METHOD OF EXTRACTION OF HIGH-VISCOSITY OIL AND NATURAL BITUMEN FROM DEPOSIT Russian patent published in 2013 - IPC E21B43/22 

FIELD: oil and gas industry.

SUBSTANCE: method includes pumping of solvent in the system of paired horizontal wells, where the upper well is injection well and the lower well is production well, removal of mixture of high-viscosity oil or natural bitumen with solvent and monitoring of change in physicochemical properties of extracted products. Composition of solvent for pumping in formation, vol %: aliphatic hydrocarbons with number of carbonic atoms 5-7 - 80-90, aromatic hydrocarbons with number of carbonic atoms 7-9 - 10-20. Proportion of components in solvent composition is determined according to physicochemical properties of extracted high-viscosity oil or natural bitumen. Change in content of asphaltene-resinous components in extracted high-viscosity oil or natural bitumen is monitored during all the period of extraction using photocolorimetry method. Proportion of solvent reducing viscosity and aromatic solvent of asphaltenes in working agent is corrected based on graph of behaviour of light absorbance coefficient: when light absorbance coefficient reduces thus indicating sedimentation of asphaltene-resinous components in formation, number of solvent of asphaltenes in working agent is being increased till no change in light absorbance coefficient occurs. As aliphatic components of solvent the following is used: petroleum ether, broad fraction of light hydrocarbons - BFLH or instable - natural gasoline. As aromatic hydrocarbons toluene, xylene, ethyl-gasoline are used.

EFFECT: increasing oil recovery due to elimination of processes reducing formation permeability.

3 cl, 9 dwg