Some Observations on Field-Scale Simulation of the In-Situ Combustion Process

This paper describes and illustrates a method for ensuring sustained combustion in coarse-grid, field-scale simulation using a kinetic-based model. For the example problem treated, as in several unreported cases, the method considerably extends the grid block size which can be tolerated without severe grid size effects. The method is applicable only in cases where one accepts the assumption that no free oxygen passes unreacted through the combustion front. The paper also presents and discusses results of very fine-grid one-dimensional simulations. Comparison of these fine-grid results with coarse-grid ID results shows, for the particular problem data used, an unexplained, significant increase in amount of oil cracked with grid block size increased over the range of 0.5 feet to 10 feet. 2D areal, 5-spot pattern simulations show that the 9-point difference scheme very significantly reduces a large grid orientation effect in 5-point simulation of the combustion process.