Use of Liner Drilling Technology as a Mitigation to Loss Intervals and Hole Instability: A Case Study in Mississippi Canyon

Abstract

Abstract Liner drilling technology provided an effective solution to hole instability issues seen while drilling with conventional methods through a narrow mud weight/pore pressure/fracture gradient window laden with depleted intervals and virgin pressured shales in the Mississippi Canyon block of the Gulf of Mexico. Two 8-1/2" x 9-1/2" wellbores were lost while drilling with Rotary Steerable Systems (RSS) in the 60° wellbore. The initial wellbore was lost as a result of RSS failure resulting in the hole packing off. A subsequent bypass wellbore encountered catastrophic lost circulation resulting in the hole collapsing as the depleted commercial sand came in unexpectedly high. In each case this resulted in the loss of the RSS Bottomhole Assembly (BHA). Liner drilling technology was identified as the most appropriate strategy for setting the 7-5/8" drilling liner and 5-1/2" production liner because: Documented lost circulation problems have been minimized or eliminated through prior use of DwL technology, largely attributed to the "smear effect" phenomenon. The narrow annular geometry created by liner drilling reduces the rate of fluid loss in the annulus as compared to conventional drilling operations enabling effective management of the annular fluid level. DwL systems historically minimize or eliminate non-productive time in operations in which uncontrolled fluid losses have been encountered previously. Ultimately, the correct application of liner drilling technology on this well allowed the operator to reach the intended drilling depth and completion objective. The equipment selection, operation, and results of the liner drilling operations will be presented in the paper.