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, all with hole instability issues, STAR SHIELD 500 wellbore stability enhancer, was requested to prevent instability 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). The operator was also able to eliminate the intermediate casing string and use a two string well design. On the three wells, STAR SHIELD 500 was used, mud losses were prevented, the casing was successfully ran to bottom and cement was completed with full returns.