The method of anchoring a tieback casing string using cement has been well documented. Industry standards for installing a tieback casing string usually have called for placing cement around the outside of the tieback casing string to provide a barrier against the potential of sustained surface casing pressure (SCP). The cement also is used to anchor the tieback casing string into the polished-bore receptacle during production. After cementing the tieback casing string, a cleanout trip is required to clean the inside diameter of the casing and to remove the landing collar and cementing wiper plugs.

A recent application in deepwater Gulf of Mexico (GOM) allowed a major oil and gas company to perform a step change in technology that enabled the operator to perform the function more rapidly and at reduced expense. Swellable packers were used instead of cement, providing a novel, cost-saving and risk-reducing approach.

This paper will discuss the use of swellable technology as an alternative method for anchoring a tieback casing string. This concept allows the operator to isolate potential downhole pressure away from the surface and to anchor the tieback casing string during production. By using swellable technology, no cleanout trip is required, which provides a substantial cost savings for deepwater operations. The unique approach also reduces the risk to the casing and drilling string from the removal of the cementing wiper plugs and the landing collar. The case history will provide the details of the new application and how it improved cost efficiency and enhanced operational safety.

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