Armada Phase II and Seymour Phase I

Abstract

The Armada development comprises three gas-condensate fields in the Central North Sea: Fleming (Paleocene Maureen Formation reservoir), Drake and Hawkins (Upper Jurassic Fulmar Formation reservoirs). Armada came on streamin 1997, with seven Phase I wells producing at a plateau rate of 450 × 10 6 SCFD. A Phase II drilling campaign, comprising three Armada wells, was implemented in 2002 with the aim of extending the duration of the Armada production plateau and, where possible, accessing new reserves. The first well was a relatively straightforward Paleocene Maureen Formation producer, although the target was revised based on a new seismic attribute study, which revealed important heterogeneities in this deep-marine reservoir. The second well targeted the undrilled western compartment of the Hawkins discovery. Unfortunately, the Fulmar Formation was water-wet with no evidence for any hydrocarbon charge, despite the fact that gas had been proved by an earlier exploration well in a downdip compartment. Fortunately, to mitigate the risks, which had been recognized pre-drill, the well had been designed with a secondary Paleocene Maureen Formation target which came in better than prognosed. A significant aspect of the Armada Phase II programme was the extensive integration across a number of disciplines. The combined team was soon able to propose a convincing explanation for the failure of West Hawkins, giving comfort that East Hawkins should be fully charged and was worth drilling. The final Phase II well was therefore targeted on East Hawkins, although it was a difficult well to plan as the key reservoir horizon had only minor stand-off from the gas–water contact. A number of different well trajectories were considered and 3Dvisualization proved invaluable in ensuring the final well path was optimized. In addition, a major benefit was derived from a recently installed onsite 3Dvisualization centre that enabled the multidisciplinary Armada team to work together very effectively. For example, the drilling engineers were truly able to appreciate what was driving the geotechnical requirements for the well and vice versa. The well came in very close to prognosis, adding valuable reserves and further extending the Armada plateau. With a rig on the Armada platform the opportunity was taken to drill the South West Seymour prospect, whose chance of success had increased dramatically after a possible direct hydrocarbon indicator was recognized on an inverted seismic volume. The well discovered hydrocarbons in the primary target, the Fulmar Formation and also in the Pentland Formation and was immediately side-tracked to a previously planned updip Fulmar development location. Supplementary material: The movie referred to in the article is available at https://doi.org/10.6084/m9.figshare.c.4811091