RU2055154C1 - Bottom-hole packer-safety valve - Google Patents

Abstract

FIELD: gas and oil producing industry. SUBSTANCE: inlet-pipe connection of safety valve is rigidly connected with packer mandrel, and cylinder with tip is located in case cavity and form annual cavity. Annular recess is made on piston outer surface and filled with buffer fluid of high viscosity. Bottom-hole safety valve has starting valve connected with rod lower end that makes it possible to install it for one round trip operation. EFFECT: higher economic efficiency and reliability. 3 cl, 1 dwg

Description

 The invention relates to the oil and gas industry and can be used in oil wells. The preferred area of use is production wells with high reservoir pressure.

Known packer-cutter, comprising a barrel with a seal, a check valve and a cutter with a receiving chamber, a cylinder, a piston with a rod and an air chamber with a cover and a bottom with a channel [1]
This packer-cutter does not have sufficient reliability, since it is necessary to create a load in the process of work by the weight of the pipe string during the operation of the chamber formed by the cover and the column of lifting pipes to prevent its opening. In addition, the check valve in the form of a flap mounted on the lower end of the packer-cutter has low reliability and does not provide reliable closure of the passage channel of the packer when removing the cutter. In addition, the packer-cutter descends on the pipes, additional tripping and installation operations are required to install the cutter. This significantly reduces the effectiveness of this packer-cutter.

Known packer type R-41, including a barrel with a seal installed on it and a slip unit, a shank, clamps for fixing the barrel with a compressed seal relative to the cone and upstream nozzles used to connect with the cutter being lowered into the well with a receiving chamber, a cylinder with a piston, a rod , valve and fluid passage [2]
The R-41 type packer-cutter has a complex structure, due to the presence of many fixing units and parts that require clear interaction when planting, installing and removing both the packer and the cutter. In the event of failure of one of them or clogging by the sediments of the well fluid, the response of the packer nodes is sharply reduced and the probability of an emergency condition increases. In addition, the descent and installation of the cutter are made on pipes, which reduces the efficiency of equipment use. The absence of a buffer fluid cavity in the cutter also reduces the reliability of its operation when it is in the well for a long time.

Known downhole packer-cutter, including a hollow barrel, a sealant placed on the barrel with a support and a slip holder, slips and a cone connected with a cone, a sleeve, a casing connected to the sleeve with a head on its upper end, installed between the sleeve and the barrel, a stepped sleeve forming with the barrel an annular cavity in which a split retainer with a clip and a shock absorber is installed, a receiving nozzle connected by the upper part to a nozzle having a seat, a cylinder with radial channels connected to the nozzle and connected to the cylinder an end for connecting with the landing tool, a piston with a rod installed in the cylinder, the supra-piston cavity of which is filled with inert gas, and the sub-piston cavity is connected through the radial channels of the cylinder with the cavity behind the cylinder, and a valve connected to the lower part of the stem and placed in the cavity of the receiving pipe with a supporting surface under saddle nozzle [2, c.21-25]
The well-known downhole packer-cutter is installed as follows: first descent on pipes and landing the lower part (the packer itself), removing the pipes, and then lowering and landing the upper part (receiving pipe with the cylinder) and its engagement with the lower part by means of a collet connection. Thus, the well-known downhole packer-cutter has low efficiency, since it requires two tripping operations to land it, and, as a result, low reliability.

 The purpose of the invention is to increase the efficiency and reliability of the downhole packer-cutter.

 The goal is achieved by the fact that in the well-known downhole packer-cutter, including a hollow barrel, a seal placed on the barrel with a support and a slip holder, slips and a cone located above the slip holder, a sleeve connected to the cone, a casing connected to the sleeve with a head at its upper end, installed between the sleeve and the barrel have a stepped sleeve forming an annular cavity with the barrel, in which a split retainer with a clip and a shock absorber is installed, a receiving pipe connected to the nozzle with a saddle connected with us by the upper part a cylinder with radial channels and a nozzle connected to shear elements with a cylinder for connecting with a landing tool, a piston with a rod installed in the cylinder, the piston cavity of which is filled with inert gas, and the piston cavity is connected through the radial channels of the cylinder with the cavity behind the cylinder and connected to the lower part of the rod and a valve located in the cavity of the receiving branch pipe with a bearing surface under the saddle nozzle, the receiving branch pipe is rigidly connected to the barrel, and the cylinder with the tip is placed in the cavity of the casing and about with them form a ring cavity.

 The installation of such a downhole packer-cutter requires one tripping operation.

 In addition, an annular groove is made on the outer surface of the piston and is filled with a high-viscosity buffer fluid. This prevents the transfer of inert gas above the piston into the cavity below the piston and the entry of well fluid into the cavity above the piston.

 The downhole packer-cutter is equipped with a start valve connected to the lower end of the rod, which reduces the force on the piston rod when the valve is opened and enables the well to work, after which the main valve is opened and the well’s maximum productivity.

 The drawing shows a downhole packer-cutter.

 The downhole packer-cutter includes a hollow barrel 1, on which a support 2 is placed, a sealing element 3 with protective washers 4, a slip holder 5, slips 6 and a cone 7. Above the cone is placed a sleeve 8 and a casing 9 connected to the sleeve with a head 10 on top end. Between the sleeve 8 and the barrel 1 there is a stepped sleeve 11, the upper end of which is attached to the casing 9. The sleeve 8 and the stepped sleeve 11 form an annular cavity with the barrel 1, in which a split retainer 12 with a clip 13 and a shock absorber 14 is installed. The stepped sleeve 11 has a protrusion 15 and forms an annular cavity 16 with the sleeve 8. The sleeve 8, in turn, has an internal protrusion 17 and is connected to the step sleeve 11 by shear screws 18. Above the barrel 1 there is a receiving pipe 19 which is rigidly attached to it and is connected by the upper part to the nozzle 20, having they have a saddle 21. A cylinder 22 is connected to the nozzle 20 with radial channels and a tip 24 for connecting with a landing tool (not shown). The tip 24 and the cylinder 22 are connected by shear elements 25. The cylinder 22 with the tip 24 is placed in the cavity of the casing 9 and form an annular cavity 26 with it. A piston 27 with a rod 28 is installed in the cylinder 22, the piston cavity 29 of which is filled with inert gas through the valve 30, and the piston cavity 31 is connected via radial channels 32 of the cylinder 22 with the cavity 26 behind the cylinder 22. The piston 27 has an annular groove 33 on the outer surface filled with a buffer fluid of high viscosity.

 A valve 34 is connected to the lower part of the stem 28, which is located in the cavity of the receiving pipe 19 and has a supporting surface 35 under the seat 21 of the nozzle 20. A trigger valve 36 is connected to the lower end of the stem 28.

 Downhole packer-cutter operates as follows.

 Before lowering into the well, the suprapercussion cavity 29 through the valve 30 is filled with inert gas and the packer-cutter is connected to the planting tool by screwing the rod of the planting tool into the thread of the tip 24 in its upper part. The stop of the landing tool abuts against the head 10 of the downhole packer-cutter.

 The packer-cutter with a landing tool is lowered into the well and installed at the required depth. In this case, the rod of the landing tool (not shown) moves up, and the stop of the tool down. The force from the rod of the landing tool through the tip 24, shear elements 25, cylinder 22, nozzles 20, the receiving pipe 19 is transmitted to the barrel 1 and support 2, compressing the sealing element 3 with protective washers 4, and acts on the slip holder 5 and slips 6. The force from the stop of the landing tool through the head 10, the casing 9, the stepped sleeve 11 and the sleeve 8 is transmitted to the shock absorber 14, the split retainer 12, the clip 13 and the cone 7, acting on the slips 6. The split lock 12 and the clip 13 are moved along the barrel 1, and the cone 7 wedges under the slips 6, which s mesh with siege column, and the seal seals the gap between the barrel 1 packer-clipper and the wall of the casing. The packer-cutter is sealed in the well, and the latch 12 fixes the packer in the sealing state. With a further increase in the force of the landing tool, shear elements 25 are cut off, the landing tool with tip 24 is removed to the surface.

 A downhole pump is lowered to the required depth (above the cutter-cutter) and the fluid is pumped out. In this case, the liquid level decreases and the hydrostatic pressure on the piston 27 from the side of the well decreases. At a certain level of fluid in the well, the force from the action of compressed inert gas in the supra-piston cavity 29 becomes greater than the hydrostatic pressure of the fluid column above the packer, the piston 27 moves downward, opening the start valve 36. The fluid enters the nozzle 20 through the gaps between the start valve 36 and the valve 34 and through channels 32 into the annular cavity 26 and further into the above-packer space. With further pumping of the borehole fluid, the rod 28, moving downward, diverts the valve 34 from the seat 21, the through hole in the nozzle increases, the flow of fluid into the over packer space increases and, therefore, the flow rate of the well.

 When the deep-well pump stops (in case of an accident), the liquid level in the over-packer space rises, the hydrostatic pressure increases on the piston 27 and exceeds the inert gas pressure in the cavity 29. The piston 27 moves upward and the valves 34 and 36 overlap the seat 21 in the nozzle 20, and the access of fluid from under the packer to the well is terminated. After lifting the deep pump, its repair and subsequent installation in the well and starting the work, the cycle of operation of the packer-cutter is repeated. In this case, well killing is not required.

 At the end of the specified service life or in other cases, the packer-cutter can be removed from the installation site. For this, a fishing tool is lowered into the well and the packer-cutter is caught by the head 10 or casing 9, creating tension on the pipe string. The force from the tension of the pipe string is transmitted through the casing 9 to the stepped sleeve 11, the sleeve 11 moves in the sleeve 8 along the annular cavity 16, the protrusion 15 abuts against the protrusion 17, and the force is transmitted to the cone 7, pulling it out from under the slips. In this case, the cone acts on the latch 12, diverts it from the barrel 1 and together with the cage 13 they are discharged into the formed cavity between the barrel 1 and the sleeve 8. The cone 7 exits from under the slips, the seal is decompressed. Thus, the packer-cutter is brought into the transport position and it is removed to the surface.

 The proposed packer-cutter is more economical and reliable, since its installation requires only one round trip. This is achieved due to the rigid connection of the receiving pipe with the barrel and the placement of the cylinder with the tip in the cavity of the casing with the formation of an annular cavity.

Claims (3)

 1. BOTTOM-BASED PACKER-SHUT-OFF, including a hollow barrel, a seal placed on the barrel with a support and a slip holder, slips and a cone placed above the slip holder, a sleeve connected to the sleeve cone, a casing with a head mounted on its upper end face mounted between the sleeve and the barrel forming an annular cavity with a barrel in which a split retainer with a clip and a shock absorber is installed, a receiving nozzle connected by the upper part to a nozzle having a saddle, a cylinder with radial channels connected to the nozzle and a tip connected with shear elements to the cylinder for connecting with the landing tool, a piston with a rod installed in the cylinder, the supra-piston cavity of which is filled with inert gas, and the sub-piston cavity is connected through the radial channels of the cylinder with the cavity behind the cylinder, and connected to the lower part of the rod and placed in the receiving cavity nozzle valve with a supporting surface under the saddle nozzle, characterized in that the receiving nozzle is rigidly connected to the barrel, and the cylinder with the tip is placed in the cavity of the casing and form with it facial cavity.  2. The packer-cutter according to claim 1, characterized in that on the outer surface of the piston an annular groove is made, filled with a buffer fluid of high viscosity.  3. The packer-cutter according to claim 1, characterized in that it is equipped with a trigger valve connected to the lower end of the rod.

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