July 2009 saw the start of production from Phase 1 of the Parque das Conchas project, an offshore cluster development located in license block BC-10, 120km off the Espirito Santo coast in the Campos Basin, Brazil. Phase 1of the project consists of three diverse, small fields with a wide range of oil types, tied back to a Floating Production Storage and Offloading vessel (FPSO). The eight producers located in the Ostra and Abalone fields flow to a subsea artificial lift manifold (ALM), where gas and liquids are separated, with the liquids pumped to surface via caisson-based electrical submersible pumps (C-ESPs). The two producers in the Argonauta field flow to a second subsea ALM, where the multi-phase fluids are pumped via non-separated C-ESPs. The produced gas is re-injected into a gas disposal well in the Ostra aquifer until export facilities are available.
On start-up, a few key uncertainties remained on the performance of the wells in the field, particularly related to initial production rate, well connectivity and the potential for fines migration inside the formation and the gravel-packs. A surveillance plan was developed before first oil to assure integrity of the wells and to determine and improve the performance over time. The plan was linked to the available measurements of permanent down-hole pressure and temperature gauges (DHPTG) and subsea multi phase flow meters (MPFM) in most wells. A schedule of interference tests, individual well tests and pressure build-ups was planned for the initial production phase.
Conclusions drawn from the surveillance plan are based on the analysis of the whole range of collected data, matched to single well and integrated system models. This paper will describe the logic of the surveillance plan and the experience gathered from the wells during the first year of production from the Parque das Conchas fields and how this information has been used to optimize production.