Multiple Wells Drilled with Star Shield® Wellbore Shielding Solution in the Delaware Basin

Offset well data in the Delaware Basin indicated the need for one Operator to extend the mud weight window in the 12¼-in. intermediate hole section to prevent a saltwater influx due to nearby injector wells. However, the extended mud weights required to hold back this water flow usually lead to substantial lost circulation events and hole instability issues when drilling through the mechanically weak formations below. A narrow window between pore pressure and fracture gradient makes drilling these wells challenging; drilling the intermediate interval with enough mud weight to prevent a fluid influx can induce whole mud losses and wellbore instability. 

The operator used Star Shield wellbore shielding additive in the past and adopted the technology across multiple wells for this application. The Star Shield additive was mixed into the water-based drilling fluid system at 5,000 ft. and maintained in the system while drilling through the Cherry, Brushy Canyon, and Avalon formations to approximately 8,500 ft. to mitigate the anticipated whole mud losses and wellbore instability issues. Offset wells in this area are traditionally drilled with 9.4- to 9.6-lb/gal saturated salt water-based drilling fluid (WBM); however while utilizing Star Shield wellbore shielding technology, mud weights as high as 10.8 lb/ gal were achieved on multiple wells without whole mud losses.