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 ofreservoir fluids of 3rd pay reservoir of Zubair field is explained. The wells in Hammar-Shuaiba area showhigh Gas Oil Ratio, exceeding 1,000 scf/stb. This is bad sign and that mean reservoir pressure is reducedramatically and gas will produced , finally the energy that use to push the oil from reservoir to thesurface will decrease. Eleven samples have been collected and analyzed from all 3rd pay reservoirs overthe years, seven samples in Hammar –Shuaiba area. The PVT data resulted to be scattered, being notpossible to define any acceptable conclusion about their trend versus depths, taking also into account thatthey are not referred to the same temperature. The main difference between the old and new PVT is theBubble Point pressure at reservoir conditions, which increases from 2646 psi to 2760 psi. Historicalpressure behavior shows that water Injection is beneficial to maintain stable pressure trend. Pressureanalysis shows a strong depletion start from 2013 in various zones of Hammar Shuaiba domes.