Halfaya oilfield in Iraq contains multiple vertically stacked reservoirs. The main oil reservoirs are under primary development at the time of writing. The remaining deepest high-gas/oil-ratio (GOR), high-pressure/high-temperature (HP/HT) carbonate reservoir, with an original pressure gradient of 0.867 psi/ft, has been drilled and tested but not yet developed. A production strategy has been proposed in which high-GOR crude can be injected into the upper oil reservoirs with partial pressure depletion as an energy-conservation measure in view of its high wellhead pressure and good productivity during drillstem tests (DST), thereby achieving production enhancement and synergy among reservoirs.
Introduction
The Halfaya field is a supergiant hydrocarbon accumulation in southeastern Iraq.
