Oil demand is increasing globally while new oil developments are getting smaller and more challenging to develop (unconventional oil & gas reservoirs, deep offshore, tight reservoirs, heavy oil, acid gas, shale gas etc). In this context, extending the life of mature, conventional oil fields plays an important role in supporting world oil demand.

Reservoir management and development of these mature fields is challenging and requires innovative solutions given the increasing technical costs as production declines and asset/well integrity costs rise. Technically, a good understanding of reservoir behaviour and production mechanisms leads to implementing appropriate solutions to maximize field life, recovery factor and curb production decline. Commercially, the challenge is to find pragmatic and economically viable solutions.

The field discussed in this paper is a mature carbonate offshore oilfield in the territorial waters of Abu Dhabi operated since 1974. After 40 years of production, the field is still producing economically and currently is producing with an average water cut of more than 90%. This paper presents the continuous evolution of the technologies that have been deployed throughout the years to further valorise resources, in response to the growing maturity and complexity of the field.

Various IOR techniques have been employed in this field ranging from ESP's, gas lift, intelligent completions, multi-lateral wells, splitter wells, dumpflood to selective completions. In addition, various EOR techniques have been used ranging from full field tertiary hydrocarbon gas injection to chemical and enzyme EOR pilots.

Given the aging production facilities, field management is a daily challenge. The complex gas scheme composed of simultaneous gas production, tertiary gas injection, gas lift, gas recompression and gas export requires continuous arbitration between activation gain and tertiary recovery.

Lessons learnt, good and bad, will help maximize future recovery in other less mature fields in the UAE.

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