RU2433246C1 - Method of well trouble isolation by profile shutters - Google Patents

Abstract

FIELD: oil and gas production. ^ SUBSTANCE: method involves landing of a profile shutter arranged between an upper seat and a calibrator with a setting tool in a space, extension of the shutter with using the calibrator and a flare bottom-up for tight and sealed pressing to well walls and removal of the setting tool from the well. Provided more than one isolation spaces, a number of similar shutters are mounted with their ends tightly overlapped above the upper seat and under the calibrator before descent, and distanced from each other and having a related length sufficient to provide installation oppositely to the appropriate isolation spaces. Before calibration, excess pressure sufficient for pre-spreading of the shutters to be fixed with respect to the well walls is generated inside of the profile shutters. ^ EFFECT: enhancement, higher quality and reliability of installation of the shutters, eliminated emergencies. ^ 3 cl, 2 dwg

Description

The invention relates to the oil and gas industry, and in particular to methods of isolating zones of complications when drilling wells and repairing casing strings from profile pipes.

It is known "Device for repairing a casing string" (ed. Certificate of the USSR No. 1041671, IPC E21B 29/10, publ. Bull. No. 34 of 09/15/1983), including a hollow core, at the lower end of which a mandrel head with an expanding head is fixed a cone, a profile pipe with an upper stop and an anchor installed above it, consisting of an upper and lower casing, the cavity between which is connected to the core cavity, and in order to simplify the design and increase its efficiency by eliminating damage to the casing, the anchor is installed with the possibility axial movement along the core and spring-loaded on both sides, while the upper and lower armature casings are equipped with fixed and movable stops, respectively, forming closed chambers connected to the core cavity with the walls of the casing and the core, and self-sealing cuffs that are inoperative are placed between the stops located inside the casings.

This device implements a method of repairing a casing string, including the descent of the device on the tubing string into the well. Then, by injecting liquid in the tubing string, excess pressure is created, which is transmitted through the hollow core and radial channels into the cavity between the upper and lower armature casings, moving them in opposite directions and releasing the sealing cuffs, which form a hydraulic chamber with the casing walls. At the same time, the cutting head extends to the working position. Further, by increasing the pressure in the hydraulic chamber and creating an additional tightness of the tubing string, a force is created that is transmitted through the lower armature casing to the upper stop of the profile pipe, which, moving down, runs into the expanding cone and pre-expands, and thanks to the subsequent moving up of the mandrel head, the final pressing the profile pipe to the casing.

The disadvantages of this method are:

- the impossibility of installing two or more shutoffs in one tripping operation and, as a result, to cover several isolation intervals, the corresponding number of tripping operations is required, which requires large material costs;

- a high probability of damage to the sealing collars during operation of the device due to the need to move them along the body of the casing, which may have surface defects;

- due to the application of the load from the armature to the device directly through the springs, their destruction is possible, which can create an emergency in the well.

Closest to the technical nature of the claimed is the "Device for installing the patch in the casing" (ed. Certificate of the USSR No. 562636, IPC E21B 33/12, publ. Bull. No. 23 from 06/25/1977), including a hollow core, at the lower end of which the forming mandrel is fixed with a guide tip and a conical punch, and above the mandrel there is an anchor with a pressure chamber connected to the core cavity by radial channels, and in order to increase the reliability of the armature in operation, its body is made with a discharge annular chamber located below the pressure head chamber, and the core on the outer surface - with longitudinal grooves, connecting after the working stroke of the punch with the discharge pressure chamber. In addition, in the working position, the distance between the pressure chamber and the longitudinal grooves of the core is greater than the distance between the radial channels of the core and the upper end of the pressure chamber.

This device implements a method of repairing casing pipes, oil, water and gas wells, including the descent of the device into the well, the creation of hydraulic pressure, which is transmitted through the hollow core and radial channels to the forming mandrel and anchor, bringing them to the working position. Then, by simply lifting the device, the forming mandrel is pulled through the corrugated patch, which is held in place by an anchor coupled to the casing, pressing the patch against the walls of the casing. As the hollow core with the mandrel tool rises, the radial channels in the core are isolated from the pressure chamber, which relieves the pressure on the armature and the flow of fluid into the discharge chamber. As a result, the anchor is released from engagement with the casing, and the forming mandrel continues to remain in the working position until the patch is completely straightened and the hydraulic pressure is relieved.

The main disadvantages of this method are:

- the impossibility of installing two or more shutoffs in one tripping operation and, as a result, to cover several isolation intervals, the corresponding number of tripping operations is required, which requires large material costs;

- the possibility of an emergency situation when the anchor is released from engagement with the casing, since the corrugated patch ceases to be held by the anchor and in the event of insufficient adhesion to the casing at that time, it can move, violating the tightness of the repaired section of the casing.

The technical objectives of the invention are the expansion of technological capabilities when isolating several zones of complications in the well and repairing casing strings due to the installation of several profile shutoffs in one round trip and improving the quality and reliability of their installation, eliminating the occurrence of emergency situations associated with the shift of shutoffs in the well.

The technical problem is solved by a method that includes the descent on the pipe string of a profile overlap, located between the upper stop and the calibrator, with the landing tool in the installation interval, the expansion of the overlap by the calibrator and the expanding cone from the bottom up for tight and tight pressing against the walls of the well and removing the landing tool from the well.

What is new is that in the presence of several insulation intervals, several overlaps of similar construction are installed, the ends of which above the upper stop and under the calibrator are hermetically sealed before the descent, at a distance between each other and with an appropriate length, sufficient to be installed opposite the corresponding insulation intervals, and before calibration inside profile overlappers create excess pressure sufficient for preliminary expansion of the overlappers and their fixation relative to the walls of the wells azhiny.

Moreover, the expansion of all overlappings is carried out by the corresponding calibrators at the same time, the final pressing to the well walls of the shutoffs is done by one expanding cone in series, starting from the bottom.

Another difference is that the expansion of all overlappings is carried out by the corresponding calibrators at the same time, the final pressing against the walls of the well of each of the overlappings is made by the expanding cones corresponding to them, located at different distances from the lower ends of the corresponding overlaps.

Figure 1 shows the profile overlaps in the layout with the installation equipment in the transport position (section); figure 2 is a section aa in figure 1 (enlarged).

The method is carried out in the following sequence.

After conducting geophysical studies and determining the number, location and lengths of isolation intervals (casing leakage zones) into the well (not shown in Fig.) On the drill pipe string 1 (Fig. 1), profile overlaps 2 are placed between the upper stops 3 and calibrators 4, made in the form of spherical punches, an expanding cone 5, located below the overlap 2, and a landing tool, which is a hydraulic jack 6, connected above to the anchor unit 7. The upper 8 and lower 9 c each of the ends of cylindrical Perekryvatel 2 respectively over upper stop 3 and for the calibrator 4 sealingly overlap before launching self-sealing cuffs 10. Perekryvatel 2 between the nozzles 11 is connected a length allowing installing Perekryvatel 2 at appropriate intervals isolated. Moreover, the length of the overlap 2 is selected based on the length of the respective insulation intervals. As the shutoffs 2 are lowered into the well, due to the non-return valve 12 mounted on the lower pipe 11, the internal cavity 13 of the connecting pipes 11 and of the drill pipes 1 is filled with borehole fluid. Next, the overlap 2, the corresponding length of which and the distance between them due to the nozzles 11 are calculated in advance, are set in front of the corresponding isolation intervals (casing leakage zones).

After that, by injecting fluid into the cavity 13 of the drill pipe string 1 and the connecting pipes 11, excessive hydraulic pressure is created, which is distributed due to the radial holes 14 (Figs. 1, 2) in the pipes 11 into the internal cavities 15 of the overlap 2, after having straightened and fixed the overlap 2 relative to well walls. The tightness of the installation of the shutoffs 2 with the walls of the well is ensured, for example, by means of elastic means 16 (Fig. 1) located closer to the ends 8 and 9 of the shutoffs 2. At the same time, the expanding cone 5 is pushed into the working position.

Then, the overlap 2 is mechanically expanded, dragging through them from bottom to top with a hydraulic jack 6 fixed from above by the anchor unit 7 (periodically reloading the hydraulic jack 6 and rearranging the anchor unit 7), calibrators 4 and the expanding cone 5 until the overlap 2 is tightly and tightly pressed against the walls wells. Moreover, the expansion of all shutoffs 2 is carried out by the corresponding calibrators 4 at the same time, distributing sections that are not straightened by hydraulic pressure, and the expansion of the cylindrical ends 8, 9 and the final pressing to the well walls of the shutoffs 2 are made by one expanding cone 5 in series, starting from the lower shutter 2. After that, the drill string is removed pipes 1 with a planting tool 6, 7 and installation equipment 3, 4, 5, 10, 11 and 12 from the well. At the same time, thanks to the upper stops 3 of the overlap 2, made in the form of spherical punches, spells are excluded when lifting the installation equipment.

With large lengths of isolation zones (large overlap lengths) to exclude accidents associated with increased wear of the expanding cone 5 and incomplete pressing of the blockers 2 to the walls of the well, the expansion of all blockers 2 is carried out by the corresponding calibrators 4 at the same time, and the final pressing to the walls of the well of each of the blockers 2 are produced by their corresponding expanding cones 5, 5 ', 5' ', located in order to reduce the load on the hydraulic jack 6 and the anchor unit 7 at different distances o t the lower ends 9 of the respective overlap 2, excluding their simultaneous interaction with the corresponding overlap 2.

Thus, the use of the invention allows to expand technological capabilities when isolating several zones of complications in the well and repairing casing strings due to the installation of several profile shutoffs in one round-trip operation and to improve the quality and reliability of their installation due to the sequential bottom-up straightening of the shutoffs with a sliding dormant tool, excluding at the same time, due to the preliminary expansion of the overlappings with hydraulic pressure, the occurrence of emergency situations Associated with a shift Perekryvatel downhole.

Claims (3)

1. A method of isolating complications in a well with profile shutoffs, including lowering on the pipe string of a profile shutoff placed between the upper stop and the calibrator, with a landing tool in the installation interval, expanding the shutoff with the calibrator and expanding cone from bottom to top for tight and tight pressing against the walls of the well and extraction planting tool from the well, characterized in that in the presence of several intervals of isolation set several similar in design overlap lei, the ends of which above the upper stop and under the calibrator are hermetically sealed before the descent, at a distance between themselves and a suitable length sufficient for installation opposite the appropriate insulation intervals, and before calibration, create an excess pressure inside the profile overlaps sufficient to pre-expand the overlap and fix them relatively well walls. 2. The method according to claim 1, characterized in that the expansion of all overlappings is carried out by the corresponding calibrators at the same time, the final pressing against the walls of the well of the overlappings is carried out by one expanding cone in series, starting from the bottom. 3. The method according to claim 1, characterized in that the expansion of all overlappings is carried out by respective calibrators at the same time, the final pressing against the walls of the well of each of the overlaps is produced by their corresponding expanding cones located at different distances from the lower ends of the corresponding overlaps.

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