Techno-economic assessment of reservoir heterogeneity and permeability variation on economic value of enhanced oil recovery by gas and foam flooding

This research introduces a detailed techno-economic model to estimate and evaluate the economics of enhanced oil recovery. The model categorizes the cost objects into three main modules: injection, production, and CO₂ recycling. These modules are composed of a number of lower-level sub-modules that represent specific cost objects. The techno-economic model utilizes reservoir simulation inputs and results such as production rate and composition, injection fluid rate and composition, and bottomhole pressure to provide detailed costs and revenue of injection, production, and CO₂ recycling, according to defined scenarios. Although the techno-economic model is a general model that can be applied to any EOR project, we illustrate it here to compare flooding scenarios for a modeled EOR project in Mississippi. Reservoir heterogeneity is the variation of petrophysical properties with space such as porosity, permeability, fluid saturation. This effect is explored for total of 81 cases considering different combinations of Dykstra-Parsons coefficient (VDP) and correlation length. For each case, 25 random realizations of the permeability field were generated and the results of realizations were averaged to provide a statistical representation of the cases. Simulations of three scenarios including Waterflood, Water Alternating Gas, and Surfactant Alternating Gas floods (using a foam model for SAG) were carried out for each realization. The results show that, under assumed cost structure and the selected foam model, on average, SAG is a better and more profitable injection scenario with an oil price of $40/bbl. The economic advantage of SAG, however, declines with greater permeability variation.