RU2487990C1 - Device for making perforation tunnels in well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device contains a case, wedge with grooves, at least two hydraulic motors placed one by one which have spring-loaded pistons and at least two cutters with hydraulic monitors and cutter holders installed in grooves of its support and wedge and capable of radial reciprocating movement. The case is formed by the wedge and walls of hydraulic motors which piston rods have axial channel connected by overflow channels with cavities under pistons and by tubes and channels of cutter holders with hydraulic monitors of cutters. Support of cutter holders is connected to piston rod which is loaded by a spring downwards in regard to the hydraulic motor.

EFFECT: improvement in efficiency of productive stratum treatment at reduction of metal consumption and material costs.

1 dwg

Description

The invention relates to the oil and gas industry, and in particular to the field of secondary drilling, by creating perforation channels in the well.

Known hydromechanical slotted perforators, which are disclosed, in particular in the patents for inventions RU 2375556, 10.12.2009; RU 2247226, February 27, 2005; RU 2241822, 12/10/2004; RU 2254451, 20.06.2005.

Analogs are a device that is lowered into a well on a tubing string (NTK), comprising a housing, at least one cutting tool, a mechanism for extending the cutting tool, including a plunger piston. At least one hydraulic nozzle nozzle communicates with the tubing cavity, where the opening fluid circulates, through a hydrochannel located, as a rule, in the pushrod piston or in the extendable console, made in one unit with the piston.

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

- the total opening surface of the casing in the form of holes or slots should be maximum. In this case, the column must retain the ability to withstand a very significant horizontal component of rock pressure;

- 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;

- within the reservoir, several deep perforation channels should be formed. 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.

All of the above known designs of hydromechanical rotary hammers are ineffective, because have significant disadvantages.

When opening the casing strings, one or two slots are formed, located in the same plane, which does not allow for 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.

The specified location of the slots does not allow the most fully cover the entire productive part of the oil reservoir. The gap should be made so that the stresses in the pipes increase by no more than 30%, because the column safety factor for the filter zone is at least 1.3. Based on this condition, the length of the gap should not exceed half the radius of the perforated column, and with the existing technology of roller (plastic) perforation, it is not possible to create a gap of 3.5-4.5 cm in length. Moreover, the creation of long slits is especially dangerous in sand wells, where significant axial loads can arise, caused by the forces of friction of the soil against the column. Another significant drawback of these perforators is the mandatory increase in the circumference (diameter) of the casing string by the thickness of the rollers embedded in it, which leads to cracking of the cement stone in the perforation zone and an even greater loss of stability of the casing string.

The most effective is spot perforation, for example, using devices equipped with piercing incisors, since such perforation keeps the column in working condition, leaving bridges between the perforations. In this case, the well is opened in a sparing mode, without imposing additional loads, while maintaining the reservoir properties of reservoir rocks and ensuring the maximum value of the coefficient of hydrodynamic perfection of the well - the main criterion for assessing the hydrodynamic connection of the formation with the well.

These include a device for creating perforation channels in the casing of a well according to the patent for utility model RU 68587, op. November 27, 2007, taken as a prototype as the closest in technical essence and the achieved result.

The prototype device comprises a tubular body with a hydraulic cylinder with a shank and a spring-loaded piston placed on it, made with the possibility of limited axial movement relative to the tubular body. The piston is spring-loaded upward relative to the hydraulic cylinder and the tube body, and from below it is equipped with a wedge pusher interacting with tool holders with perforating cutters, which are placed at the end of the shank with the possibility of radial reciprocal-longitudinal movement under the action of the wedge pusher. The tool holder and cutter have hydraulic monitor channels in communication with the overflow channels of the wedge pusher. One or more additional hydraulic cylinders with additional pistons that are connected to the piston and are mounted so that between the pipe body and additional pistons there is an annular cavity in communication with the over-piston cavity of all cylinders above the hydraulic cylinder. The pipe casing is separated by a blank partition, the upper cavity of which is in communication with the annular cavity, and the lower cavity is provided with transfer holes with a piston cavity of the hydraulic cylinder. The lower cavity of the tube body is also configured to interact with the annular cavity when the spring-loaded piston is moved down.

The disadvantages of the prototype are the low hydromonitor effect when forming channels in the bottomhole formation zone, due to the design features of the device that do not allow tightness of the connection of the overflow channels of the wedge and the tool holder, which leads to significant losses in the volume of working fluid and its pressure entering the hydraulic monitors. It should be noted that even with a slight change in the inner diameter of the casing, the alignment of the wedge channels and the tool holder "is lost", which also negatively affects the tightness of the hydraulic system and, accordingly, the hydraulic monitoring effect. Another big drawback of this design is a sharp drop in the hydromonitor effect during the periods until the tool holder overlaps the overflow channels in the wedge. To maintain pressure in the system, these channels must have a small cross section comparable to the flow cross section of hydraulic monitors. All of the above has an extremely negative effect on the energy of the jet, which will not be enough to wash cavities and therefore for the efficiency of the formation treatment. In addition, the device has a rather complicated design.

The use of advanced devices for the entire range of operations of the secondary penetration is crucial for the effective operation of the well.

The problem to which the invention is directed, is to increase the efficiency of processing a productive formation while simplifying the design, reducing metal consumption and material costs.

The technical result is achieved in that the device for creating perforation channels in the well comprises a housing, a wedge with grooves, at least two hydraulic cylinders placed one after the other with connected piston rods, one of which is spring-loaded. At least two cutters with hydraulic monitors and tool holders are installed in the grooves of their support and wedge with the possibility of radial reciprocating movement. What is new is that the casing is formed by a wedge and walls of hydraulic cylinders, the piston rods of which are made with an axial channel communicated by transfer channels with their piston cavities, and the tubes and channels of the tool holders with hydraulic monitors of the cutters. In this case, the support of toolholders with cutters is connected to the piston rod, which is spring-loaded downward relative to the hydraulic cylinder.

Unlike the prototype, in the proposed design, the housing is formed by a wedge and hydraulic cylinders at the same time integrally and rigidly connected to the tubing string, which guarantees the reliability of the device and the exclusion of its "anchoring" when removing the cutters from the casing string. At the same time, the presence of an axial channel in the piston rods in communication with the piston cavities of the hydraulic cylinders and the hydraulic monitors of the cutters ensures reliable supply of the working fluid to the productive formation of the well without hydraulic losses and the effective operation of the entire device.

The inventive device is illustrated by an example of its implementation with two hydraulic cylinders, two cutters and an accompanying drawing of a General view.

The device comprises a housing 1 formed by the walls of hydraulic cylinders 2, 3 and a wedge 4 having grooves 5, in which two diametrically located tool holders 6 are installed, mounted in radial grooves 7 of the support 8. Perforating cutters 9 with hydraulic monitors 10 are placed on tool holders 6. 11 and 12 of the respective hydraulic cylinders 2 and 3 are interconnected and have a common axial channel 13, which communicates with their piston cavities 14 and 15 by means of transfer channels 16 and with hydraulic monitors 10 by means of tubes 17 and channels 18. Rod-piston 12 spring-loaded downward relative to the hydraulic cylinder 3 by a compression spring 19 and connected to the support 8. To seal the device, all connections of the structure are equipped with seals.

The operation of the device is as follows.

The device on the tubing string is lowered into the well to the perforation interval and the working fluid is supplied under pressure, which, passing through the channels 13 and 16 into the piston cavities 14 and 15, acts on the piston rods 11 and 12, moving them upward, compressing the spring 19 and dragging the support 8. The tool holders 6 with cutters 9 move along the grooves 5 of the wedge 4 and the radial grooves 7 of the support 8 until the walls of the casing string are touched 20. The piston rods 11 and 12 are fixed relative to the casing string 20, and the housing 1. is “stretched” the tubing string, moves down, pushing p Cutter holders 6 with cutters 9, which perforate the walls of the casing 20. At the same time, the working fluid passing through the pipes 17 and channels 18 comes out through the hydraulic monitors 10. The jets of the working fluid erode the cement stone and adjacent rock, forming caverns in the bottomhole formation zone. After perforation, the fluid pressure is relieved, the NTK string “shrinks”, dragging the casing 1 along with the wedge 4 and pulling the cutters 9 from the walls of the casing 20. The support 8 is returned to its original position by means of the spring 19, dragging the tool holders 6 with cutters 9 to their original position . Then the device is lowered to the calculated distance, the pressure of the working fluid is raised again, and the casing is perforated and channels are formed at the same time. The cycle is repeated as many times as necessary without removing the device from the well. After the formation of all channels in the well is completed, the flow of working fluid is stopped, the pressure is released to atmospheric pressure, the support returns to its original transport position, and the device is removed from the well.

If necessary, in the design of the proposed device, the number of hydraulic cylinders installed one after another and / or toolholders with cutters placed on a support can be increased. The total area of the pistons depends on the number of hydraulic cylinders to create the necessary effort to cut the cutters, the number of which is determined by the required number of channels in the well for opening the formation in one cycle.

The use of a simple, reliable and easy-to-use device design will reduce processing time, significantly increase the efficiency of the secondary opening of formations and reduce material and financial costs.

Claims (1)

A device for creating perforation channels in a well, comprising a housing, a wedge with grooves, at least two hydraulic cylinders placed one after another with connected piston rods, one of which is spring-loaded, and at least two cutters with hydraulic monitors and tool holders placed in the grooves of the support and the wedge with the possibility of radial reciprocating movement, characterized in that the housing is formed by a wedge and the walls of the hydraulic cylinders, the piston rods of which are made with an axial channel communicated by transfer channels with their dporshnevymi cavities and tubes - with jetting cutters through channels toolholders, support which is connected to the piston-rod, a spring-loaded downwards relative to the hydraulic cylinder.

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