PVT Investigation of an Iraqi Reservoir

Abstract

This investigation was made to clarify the type of reservoir fluids in an Iraqi field reservoir
regarding the controversy about its type. It was known for many years as a condensate field, but
in this study a different theory was investigated and proved using Winprop of CMG® software.
Two equations of state (EOS) were tested and the one with minimum error percentage was used.
Also, three correlations were tested to calculate the original C6
+ properties, which are: Lee-
Kesler , Twu and Riazi . Twu`s correlation prevailed because the results of this correlation were
the nearest to the original data, and it permits using a wide range of pressures (from zero to
infinite pressure values), which minimizes the discrepancies between the results of any equation
of state, which was investigated.
After achieving the closest possible match of all available properties, the envelopes were
constructed. Winprop of CMG needs a full set of oil and gas properties from a single sample.
Therefore, a recombination for the available gas and oil samples were made to construct the
phase envelopes for the field system in addition to individual gas and oil phase envelopes
The result of this investigation and analysis is that the reservoir is actually a black oil field with a
gas cap, despite what was believed earlier as being a condensate field.