The remotely located Z field has no testing, processing or gathering facilities and production is currently processed at the closest field production station 20 km away. The Z field consists of multiple stacked Permian clastic reservoirs in a low relief three way dip-closed structure bounded to the east by a north northeast–south southwest trending fault. Few other faults exist in the field and the identified faults most likely act as baffles to flow. Hydrocarbons are trapped in the marginal marine Middle Gharif (MG3) reservoir unit and in the younger MG2 fluvial sand bodies. The fluid properties range from high gravity crude oil in the MG3 (45°API) to volatile oils in MG2. This high GOR fluid limited the artificial lift options. The initial reservoir pressure is 26 bar in the MG3 with a bubble point pressure of 22.2 bar.

Despite challenges and uncertainties, the Z field was successfully developed by an optimised IOR method utilising onsite waterflood development to maximise field NPV. Artificial lift options are continuously modelled to find the optimum lift mechanism (mix of free flowing and ESP wells). The field production stabilised since 20005 when water injection was implemented to avoid drawdown below bubble point.

Integrated field reviews and analysis lead to a better understanding of reservoir performance. The interference tests and transient analyses performed for both injectors and producers provided insight into the field performance. These reviews led to successful drilling in 2009 with an additional upside potential of doupling the field production.

The plan for this field is to further develop the MG3 with a water flood utilising streamline simulation and start the MG2 appraisal development since more well control points are now available.

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