The Champion field is a large offshore oil field in Brunei Darussalam, which has been on production since 1972. The field is complex both geologically and in terms of the production system. The reservoir has over 500 stacked sandstone reservoirs across 15 fault blocks. Over time production facilities have increased to 40 surface structures supporting production and processing from over 1300 completion intervals. Although the field is considered a mature field and with aging facilities, there is a clear long-term vision to rejuvenate the field to sustain production for another 30 years through re-development and expansion of the water injection scheme.
Ongoing maturation of the waterflood project is supported by continuous Reservoir Performance Reviews (RPRs). The RPRs bring together the reservoir understanding, hydrocarbon saturations and production data. The purpose of the RPRs is to identify opportunities – restoration, acceleration and reserves addition and compile them in an integrated development plan covering the short, mid and long term. RPRs are carried out at the flow unit level - a small group of commingled reservoirs within a single fault block.
Top Quartile Recovery Factor (TQ RF) analysis is an integral part of the RPR. With the Top Quartile Estimated Ultimate Recovery (TQ EUR) tool, Shell developed a benchmarking tool which provides a conceptual framework that probes the performance of each field in a consistent manner. Basic geological and fluid properties as well as economic parameters are used to determine a complexity factor for each flow unit. The current and expected ultimate RF of the unit is then compared to the TQ RF (from reservoirs of the same complexity).
A systematic approach is taken to bridge the gap to TQ RF. Closed-in well reviews identify restoration and water injection candidates. Deterministic analysis of sweep patterns and high remaining oil saturations are compared with streamlines in the NFA forecast model. Potential gains are quantified by the simulator. The outcomes are near-, mid- and long-term surveillance and development plans to move the recovery up to TQ and beyond to the technical limit (TL).
By applying this systematic RPR/TQ process per flow unit across the whole field, a detailed reservoir understanding of this giant, complex field is achieved. This approach enabled the integrated WRFM team to deliver significant value in terms of increased production, optimization of Waterflood development and new in-well and infill opportunities.