Coefficient of Isothermal Gas Compressibility for Reservoir Fluid in Niger Delta Region

The Isothermal gas compressibility is a point function and has the dimensions of reciprocal pressure. This property is usually determined from various equations of state developed from other western country’s field data. This study is based on developing a new correlation and using the correlation to obtain a data base for the isothermal gas compressibility coefficient based on the Niger Delta hydrocarbon fields. The Ghedan et al formular for finding the dimensionless Isothermal gas compressibility coefficient in combination with the Beggs and Brill z factor correlation was used in obtaining the various values of the Isothermal gas compressibility coefficient. The values obtained were used to develop a chart of dimensionless isothermal gas compressibility versus pseudo-reduced pressure at a constant pseudo-reduced temperature. Evaluation of the obtained result was carried out using statistical methods and the ranking method. It was observed that this study had a better statistical evaluation with average absolute percentage error of 5.34 and correlation coefficient of 0.94 as compared to other correlations. Also, this study had the lowest rank of 2.42 with Mattar et al correlation having the highest rank of 4.94. Therefore, this agrees with literature that, the lower the rank value, the better the correlation. The better evaluation of this study can be linked to the more accurate EOS model of the z factor applied which requires no iteration, consuming less time in arriving at the desired result and this procedure can be easily programmed.