Heavy oil recovery using in situ steam generated by thermochemicals: A numerical simulation study

This paper introduces a novel approach to generate downhole steam using thermochemical reactions to overcome the challenges associated with heavy oil resources. The procedure developed in this paper is applied to a heavy oil reservoir, which contains heavy oil (12-23 API) with an estimated range of original oil in place (OOIP) of 13-25 billion barrels while its several technical challenges are limiting its commercial development. One of these challenges is the overlying 1800-2000-ft thick permafrost layer, which causes significant heat losses when steam is injected from the surface facilities. The objective of this research is to conduct a feasibility study on the application of the new approach in which the steam is generated downhole using the thermochemical reaction (SGT) combined with steam-assisted gravity drainage (SAGD) to recover heavy oil from the reservoir. A numerical simulation model for a heavy oil reservoir is built using a CMG-STARS simulator, which is then integrated with a matlab framework to study different recovery strategies on the project profitability. The design and operational parameters studied and optimized in this paper involve (1) well configurations and locations and (2) steam injection rate and quality as well as a steam trap in SAGD wells. The results show that the in situ SGT is a successful approach to recover heavy oil from the reservoir, and it yields high-project profitability. The main reason for this outperformance is the ability of SGT to avoid the significant heat losses and associated costs associated with the surface steam injection.