While drilling through the Eagle Ford shale, one operator experienced a large amount of gas requiring a higher mud weight. The operator increased the mud weight to 13.5 lb/gal in the troublesome Wilcox interval. While placing the mud cap lost circulation occurred, breaking down the Wilcox. Significant non-productive time resulted and large volumes of oil-based mud was lost to the formation.
The operator utilized STAR SHIELD® through the active system with concentrations ranging from 6-8 lb/bbl. The Wilcox was drilled with a mud weight of 13.5 lb/gal. Below the Wilcox, (+/- 10,000 feet) the mud weight was increased to 14.5 lb/gal with full returns. At the kick-off point (+/- 13,000 feet) the operator began a 6 ¾-in. slim-hole design to total depth of 19,000 measured depth.
The operator significantly reduced the total well cost by eliminating the casing string and drilled to total depth with full returns. The operator eliminated wellbore instability and NPT due to insufficient mud weight. Currently, the operator continues to use STAR SHIELD as a standard operating procedure in their drilling program for the Eagle Ford.