Challenge

An Operator drilling a challenging well in Vietnam with plans to complete the well with 9-5/8 in production casing at total depth encountered an unstable formation and were experiencing total losses which meant they had to set their 11-3/4 in. casing prematurely. This meant they would not be able to reach total depth (TD) with the planned production casing. The Operator decided to cut and pull the 13-3/8 in. casing above the11-3/4 in. and leave the open hole section below the 16 in. liner. The Operator would still be able to reach the target zone by sidetracking below the 16 in. liner and running 13-3/8 in. casing. While running the 13-3/8 in. casing, they again experienced total losses and unstable hole conditions and had to set the casing prematurely, leaving ~75m of rat hole. A solution was needed that would cover the unstable hole section and allow the operator to continue drilling and complete the well with the planned production casing.

Solution and Results

An 11-3/4 x 13-3/8 in ESET® liner was installed and expanded to cover the 555 ft. section to isolate the unstable zone. The ESET expandable liner’s robust design enables the system to withstand harsh drilling conditions, which was required during this installation.  By setting and expanding the 11-3/4 in. ESET liner, the trouble zone is sealed off and the post-expanded drift ID allows for the Operator to complete the well with the planned 9-5/8 in. production casing. The ESET Openhole Liner is the ultimate solution to mitigate risk and reduce NPT caused by unstable formations often encountered by Operators drilling in Permian Basin.