Ran OBMI last night in an 8.5-in lateral through interbedded shale/siltstone and saw asymmetric breakouts rotating about 20° over about 600 m despite holding about 0.2 ppg above predicted collapse mud weight. I’m rechecking stress orientation, bedding-plane weakness, and potential near-wellbore anisotropy versus drilling-induced tensile signatures, but has anyone seen bedding-parallel shear dominate breakout azimuth like this? Any practical heuristics you use to tweak MW or trajectory when the breakout direction drifts while ROP and WOB remain steady?
Saw almost the same about 20° drift over about 600 m in an 8.5-in shale/silt lateral on OBMI; it was bedding-dip rollover plus swelling tied to slide/rotate cycles. “breakout azimuth like this? Any practical heuristics you use to tweak MW or trajectory when the breakout direction drifts” We bump ECD about 0.1 ppg via flow/ROP when the drift starts and, if it persists, nudge azimuth 5–7° to cross beds more obliquely, and double-check OBMI pad bias so you’re not chasing a tool artifact. Caveat: your +0.2 ppg can still be low when PWD swings, so time the bump to slides and clean out.
Quick thought: before chasing stress rotation, have processing recheck OBMI orientation — I’ve had a clean about 18–20° “drift” over about 500 m in an 8.5-in lateral that was just magnetometer bias from a magnetized mule shoe; once we tied to MWD azimuth and fixed pad index, the breakouts snapped back. If it still holds after re-orient, I’m with @mperry1973 on bedding-dip rollover, but that 0.2 ppg margin is razor-thin and can make the rotation look worse.