Abstract
Injection of lean gas into volatile oil reservoirs to recover oil by vaporisation is frequently identified as an attractive development option. This mechanism is a significant feature in reservoirs with large-scale gas recycling projects.
A fundamental evaluation of the process has been undertaken for a specific reservoir application to validate our understanding of the physical mechanisms. The local contact efficiency on a microscopic scale and the rescaling of data from the laboratory scale to simulator grid block scale were identified as areas of significant uncertainty.
In this study, accurate measurements of the local contact efficiency for a lean gas stream vaporising residual oil from a gravity drainage process have been made. The experiments were conducted at reservoir conditions using core from the Prudhoe Bay reservoir.
Use of the experimental measurements to validate a field scale model capable of process optimisation requires a number of steps. Firstly, a detailed simulation analysis of the core scale displacement is required to validate the model of the physical process on the microscopic scale. Then, as model length scales increase the effects of heterogeneity become increasingly important. The outstanding steps in the validation procedure are outlined.
