Patent Grant
9719319
The field of the invention is removable barriers and more specifically barriers used in completions such as treating which includes fracturing, stimulation or acidizing that then are removed for further operations and where the barriers are retained with an annularly shaped expandable ring for grip and sufficient seal to allow pressure operations against the barrier.
Barriers are used to isolate zones in a borehole to complete an operation. Some operations involve multiple spaced barriers that are sequentially deployed so that fluid at high pressures can be pumped into perforations to fracture the underground rock formation. In such applications the barriers need to redirect the pumped fluid into the perforations and complete sealing to the wellbore wall is desirable but not required. After all the intervals are sequentially treated the barriers need to be removed. Milling the barriers out is time consuming and creates the need for debris removal from the borehole.
Disintegrating materials such as controlled electrolytic materials have been used in barrier components for the purposes of minimizing or eliminating milling in some instances. Controlled electrolytic materials have been described in US Publication 2011/0136707 and related applications filed the same day. The related applications are incorporated by reference herein as though fully set forth.
Slip members referred to as barrel slips are described in U.S. Pat. No. 6,481,497 and U.S. Pat. No. 6,378,606 and are annular shapes alternatively scored longitudinally from opposing ends at spaced circumferential intervals and having multiple ramps internally to mate with a conforming shape to enlarge the diameter of the annular shape. This design had hardened inserts on an outer face that were there to penetrate the surrounding tubular for enhanced grip for the seal assembly located nearby. These barrel shapes were not intended to seal and the hardened inserts created a standoff for the annular shape keeping much of the shape away from the surrounding tubular wall to the extent that there were acceptable leak paths among the inserts that were closed off nearby with the seal assembly put in the sealing position against the surrounding tubular wall. These types of packers had to be either milled out or released in separate trips in the hole which was expensive. Such designs did not lend themselves to removal by dissolving or disintegrating as their focus was to hold differential pressures without leakage for a long period of time, such as many years.
U.S. Pat. No. 5,701,954 and U.S. Pat. No. 5,944,102 are a variation where the gripping surface is a series of serrations as opposed to small external bores where hardened inserts were affixed. In this design the serrations themselves were hardened but the basic alternating longitudinal serration design was similar.
These designs differ from the present invention where an annular structure with scores is deployed to do double duty as a seal and an anchor. Variations are contemplated where a continuous strip of sealing material can be placed on the interior and/or the exterior faces of the structure to enhance the sealing and gripping capability. Alternatively, an abutting annular shape for a seal can be placed adjacent to the scored annular shape that can do some sealing. A single ramp can be used to move both structures against the surrounding tubular. Drilled holes wider than the slots are placed at the slot ends to minimize stress concentration in that area and to prevent initiation of cracks. Another alternative is that the present invention could be manufactured from non-degradable materials. Also, the present invention could be used in combination with a conventional slip system. In this variation the present invention will only seal and the conventional slip system will grip. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.
An annularly shaped structure serves as a support and seal when pushed out on a ramp. A continuous seal in a groove is used on one or two sides to enhance sealing. A separate annular structure for sealing can be disposed adjacent to the shape having alternating longitudinal slots so that each structure is targeted to a different purpose. The structures disintegrate when made of a disintegrating material such as for example controlled electrolytic material (CEM) so that removal of the barrier can occur after a treating operation such as fracturing where many such barriers are deployed. The slots have enlarged holes at their ends to reduce stress concentration that can lead to cracking.
In another feature of the present invention the member 10 is made from a disintegrating material such as for example CEM so that in a multiple barrier completion where a ball 52 has been landed on a seat 50 such as in fracturing, the introduction of a reacting material in the borehole or the existing well fluids or both, can disintegrate the member 10 as well as the remaining barrier components such as the mandrel and the cone 16 so that little or nothing else is left. The balls 52 can also be brought to the surface with production or could themselves be disintegrated as the member 10 and other parts of the barrier of which it is a part are removed to permit subsequent operations such as production or injection.
As an alternative to a continuous seal in an associated groove, surfaces 12 and 24 can be coated with a sealing material. The coating can be interrupted for the slots and end bores or could also simply span them and either stretch as the member 10 expands and the slots 30 and 32 get wider or alternatively the coating can be scored or otherwise weakened to fail at the slots as expansion occurs and still serve well for sealing to the tubular surface 26 or the cone surface 14. The coating can be an elastomer or another resilient material that may or may not disintegrate when fluid such as an acid is introduced to initiate the disintegration process.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:
| Number | Name | Date | Kind |
|---|---|---|---|
| 3385679 | Current | May 1968 | A |
| 5701954 | Kilgore et al. | Dec 1997 | A |
| 5944102 | Kilgore et al. | Aug 1999 | A |
| 6378606 | Swor et al. | Apr 2002 | B1 |
| 6481497 | Swor et al. | Nov 2002 | B2 |
| 20110136707 | Xu et al. | Jun 2011 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20150361758 A1 | Dec 2015 | US |
