APPLICATION OF MANAGED PRESSURE DRILLING TECHNIQUE IN N8 WELL

Based on the circulation loss during deep drilling under Qianshan layer for prior-period development of Bohai BZ28-1 oil field, BZ28-1-N8 well was applied successfully underbalanced pressure control drilling technology in 152.4 mm well bore in Ordovician formation at first time. It solved the circulation loss during drilling in Ordovician layer, and found out and protected oil-gas layer directly and exactly. This technology brought a better effect.