Patent Application
20090107670
The field of the invention is repair of damaged existing seal bores in downhole assemblies without removal of the string from the wellbore.
Seal bores are frequently used downhole to isolate zones or to facilitate the operation of accessory or auxiliary equipment. They can be accessed by a tool on a string that is placed into position by means of wireline services or coiled tubing. The tool can have external seals that interact with the seal bore to get a fluid tight seal. Thereafter, other tools can be passed through the seal bore or fluids that have erosive characteristics. Over time, there can be damage from these activities to the surface of the seal bore. In the past this has required pulling the string that includes the seal bore or taking other measures that decrease drift diameter by inserting another bore within the existing bore or decreasing pressure rating of the tubular by simply machining a larger bore at the location of the original bore.
Illustrative of techniques for creating a seal bore downhole are US Application 2004/0112609 and U.S. Pat. No. 6,523,615. U.S. Pat. No. 5,351,758 illustrates adhering strips of material to the well interior and of general interest to this field are U.S. Pat. Nos. 6,910,537; 5,009,265; 6,679,328; 4,542,797; 4,482,014; 6,439,313; 4,455,789; 5,743,335; 2,280,769; 5,351,758; JP 07252986 and EP 0549821.
The present invention allows repair of damaged seal bores in place. It fills in voids or cracks and polishes them to the requisite tolerance so that a troublesome or leaking seal bore can again be serviceable without removal from the well. These and other features of the present invention will become more clear to those skilled in the art from a review of the detailed description and the associated drawings while recognizing that the full scope of the invention is in the appended claims.
A tool is preferably landed in a downhole profile commonly found adjacent to seal bores. Once landed, preferably with coiled tubing, pressure in the coiled tubing triggers a switch to power a motor to rotate a polishing cylinder that features spirally wound vanes. A reservoir of resin or other repair material is connected to an injection pump to deliver the material as the vanes are rotating. The material exits between the vanes so that the vanes can spread it and work it into surface irregularities. After the material is sufficiently spread into voids and the requisite polishing completed, the seal bore is again ready to accept a tool in a sealed relationship.
The tool 10 is preferably conveyed into tubing 12 that has a seal bore 14 and a locator groove 16 nearby. The tool 10 has a latch, or locking device, 18 to find support in the groove 16 so that the head 20 will line up with the seal bore 14. Seal bore 14 is damaged and the objective of the tool 10 is to make it again serviceable without removing the tubing 12.
Referring now to
There are options to vary the preferred embodiment. The repair fluid can be injected with pressure developed from moving piston 28. Motor 36 can be a fluid motor rather than being operated by a local 12 volt power supply. Power can be delivered through an umbilical rather than a local power supply. Power can come from a hydraulic control line. Signals can come from the surface through a control line, a fiber optic line or an electric line for example. The vanes such as 46 and 48 can be at varied spacing, parallel or askew to each other and spiral around less than one time to a number of times around the drum 20. The outlets 46 can be a singular outlet or multiple outlets generally aligned with an adjacent vane. Controls can allow drum 20 to rotate for a given time before injection starts from outlets 46. Drum 20 can also be fitted with light and a camera, shown schematically as 47, to transmit a view of the seal bore 14 either through the drum 20 or mounted just above or below it. Sensors, also shown schematically as 47, can be mounted to the drum 20 to measure surface irregularity to provide surface feedback that the seal bore is serviceable to seal against a downhole tool. Known materials such an epoxy resin or liquid metal are contemplated to be applied to the seal bore 14 to fill the voids and fissures in it.
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.
