Three installations of a new expandable casing patch in 5 ?”production casing are described. During field trials, 2,530 ftand 8,380 ft patches were installed in Wyoming and Texas gaswells previously shut-in due to corrosion leaks. The thirdapplication was in a new-drill well where a 205 ft patchisolated holes in casing from a perforating gun misfire. Allthree patches pressure-tested successfully thus enabling thewells to be fracture stimulated and produced.The product provides high-strength flush-bore expandableseals at the ends of a liner comprised of conventional OCTGpipes. Unique about this system is that the expansion mandrelbecomes integral with the seal assembly to provide internalyield and collapse resistance comparable to the OCTG liner.A hydraulic setting tool powered via work string by a highpressure/low-volume pump (I.e., typical BOP or tubing tester)drives the expansion mandrel into the patch body.The product, built initially as a one-trip system, wassimplified and made more reliable by running as a two-tripsystem. First, the lower expandable seals and polished borereceptacle are installed. Next, the spacer string with upperseal is stung into the lower receptacle and the upper seals areexpanded. The system is versatile in that the upperexpandable seal also provides a receptacle to which a tiebackliner, production tubing or another patch can be attached.The paper highlights job design and execution includinguse of casing inspection logs, problems encountered, systemimprovements and best practices resulting from this work.
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