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Pressure-activated sealants are used to repair small surface and downhole leaks and have been successful remediating many instances of small pressure anomallies in mature Alaska fields since 1999. The sealants are unique in that the pressure drop through the leak site causes the sealant to polymerize into a flexible solid. Only at this point of differential pressure will the sealant polymerization process occur. As the reaction proceeds, polymerized sealant forms at the edges of the leak site and simultaneously links together to form a flexible bond across the leak site. The remainder of the sealant in the system remains liquid. This paper discusses the history, implementation, and success rate of pressure activated sealants in Alaska including successful deployment methods used to repair small production casing leaks in naturally flowing wells and injectors. The advantage sealant repair has over a conventional RWO for casing repair is that there is no need to pull tubing, resulting in the well being returned to service faster. Typical sealant procedure costs are less than 5% of the costs for production casing repair with a rig workover (RWO). Pressure activated sealants are particularly attractive in areas where RWO cost is high, such as subsea, offshore, remote, or arctic locations. Results will be presented from a study of jobs performed in Alaska from 2005 to 2012. Since 2005, Alaska has performed 56 of BP’s 102 worldwide treatments with a 77% success rate to repair wellhead packoffs, casing, bradenheads, tubing, cement microannuli (Table 1). |
