Improved Oil Recovery from Sub-Optimal Reservoirs

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This program aims to help the Canadian oil industry currently struggling to economically produce oil from reservoirs of marginal quality. These include bitumen deposits that are too deep for surface mining but not deep enough for normal SAGD operation, heavy oil deposits in naturally fractured carbonate formations, thin heavy oil formations, heavy oil deposits that have been depleted by cold production but still contain high oil saturation.***The proposed work involves experimental and theoretical examination of mechanisms involved in improved oil recovery processes and modifying the existing technologies to overcome their shortcomings in recovering oil from reservoirs of sub-optimal quality. The following research themes are proposed for the continuation of this program.***i. Solvents Assisted Gravity Drainage in Naturally Fractured Reservoirs: Large volumes of heavy oil and extra heavy oil are found in naturally fractured reservoirs but successful exploitation of such reservoirs remains challenging. Thermal processes like steam assisted gravity drainage and cyclic steam stimulation do not work too well because very often the reservoir porosity is low and the volume of rock that must be heated per unit volume of oil becomes too large. The low porosity is not a problem in solvent based non thermal processes, but such processes generally fail to provide high enough oil production rates. This program aims to find ways of improving the oil recovery rate of non-thermal processes. ***ii. Nanoparticles for Improved Polymer Flooding: This segment of the program is aimed at exploitation of heavy oil reservoirs that are too thin for thermal recovery. Primary depletion with horizontal wells leaves a large fraction of oil unrecovered, which is difficult to produce with currently available technology. The process that we propose to examine for such reservoirs is improved polymer flooding with nanoparticle enhanced polymer solutions. We believe that addition of nanoparticles with modified surface characteristics to polymer solutions can overcome some of the current the limitations in using polymers for heavy oil displacements. These limitations are low injectivity of high viscosity polymer solutions and shear degradation of polymers during injection.***iii. Recovery of Heavy Oil from Reservoirs Depleted with CHOPS: The focus of this work will be to develop a robust cyclic solvent injection process that can work in the presence of wormholes. New solvent mixtures with added oil soluble foaming agents will be evaluated to find combinations that can rekindle the foamy oil drive in the depleted reservoirs.***The knowledge generated by this program will not only help the Canadian oil industry, it will also enhance the basic understanding of fluid flow in fractured formations, interactions of nanoparticles with polymers and mechanisms involved in the cyclic solvent process.**