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摘要
In this paper, a circular solvent chamber model is formulated to simulate the vapor extraction (VAPEX) heavy oil recovery process in three different production phases, namely, the solvent chamber rising, spreading, and falling phases. In addition to the prediction of the transient solvent chamber evolution, the cumulative heavy oil production is also simulated in each production phase. This theoretical model is developed in terms of the solvent chamber geometry and the gravity-drainage zone. The transition-zone thicknesses in the solvent chamber rising phase and in the solvent chamber spreading/falling phase are used as two unknown adjustable parameters and obtained by best fitting the theoretically simulated oil production data to the experimentally measured data in the three production phases. It is found that the transition-zone thickness in the solvent chamber rising phase is larger than that in the solvent chamber spreading/falling phase. Moreover, the average transition-zone thickness increases as the reservoir permeability decreases. Once the transition-zone thicknesses are found, the theoretical model is used to simulate the solvent chamber evolution and the heavy oil production. The theoretically simulated solvent chamber evolution and heavy oil production are in good agreement with the observed solvent chamber evolution and the measured heavy oil production in the entire VAPEX test. The simulated oil production rate can much better represent the measured oil production rate than the constant oil production rate predicted from the Butler-Mokrys analytical model, which is valid for the solvent chamber spreading phase only. It is anticipated that the newly developed VAPEX model will help to better simulate and design the future VAPEX heavy oil recovery projects.
- 出版日期2014-6
