RU2393341C2 - Hydromechanical slit perforator - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: hydromechanical well perforator includes housing, power assisted mechanisms, cutting tool in the form of rolling disc, which is installed with possibility of being extended from the housing at the action thereon of power assisted mechanism, and the above mechanisms are installed in the housing, and a jet nozzle. Housing is fixed on the flow string by means of movable joint in order to provide rotary movement. Rolling disc is installed at an angle to the perforator axis so that the torque moment transmitted to the housing can be created on it during the movement of the housing in production column, and cut slot in production column along helical line.

EFFECT: improving manufacturability, increasing the efficiency of the perforation process and quality of the formation drilling process.

3 cl, 2 dwg

Description

The invention relates to the field of drilling and operation of oil, gas and injection wells, and in particular, to a device for secondary opening of formations by creating longitudinal perforation slots in production casing and forming filter channels in the bottomhole formation zone.

The prior art devices for slotted perforation of casing strings based on the use of a cutting tool in the form of a retractable rolling roller. Such a device is disclosed, for example, in RU 2182221 C1, 05/10/2002; RU 2151858 C1, 06/27/2000; RU 2087683 C1, 08.20.1997; RU 2030563 C1, 03/10/1995; RU 2007549 C1, 02.15.1994; US 4119151 A, 10/10/1978; US 4220201 A, 09/02/1980. The described devices differ mainly in the design of the mechanism of attachment and extension of the cutting tool.

One of the disadvantages of the above devices is the rapid wear of working parts, including the cutting unit, the difficulty of replacing and repairing them, as This requires complete disassembly of the device. Another disadvantage is the inefficient treatment of the bottom-hole zone.

The geological and technical conditions for the secondary opening of reservoirs in cased wells dictate at least three criteria for its effectiveness:

1. The total opening surface of the casing (in the form of holes or cracks) should be maximum. However, the column must retain the ability to withstand the horizontal component of rock pressure, which is very significant.

2. The productive part of the reservoir must be fully opened, the remains of the cement ring are unacceptable. At the same time, outside the opening interval, the safety of both the casing and the cement ring must be ensured.

3. Within the reservoir, several deep perforation channels should be formed. The question of the number and depth of channels is obvious: the more the better. This condition is dictated by the requirement of reliable communication between the formation and the well even with a low quality of initial drilling (high repression, unfavorable drilling fluid parameters, etc.) and the negative consequences of grouting.

Almost all known hydromechanical perforators used to open the casing form one or two slots located in the same plane, which does not allow a long time to withstand the rock pressure of tens of MPa. As a result, the geological effect from the application of the technology is short-lived, and the broken support of the well remains, resulting in a high probability of crushing of the production string. In addition, this arrangement of cracks does not allow the most complete coverage of the entire productive part of the oil reservoir.

The closest analogue of the proposed perforator can be considered a hydromechanical perforator according to the patent RU 2182221 C1, 05/10/2002, containing a power mechanism located in the housing, including a pusher-piston that acts on the cutting tool - a thumb wheel, and a hydraulic monitor. When moving the puncher along the production string when pressure is applied to the plunger piston, the latter pushes a rolling disk cutting the production string in a vertical line.

This punch also has the above disadvantages.

The technical result of the proposed solution is to improve manufacturability, increase the productivity of the perforation process and the quality of the formation. This ensures the preservation of the residual strength characteristics of the production string and its ability to withstand the effects of rock pressure due to the screw arrangement of the gap.

The specified technical result was obtained due to the fact that in a hydromechanical borehole perforator including a housing, a power mechanism located therein, a cutting tool in the form of a knurled disk mounted with the possibility of sliding out of the housing when the power mechanism is exposed to it, and a hydraulic nozzle, according to the invention, the housing mounted on a tubing string (tubing) using a movable connection with the possibility of providing rotational movement of the housing, while the rolling disk is installed at an angle ohm to the axis of the punch to ensure that on it when the case moves along the production casing, torque is transmitted to the casing and the slot is cut through the helix in the production casing.

The movable connection of the punch body to the tubing string is made in the form of a movable coupler.

The angle φ of the inclination of the rolling disc to the axis of the punch is selected from the condition for obtaining a given pitch T of the screw gap, determined by the formula

,

,

where D is the outer diameter of the column, mm;

The design of a hydromechanical slotted puncher with the location of the rotary disk at an angle of φ ° to the axis of the punch and using a movable joint ensures that when the puncher moves along the column axis and the disk extends, a torque appears on the disk, which is transmitted to the housing, and the puncher receives rotational movement. In this case, the disk moves along the helix and forms a helical gap in the production casing.

Figure 1 presents a view of the perforator from the side of the rolling disk, figure 2 is a section along aa in figure 1, showing in more detail the design of the nodes of the perforator.

The perforator contains a housing 1 in which a cutting tool is installed - a pendulum 2 with a knurling disk 3 located at an angle φ ° to the axis of the perforator. The power mechanism (the piston 5 installed in the housing 1, connected to the rod 4) acts on the pendulum 2 with a thumb drive 3, which leaves the housing 1 and forms a gap in the production string along a helix. The rod 4 and piston 5 are made with flushing channels for supplying flushing fluid to the perforator. Hydromonitors 6, through which the working fluid is supplied, are fixed, for example, on the piston 5 of the power mechanism, communicated with the cavity of the piston 5, which in turn are connected with the cavity of the housing 1, and after the formation of the gap forms, the cement ring, rock are washed out and formation of filtration channels. The spring 7 is installed between the ring 8, mounted on the housing 1, and the piston flange 5 and is designed to return after bleeding the pressure of the working fluid in the tubing to the atmospheric piston 5 in its original position. The spring 10 is located in the lower part of the housing 1, acts on the pendulum 2 and is designed to return to the initial position of the pendulum 2 with a thumb wheel 3.

The case of the punch is connected to the tubing 12 with a movable coupling 13, which provides free rotation of the punch relative to the tubing 12.

The punch works as follows.

On the tubing string, the perforator descends into the production string 14 of the well at a predetermined perforation interval. Having installed a perforator in the well, a direct washing of the tubing cavity and the perforator is carried out from various mechanical impurities, scale falling into the pipe cavity during geophysical work to bind the perforator to a given interval. Then, a small diameter ball (not shown) is thrown into the tubing cavity 12, which, passing through the tubing suspension 12 and the hollow rod 4, is lowered into the seat 15 of the piston 5 and closes the central flushing channel. After that, the working pressure is created in the tubing 12, which begins to act on the piston 5, which, moving progressively along the axis of the perforator, rotates the pendulum 2 and thus pushes the cutting tool with the thumb wheel 3. The hammer starts to rotate under the action of the torque generated on the inclined gear drive 3, as described above. When this knurled disk 3 moves along a helix. By gradually creating a pressure of 1.0 to 8.0 MPa in the tubing cavity, the puncher is moved up and down and the cutting knurled disk 3 is gradually pressed into the wall of the production string 12.

After the formation of a helical perforation gap in the production string 12, the pressure in the tubing cavity is raised to 15.0 MPa, realizing the jet monitor effect. The jets of liquid flowing out of the hydraulic nozzles 6 with great speed, destroy the cement stone and rock behind the production string 14, forming a filtration channel. Then the pressure in the cavity of the tubing 12 is reduced to atmospheric, and under the action of the return spring 10, the cutting tool is drawn into the perforator.

The helical arrangement of the slit significantly preserves the residual strength characteristics of the production string and its ability to withstand the effects of rock pressure, which is important for long-term operation of the wells.

The technical solution will allow you to cover the entire capacity of the reservoir and equip the well with a system of long cruciform channels, while achieving 2, 3-fold increase in inflow.

Claims (3)

1. Hydro-mechanical downhole perforator, comprising a housing, a power mechanism located therein, a cutting tool in the form of a rolling disk mounted with the possibility of sliding out of the housing when the power mechanism is exposed to it, and a hydraulic nozzle, characterized in that the housing is mounted on a tubing string pipes using a movable connection with the possibility of providing rotational movement of the housing, while the rolling disk is installed at an angle to the axis of the punch to ensure that it is created on and the casing along the production casing of the torque transmitted to the casing and cutting a slot in the casing along the helix. 2. The hammer drill according to claim 1, characterized in that the movable connection of the housing of the hammer with a string of tubing is made in the form of a movable coupling. 3. The hammer drill according to claim 1, characterized in that the angle of inclination of the knurled disk to the axis of the hammer drill is selected from the condition for obtaining a given pitch T of the screw gap, determined by the formula:

where D is the outer diameter of the column, mm; φ is the angle of inclination of the thumb wheel to the axis of the punch.

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