Title: Analysis of the impact of CO₂ content on the physical properties of the liquid phase mixtures in oil production wells

Authors: Jiaming Zhang; Xiaodong Wu; Zhangxin Chen; Jingyao Wang; Zongxiao Ren

Addresses: Research Institute of Economy and Techniques of PetroChina, 6 Liupukang St, 100011,Beijing, China ' Key Laboratory for Petroleum Engineering of the Ministry of Education, China University of Petroleum, 18 Fuxue Rd, 102249,Beijing, China ' Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive NW, T2N 1N4, Calgary, Alberta, Canada ' PetroChina Exploration and Development Research Institute, 20 Xueyuan Rd, 100083, Beijing, China ' Key Laboratory for Petroleum Engineering of the Ministry of Education, China University of Petroleum, 18 Fuxue Rd, 102249,Beijing, China

Abstract: CO₂ injection not only enhances oil recovery dramatically, but it also has a potential to reduce the greenhouse effect. During the process of CO₂ displacement, when CO₂ breaks through in oil production wells, CO₂ content will impact the phase state and physical properties of the liquid phase mixture in wellbore. As a result, it will affect the calculation of temperature and pressure in oil production wells. Therefore, it is unacceptable to use the conventional black-oil model for calculating the phase state of miscible fluids. For dealing with this problem, we use a gas-liquid flash theory and a compositional model to develop a new model. The Jilin oilfield is used as a case study; the phase state (gas, liquid or gas-liquid) and physical properties of the liquid phase mixture (including CO₂ and hydrocarbons) under initial conditions are calculated by this new model. The results indicate that the molar content of CO₂ has a great impact on the physical properties of the liquid phase mixture in oil production wells under certain temperature and pressure. A scientific guide for the calculation of temperature and pressure in oil production wells can be provided with the developed model.

Keywords: CO₂ displacement; gas-liquid equilibrium; constituent; flash.

DOI: 10.1504/IJGW.2017.084508

International Journal of Global Warming, 2017 Vol.12 No.2, pp.261 - 271

Received: 19 Feb 2015
Accepted: 23 Jun 2015
Published online: 12 Jun 2017 *

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