We essentially supervised the fluid sampling and analysis program on one of the first major sour gas development projects. The fluid compositions changed both aerially and vertically although there was no consistent variation with depth across the sub reservoirs. The final step of the project was to develop a lumped EOS for use in the compositional reservoir simulation model. Key components of the project included:

• Implementing wellhead sampling as a cost-effective method of collecting representative single-phase samples of the produced reservoir fluid from the main producing formation.
• On site witnessing of the collection of representative single-phase open hole samples from the different producing formations.
• Working closely with the analytical laboratory in real-time to fine tune analysis techniques such that a high-quality final database of produced fluid properties was available to the client.
• Developing a lumped EOS which successfully predicted the aerial variations in fluid properties whilst at the same time accurately calculating the fluid properties from the different sub-reservoirs.

The grid block of the compositional reservoir simulator was automatically filled both aerially and vertically by correlating the fluid compositions with the H2S contents of the fluids in the different formations. The simulator has been successfully history matched against the production history and is being used by the subsurface group.