Numerical Simulation of Electromagnetic Driven Heavy Oil Recovery

Abstract

Abstract This work presents a feasibility study of a heavy oil recovery process driven by electromagnetic heating (EMH). Previously EMH has been subject of many research works on heavy oil recovery, including laboratory, theoretical and numerical simulation studies. These works have demonstrated that EMH constitutes a promising recovery process; however the simulations of this challenging coupled multi-physics phenomenon were not straightforward and required special efforts in model development. The major part of previous theoretical and numerical models has been based on simplifications of the Maxwell equations for the EMH source description. The advantage of such a model is its simplicity which helps to gain a conceptual knowledge via order of magnitude estimations at reasonable computational expenses. A typical example is the use of conventional constitutive relation for the EMH source, i.e. the so-called Beer-Lambert-Bouguer law which, strictly speaking, can be applied to a limited number of practically valuable cases. Other models are required, for instance, to estimate the influence of water evaporation and resulting multiphase flow on EMH driven oil recovery. Taking advantage of a coupled numerical simulation tool recently developed in our group, a few instructive EMH application cases capturing the effects of EM wave propagation in a non-homogeneous medium, on one side, and thermal multiphase flow in a heavy oil reservoir, on the other, are presented and analyzed in this paper. Major attention is paid to the production efficiency. Conventional criteria adopted for such an IOR method may not be always applicable, so a comparison to known methods like SAGD or recovery by conductive heating is provided for analysis purposes. Although a number of process scenarios and options are possible, in our current study we chose for the base case a horizontal SAGD-like well pair, the upper well being equipped with an EM wave emitting facility (the EM well). Different process stages (preheating, steam chamber offset and development, and production) are considered in detail and the critical analysis of heating zone and oil flow configurations is done to find out conditions of improved recovery. In particular, the results indicate that while the preheating period can be successfully modeled using the BLB law, starting from the steam chamber offset a more realistic electromagnetic model is to be applied to adequately describe EMH heating source and production dynamics. The EMH assisted recovery process is a promising IOR method especially for unconventional oil reservoirs. The results obtained in this work via coupled EMH/reservoir flow simulations provide an improved understanding on this challenging multi-physics problem.