Thermal recovery methods are viable and commonly used to recover heavy oil reservoirs by reducing oil viscosity and improving oil displacement. However, there are many challenges associated with conventional steam injection methods. These challenges include the significant heat energy losses before steam reaches the reservoir, the high cost of steam generation and injection, as well as the emission of greenhouse gases. Therefore, it is essential to introduce a heavy oil recovery approach in which steam can be generated downhole to overcome these challenges associated with conventional steam injection methods. However, this novel heavy-oil recovery method has several designs and operational parameters that must be efficiently optimized, to achieve maximum recovery from heavy-oil reservoirs with less cost and minimum environmental impact.

The objective of this work is to introduce a novel heavy-oil recovery technique using in-situ steam generated by downhole thermochemical reactions and investigate the key design and operational parameters of this complex recovery process. Modified self-adaptive differential evolution (MSaDE) and particle swarm optimization (PSO) methods are used in this work as global optimizer to find the optimum design and operation parameters to achieve the maximum net present value (NPV) and highest oil recovery (RF) of a heavy-oil reservoir after ten years of development. Comparison of the two proposed optimization methods is introduced as well.

The results show that downhole thermochemical reactions can be used to generate in-situ steam, to efficiently reduce the heavy-oil viscosity and improve oil mobility. It has also shown that utilizing MSaDE and PSO methods to optimize the key components of this novel recovery process, significantly enhanced the recovery performance, in terms of higher NPV and RF.

This study provides the first known in-depth optimization and uncertainty analysis to outline the significance of each design and operation parameter of the proposed novel thermochemical recovery process. This work showed and verified the concept of using downhole thermochemical reactions as an environmental-friendly solution to recover oil from heavy-oil reservoirs and is considered as a step forward to eliminate the greenhouse gases emission related to thermal recovery methods.

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