Revisit a mature oil field’s facilities to extend its economic life

Abstract

Mature fields hold large volume of remaining hydrocarbon in reservoir. However, they are exposed to many challenges, for example increasing GOR, increasing water cut, and integrity issue of facilities which restrict the economic viability of the fields. The net operating cash flow is on a decreasing trend and the economic limit is approaching closer. Multidisciplinary approach which involves subsurface strategies and surface optimization are required to extend the economic life of mature fields. The purpose of this study is evaluate the impact of rejuvenation of mature fields by integrating subsurface optimization through infill wells and surface facilities optimization by converting a manned Central Processing Platform (CPP) to an unmanned Wellhead Platform (WHP) on the extension of mature fields’ economic life. Isolation of rotating equipment and reduction of equipment count on the CPP are required to reduce the maintenance frequency and gives opportunity to unman the CPP. However, the additional gas production from the new infill wells introduces another challenge on the surface facilities’ capacity limit of the platform. Process changes are required on the existing platform and were evaluated using hydraulic simulation tool, PIPESIM to determine the new operating condition at the existing platform after conversion of that CPP to WHP. Brownfield modifications required to accommodate high gas production from new infill wells were evaluated based on the results of adequacy check on existing equipment. CAPEX and OPEX required for the subsurface and surface optimization plan were estimated to evaluate the economics of the mature fields based on the new scenario. From the results, it is shown that conversion of the manned platform to unmanned platform can reduce the OPEX by 12% and economic limit is extended four years longer.