Assessment of the Common PVT Correlations in Iraqi Oil Fields

Pressure volume temperature (PVT) analysis is the process of determining the fluid behaviors and properties of oil and gas samples from an existing well. Normally, PVT properties are experimentally measured in the laboratory. However, the absence of PVT measurement negatively impacts the application of many petroleum engineering calculations such as reserves estimation, material balance, reservoir simulation, production equipment design, and optimization of well performance. In this work, we developed a program using VBA and MS EXCEL to compare between the collected measurements of PVT properties that were collected from 41 Iraqi oil cruds and the values obtained from the correlations. After the comparison process, we chose the correlation that have the close values to the PVT measurements that were collected previously. This type of study, in which we compare the results of existing literature correlations to the measured value in a laboratory for a specific country or location, has been conducted in a number of countries, including Kuwait, the United Arab Emirates, and Egypt, but not in Iraq, which is where the value of this study lies. A total of 92 correlations were involved in this study including, (19) Bubble point pressure, (10) gas-oil ratio, (20) oil FVF, (10) saturated Viscosity, (3) density at bubble point, (7) undersaturated oil compressibility, (12) dead viscosity, (3) undersaturated oil FVF, (8) undersaturated viscosity. Over all,  the best performance was obtained using the “Elsharkawy and Alikhan [1] “correlation for ( Pb, Rs, Bo) , “Standing [2]” correlation for Density at bubble point , “Almehaideb [3]” for below bubble point viscosity , “Labedi [4]” for Dead viscosity, “Al-Marhoun [5]” for above bubble point oil FVF, “Standing [2]” for above bubble point oil compressibility, “Petrosky and Farshad [6]” for above bubble point viscosity, based on consistently low values of (AAPE) and (RMS) and cross plot.