Wells drilled through the challenging depleted Red Fork formation typically experience irreversible formation integrity issues and lead to severe mud losses and dramatically increased drilling costs. The effort to keep mud weights lower than the fracture gradient while drilling through the Red Fork can be problematic prior to entering the sloughing shale in the lateral Woodford section.
Impact suggested pre-treating the drilling fluid system with a combination of STAR SHIELD and STAR SHIELD 500 at 5 lb/bbl prior to displacing tooil-based mud (OBM). The same concentration of the wellbore shielding additives was maintained to totaldepth (TD).
The operator significantly reduced the total well costs by eliminating the intermediate casing string and drilling 20,619-ft. open hole. The operator successfully drilled the two- string Woodford horizontal well to 22,164-ft. measured depth with zero mud losses or hole instability issues. The operator ran casing to bottom and cemented with full returns.