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Anchor that can be set and released hydraulically

IP.com Disclosure Number: IPCOM000247751D
Publication Date: 2016-Oct-05
Document File: 4 page(s) / 77K

Publishing Venue

The IP.com Prior Art Database

Abstract

A hydraulic set anchor is presented that can be deployed into a well with the slips in the retracted position. Once at depth drill pipe pressure will set the anchor. The anchor includes a check valve that maintains pressure on a chamber that keeps the slips in the set position.When the anchor is no longer needed pressure is applied to a piston to break shear screws that will allow the piston to move axially. Axial movement of the piston opens an annular port that releases the pressure in the chamber below the slips. The annular port prevents pressure from being retained in the chamber. Springs will then permanently retract the slips.

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Anchor that can be set and released hydraulically


A hydraulic set anchor is presented that can be deployed into a well with the slips in the retracted position. Once at depth drill pipe pressure will set the anchor. The anchor includes a check valve that maintains pressure on a chamber that keeps the slips in the set position. When the anchor is no longer needed pressure is applied to a piston to break shear screws that will allow the piston to move axially. Axial movement of the piston opens an annular port that releases the pressure in the chamber below the slips. The annular port prevents pressure from being retained in the chamber. Springs will then permanently retract the slips.

There are two known applications for an anchor that is set and released hydraulically. The Hydraulic Pulling Tool (HPT) includes a hydraulic set anchor and a power section. It is used with a mechanical set Spear to recover stuck casing. The Spear engages a section of stuck casing (9-5/8 in. OD). The anchor is set in a larger piece of casing (13-3/8 in or larger OD) above the casing that is being retrieved. The power section pulls the spear towards the anchor, thus creating an over-pull in the stuck casing. If the spear is not as strong as the anchor and power section a second hydraulic set anchor could be set in the smaller casing above the spear. The lower hydraulic set anchor would prevent all of the over-pull from being transmitted to the spear. Once the smaller string of casing is pulled free the pressure in the drill string is released and the upper hydraulic set anchor automatically releases from the larger casing. The smaller casing can then be retrieved from the well. The lower hydraulic set anchor can be deactivated before or after the casing is retrieved. Another application for a releasable hydraulic set anchor is when doing the cut-out with a section mill. It is desirable to make sure the drill string does not move axially when the knives are cutting through the casing. Drill pipe movement at this time can cause significant damage to the knives. Once the knives are fully extended the anchor must be deactivated so the drill pipe can move axially to mill the casing. Reference the attached sketch for clarification of how the hydraulically set anchor is activated and released. Slips will be used to anchor the drill string in place. The slips are extended when internal pressure is applied to the drill string. The anchor will then hold the drill string in place while the knives on the section mill do the initial cut out through the casing. After the initial cut out...