Laurie Duthie

Saudi Arabia's Two World Records for Aided Coiled Tubing Reach and Real Time Logging in Extended Reach Well

Two new records exist in one of the world’s largest oil increment fi eld development projects in Saudi Arabia. Th e records set while achieving a well’s intervention objectives include: (1) Attaining the deepest coiled tubing (CT) reach for rigless well intervention at 29,897 ft (9.11 km) measured depth in an extended reach open hole horizontal power injector well using a CT tractor, and (2) Th e fi rst application of real time logging enabled through a wired motor head assembly via the tractor. Th e intervention objectives were to acid stimulate an open hole completed relatively deep in the reservoir with total depth (TD) of 29,897 ft and open hole length of 6,697 ft utilizing 2” CT with open hole tractor, to perform injectivity/falloff test, and to conduct real time logging for evaluating the reservoir’s injectivity profi le. Th e paper examines several challenges that engineers and operators encountered during intervention in this well. A partially sealing high viscosity tar layer exists between the overlaying oil column and underlying aquifer. Operationally, the challenge was to overcome obstructions arising from tar accumulation during the well intervention. Th is challenge was overcome by the use of a solvent and the well was successfully acidized with the aid of the CT tractor. Th e other concern was the tractor integrity while a large amount of acid is pumped and the extended exposure time of tractor to acid. Th e tractor successfully handled huge amounts of corrosive fl uids in a sour environment while providing the required pulling force to reach the TD of the well to set the intervention record for tractor reach without adverse eff ects on the integrity of its O-rings, seals, and mechanical parts. In addition Saudi Arabia’s Two World Records 22