The Greater Plutonio development, deepwater offshore Angola, is BP's largest subsea development. The "soft" rock reservoirs require sand-control completions that are some of the most complex and challenging in the world. A commonly accepted view is that effective sand-control can result in sacrificing well productivity; however, the 23 wells completed to date have broken that paradigm with world class results and the largest well potentials in the history of BP.
All twelve deepwater production wells employed Open Hole Gravel Pack completions, achieving outstanding results and technical limit productivity along with exceptional mechanical reliability and integrity. From the first well, they have all shown zero formation damage, resulting in individual well potentials up to 80 MBD. To support this prolific production capability, effective voidage replacement has been essential. Therefore, the injection well completions were designed to deliver equivalent well performance, while still providing robust sand-control. Based on this, Cased Hole Frac-Pack completions were selected for the initial gas and dual service injection wells with Stand-Alone Screen completions for the water injectors. The injector completions were as successfully deployed as their producer counterparts with technical limit injectivity on all the wells, setting a new standard for flow efficiency in high transmissibility reservoirs and delivering some of the largest water injector completions in BP's portfolio.
The Greater Plutonio completions excellence story is one of a truly performance driven and innovative team. Productivity indices are up to four times greater than prognosed and mechanical skins in production wells are all zero (compared with +5 to +20 in analogous fields). This is underpinned by comparable injection performance and furthermore, the over 99% mechanical reliability and full data acquisition uptimes have substantially reduced the probability of costly well interventions in the future.
This paper discusses the keys to the successful delivery of this world class completions performance and covers best practices and resultant well performance data of the first 23 wells from the planned initial 43 subsea well development.