PVT and Pressure Analysis in Third pay Reservoir of Zubair Oilfield Southern Iraq

Abstract

In this paper the pressure drop and PVT data that used in the model to describe the behavior of
reservoir fluids of 3rd pay reservoir of Zubair field is explained. The wells in Hammar-Shuaiba area show
high Gas Oil Ratio, exceeding 1,000 scf/stb. This is bad sign and that mean reservoir pressure is reduce
dramatically and gas will produced , finally the energy that use to push the oil from reservoir to the
surface will decrease. Eleven samples have been collected and analyzed from all 3rd pay reservoirs over
the years, seven samples in Hammar –Shuaiba area. The PVT data resulted to be scattered, being not
possible to define any acceptable conclusion about their trend versus depths, taking also into account that
they are not referred to the same temperature. The main difference between the old and new PVT is the
Bubble Point pressure at reservoir conditions, which increases from 2646 psi to 2760 psi. Historical
pressure behavior shows that water Injection is beneficial to maintain stable pressure trend. Pressure
analysis shows a strong depletion start from 2013 in various zones of Hammar Shuaiba domes.