Abstract: Methods for recovering viscous oil include receiving electrical power from an electrical grid fed by at least one fluctuating electricity supply. The methods also include using at least a portion of the received electrical power to heat a first fluid stream using an electrical heater. The methods also include heating a second fluid stream with a fired-heater using a combustible fuel. The methods further include using both the first and second heated fluid streams to aid oil recovery. In accordance with these methods, the heat output of the electrical heater is adjusted during production operations to at least partially match an estimated mismatch between electrical power supply from and demand on the grid. At the same time, the heat output of the fired-heater is adjusted to at least partially compensate for fluctuations in the electrical heater heat output.

Abstract: Described are methods of distributing a viscosity reducing solvent to a set of wells terminating in an underground oil reservoir where the variation in the net solvent injection rate is minimized. The net solvent injection rate is the difference between the total solvent injection rate and the total solvent production rate from the set of wells, for example on an instantaneous or daily rate basis. Minimizing this variation can reduce costs associated with surface solvent storage, subsurface solvent storage, and solvent supply, since solvent supply often is least expensive when supplied at near a fixed rate. One option is to operate well pairs and to inject solvent into one well of the pair while producing oil and solvent from the other well of the pair. These methods are particularly useful in solvent-dominated, cyclic or non-cyclic, viscous oil recovery processes.

Abstract: Described is a way to reduce solvent usage in solvent-dominated oil recovery processes through the use of an emulsion. Injection of an emulsion into an oil reservoir is performed as an alternative or supplement to solvent injection to minimize solvent usage per unit amount of oil recovered. The emulsion may contain solvent and the solvent may form an external-phase of the emulsion. A solvent-external emulsion may be injected and formed using an aqueous liquid or a gas as the internal phase. The emulsion may be an aqueous-external, vapor-internal emulsion with solvent being injected separately or simultaneously. Polymer may be added to viscosify the emulsions and use them for flow diversion in a solvent-dominated process.

Abstract: Described is a method of operating a cyclic solvent-dominated recovery process (CSDRP) for recovering viscous oil from a subterranean reservoir of the viscous oil to enhance recovery effectiveness. The cyclic solvent process involves using an injection well to inject a viscosity-reducing solvent into a subterranean viscous oil reservoir. Reduced viscosity oil is produced to the surface using the same well used to inject solvent. The process of alternately injecting solvent and producing a solvent/viscous oil blend through the same wellbore continues in a series of cycles until additional cycles are no longer economical. Conventionally, the solvent composition remains constant over time within each injection cycle and among cycles. In the present method, by contrast, the solvent composition is varied over time thereby providing operational benefits as described herein.

Abstract: The present invention relates generally to in situ hydrate control during hydrocarbon production when applying a recovery method utilizing cyclic injection of light hydrocarbon solvents. Hydrate formation is limited by creating an energy reserve within a hydrocarbon reservoir adjacent to the wellbore. A heated solvent is injected during an injection phase of a cyclic solvent dominated recovery process to form a heated region adjacent to the wellbore at the end of an injection cycle. The energy reserve is used to act against the evaporative cooling effect caused by subsequent production and associated depressurization to maintain reservoir conditions outside of hydrate formation conditions. In situ conditions are estimated and injected energy amounts are controlled.

Abstract: A method of operating a cyclic solvent-dominated recovery process (CSDRP) for recovering viscous oil from a subterranean reservoir of the viscous oil. The cyclic solvent process involves using an injection well to inject a viscosity-reducing solvent into a subterranean viscous oil reservoir. Reduced viscosity oil is produced to the surface using the same well used to inject solvent. The process of alternately injecting solvent and producing a solvent/viscous oil blend through the same wellbore continues in a series of cycles until additional cycles are no longer economical. Aspects of the invention relate to the particular volume of solvent injected in each cycle, when to switch from production to injection, the injection pressure to be used, the production pressure to be used, and to middle and late life operation.

Abstract: Methods for recovering viscous oil include receiving electrical power from an electrical grid fed by at least one fluctuating electricity supply. The methods also include using at least a portion of the received electrical power to heat a first fluid stream using an electrical heater. The methods also include heating a second fluid stream with a fired-heater using a combustible fuel. The methods further include using both the first and second heated fluid streams to aid oil recovery. In accordance with these methods, the heat output of the electrical heater is adjusted during production operations to at least partially match an estimated mismatch between electrical power supply from and demand on the grid. At the same time, the heat output of the fired-heater is adjusted to at least partially compensate for fluctuations in the electrical heater heat output.

Abstract: To recover in situ viscous oil from an underground reservoir, electricity is conducted through the underground reservoir by at least two electrodes in an amount that would, in the absence of solvent injection, cause water in the reservoir to vaporize adjacent to the electrodes, and injecting solvent into the reservoir to mitigate water vaporization adjacent to the electrodes by vaporizing solvent in this region. Oil and solvent are produced through one or more production wells.

Abstract: Described are methods of distributing a viscosity reducing solvent to a set of wells terminating in an underground oil reservoir where the variation in the net solvent injection rate is minimized. The net solvent injection rate is the difference between the total solvent injection rate and the total solvent production rate from the set of wells, for example on an instantaneous or daily rate basis. Minimizing this variation can reduce costs associated with surface solvent storage, subsurface solvent storage, and solvent supply, since solvent supply often is least expensive when supplied at near a fixed rate. One option is to operate well pairs and to inject solvent into one well of the pair while producing oil and solvent from the other well of the pair. These methods are particularly useful in solvent-dominated, cyclic or non-cyclic, viscous oil recovery processes.

Abstract: To recover oil, including viscous oil, from an underground reservoir, a cyclic solvent-dominated recovery process may be used. A viscosity reducing solvent is injected, and oil and solvent are produced. Unlike steam-dominated recovery processes, solvent-dominated recovery processes cause viscous fingering which should be controlled. To control viscous fingering, operational synchronization is used within groups and not between adjacent groups.

Abstract: Described is a way to reduce solvent usage in solvent-dominated oil recovery processes through the use of an emulsion. Injection of an emulsion into an oil reservoir is performed as an alternative or supplement to solvent injection to minimize solvent usage per unit amount of oil recovered. The emulsion may contain solvent and the solvent may form an external-phase of the emulsion. A solvent-external emulsion may be injected and formed using an aqueous liquid or a gas as the internal phase. The emulsion may be an aqueous-external, vapor-internal emulsion with solvent being injected separately or simultaneously. Polymer may be added to viscosify the emulsions and use them for flow diversion in a solvent-dominated process.

Abstract: The present invention relates generally to in situ hydrate control during hydrocarbon production when applying a recovery method utilizing cyclic injection of light hydrocarbon solvents. Hydrate formation is limited by creating an energy reserve within a hydrocarbon reservoir adjacent to the wellbore. A heated solvent is injected during an injection phase of a cyclic solvent dominated recovery process to form a heated region adjacent to the wellbore at the end of an injection cycle. The energy reserve is used to act against the evaporative cooling effect caused by subsequent production and associated depressurization to maintain reservoir conditions outside of hydrate formation conditions. In situ conditions are estimated and injected energy amounts are controlled.

Abstract: A method is described for recovering viscous oil such as bitumen from a subsurface formation. The method involves creating an artificial barrier in a subterranean zone above or proximate a top of the subsurface formation. The barrier is largely impermeable to fluid flow. The method also includes reducing the viscosity of the viscous oil and mobilizing hydrocarbons into a readily flowable heavy oil by addition of heat and/or solvent. Heating preferably uses a plurality of heat injection wells. The method further includes producing the heavy oil using a production method that preserves the integrity of the artificial barrier.