Challenge

An Operator drilling multiple wells in South Texas encountered a loss zone 500 ft. below the shoe of the intermediate casing in their well. The Operator had also encountered this loss zone on two offset wells and was prepared with options to address the loss zone. Normally 9-5/8 in. casing is run as an intermediate casing string, but when this loss zone is encountered and 7-5/8 in. casing set, completing the well with 5-1/2 in. production casing becomes a challenge.

Solution and Results

After evaluating several options, the Operator decided to run 10-3/4 in. 65.7 lb/ft intermediate casing string. This would allow for the use of an 8-5/8in. ESET solid expandable liner if the loss zone was encountered. By setting and expanding the 8-5/8 in. ESET liner, the loss zone is sealed off and the post expanded 8-1/2 in. ID allows for the 7-3/4 in. flush joint casing to be set deeper in the well and the 5-1/2in. production casing to be run. This optimized design using the 10-3/4 in. casing and 8-5/8 in. ESET liner with Tendeka SwellFix Packers allowed the trouble zone to be cased off, avoiding mud losses, and allowed for the larger production string to be run and saved 25 days of NPT as seen on the offset well.

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