RU2098607C1 - Device for creating perforation channels in casing string in borehole - Google Patents

Abstract

FIELD: oil and gas production. SUBSTANCE: device consists of tubular body on which hydraulic cylinder with spring-loaded piston is placed. Device also has wedge-type pusher with tail and cutter holder with perforation cutters interacting with wedge pusher. Tubular body is connected with tail to transmit reciprocating displacement to the latter at lowest piston position. Hydraulic cylinder may reciprocate in relation to tubular body. Cutter holder is placed on the end of tail. EFFECT: simplified device and enabled perforation of small- diameter casing strings. 2 dwg

Description

 The invention relates to the oil and gas industry, and in particular to the field of oil drilling to create perforations in the casing.

 It is known "A device for creating perforation channels in a casing string [1] including a tubular body with a reciprocating housing of the hydraulic cylinder body, a hydraulic cylinder piston connected to a wedge pusher, a tool holder with perforating cutters, a wedge pusher and a return spring.

 The disadvantage of this device is that, firstly, it is difficult in design; secondly, it cannot be used in casing strings of small diameter, since, due to design features, when manufacturing it in a reduced form, the length of the cutters exit is less than the thickness of the perforated pipe; moreover, it does not develop forces sufficient for cutting perforation channels.

 Closer in technical essence is the "Device for creating perforation channels" [2] including a tubular body, a hydraulic cylinder with a spring-loaded piston placed on it, a wedge pusher and a tool holder with perforating cutters interacting with the wedge pusher.

 The disadvantage of this device is that for the formation of cracks in the wall of the casing string it requires a reciprocating motion of the cutter, which complicates the technology of perforation and operation of the device, in addition, the creation of perforation channels in the form of longitudinal slots mechanically weakens the string, which can lead to emergency situations.

 The objective of the invention is to provide a simple in design device for perforating casing strings of small diameter.

 The problem is solved by a device for creating perforation channels in the well casing, including a tubular body with a hydraulic cylinder with a spring-loaded piston placed on it, a wedge pusher and a tool holder with perforating cutters interacting with the wedge pusher. What is new is that the piston is made with a shank, and the tubular body has a connection with the shank for transmitting reciprocating movement to the latter at the lowermost position of the piston, while the hydraulic cylinder is made with the possibility of reciprocating movement relative to the tubular body, and the tool holder is located at the end of the shank .

 The analysis of patent and scientific and technical literature did not reveal technical solutions with a similar set of essential features, which allows us to conclude that the criteria for "novelty" and "significant differences" of the proposed solution are met.

 In FIG. 1 schematically shows the proposed device in its original position; in FIG. 2 section of the device along AA.

 The device comprises a tubular housing 1 with a reciprocating movement of the hydraulic cylinder housing 2 and a composite shank 3. A piston of the hydraulic cylinder 4 is placed inside the hydraulic cylinder housing 2. A saddle 5 and a corresponding ball valve 6 are placed inside the tubular housing 1, in the end of the tubular of the housing 1, a hole is made in which a finger 7 is placed, passing through the slotted slot 8 of the piston of the hydraulic cylinder 4. The finger 7 supports an annular stop 9, which serves as a stop for the return spring 10, the other end into the piston of the hydraulic cylinder 4. In the tubular casing 1, a window 11 is made, which is placed in the initial state opposite the cavity-cylinder formed by the inner end of the hydraulic cylinder 2, the piston of the hydraulic cylinder 4 and the outer surface of the tubular casing 1. All movable joints necessary for operation are equipped with seals 12, 13 and 14. The tubular body 1 is screwed into the adapter 15 for connection to the tubing string, which at the same time serves as a stop for the cylinder body 2. Inside the composite tail Ike 3 has a wedge 16 connected to the piston of the hydraulic cylinder 4, a transfer hole 17 is made within the wedge 17. In the longitudinal fixing grooves of the wedge 16, toolholders 18 are installed with the possibility of reciprocating movement, in which the cutters 19 are fixed with a dovetail connection supported by the stop 20. Auxiliary fasteners are not shown in the drawing.

 During operation, the device is connected to the string (tubing) and lowered into the well (not shown in the drawing).

 The device operates as follows.

 When the device is lowered into the well, the borehole fluid passes through the transfer hole 17 and valve 6, thereby reducing the buoyancy of all equipment. Upon reaching the calculated place, the valve b sits in its seat 5, thereby preparing the device for operation.

 The perforation process is started by pumping liquid into the tubing string. The latter through the hole 11 enters the cavity of the hydraulic cylinder formed by the inner end of the cylinder body 2, the piston of the hydraulic cylinder 4 and the outer surface of the tubular body 1, while the piston of the hydraulic cylinder 4 begins to move (Fig. 1) down. Together with it, the wedge 16 attached to it moves, pushing the tool holders 18, held from axial movement by the end of the shank 3, which are embedded and cut through the perforation holes in the perforated production string. After completing their cutting, the fluid injection is stopped and the pressure is released to atmospheric pressure.

 The tubing begins to lift, while the tubular body 1 is lifted, and the cylinder body 2 with the shank 3 and the wedge 16 remain in place, held by the cutters 19 embedded in the perforated production casing. The finger 7, moving together with the tubular body 1, compresses the return spring 10 and carries away the piston of the hydraulic cylinder 4. is followed by the window 11 reaching the well cavity and the pressure inside the device is released to the pressure of the hydrostatic column of fluid and the cutters 19 exit the perforated production string, releasing the wedge 16 and the associated piston of the hydraulic cylinder 4, the return spring 10 then returns the piston of the hydraulic cylinder 4, and with it the entire device to its original state, that is, the device is ready to perforate the next interval.

 If necessary, lifting the device to a predetermined height, the perforation process is repeated.

 Technical appraisal and economic advantages of the device are as follows. Possibilities have appeared to perforate production cores of small diameter, which is especially important in wells with horizontal bottom hole. The use of the device reduces material costs and time for perforation, maintains well support by creating a gentle opening mode (creating holes), which in turn prevents premature flooding of the well.

Claims (1)

 A device for creating perforation channels in a casing of a well, including a tubular body with a hydraulic cylinder with a spring-loaded piston placed on it, a wedge pusher and a tool holder with perforating cutters interacting with a wedge pusher, characterized in that the piston is made with a shank and the tubular body has a connection with the shank for transferring the reciprocating movement to the latter at the lowermost position of the piston, while the hydraulic cylinder is made with the possibility of reciprocating relative movement relative to the tubular body, and the tool holder is located at the end of the shank.

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