Dynamics of water coning

Water beneath a layer of oil in a producing reservoir may rise and form a bell-shaped cone in the vicinity of the well. We discuss how the dynamics of cone formation in two dimensions depends on the gravitational contrast, the interfacial tension, and the flow rate of oil. For a constant flow rate below a critical rate Q(c), stable cones are formed. At rates above Q(c), two dynamical regimes are expected. These are slow initial formation and fast breakthrough to the well. Quasi-two-dimensional transparent porous models were used to perform cone formation experiments. Effective acceleration due to gravity was systematically varied. The experiments were simulated using a stochastic model based on invasion percolation in which capillary forces were explicitly taken into account. We find agreement between experiments and simulations, and consistency with the theoretical predictions.