Monobore Expandable Liner Extension Deployment Saves Well From Abandonment

摘要

Caving, sloughing, and swelling shale sections, combined with lost returns below 13-3/8-in. casing, were encountered in an Egyptian well. Before the 12.25-in. hole section was completed, shales packed off the drillstring and part of the bottomhole assembly (BHA) was left in the hole. Casing (9-5/8-in.) was run as deep as hole conditions allowed, with a recess shoe to enable a monobore expandable liner extension. Following drillout of the shoe, conditions presented the same challenges previously experienced. The 8-in.outside diamer (OD) liner extension system was run, but well conditions prevented getting the liner to depth and it was pulled out of the hole. Conditioning trips with increased mud weight up to 12.3 pounds per gallon (ppg), reaming and backreaming, along with an open hole cementing effort, were performed for stabilization. A second attempt was made to run in the hole. The hanger located in the recess shoe profile of the 9-5/8-in. casing and the system was expanded to the same inside diameter as the casing above. The expanded liner’s shoe was now located just above the previously left BHA, but the trouble zone sections were isolated with no reduction in hole size from the previous casing. The expanded liner was pressure tested to 1,000 psi before cementing. Recess shoe ports were enabled and initial circulation established, and the wellbore did indeed pack off and build pressure, preventing full annular cement. Pressure inside the casing was applied and 15 barrels (bbl) of cement were squeezed into the hole. A casing exit was milled in the expanded monobore liner to enable bypassing the BHA that was left in the hole from previous drilling operations. The case history explored in this paper highlights overcoming substantial issues using expandable drilling liner technology via a monobore liner extension that resulted in successful installation and circulation. The preplanning, installation considerations, expansion process, lessons learned and post-deployment results will be discussed.