Successful HP/HT Drilling Through Innovative Practices: Sharing a Case Study of a Deep HP/HT Well

Abstract

Despite the short planning time of 18 months and very limited geological data, TTD-1 HPHT Exploration well in Block SK of East Malaysia, was successfully drilled to its technical limit by adopting some innovative HPHT practices. Various technical challenges were successfully overcame including an abnormally steep pressure ramp (17 psi/ft), high mud weight (18 ppg), high overbalance (3,000 psi), narrow drilling margin (until 0.7 ppg window), wellbore breathing, pore pressure of 14,000 psi and temperatures of 325° F.During drilling, the actual operating window was successfully mapped out in real-time. The lower boundary was defined by pore pressure modeling, MDT logging and dynamic flow checks using MPD. The upper boundary, fracture gradient, was derived from dynamic formation integrity tests & leak-off tests utilizing MPD. Other techniques such as use of smaller tubular, low-flow MWD tools and bridging agent also contributed to the success. Wellbore breathing was well controlled to a minimum level.Various simulations have assisted the HPHT section to be drilled beyond conventional defined limits. Two real-time monitoring centers assisted in improving drilling efficiency and real-time decision making. The well highlighted limitations of acquiring formation pressure in tight formation using FPWD tools, life of MPD seal element and gas invasion in production zone cementation.The authors will present and share the HPHT drilling practices adopted to successfully drill the deepest HPHT well to date for PETRONAS Carigali in Malaysia.