Managing Circulation Losses in a Harsh Drilling Environment: Conventional Solution vs.CHCD Through a Risk

The presence of extensive karst/fractures along with severe circu-
lation losses prevents successful drilling using the conventional
circulation technique. For this scenario, the pressurized-mud-cap
closed-hole circulation-drilling (CHCD) technique was applied,
and it proved to be the most effective method to drill through the
Lower Carboniferous carbonate.