RU2144606C1 - Device for interval-after-interval pressure-testing of pipe strings - Google Patents

Abstract

FIELD: oil and gas production industry. SUBSTANCE: device relates to mechanisms intended for disengaging zones of casing strings for carrying out repair, insulation, and investigation operations. Device for pressure-testing of pipe strings is suspended from cable line. Device is made up of following components: hollow body with radial passages, sealing member with upper flange and lower flanges, movable bush, cone with slip sockets, electric drive unit located in body with screw pair, pusher, tie-rod. Tie-rod is additionally provided with washer, disruptable cotter pin, and protrusion serving as stop. Application of embodiment of device ensures reliable sealing of well bore at multiply repeated operation with possible removal of device for interval-after-interval pressure-testing of pipe strings at emergency failures of electric drive unit. EFFECT: higher efficiency. 2 dwg

Description

 The invention relates to the field of oil and gas industry, and in particular to devices for separating zones of casing strings during repair, insulation and research works.

 Known packer, consisting of a housing with an axial channel, a sealing element with upper and lower stops, a conical sleeve with slips and a spring, a hollow fairing, in which cylinders are installed with atmospheric pressure, an elastic element divided by a partition with a valve in the form of a diaphragm [1].

 When using this packer, it is difficult to guess the interval of its landing, since it descends into the well under its own weight in the free fall mode.

 Removing this packer is difficult, for this it is necessary to lower the trap into the well, fill up and remove the packer. Disruption of the packer occurs due to the elastic forces of the sealing element. The sealing elements used on the packers lose their elastic properties within 1.5 to 2 hours after planting under a pressure of 150-200 atm, which casts doubt on the possibility of removing the packer, the packer must be drilled, which is associated with high material costs. This packer does not have a knot to break the packer. You can not use it for multiple landing without extraction to the surface, where it is necessary to carry out preparatory work.

 Also known is a packer, lowered on a rope, consisting of a housing, a sealing element, a pusher, a cone, a sleeve, the upper and lower anchoring units and the valve [2].

 The disadvantages of this packer are the complexity of stalling and removing it from the well, the complexity of the design - eight sealed movable joints are eight, which reduces its reliability.

 A well-known electromechanical packer on a cable rope, selected as a prototype, consisting of a hollow body with radial channels mounted on the body of the sealing element with upper and lower flanges and a pusher, a cone with slips placed on it, installed in the cavity of the barrel body forming with the body a circulation channel communicating through the radial channels of the housing space behind it, above and below the sealing element and installed with the possibility of overlapping the circulation channel after sealing and a well and an electric drive installed above the sealing element and connected with the body and the barrel [3].

 The prototype does not provide reliability during multiple landing and disruption, as well as the tightness of the wellbore.

 The purpose of the invention is to ensure the reliability of the sealing of the wellbore during multiple landing and the ability to remove the device for interval testing of the columns in case of emergency drive failure.

 This goal is achieved by the fact that the device for interval testing of the columns is equipped with a sleeve on which a cone is mounted, telescopically connected to the body and rigidly with the lower flange and the rod interacting with the pusher, the rod in turn is equipped with a washer, a breakable cotter pin and a protrusion serving as a stop. The invention is illustrated in the drawing, where in FIG. 1 shows a device for interval testing of columns in a transport (initial) position; FIG. 2 in working position when it is planted. The device for interval testing of the columns consists of a housing 1, in which an electric drive 2 is placed, a screw pair - a screw - 3 and a nut 4, on which the sealing rings 5 are located, the nut 4 is connected to a rod 6 having a protrusion 7, which serves as a stop, and a pusher 8 with a washer 9 and a collapsible cotter pin 10. A stop flange 11, a rubber sealing element 12, bounded on the bottom side by a flange 13, mounted on the movable sleeve 14 are mounted on the outer surface of the housing 1. On the movable sleeve 14 is mounted a unit consisting of rigidly closed captive cone 15 with guiding grooves of the "dovetail" type, in which the corresponding protrusion slides are slidably mounted 16. On the housing 1 and on the movable sleeve 14, holes 17 and 18 are provided for the flow of fluid through the internal cavity of the device. Inside the housing 1 below the hole 17 is a seat 19, which together with the sealing rings 5 forms a valve that blocks the flow of fluid through the internal cavity of the device. The device is connected by a cable rope 20, which serves for lifting and lowering, as well as for supplying electricity to the electric drive 2 from the wellhead. Limit switches 21 and 22 are located in the housing 1 and serve to limit the movement of the nut 4 and provide information about the extreme positions of the nut 4 on the day surface through the cable-rope 20. On the upper part of the nut 4 there is a protrusion 23 (Fig. 1), interacting with the end switches 21 and 22.

 A device for interval testing of columns works as follows.

 The assembled device (Fig. 1) is lowered into the well on a cable-rope 20. The fluid flows through the openings 17 and 18 from the under-packer space into the over-packer space, and when lifting, on the contrary, the formation of a piston effect during descent and ascent is eliminated. After reaching the required interval, electric power is supplied to the electric drive 2 through the cable-rope 20, the nut 4 moves up and through the rod 6 raises the pusher 8 upwards, in turn, the pusher 8 moves up the slots 16 located on the conical surface of the cone 15, they are pulled out and fixed on the surface of the casing and remain stationary under the action of the actuator 2. Rod 6 begins to move the housing 1 downward, the thrust flange 11 presses through the rubber sealing element 12 onto the flange 13, rigidly fixed to the movable w lke 14, the cone 15 moves downwardly within the elastic deformation of the walls of the casing, as the greater the pressure force of the slips 16 on the walls of the casing, the greater the magnitude of the deformation of its walls. At the same time, the rubber sealing element 12 is deformed and overlaps the wellbore (Fig. 2). O-rings 5, located on the nut 4, go into the saddle 19 and block the message of the overpacker space with the underpacker space. The movement of the housing 1 down stops as soon as the protrusion 23 touches the limit switch 21, which turns off the electric drive 2 (Fig. 2), which means that the device is planted, the barrel is closed.

 From the wellhead, a test pressure is generated in the well according to the specifications; in the order of 80-100 atm and lasts for 15-20 minutes. If during this period the pressure in the well does not decrease - the casing is intact, there are no violations, the test pressure in the well is relieved.

 Disruption of the device is as follows.

 A signal is sent to the electric drive 2 through the cable rope 20, the nut 4 moves downward relative to the housing 1, the sealing rings 5 exit the seat 19, a gap is formed between the seat 19 and the nut 4. The over-packer space communicates with the under-packer space, the static pressure is equalized, i.e. . the hydrostatic pressure of the liquid column on the device is removed, without which it is impossible to remove the device.

 As soon as the protrusion 7 on the rod 6 abuts against the pusher 8, the housing 1 begins to move up, because the slips 16 are so far wedged between the wall of the casing and the cone 15.

 As you move up the housing 1, the sealing rubber element 12 will deform (i.e., takes its initial position). The housing 1 abuts against the flange of the movable sleeve 14 and moves it upward along with the cone 15. The cone 15 releases the slips 16, they take their initial position (Fig. 1).

 The protrusion 23 of the nut 4 reaches the switch 22 and turns off the drive 2. The signal from the switches 21 and 22 goes through the cable-rope 20 at the mouth, the signal lamp lights up, which makes it possible to control the position of the device: if the signal lamp lights up from the switch 22 , then the device is broken, you can lift it up for subsequent crimping of the upper part of the casing.

 If the column somewhere has a violation and the test pressure has dropped, the device rises to the upper interval to search for the place of violation, el. energy to the electric drive 2, the device is planted on the casing. A test pressure is generated in the well, if again the pressure drops, the device breaks and rises to the next interval. Moving up the device, the place of violation of the production string is determined with an accuracy of ± 0.5 meters.

 In the event of an emergency breakdown of the electric drive 2 by means of the cable rope 20, we pull the device upward, while the force from the cable rope 20 is transmitted through a screw pair 3, 4 and rod 6 to the pusher 8 through the washer 9 and the collapsible cotter pin 10. Since the pusher 8 is stationary , collapsing cotter pin 10 does not withstand the load and collapses, thereby the rod 6 is freed from the pusher 8 and the housing 1 is moved upward, while the sealing rubber element 12 is deformed and takes its original shape, the cone 15 is moved up and released from the slips 16. Slips 16 in turn, along the guides they go down and are freed from the walls of the column.

 Thus, this device allows you to periodically test the production casing for leaks, without removing it to the day surface, while eliminating emergency breakdown.

 At present, working drawings of the device have been developed, and an anchoring unit is made in metal. Bench tests were conducted at the TatNIPIneftemash Institute.

 The results are positive, this confirms that the design and principle of operation of the device are functional.

References
1. A.S. USSR N 1112114 E 21 B 33/12 "Packer".

 2. A.S. USSR N 775291 E 21 B 33/12 "Packer".

 3. US patent N 3542126 E 21 B 43/00, 1970, "Packer".

Claims (1)

 A device for interval testing of columns on a cable rope, consisting of a hollow body with radial channels, a sealing element with upper and lower flanges, a movable sleeve, a cone with slips, an electric drive located in the housing having a screw pair, a pusher, a rod, characterized in that that the rod is equipped with a washer, a breakable cotter pin and a protrusion serving as an emphasis.

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