Production Strategy Calls for Injection of High-Gas/Oil-Ratio HP/HT Crude
The authors discuss a production strategy in which high-gas/oil-ratio crude can be injected into the upper oil reservoirs with partial pressure depletion to achieve production enhancement and synergy among reservoirs.
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.
The Halfaya field is a supergiant hydrocarbon accumulation in southeastern Iraq.