Recovery of heavy oil and bitumen using Vapex process in homogeneous and heterogeneous reservoirs

Vapex, a process using light hydrocarbon vapours (propane or butane or their mixtures) as solvents to recovery heavy oil or bitumen from reservoirs, was studied experimentally using scaled packed models. Both homogeneous and heterogeneous reservoirs were studied using models packed uniformly with different Ottawa sands or in continuous layers or in discontinuous lenses. Tangleflags crude, Peace River bitumen and Atlee Buffalo crude were extracted using either butane or propane as solvents. Pure solvents, mixtures of butane and propane as well as mixtures of solvents and non-condensible gases were injected at pressures ranging from near the vapour pressure of the solvents to 300 psig. The effects of well configurations, well spacings, temperature, viscosity of original oil, permeability and solvent injection rates on the Vapex performance were investigated.; It was found that the effect of reservoir heterogeneity on the Vapex process is more important than with the Steam Assisted Gravity Drainage (SAGD) process, especially when continuous low-permeability layers or shales are present in the reservoir.; Operation of the Vapex process at a pressure higher than the vapour pressure of the solvents is feasible with the co-injection of non-condensible gas as a carrier gas for the solvent. The use of mixed solvents to replace pure solvents gives similar production performance.; Optimal solvent injection rate and the net solvent requirements depend largely on the well configuration, spacing and permeability. Experiments conducted at reservoir pressure and temperature indicate that the field application of the Vapex process is promising in terms of oil production rates and net solvent requirements. A field prediction is provided.