To enhance well performance intervention work is often necessary in field developments. Challenges exist in vertical well interventions and these have been studied and improved over the years. However, horizontal well interventions pose a completely new challenge and a magnified level of difficulty. With extended reach wells certain challenges become almost insurmountable. Basic data acquisition such as production logging where profile data flow is acquired becomes almost impossible to acquire. Yet, this data is vital for decision making. While tractor aided coiled tubing has largely been demonstrated as a preferred deployment technique for cost-effective production logging and acid stimulation combined operations, most of the initial jobs where accomplished via memory production logging in these extended reach wells. This was because the Coiled tubing tractor had no inner wiring. This led to a situation where the subjects of real time evaluation of production flow profile, treatment effectiveness, and injection zone monitoring have remained an industry challenge. A hydraulic tractor aided coiled tubing intervention was introduced as a solution for the development of the extended reach wells in a Saudi field three years ago. This solution aided in the acquisition of the previously difficult data and in addition, aided in deduction of the specific stimulation benefits such as damage skin reduction, improved drawdown, and treatment gains from injectivity increase. Some records which were also set while achieving the well's intervention objectives include 1) attaining the deepest coiled tubing (CT) reach at 29,897 feet (9.11 km) in an extended reach open hole horizontal injector well using a tractor and 2) the first application of real-time water injection profiling enabled through a wired motor head assembly via the tractor. In addition to data, other operational benefits include less equipment to the well site because the same equipment was used for both production logging and stimulation -in particular the coiled tubing reel, amongst others.The application of real-time informed decisions was critical in overcoming challenges affecting spinner response, operating time and cost, optimizing stimulation design, and yielding a consistent injectivity increase with a true reflection of deep penetration into the damage zone will benefit operators confronting similar intervention challenges.
BackgroundAn extensive study of the field and its predominant drive mechanism revealed that production and simultaneous peripheral matrix water injection is the preferred depletion strategy. Extended reach wells and relatively complicated trajectories typically characterize the powered water injectors (PWI) drilled for reservoir pressure maintenance. The injectors will support oil production from one of the largest field developments in the history of Saudi Aramco in the M field. The field development consists of 27 artificial islands linked by 41 kilometers of causeway spanning the Arabian Gulf. The blend of onshore, offshore, causew...
