Drillstem Testing For High Pressure Deepwater Wells: A Noncemented Floating Tieback Liner Technique

Abstract

Current and future offshore exploration activity is penetrating to deeper reservoirs, driving the need for increased drillstem testing (DST) for high pressure and high temperature wells. Typically, liners are tied back to the surface to achieve reliable wellbore integrity and flow. In the past, these tiebacks require expensive cementing operations which also limit future wellbore re-entry options.An innovative non-cemented floating liner tieback with reliable floating seals can improve the entire DST process by eliminating the cost and risk of cementing operations. In addition, the operator is able to retrieve the casing tieback and have the option to use the same well for appraisal or development phases.The paper discusses the floating tieback system and details a case history on a high pressure well in which the operator completed the DST operation safely and met all well objectives. Discussion of system reliability includes casing design and modeling by both operator and suppliers, plan changes based upon pressure data obtained during the drilling phase, detailed operational procedure in a deepwater environment, successful tieback retrieval and future operations.