Restoring lost circulation

Enel Green Power, one of the world’s leading geothermal operators, was experiencing lost circulation in wells drilled to TD. Historically, after running casing during the cementing job, the cement often did not come above the liner hanger. The operator, at that point, expected to have to run a cement bond log (CBL) and invest in a remedial squeeze cement job using a cement retainer. To avoid these costs and the time necessary for a remedial squeeze job, Enel Green Power contacted Schlumberger for a solution and decided to use the Losseal pill as an engineered approach to the lost circulation issues.

Applying Losseal pill

Using detailed job design and a proprietary blend of fibers and solids that are combined into an optimized particle-size distribution pill, the Losseal pill was successfully applied to bridge fractures in the carbonate formation and placed through a BHA or open-ended drillpipe.

In this case, 32 m3 of the Losseal pill was placed in front of the lost circulation zone. The pill placement plot showed a reduction in pressure buildup time, indicating that the fractures were effectively plugged.

The liner was then run to TD and cemented using conventional techniques. No losses appeared during the running of liner and cementing, and there was a perfect match between predicted and acquired pressure.

Saving time

The success of the Losseal pill saved Enel Green Power 3 days of rig time. The Losseal pill effectively prevented lost circulation issues during casing and cementing operations.

The successful cementing of the liner in a single stage improved well integrity. With the entire string covered by cement, the client achieved improved zonal isolation and improved casing protection that, together, will increase the life of the well.