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Journal of Chemistry
Volume 2016, Article ID 2742696, 10 pages
http://dx.doi.org/10.1155/2016/2742696
Research Article

Experiment and Simulation Study on the Special Phase Behavior of Huachang Near-Critical Condensate Gas Reservoir Fluid

Dali Hou,1,2 Yang Xiao,1,2 Yi Pan,3 Lei Sun,3 and Kai Li1,2

1School of Energy, Chengdu University of Technology, Chengdu, Sichuan 610059, China
2State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, Sichuan 610059, China
3State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum, University of Technology, Chengdu, Sichuan 610500, China

Received 5 November 2015; Revised 16 January 2016; Accepted 10 February 2016

Academic Editor: Casimiro Mantell

Copyright © 2016 Dali Hou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Due to the special phase behavior of near-critical fluid, the development approaches of near-critical condensate gas and near-critical volatile oil reservoirs differ from conventional oil and gas reservoirs. In the near-critical region, slightly reduced pressure may result in considerable change in gas and liquid composition since a large amount of gas or retrograde condensate liquid is generated. It is of significance to gain insight into the composition variation of near-critical reservoir during the depletion development. In our study, we performed a series of PVT experiments on a real near-critical gas condensate reservoir fluid. In addition to the experimental studies, a commercial simulator combined with the PREOS model was utilized to study retrograde condensate characteristics and reevaporation mechanism of condensate oil with CO2 injection based on vapor-liquid phase equilibrium thermodynamic theory. The research shows that when reservoir pressure drops below a certain pressure, the variation of retrograde condensate liquid saturation of the residual reservoir fluid exhibits the phase behavior of volatile oil.