While drilling the vertical and curve sections below the intermediate casing point on wells in Blaine County, Oklahoma, an operator was experiencing severe oil-based mud (OBM) losses with mud weights of 13.8 lb/gal. Gas influxes from the over-pressured Morrow sandstone formation would cause the to mud weights to exceed the fracture gradient of the highly-depleted Springer shale formation. In the past, the operator ran a liner to minimize OBM losses and reduce overall non-productive time (NPT) prior to drilling the lateral section.
The operator implemented STAR SHIELD into the drilling fluid system at a concentration of 5-6 lb/bbl which allowed for mud weights as high as 15.1 lb/gal while drilling through the depleted Springer formation. The operator reduced NPT and OBM losses to zero. The use of Impact’s Wellbore Shielding technology designed to enhance hole stability while optimizing mud weight in the fluid system allows operators to extend their mud weight windows while drilling through over-pressured and highly depleted formations.
The operator routinely uses STAR SHIELD in this area to eliminate a liner. The use of STAR SHIELD has allowed the operator to drill with mud weights higher than the normal fracture gradient without inducing mud losses. The operator now continuously drills the lateral section without encountering hole instability issues.