There had been severe losses when a major operator in the Gulf of Mexico was drilling a 20” section below a 16” casing, using 11.3 ppg mud.

1. To shut off the loss zone it was decided to perform a squeeze cement job using a 2 ½” Cement Support Tool (CST) as base. The loss zone was expected to be between the 16” casing shoe @ 11 585 ft and 11 615 ft. The 2 ½” CST was therefore deployed in the 20” open hole @ 11 615 ft prior to the cement job.
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2. A balanced cement plug with 16.4 ppg cement was set from the CST and up to 10 723 ft. Then 90 bbl was squeezed into the loss zone with the CST as base. After waiting on the cement to harden the cement plug was drilled out. Firm cement was tagged @ 11 145 ft and bottom of cement was found @ 11 614 ft, which is only 1 ft from the CST setting depth. No cement was found below the CST and the loss zone was successfully shut off. The cement and CST was drilled out using PDC bit.

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