Environmental Engineering Reference
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Simulation of In-situ Combustion
in a Matrix-Fracture System
at Laboratory Scale
O. Cazarez-Candia and C.G. Aguilar-Madera
Abstract
In this work, a mathematical model for in-situ combustion (ISC) was
numerically solved for one heterogeneous systemcomposed by a porous-matrix adja-
cent to a fracture. The main aim was to investigate the effect of fractures on the ISC
behaviour. Three mobile-phases were considered: non-volatile single-component oil,
incondensable gas, and water. The combustion process was modeled with a kinetic
model and two chemical reactions: cracking reaction (coke production), and combus-
tion reaction (coke consumption). A benchmark case was established by comparison
of suited numerical results against experimental data from a homogeneous com-
bustion tube experiment reported from the literature. It was found an acceptable
agreement between theoretical and experimental data for the temperature field and
other variables of interest. The validated mathematical model was extended for one
system including adjacent fractures, and their effects over the ISC were investigated.
It was observed gas breakthrough because it moves preferably through fractures. It
was found that around the combustion front, significant amount of oxygen penetrates
from the fracture to the porous matrix, as here the coke combustion takes relevance.
In addition, an important amount of oil is expelled from the matrix to the fracture.
1 Introduction
ISC is an enhanced oil recovery technique for mature or non-conventional reservoirs.
Its main objective is to enhance oil mobility by reduction of viscosity occurring when
temperature increases in the reservoir. Before the implementation to a commercial
scale, previous field- and lab-scale assessments are required in order to evaluate
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