Locating the remaining oil in the Nelson Field

Abstract

AbstractThe Nelson Field has been in production since 1994 and is at the mid-mature stage of field life. The current management strategy has focussed on identifying infill well locations with the aim of recovering bypassed oil. An increasingly detailed reservoir description is required in order to locate these opportunities and to help screen them for their economic viability. A systematic workflow has been followed through to localize those areas of the Nelson Field where the target oil volumes are most likely to be found. This workflow is given the name ‘locate the remaining oil’ within Shell. The aim of this workflow is to understand the relationship between sweep and the geological framework of the reservoir. On this basis, drainage cells are defined within the reservoir. Rather than behaving as a single ‘tank’ of oil with a common rising oil–water contact, the Nelson Field produces from nine discrete drainage volumes, each with separate producing oil–water contacts. The drainage cells have been defined on the basis of sedimentology, oil and water geochemistry in combination with quantitative volumetric analysis. Screening of the nine drainage cells in the reservoir has identified four cells that contain significant remaining volumes of mobile oil. These have then been investigated in further detail with a view to locating any stranded oil volumes that are unlikely to be produced by the existing well stock, and to determine if these are large enough to justify infill well drilling.