Abstract
Due to the critical nature of the ramp-up phase of an efficient steam-assisted gravity drainage (SAGD) process, it is important to understand the physics of the steam chamber ramp-up phase in order to improve SAGD production performance. In conventional numerical simulation models, the dynamics of the steam chamber ramp-up phase are not fully resolved because of unclear steam−oil−water interactions during the vertical growth of the steam chamber and how its state changes as the reservoir parameters vary. This work provides an efficient approach for the numerical modeling of the steam chamber ramp-up phase in an SAGD operation. The steam chamber ramp-up phase was fully examined through the consideration of the effects of the temperature-dependent oil−water−gas multiphase flow system and the vertical countercurrent flow. The simulation results revealed that for the large temperature gradient of the mobile oil zone at the edge of the steam chamber, a delicate temperature-dependent multiphase flow system was essential for the reliable estimation of the SAGD ramp-up phase. The vertical countercurrent flows of oil−gas and oil−condensate were the dominant mechanisms over cocurrent flow, which significantly impacted the steam chamber ramp-up rate. The numerical model physically predicted the steam chamber ramp-up phase and could be used to efficiently compute a field-scale simulation using a dynamic gridding function that was based on a fine grid model.