Two-phase and three-phase equilibrium K-values for modelling of non-condensable gas Co-Injection processes

Abstract

To improve the efficiency of Steam Assisted Gravity Drainage process (SAGD), a small amount of non-condensable gases can be added to steam. The non-condensable gas creates an insulation film at the top of the steam chamber as a result of gas accumulation. This could prevent heat loss to the overburden, increase steam chamber propagation in the lateral direction, and consequently improve the SAGD performance. Field-scale modelling and simulation of non-condensable gas injection in a hybrid SAGD process requires a comprehensive numerical model that includes variety of mechanisms involved in the processes. During the steam/non-condensable gas co-injection, the non-condensable gas may partially be dissolved in bitumen and water, accounting for a portion of gas production from the chamber. Therefore, in order to accurately model the non-condensable gas injection process, the partitioning of the gas among the phases (oleic and aqueous) must be well understood.The most significant challenge of modelling multi-phase equilibrium in gas/bitumen/water systems is the lack of three-phase equilibrium data. This study presents a methodology to generate two-phase and three-phase K-values from the experimental solubility data. The data for binary systems at certain temperatures and pressures is translated into equilibrium K-values. The K-values were calculated either from a correlation representing the phase behavior data or from an equation of state coupled with Henry's law. Then, the generated two-phase and three-phase K-values were directly implemented in reservoir simulators to account for component partitioning in different phases. The results indicate that the generated K-values would be applicable for different types of bitumen.