Hydromecanical piercing perforator and method of operation thereof

Proposed devices provide for a jetting process of formation critical areas after opening up a column, increasing a perforator's punch power and reliability, significantly preventing accidents. A hydro-mechanical piercing-type perforator includes a casing containing a hydraulic cylinder with a pusher, an operating tool radially movable and capable of interaction with the pusher. The tool is designed as a puncher, placed on a piston (plunger), mounted in a camera. The tool includes at least one through hydraulic channel and a jet. The camera is hydraulically connected with the cylinder. A proposed method for operating the perforator includes supplying a working fluid to the perforator through the column, creating pressure of the working fluid for an extension mechanism actuating the tool, extending the tool by applying the pressure through a piston rod system, to the piston with the puncher, and applying pressure to the piston through the hydraulic cylinder to the chamber.

FIELD OF THE INVENTION

The proposed invention relates to drilling and well operations, in particular to the design of devices for drilling-in of productive stratums through a piercing perforation, and may be used in the construction and repair of wells for various purposes.

BACKGROUND OF THE INVENTION

In the prior art, there are known devices for perforation of wells by piercing, disclosed in Russian Federation Patents RU 2129655 C1, IPC 6 E21B 43/112, 27 Apr. 1999; RU 2355877 C2, IPC E21B 43/112, 20 May 2009, including a casing, tool pistons with piercing elements—punchers with a mechanism of their extension, which is based on the principle of fluid expansion during heating and making of its high-pressure supplied to the tool pistons, as a result a radial moving of the tool pistons and an extension of the punchers happen. Significant disadvantages of these devices are low productivity, insecurity and design complexity, including energy drive with a heat source. Moreover, such perforator designs exclude a jetting process possibility of a critical area of formation immediately after an opening up of the column, which reduces the efficiency of the opening up.

In the prior art a large number of piercing perforating devices are known, their method of operation is based on the extension of pushers by hydraulic mechanisms disclosed in Russian Federation Patents: RU 2373382 C1, IPC E21B 43/112, 20 Nov. 2009; RU 2172394 C1, IPC 7 E21B 43/112, 20 Aug. 2001; RU 2069741 C1, IPC 6 E21B 43/112, 27 Nov. 1996; RU 2069740 C1, IPC 6 E21 B 43/112, 27 Nov. 1996, RU 2043486 C1, IPC 6 E21B 43/114, 10 Sep. 1995. The devices include a casing, comprising a system of chambers, pistons and rods, leading the working fluid coming to the perforator through the column of tubings to the punch piston. Such hydraulic mechanisms often have a low penetration. In order to increase the penetration they can include pressure boosters, which complicate the devices' design and increase manufacturing costs, the productivity and efficiency of the devices are not high enough at the same time. Moreover, when using such perforators with boost pressures the tightness problems of all design units and accelerated wear of seal elements of the pistons are arisen.

In the prior art, there is known a device for creating perforating channels in a casing string according to Russian Federation Patent RU 2395671 C1, IPC E21B 43/112, 27 Jul. 2010. The device comprises a tube and support housings, a cylinder connected to the support housing and comprising an actuating piston with a return spring and a slip pusher, equipped with working cutters longitudinally moveable in relation to the slip pusher when actuated by the support housing, a valve gear with its casing, mounted above the cylinder, and a secondary return spring, and the tube housing is connected to the piston to perform a constrained longitudinally movement. The cylinder above the support housing is provided with a ring seat, the piston has a collar, and the return spring is mounted between the external collar of the piston and the ring seat of the cylinder. The tube housing has a seat above the ring collar of the piston, while the secondary return spring is mounted between the seat and the piston in the cylinder. The casing of the valve gear is fixedly connected with tube housing and it has a valve seat at the top and an unsealed internal seat at the bottom. The spring is applied to press the valve to the seat of the valve gear casing from the internal seat, so that to hold a liquid column forcing the valve in the perforation interval.

The connection of the valve gear and tube housing can be made built-up (for example, a thread) for convenience of assembling and disassembling. The number of cylinders and their respective actuating pistons is selected based on forces necessary for the opening up of the casing string of the well: the thicker wall of the casing string, the greater a number of cylinders with the actuating pistons need to be used. Unauthorized overflows of liquid in the device are excluded by seals.

This device has no disadvantages of hydraulic piercing-type perforators, it has a high punch capability, sufficient power and it opens up the column effectively, but its design excludes the jetting process possibility of a critical area of formation immediately after the opening up of the column, which reduces the efficiency of the opening up.

To offer a more powerful device for drilling-in the effort is made in the useful model according to Russian Federation Patent RU 115407 U1, IPC E21B 43/114, 27 Apr. 2012. This device is the closest analog of the proposed invention and it is herein further referred to as a ‘prototype’.

The prototype device for creating of perforating channels in the well comprises a casing, a wedge with grooves, at least two hydraulic cylinders placed one behind the other with connected piston rods, one of which is spring-loaded, and at least two cutters with jets and cutters' holders, placed in grooves of a support and a wedge with an ability of radial reciprocating moving, the casing is made by the wedge and walls of the hydraulic cylinders, in which the piston rods are made with an axial channel connected downpipe with their piston cavities and with tubes of cutters' jets through channels in the cutters' holders, the support of which is connected to the piston rod, which is spring-loaded downward relative to the hydraulic cylinder.

The disadvantage of the device according to the prototype is unreliability of the design of the working fluid supply in the jet nozzle. There is a high probability of a pipe break or seal failure of the pipes in operating conditions; therefore not only caverns washout would be impossible to execute, but also the column opening, because the working fluid from the hydraulic cylinders would flow through the tube during creating an operating pressure. This can lead to an emergency in the well.

OBJECT AND SUMMARY OF THE INVENTION

The objective of the proposed invention is to create a highly efficient and reliable design of a hydro-mechanical piercing perforator and a method of operation thereof, providing a guaranteed opening up of the production string and the possibility of a subsequent jetting process of a critical area of formation in the area of opening.

The proposed invention achieves the following result:

1. Increasing the punch force, improving the quality of the opening up of the production string (herein also called ‘column’), increasing productivity of the perforator.

2. Increasing the perforation efficiency and improving the hydrodynamic connection to the layer due to a guaranteed possibility of the jetting process of a critical area of formation immediately after the opening of the column.

3. Reducing accidents, increasing the reliability of the perforator.

The mentioned result is achieved by providing a method of puncher ejection in a piercing perforator, including a puncher, wherein this method is based on a combination hydro-mechanical principle of operation: a tool piston or a plunger of the puncher is affected by mechanical force of a wedge pusher and, on the other hand, at the same time, by hydraulic pressure force of a working fluid, supplied to a process chamber (herein also called ‘chamber’) of the tool piston (or the plunger).

The inventive hydro-mechanical piercing perforator comprises: a casing; at least one operating hydraulic cylinder placed in the casing; at least one wedge pusher (i.e. a pusher having a wedge shape); at least one operating tool, including at least one through hydraulic channel and at least one hydro-monitor (herein also called ‘jet nozzle’); wherein the operating tool is capable of interaction with the wedge pusher, and capable of radial movement as a result of the interaction.

According to the invention, the operating tool is designed as a piston with a puncher (tool piston), which piston is equipped by seals, mounted in the chamber; or a plunger with a puncher (tool plunger) mounted in the chamber, which chamber is equipped by seals; and the chamber is designed with a capability of hydraulic connection with the operating hydraulic cylinder.

The connection of the process chamber of the tool piston (plunger) with the hydraulic cylinder can be designed in different ways.

The chamber is connected with the operating hydraulic cylinder by means of one or several channels made in the wedge pusher.

The chamber is connected with the operating hydraulic cylinder by means of areas (flats, chamfers) or grooves made on the external surface of the wedge pusher.

The chamber is connected with the operating hydraulic cylinder by means of grooves, made on the internal surface of the perforator's casing, or on the external surface of the wedge pusher and on the internal surface of the casing.

The chamber is connected with the operating hydraulic cylinder by means of one or several channels made in the perforator's casing.

The wedge pusher of the perforator can be equipped by seals, in which case the wedge pusher is embodied as a piston.

A cavity, wherein the wedge pusher is moving, can be equipped by seals, in which case the wedge pusher is embodied as a plunger.

The method of operation of the inventive hydro-mechanical piercing perforator comprises: supplying a working fluid to the perforator through a column of pump compression tubes (herein also called “tubings”); creating an operating pressure of the working fluid for actuating an extension mechanism of the operating tool; extending the operating tool; and carrying out the perforation. According to the method of the invention, the extension of the operation tool is made:—by impact of the pressure of working fluid transmitted through a piston-rod system to the wedge pusher, in turn, pushing the tool piston (plunger) with the puncher; and also—by impact on the tool piston (plunger) of the working fluid supplied under pressure through the hydraulic cylinder of the perforator to the process chamber of the tool piston (plunger).

Designing the operating tool in the form of a piston with a puncher or a plunger with a puncher (tool piston/plunger) enables supply of the operating fluid pressure to the operating tool and creating an additional force, directed at the extension of the operating tool. Designing the chamber of the tool piston/plunger with a capability of hydraulic connection with the operating hydraulic cylinder enables supply of the operating fluid to the chamber from the hydraulic cylinder for impact on the tool piston/plunger. Thus, proposed design and the method of operation of the perforator provide for a double force impact on the puncher, which is a combination of the mechanical force of the wedge pusher and the hydraulic force of operating fluid applied to the tool piston/plunger. This double force impact increases the punching capability of the puncher, and improves quality of the opening up of the production string (column).

Moreover, designing the chamber of the tool piston/plunger with a capability of hydraulic connection with the operating hydraulic cylinder enables supplying the operating fluid to the hydraulic channel of a nozzle of the hydro-monitor, so that immediately after opening the column up the jetting process of the critical area of formation can be done, that significantly increases the efficiency of the opening up of the column.

If the wedge pusher of the perforator is made in the form of a piston or plunger, it can carry out a function of an additional hydraulic cylinder, thereby increasing the operating force applied to the tool piston/plunger.

The proposed design and the method of operation of the inventive device is characterized with simplicity and reliability, which allows for a trouble-free operation of the perforator.

DETAIL DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

According to a preferred embodiment of the invention, the device comprises a casing1, at least one operating hydraulic cylinder2, placed in the casing1, at least one wedge pusher3, at least one operating tool4, which includes at least one through hydraulic channel5and at least one jet6. The operating tool4is mounted with a capability of interaction with the wedge pusher3and a capability of radial movement. The operating tool4is designed as a plunger7with a puncher8(of the tool plunger7), mounted in a process chamber9, wherein the chamber9is designed with a capability of hydraulic connection with the operating hydraulic cylinder2.

The connection of the process chamber9of the tool plunger7with the hydraulic cylinder2can be carried out by means of channels10, made in the wedge pusher3, or by means of areas (flats11, chamfers12) or grooves13, made on an external surface14of the wedge pusher3, or by means of grooves15, made on an internal surface16of the perforator's casing1, or made on the external surface14of the wedge pusher3and on the internal surface16, or, for example, by means of one or several channels10, made in the perforator's casing1.

The inventive device operates as follows. The perforator secured on the column of pump-compressor tubes (tubings) is lowered into the well, the working fluid is supplied to the perforator, and the operating pressure is created for actuating the extension mechanism of the operating tool4. The extension of the operation tool4is made by impact of the working fluid pressure through a piston rod system, including one or several hydraulic cylinders2, upon the wedge pusher3, while the wedge pusher3pushes the tool piston/plunger7with the puncher8, and also by impact of the working fluid on the tool piston/plunger7, while the working fluid is supplied under pressure through a hydraulic cylinder2of the perforator to the process chamber9of the tool piston/plunger7. As a result of the application of the combined hydro-mechanical forces to the tool piston/plunger7, it moves radially, pushing the puncher8and thereby opening up the column. Thereafter, the processing of the critical area of formation is executed, if it is necessary, through the jet nozzles6.

Upon completion of the work, the inventive device is brought in the transportation position by a known manner, for example as follows: the working fluid pressure is released, under the influence of one or several springs18, the operating hydraulic cylinder2and the wedge pusher3are moved to an uppermost position, with the help of a T-shaped connection17or a connection of the “dovetail” type, the wedge pusher3, moving up, retracts the operating tool4into the casing, thereby placing it in the transportation position.

The perforator is lifted on the surface or transferred to a new perforation interval.