Richard Huis in ‘t Veld (Wintershall Noordzee)
The Wingate gas eld was discovered in August 2008 by Wintershall Noordzee exploration well 44/24b-7, which targeted a Base Permian closure with subcropping reservoirs of the Late Carboniferous Lower Ketch Formation. Pre-drill, significant upside was identified as a result of ConocoPhillips’ nearby 44/23b-13 well (drilled in2006), where the Westoe Coal Formation provides a seat seal to the Lower Ketch Formation. Because of the large difference in free water level between the two wells, the volumetric uncertainty of undrilled compartments with reservoirs in the Lower Ketch, as well as the Caister Formation, remained relatively high. To manage development risk and uncertainty without further appraisal expenditure, and to allow for early gas production, a phased field development was planned: that is, to appraise through development and production. Gas production, through a six-slot platform and export to the Dutch Neptune Energy operated D15-A platform, commenced in October2011, only 3 years after discovery. Initial development comprised the tieback of the exploration well and drilling of the second compartment with well 44/24b-A2Y.Subsequently, three more compartments were drilled as soon as production dropped off plateau. During the appraisal/development and 7 years of production, knowledge of the reservoirs increased significantly, improving the understanding of the challengingWestphalian gas play.
Knowledge acquired during the development and production phases of the Wingate Field, as well as the analogous Dutch D12-A and D15-A Fields and studies on released data of nearby UK fields in the Caister-Murdoch System and Tyne Field, is applied by the operator Wintershall Noordzee in managing the complex Westphalian reservoirs and constructing the static-dynamic 3D reservoir models. It also resulted in further exploration success and the current development of the Sillimanite Field, which has significantly extended the life expectancy of key offshore gas producing infrastructure, the D15-A production platform and the WGT pipeline system. The most important subsurface production issues of the analogues, such as dynamic pressure behaviour, aquifer response and downhole halite scaling, and their relationship with reservoir architecture and quality, will also be discussed during the presentation.