Reservoir Heterogeneity Affecting Steam Communication between Multiple Well-Pairs for Steam Assisted Gravity Drainage

Abstract

This paper investigates the effects of reservoir heterogeneity on steam communication and well-interference between multiple steam chambers during SAGD (steam assisted gravity drainage) process. The conventional steam stimulation for developing oil sands uses well pad system composed of several well pairs, so that the heat interference occurs when the steam chambers merge with each other. The numerical simulations using multiple SAGD well pairs were conducted in a heterogeneous formation and compared with those of a homogeneous case in terms of the production performances. Reservoir heterogeneity could make uneven steam communication, unequal chamber growth and leave unrecovered area, thereby giving the negative effect on oil production. Both production profiles of water and oil, and cSOR (cumulative steam to oil ratio) of individual SAGD pair would be good indicators to diagnose steam movement between chambers. The results discussed the negative effect of reservoir heterogeneity making unequal growth of vapor chamber and energy inefficiency due to horizontal movement of injected steam, and the necessity of identifying the indicators to characterize the chamber growth.