention

FIG. 3 is a cross-sectional view taken along the direction B in FIG. 1 according to the present invention

FIG. 4 is a cross-sectional view taken along the line C in FIG. 1 of the present invention

FIG. 5 is a plan view of a stop lever of the present invention

Fig. 6 view of the knife retraction of the present invention

In the drawing, 1, a connecting rod, 2, a nozzle, 3, a limiting rod, 3a, a limiting rod axial through hole, 3b, a limiting rod circumferential through hole, 3c, a limiting rod eccentric through hole, 4, a limiting sleeve, 5, a piston, 5a, a piston axial through hole, 5b, a piston axial bypass blind hole, 5c, a piston radial bypass hole, 6, a sealing plug, 7, a spring I, 8, a pin, 9, a cutting knife, 10, a limiting baffle, 11, a spring II, 12, a recovery baffle, 13, a sealing ring I, 14, a cutting knife body, 15, a screw and 16, a sealing ring II

Detailed description of the invention

The present invention is not limited to the following embodiments, and the specific embodiments may be determined according to the technical solution and the practical situation of the present invention. The invention is described below with reference to fig. 1. The positional relationship of up, down, left, right, etc. is determined in accordance with the layout direction of fig. 1 in the specification.

As shown in fig. 1, fig. 3 and fig. 4, a hydraulic cutter device for cutting a multi-layer casing comprises a connecting rod 1, a nozzle 2, a limiting rod 3, a limiting sleeve 4, a piston 5, a sealing plug 6, a spring I7, a spring II 11, a cutter 9, a pin 8, a limiting baffle 10, a recovery baffle 12 and a cutter body 14, and is characterized in that: the connecting rod 1 is in threaded connection with the cutter body 14, cutter grooves are uniformly distributed in the circumferential direction of the cutter body 14, cutters 9 are fixed in the cutter grooves through pins 8, the cutters 9 can rotate by taking the pins 8 as axes, and the pins 8 are limited by screws 15; a limiting rod 3, a limiting sleeve 4 and a piston 5 are sequentially arranged in the cutting knife body 14; one end of the limiting rod 3 is in threaded connection with the cutting knife body 14, the other end of the limiting rod stretches into the piston axial through hole 5a, and the end part of the limiting rod 3 is in threaded connection with the nozzle 2 in the direction close to the connecting rod 1; the limiting sleeve 4 is in threaded connection with the cutting knife body 14, and the end part of the limiting sleeve 4 is in contact with the end part of the limiting rod 3; be provided with the annular space between piston 5 and the cutting knife body 14 and install spring I7, the upper end and the lower extreme of spring I7 are spacing by the circular bead of piston 5 and the circular bead of cutting knife body 14 respectively, piston 5 has recovery baffle 12 and limit baffle 10 in proper order in the one end of keeping away from gag lever post 3, it reciprocates to retrieve baffle 12 nestification in piston 5 surface and can follow piston 5, limit

baffle

10 and 5 threaded connection of piston, be provided with spring II 11 between recovery baffle 12 and the limit baffle 10, retrieve

baffle

12 and 9 tip contacts of cutting knife all the time under the spring force effect.

As shown in figures 1, 2 and 3, the end part of the piston 5 is provided with an axial through hole 5a and an axial bypass blind hole 5b, a radial bypass hole 5c is arranged in the circumferential direction, the radial bypass hole 5c is communicated with the axial bypass blind hole 5b and the piston axial through hole 5a, and a sealing ring I13 is arranged at the contact part of the piston 5 and a cutter body 14.

As shown in fig. 1, fig. 2, fig. 3 and fig. 5, the limiting rod 3 is T-shaped, an axial through hole 3a and eccentric through holes 3c are uniformly distributed around the central portion of the large-diameter end of the limiting rod 3, the small-diameter end of the limiting rod 3 is connected with the axial through hole 5a of the piston 5 in a sliding fit manner, through holes 3b are uniformly distributed in the circumferential direction, the circumferential through hole 3b of the limiting rod can be communicated with the radial bypass hole 5c of the piston, and a sealing ring ii 16 is arranged on the sliding contact portion of the limiting rod 3 and the piston 5.

As shown in fig. 1 and 2, a sealing plug 6 is arranged at the outer end of the piston radial bypass hole 5c, and the sealing plug 6 cannot extend into the axial bypass blind hole 5b of the piston 5.

As shown in figures 1 and 3, the cutting knife body 14 has a convex structure on the shoulder in the radial direction, the piston 5 has a groove matching with the convex structure of the cutting knife body 14, and the piston 5 can move up and down along the cutting knife body 14 shoulder. And a pin 8 is arranged on the shoulder in the radial direction, the pin 8 is matched with the groove of the cutter body 14, and the cutter body 14 is limited to rotate in the circumferential direction and only can move along the axial direction of the piston 5.

A hydraulic cutter device for cutting a multi-layer casing will be described in further detail below, as shown in fig. 6.

Preparation before work: and selecting a proper limit sleeve 4 according to the maximum pipe diameter of the cutting sleeve. After the assembly is completed, a test is carried out on the ground to verify that the cutting knife 9 can work normally.

In the working process: and after the underwater cutting knife reaches the designated position, drilling fluid is introduced. At the beginning, drilling fluid flows downwards from the connecting rod 1 through the flow channel of the nozzle 2, the limiting rod 3 and the piston 5, and the other part of the drilling fluid flows through the 4 limiting rod eccentric through holes 3c and then flows to the 4 piston axial bypass blind holes 5b through the limiting sleeve 4. Because the starting moment, gag lever post circumference through-hole 3b is located the radial by-pass hole 5c lower extreme of piston, and the radial by-pass hole 5c of piston and gag lever post circumference through-hole 3b do not communicate, and drilling fluid can not flow. Due to the throttling effect of the nozzle 2, the drilling fluid generates pressure loss at the nozzle 2, the valve rod is long, the drilling fluid generates on-way resistance loss when flowing through the limiting rod 3, the liquid pressure generated by the pressure loss of the two parts pushes the piston 5 to move downwards, the piston 5 pushes the upper end part of the cutting knife 9 to move downwards, and the cutting knife 9 rotates around the pin 8 to extend and open and circumferentially cuts the casing pipe under the driving of the drill rod as the cutting knife 9 is connected with the cutting knife body 14 through the pin 8. The end part of the cutting knife 9 is always contacted with the recovery baffle 12, the end part of the cutting knife 9 pushes the recovery baffle 12 to move downwards, and the elastic restoring force generated by the compression of the spring II 11 generates supporting force for the cutting knife 9, so that the knife points of the cutting knives 9 are ensured to be on the same horizontal line when the hydraulic cutting knife 9 rotates for cutting, the occurrence of elliptical cutting is reduced, and the cutting stability and safety are improved.

Judging that the cutting is finished: when the cutting is completed, the downward force of the piston 5 is equal to the restoring force generated by the spring I7, the limiting rod circumferential through hole 3b is communicated with the piston radial bypass hole 5c, the other part of drilling fluid enters the limiting rod axial through hole 3a through the limiting rod eccentric through hole 3c, the piston axial bypass blind hole 5b, the piston radial bypass hole 5c and the limiting rod circumferential through hole 3b, the pressure drop generated at the moment is obviously lower than that in the normal operation of the cutter, and therefore whether the cutting is completed or not can be judged through the obvious change of the pressure drop on the platform.

The retraction process of the cutting knife: when the pressure drop is obviously changed, the cutting of the casing is finished, the drilling fluid is stopped to be introduced at the moment, the cutting knife 9 moves upwards under the action of the restoring force of the spring I7 to push the cutting knife 9 to be retracted, and the piston 5 is pushed to move upwards to enable the cutting knife 9 to be fully retracted.

After the cutting knife 9 is completely retracted, the drill stem is lifted upwards, and if the hanging weight is increased, the drill stem can be lifted, so that the underwater wellhead system can be lifted to the platform through the external hanging tool, and the cutting and recovery operation of the whole casing is completed.

Claims

1. The utility model provides a water conservancy cutting knife device for cutting sheathed tube, includes connecting rod, nozzle, gag lever post, stop collar, piston, sealing plug, spring I, spring II, cutting knife, pin, limit baffle, retrieves baffle and cutting knife body, its characterized in that: the connecting rod is in threaded connection with the cutting knife body, knife grooves are uniformly distributed in the circumferential direction of the cutting knife body, the cutting knife is fixed in the knife grooves through pins, and the cutting knife can rotate by taking the pins as axes; a limiting rod, a limiting sleeve and a piston are sequentially arranged in the cutting knife body; one end of the piston is provided with an axial through hole and an axial bypass blind hole, and a radial bypass hole is formed in the circumferential direction and is communicated with the axial bypass blind hole and the piston axial through hole; one end of the limiting rod is in threaded connection with the cutting knife body, the other end of the limiting rod stretches into the piston axial through hole, the end part of the limiting rod is in threaded connection with a nozzle in the direction close to the connecting rod, an axial through hole is formed in the center of the large-diameter end of the limiting rod, eccentric through holes are evenly distributed on the periphery of the large-diameter end of the limiting rod, the small-diameter end of the limiting rod slides relative to the piston axial through hole, and circumferential through; when the limiting rod circumferential through hole is communicated with the piston radial bypass hole, fluid enters the limiting rod axial through hole through the limiting rod eccentric through hole, the piston axial bypass blind hole, the piston radial bypass hole and the limiting rod circumferential through hole, so that the pressure drop is reduced, and the completion of sleeve cutting is judged; the limiting sleeve is in threaded connection with the cutting knife body, and the end part of the limiting sleeve is in contact with the end part of the limiting rod; an annular space is arranged between the piston and the cutting knife body, a spring I is arranged between the piston and the cutting knife body, and the upper end and the lower end of the spring I are limited by the shoulder of the piston and the shoulder of the cutting knife body respectively; the piston has recovery baffle and limit baffle in proper order in the one end of keeping away from the gag lever post, retrieves the baffle nestification in the piston surface and with piston relative slip, limit baffle and piston threaded connection are provided with spring II between recovery baffle and the limit baffle, retrieve the baffle and contact with the cutting knife tip all the time under the spring force effect.

2. The hydraulic cutter device for cutting casing according to claim 1, characterized in that: a sealing ring I is arranged at the contact part of the piston and the cutting knife body; the limiting rod is T-shaped, and a sealing ring II is arranged on the sliding contact part of the limiting rod and the piston.

3. The hydraulic cutter device for cutting casing according to claim 1, characterized in that: and a sealing plug is arranged at the outer end of the piston radial bypass hole and cannot extend into the piston axial bypass blind hole.

4. The hydraulic cutter device for cutting casing according to claim 1, characterized in that: the circular bead of cutting knife body has protruding structure radially, has the recess with cutting knife body convex structure matched with on the piston, and the piston can reciprocate along cutting knife body circular bead.