Evaluation of compositional models and PVT correlations for Iraqi light crude oils properties

Abstract

Evaluation of common compositional models and pressure-volumetemperature (PVT) correlations are carried out against field data for light crude oil from north Iraqi reservoirs. The reported data and the evaluation are significant to the petroleum industry, as various international and local oil companies operate in this region. The comprehensive PVT program Multiflash™ 7.2 is utilized, employing the Peng-Robinson (PR) and Redlich-Kwong-Soave (RKS). The oil formation volume factor, bubble point pressure, solution gas-oil ratio (Rso), and saturated oil viscosity are chosen for this evaluation. The results demonstrate that the PR and RKS compositional models, with some adjustments, exhibit much higher accuracy as compared to PVT correlations. For example, the errors between the model's predictions and the field data for the Rso are 9% for PR ad 17% for the RKS model. In contrast, for the PVT correlations, much higher errors are obtained. The lowest errors (32%) are obtained with the Ikiensikimama and Ajienka, while above 90% errors (the highest) are reported by Petrosky and Farshad. This study will enable the petroleum industry to improve and optimize the production operations in north Iraq-Kurdistan region.