An operator was drilling a lateral section with a 6 1/4-in bit. The mud weight was continuing to rise from 12.65 to14.1 lbm/galUS while the fluid loss remained the same at 8.8 cm3. The emulsion stability was also decreasing as the mud weight increased while drilling the lateral section.

The decision was made to lower the fluid loss for the remainder of the lateral section. VERSATROL M1 blended asphaltic resin was added to the MEGADRIL oil-based temperature-stable invert-emulsion drilling fluid system at 4.2 lbm/bbl. This product was added at 15,143 ft prior to tripping out of the hole to replace a bottomhole assembly.