Embodiments are provided herein for in situ upgrading of a heavy hydrocarbon in a reservoir having an injection well and a production well, or a well that is alternately operated as an injection well and a production well. Embodiments are also provided herein for selecting a degradable solvent for use in a process for in situ upgrading of a heavy hydrocarbon in a reservoir having an injection well and a production well, or a well that is alternately operated as an injection well and a production well.

Embodiments are provided herein for in situ upgrading of a heavy hydrocarbon in a reservoir having an injection well and a production well, or a well that is alternately operated as an injection well and a production well. Embodiments are also provided herein for selecting a degradable solvent for use in a process for in situ upgrading of a heavy hydrocarbon in a reservoir having an injection well and a production well, or a well that is alternately operated as an injection well and a production well.

Disclosed is a combined catalytic viscosity reducing system and a use of the combined system. The combined catalytic viscosity reducing system comprises four slugs, the four slugs are a catalyst slug, a heat generating system slug, a gas injection slug, and a water-soluble viscosity reducing system slug; the catalyst slug includes 10%-15% of azacarbene iron, 15%-30% of tert-butyl hydroperoxide, 2%-5% of phosphoric acid, 2%-5% of hydrogen donor, and 0.5%-1% of emulsifier agent, and the others are solvent; the heat generating system slug includes 10%-30% of NaNO.sub.2, 8%-25% of NH.sub.4Cl, and 3%-10% of acid initiator, and the others are water, totaling 100%; the water-soluble viscosity reducing system slug, according to mass percentage, includes 0.2%-0.5% of surfactant and 2%-10% of alkali, and the others are water. The combined catalytic viscosity reducing system can effectively reduce viscosity without injecting steam, and the viscosity reduction rate can reach 96.5%.

Disclosed is a combined catalytic viscosity reducing system and a use of the combined system. The combined catalytic viscosity reducing system comprises four slugs, the four slugs are a catalyst slug, a heat generating system slug, a gas injection slug, and a water-soluble viscosity reducing system slug; the catalyst slug includes 10%-15% of azacarbene iron, 15%-30% of tert-butyl hydroperoxide, 2%-5% of phosphoric acid, 2%-5% of hydrogen donor, and 0.5%-1% of emulsifier agent, and the others are solvent; the heat generating system slug includes 10%-30% of NaNO.sub.2, 8%-25% of NH.sub.4Cl, and 3%-10% of acid initiator, and the others are water, totaling 100%; the water-soluble viscosity reducing system slug, according to mass percentage, includes 0.2%-0.5% of surfactant and 2%-10% of alkali, and the others are water. The combined catalytic viscosity reducing system can effectively reduce viscosity without injecting steam, and the viscosity reduction rate can reach 96.5%.

Methods of evaluating a surfactant may include ultrasonicating a mixture of oil, water, and the surfactant to form at least one of the following: a sub-macroemulsion, a macroemulsion phase or a combination of the aforementioned; separating the sub-macroemulsion from the macroemulsion phase; introducing the sub-macroemulsion into a foam container; performing a first automated phase identification of the sub-macroemulsion; introducing a gas into the sub-macroemulsion to generate a column of foam, where the column of foam has a height in the foam container; performing a second automated phase identification of the sub-macroemulsion; and measuring the height of the column of foam in the foam container. In these methods, the first and second automated phase identifications may be configured to quantify one or more liquid phases and a foam phase in the column.

Methods of evaluating a surfactant may include ultrasonicating a mixture of oil, water, and the surfactant to form at least one of the following: a sub-macroemulsion, a macroemulsion phase or a combination of the aforementioned; separating the sub-macroemulsion from the macroemulsion phase; introducing the sub-macroemulsion into a foam container; performing a first automated phase identification of the sub-macroemulsion; introducing a gas into the sub-macroemulsion to generate a column of foam, where the column of foam has a height in the foam container; performing a second automated phase identification of the sub-macroemulsion; and measuring the height of the column of foam in the foam container. In these methods, the first and second automated phase identifications may be configured to quantify one or more liquid phases and a foam phase in the column.

The invention concerns synthesized amido-amine-based cationic gemini surfactants with flexible and rigid spacers and different hydrophobic. These gemini surfactants were prepared by modified procedure through amidation of long chain carboxylic acids using 3-(dimethylamino)-1-propylamine followed by treatment with halohydrocarbons and showed excellent thermal stability and surface properties useful for various oilfield applications such as enhanced oil recovery.

The invention concerns synthesized amido-amine-based cationic gemini surfactants with flexible and rigid spacers and different hydrophobic. These gemini surfactants were prepared by modified procedure through amidation of long chain carboxylic acids using 3-(dimethylamino)-1-propylamine followed by treatment with halohydrocarbons and showed excellent thermal stability and surface properties useful for various oilfield applications such as enhanced oil recovery.

The present disclosure is directed to surfactants (in particular olefin sulfonates), surfactant packages, compositions derived thereof, and uses thereof in hydrocarbon recovery. Methods of making olefin sulfonate surfactants are also described.

The present disclosure is directed to surfactants (in particular olefin sulfonates), surfactant packages, compositions derived thereof, and uses thereof in hydrocarbon recovery. Methods of making olefin sulfonate surfactants are also described.