PRESSURE SWING SOLVENT ASSISTED WELL STIMULATION

摘要

There is provided a method of initiating or accelerating the establishment of fluid communication between injection and production wells located in a formation, comprising injecting sufficient solvent into the wellbores of the wells that the solvent more than occupies the horizontal sections of the wells; pressurising the solvent column in the injection wellbore and optionally also production wellbore by the injection of gas such that the pressures of the horizontal section of the injection well and optionally the production well are greater than the formation fracture pressure; maintaining the pressure in the injection wellbore and optionally also the production wellbore; depressurising the injection wellbore and, if pressurized, the production wellbore, the differentials in pressure between the two resulting in backflow of a mixture of solvent and heavy hydrocarbons into the horizontal sections of the production well and/or injection well; and repeating the pressurisation and depressurisation steps for at least one more cycle to generate pressure swings, thus creating enhanced convection of solvent/solvent-heavy hydrocarbon in the porous media of the formation around the well and in the region between the two wells.