PTT Exploration and Production Company Limited (PTTEP) drills more than 50 gas wells each year with static reservoir temperatures greater than 200 degC. These ultraHT wells are located in the shallow water of the Gulf of Thailand and are typically deviated. The established method for developing ultraHT wells in this field involves drilling until a circulating temperature of 175 degC [347 degF] is reached and tripping out of hole to remove measurement technologies to protect electronic components. The remainder of the well section is drilled blindly to TD, followed by a gyro trip to determine the location of the wellbore.
While planning the 6 1/8-in section of a ultraHT well in the Arthit field, PTTEP began searching for a more efficient method of developing its ultraHT wells.
SLB recommended using the TeleScope ICE ultraHT MWD service, a high-speed telemetry service designed to obtain real-time downhole measurements in harsh drilling conditions. Using proprietary ultraHT-rated electronics that are ruggedized for extreme temperatures, the TeleScope ICE service operates normally at 200 degC. This capability enables real-time well placement and would eliminate the BHA trip and gyro run that PTTEP typically performs.
In its first field run, the TeleScope ICE service performed reliably in reservoir temperatures of 204 degC and circulating temperature of 186 degC [367 degF]. Despite these harsh drilling conditions, PTTEP obtained real-time downhole measurements and drilled the well to total depth in one run. By eliminating a BHA trip and a gyro run, PTTEP saved 12 hours of rig time and decreased operational costs by USD 167,000.
