A customized expandable steel patch enabled shutting off casing perforations while maintaining sufficient ID to enable subsequent passage of the drilling BHA.

Perforation shutoff required after remedial cement job

In a new well in the Eagle Ford Shale, the cement behind the 9 5/8-in casing was incomplete. Perforation of the casing was required before recementing. Subsequently, the operator's major concern was to shut off the perforations and then be able to pass through with the directional drilling BHA (mud motor with 2° bend angle and an 8 3/8-in drill bit). The depth of the zone to be sealed was 560 ft [170 m]. Setting a standard 9 5/8-in patch was not possible because of the small ID of the set patch.

Custom-manufactured solution supplied

After completing an analysis of the job, SLB manufactured a customized 9 5/8-in patch with the thinnest sealing element possible, reducing its thickness to 0.0509 in [1.29 mm] from the standard 0.088 in [2.24 mm]. Positioned by wireline and expanded within 2 hours, the patch was then pressure tested up to 1,500 psi [10.3 MPa] for half an hour.

Drilling operations continued after successful patching

The drill bit and motor passed through the customized 12-ft [3.7-m], 9 5/8-in patch, and the well was successfully drilled as planned. In this specific case, the SLB expandable steel patch was the only product capable of completing the operation effectively.