Operators encounter a high risk of induced mud losses, sloughing shale and stuck pipe while drilling in the Woodford formation in Oklahoma. On a seven well pad, one operator was experiencing severe mud losses, stuck pipe, pack-offs and side-tracking while utilizing conventional lost circulation material (LCM).
After four wells were drilled with hole instability issues, STAR SHIELD® 500 wellbore stabilizer was requested to prevent further drilling fluid related problems. STAR SHIELD 500 is an ultra-low invasion additive that protects the formation by minimizing fluid and pressure invasion into microfractures and permeable formations. STAR SHIELD 500 was initiated and maintained at 6 lb/bbl in oil-based mud (OBM) from surface casing to total depth (TD). By maintaining this engineered concentration, the operator successfully drilled through the Springer, Caney and Woodford formations with no further mud losses or hole instability issues.
The operator used STAR SHIELD 500 on the sixth and seventh wells and eliminated non-productive time (NPT) and the intermediate casing string by using a two string well design. On the three wells where STAR SHIELD 500 was used to prevent losses, casing was successfully run to bottom and cement was completed with full returns.