SU1668641A1 - Method of cased well perforation - Google Patents

Abstract

The invention relates to the mining industry, in particular, to methods and devices for perforating oil wells. The goal is to increase efficiency by providing the possibility of hydraulic fracturing and processing the bottom-hole zone without additional tripping, while reducing the flow rate of the working fluid. For this, the casing wall is forced mechanically and the working fluid is fed into the formation through the hole. In the process of punching the casing wall, the annular space is sealed in the zone of contact of the external surface of the piercer with the edge of the perforation of the column. The device comprises a housing 1 with an axial channel 2, pistons 4. A piercer with a channel is rigidly fixed on the housing 1. Lamellar springs 8 are installed on the outer surface of the housing 1 on the side of the piercer 8. The piercer is provided at the base in the form of a truncated irregular pyramid to ensure sealing of the annular space. After creating a pressure of the working fluid in the axial channel 2, the pistons 4 press the punch against the wall of the casing string and push it. The lower part of the piercer seals the entrance to the annular space. Through the channel, the working fluid (acid solution) is fed into the annulus and fractures the formation. The leaf springs 8 provide the exit of the piercer from the perforation hole after depressurizing the working fluid. 2 hp f-ly, 3 ill.

Description

The invention relates to the petroleum industry and is intended to perforate a well.

The purpose of the invention is to increase efficiency by providing the possibility of hydraulic fracturing and processing of the near-wellbore zone without additional lifting and reducing the flow rate of the working fluid.

FIG. 1 shows an axial section of the device in the transport state; in fig. 2 - the same, at the time of perforation of the well; in fig. 3 is a cross section A-A at the level of the piercer channel.

The method of perforating a well cased with a casing consists in mechanically pushing the casing wall and feeding the working fluid into the formation through the perforation

hole. In the process of forcing the wall, the casing seals the annular space along the outer surface of the punch in the place of its contact with the casing in the area of the perforation hole.

A device for perforating a well cased with a casing string comprises a housing 1 with an axial channel 2 and a saddle 3 for a drop ball valve, pistons 4 placed in cylindrical radial bores 5 of housing 1. A piercer 6 is rigidly fixed to the housing 7, Channel 7 is connected with an axial channel 2 of the body and is oriented radially relative to the latter. On the outer surface of the housing 1 on the side of the piercer 6, leaf springs 8 are installed. The piercer 6 is designed to ensure sealing of the annular space at the base in the form of a truncated irregular pyramid.

The device for perforation of the well works as follows.

The perforator on the pump-compressor pipes is installed opposite the intended perforation interval. The ball valve is released, which, when seated in the saddle 3, creates pressure in the column of pump-compressor pipes. When the pressure is applied through the axial channel 2, the pressure is transferred to the cylindrical bores 5. The pistons 4 move in the bores 5 until they stop in the casing. Under pressure, housing 1 moves in the opposite direction. At the same time, the punch 6 is inserted into the casing and, with a certain force, forms a perforation in it, which is sealed with the faces of the base of the punch. Through channel 7, the working fluid (acid solution) is injected into the annular space under a pressure exceeding the fracture pressure of the rocks. As a result, a fracture crack system with high hydraulic conductivity is formed in the bottomhole zone.

At the end of the process, the pressure is released. Plate springs 8 provide the exit of the piercer from the punched hole. The hydraulic perforator is raised by the tubing and compression pipes and installed in a new place.

Claims (2)

1. A method of perforating a well cased by a casing, which consists in mechanically pushing the casing wall followed by feeding the working fluid into the formation through a perforation hole characterized in that, in order to increase efficiency by providing the possibility of hydraulic fracturing and processing of the bottomhole zone without additional tripping while reducing the flow rate of the working fluid, in the process of mechanically forcing the casing wall, seals the annular space along the outer surface of the punch at the point of its contact with a casing in the area of the perforation. 2. A device for perforation of a well cased with a casing, comprising a housing with an axial channel and a saddle under the reset ball valve, pistons placed in radial bores of the housing, a punch rigidly fixed on the housing with a channel connected to the axial channel of the housing and oriented radially relative to the latter, plate springs mounted on the outer surface of the housing from the piercer side, characterized in that in order to increase efficiency by providing the possibility of hydraulic fracturing and processing of the bottomhole zone without additional tripping and simultaneous reduction of the flow rate bochey liquid piercer in the base is in the form of a truncated pyramid of irregular. five Fig. / FIG. / Aa