Satisfying Profitability and Non-Flaring Gas Policy in an Emerging Gas Market Context:A Case History

摘要

A zero gas flaring target was established by Nigeria based onthe Kyoto Protocol, meanwhile a gas market was emerging inthe Country.This paper deals with a Nigerian onshore multilevel oilfield on production for thirty-one years, where the associatedproduced gas was flared except a part that was re-injected.An integrated revision study was carried out to investigatethe possibility to improve the oil recovery and simultaneouslyhonour the target of not flaring the gas and seize the gasmarket opportunity.Several scenarios were studied based on the mainalternative concepts to increase the gas injection activity orchange the drive mechanism by performing the waterinjection, with the fixed constraint of not flaring the gas. Anupgrade of the existing gas compression unit was required forthe gas injection option, whilst a new plant was necessary forthe water injection option. The benefit of higher oil recoveriesdue to gas injection and the advantage of larger gas amountsfor the market in the case of water injection were assessedthrough the economic evaluation.The highest profitability was achieved in the case of a gasinjection increase followed by the conversion of the injectorsinto gas producers and was the consequence of the gas sale,which largely compensated the shortfall in oil recovery.The conclusion was that it was possible to satisfy both thezero gas flaring requirement and the economic profitabilitythrough the opportunity of the gas market.A lesson learnt was that the technical results based on theoil recovery alone were not enough to select the optimumdevelopment scenario, since the overall economic evaluationplayed the fundamental role.