Predicting Compressibility Factor for Gas Condensate under High Temperature High Pressure Conditions by Using a New Combinational Method

Jingya Dong,Yang Peng,Hongyu Ren,Yuzhan Liu

doi:10.19026/rjaset.12.2748

Abstract

Gas condensate is commonly located in the deep strata under High Temperature High Pressure (HTHP) conditions, which is mainly composed of methane and derived its high molecular weight from the quantity of plus fractions (C<sub>n</sub>+). Thus, in order to accurately predict the volumetric behavior for gas condensate, the selection of suitable characterization methods for the C<sub>n</sub>+ is of key importance. The compressibility factor as an essential volumetric parameter is often used to analyze the PVT behavior in gas condensate engineering. In this study, four empirical correlations for plus fraction characterization are evaluated and then a new combination method is presented to determine the compressibility factor for gas condensate under HTHP conditions.

Highlights

With the improvement of the exploration and exploitation technology, several unconventional natural gas resources have been discovered in the world
Some gas condensate reservoirs at pressure above 110 MPa have been found in the North Sea according to the research by Ungerer et al (1995); In the Tarim region of China, more than 70 condensate gas reservoirs have been discovered with high reservoir pressures and temperatures reported by Yi Cun and Bao Xin (2001)
For the sake of evaluating the gas volumetric behavior accurately, the selection of suitable characterization methods for the Cn+ is of key importance according to the research by Elsharkawy and Elkamel (2000)

Summary

INTRODUCTION

With the improvement of the exploration and exploitation technology, several unconventional natural gas resources have been discovered in the world. It includes gas condensate reservoirs under High Temperature High Pressure (HTHP) conditions. Xu Qiang et al (2000) measured the compressibility factors of 10 natural gas samples at the temperature and pressure ranges of 322.5-413.4 K and 20.1-95.9 MPa, respectively. Four empirical correlations including two mixing rules and two empirical methods for critical properties for plus fraction characterization are evaluated and a new combination method is presented to determine the compressibility factor for gas condensate under HTHP conditions.

METHODOLOGY

Method No Characterization methods Mixing rules

AND DISCUSSION

CONCLUSION