Liner Drilling Technology as a Mitigation to Wellbore Ballooning - A Successful Case Study in the Gulf of Mexico Shelf

Abstract

Abstract Conventional drilling techniques proved problematic when employed in a well in the Gulf of Mexico shelf, causing the well to exhibit severe lost circulation (~25 barrels per hour) and wellbore ballooning in the interval at 10,700 ft MD. After a detailed review of the situation liner drilling technology was identified as the most appropriate technique for reaching the well objective and setting the liner at planned depth without losing hole size because of the following advantages that this technology provides: Documented lost circulation problems have been minimized or eliminated through prior use of liner drilling technology, largely attributed to the "smear effect" phenomenon.The liner system selected provided for high torsional capability as well as requiring both a mechanical and pressure event to release the setting tool, minimizing chances for premature release.The 7-in liner drilling system can help to minimize or even eliminate non-productive time in case of induced fluid losses while drilling hazards are experienced in the well.This technology has a proven track record as an effective solution to lost circulation in the Gulf of Mexico shelf. Ultimately, the correct application of liner drilling technology on this well allowed the operator to reach the intended drilling depth and completion objective and to set the 7-in liner in place. This despite the fact that a drillable casing bit with displaceable PDC cutting structure, which was used to drill the 8-1/2 in hole section, could not be displaced as planned. In this paper the authors will review the benefits of liner drilling technology successfully to drill the operator's 7-inch liner in place and describe in detail the equipment selection. They will go on to provide a detailed description of the liner drilling process which resulted in the wells objective being realized despite the fluid loss and wellbore ballooning that was experienced and discuss the reasons for the failure of the PDC displacement sequence.