RESEARCH THE PROCESS OF DISPLACING HEAVY OIL BY HYDROCARBON SOLVENTS FROM A MODEL OF FRACTURED CARBONATE CORE

Abstract

Introduction: due to the low rate of solvents reaction with heavy oil at the reservoir temperature, solvent injection must be combined with thermal fluids. Solvent and thermal fluids injection order depends on reservoir geological and physical properties. The mechanism of heavy oil intensification from carbonate rock with single fracture by injection of solvents at various temperature and rate has been studied in this paper. Materials and methods: The rheological property of the heavy oil with solvents has been studied. Heavy oil samples and carbonate core of one field from Samara Region used as an object of research. For simulate longitudinal fracture the core has been cut before filtration experiments. Chemical compositions and individual substances were used as solvents. Results: The dependences of the heavy oil dynamic viscosity on the type and concentration of solvent for temperatures 20-70 °C has been defined. The dependences of the oil recovery factor on the system temperature and injected solvent flow rate for model of carbonate rock with single fracture has been experimentally determined. The mechanism of oil production (diffusion/ convective) during solvent injection has been calculated. Analytically calculated solvent penetration depth into the matrix depending on the time and the temperature of the core Discussion and conclusion: on the basis of analytical calculations, the low eficiency of solvent injection at reservoir temperature has been justiied due to the need long time for diffusion exchange. For the studied reservoir properties method for solvent injection and its composition have been proposed.