An operator sought to expedite drilling an exploration section in a zone with highly dispersive shale. When drilling an offset well with standard water-based mud, 2 days NPT had been spent cleaning out the 8 1/2-in section before logging. Cuttings samples from the offset well showed clearly a lack of inhibition that worsened with depth.

To solve the problem and reduce NPT for the next well, M-I SWACO recommended HydraGlyde Optima flexible high-performance water-based drilling fluid system based on accretion laboratory test results. The results showed a reduction in accretion of about 50%, from 33% to 18%.

No major challenges or fluid-related problems were encountered drilling the problematic 8 1/2-in section. The fluid viscosity and other fluid parameters remained very stable throughout the section.