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.

A method of determining foam stability includes placing a core plug and two porous plates into a core holder of a vesselcore plug. The first porous plate and the second porous plate are disposed on opposite sides of the core plug, and the core plug, the first porous plate, and the second porous plate are saturated with surfactant. The method further includes alternating surfactant solution injections between a first injection area located on the first porous plate and a second injection area located on the second porous plate, while ensuring that the surfactant solution is being continuously fed, thereby forming continuously flowing foam in-situ within the core plug, in which the surfactant solution comprises gas and the surfactant; and monitoring the pressure drop to determine the stability of the foam in the core plug.

Provided is a device which is capable of ongoing measurement of variable foaming tendencies in a fluid system and provide a signal to regulate the feed rate of defoamer accordingly to maintain foaming at an acceptable target level. The regulation of feed can be accomplished automatically or manually.

A method of determining foam stability includes placing a core plug and two porous plates into a core holder of a vesselcore plug. The first porous plate and the second porous plate are disposed on opposite sides of the core plug, and the core plug, the first porous plate, and the second porous plate are saturated with surfactant. The method further includes alternating surfactant solution injections between a first injection area located on the first porous plate and a second injection area located on the second porous plate, while ensuring that the surfactant solution is being continuously fed, thereby forming continuously flowing foam in-situ within the core plug, in which the surfactant solution comprises gas and the surfactant; and monitoring the pressure drop to determine the stability of the foam in the core plug.

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.

Provided is a device which is capable of ongoing measurement of variable foaming tendencies in a fluid system and provide a signal to regulate the feed rate of defoamer accordingly to maintain foaming at an acceptable target level. The regulation of feed can be accomplished automatically or manually.

A method for evaluating the foamability of a test solution. The method includes forming foam in a vertical measurement column including an open top end and a fritted plate proximal to a bottom end by passing a gas stream through the fitted plate and through the test solution present in the vertical measurement column at a gas volume rate (GVR) and a gas flow rate (GFR). The foam travels upwards in the vertical measurement column while the gas stream is passing through the test solution. The method further includes measuring the viscosity of the foam with a vibration viscometer disposed proximal to the top end of the vertical measurement column, and further recording a plurality of vibration viscometer measurement results and storing the results (a surfactant amount C.sub.surf, the GVR, and the GFR) in memory to determine one or more foam properties of the test solution.

Screening multiple surfactants is performed by a screening method including passing foam compositions comprising a surfactant through a porous media while measuring pressure drop across the porous media until a first steady state pressure drop is achieved. Magnitude and frequency in oscillations of the first steady state pressure are measured. A gas is injected through the porous media while measuring the pressure drop across the porous media until a second steady state pressure drop is achieved. Magnitude and frequency in oscillations of the second steady state pressure drop are measured. Foam stability is determined based on the first steady state pressure drop, second steady state pressure drop, and magnitude and frequency of oscillations during the first and second steady states. Secondary oil recovery may include injecting a foam composition into an oil-containing reservoir, wherein the foam composition is based on results of the screening and properties of the oil-containing reservoir.

A method for evaluating the foamability of a test solution. The method includes forming foam in a vertical measurement column including an open top end and a fritted plate proximal to a bottom end by passing a gas stream through the fitted plate and through the test solution present in the vertical measurement column at a gas volume rate (GVR) and a gas flow rate (GFR). The foam travels upwards in the vertical measurement column while the gas stream is passing through the test solution. The method further includes measuring the viscosity of the foam with a vibration viscometer disposed proximal to the top end of the vertical measurement column, and further recording a plurality of vibration viscometer measurement results and storing the results (a surfactant amount C.sub.surf, the GVR, and the GFR) in memory to determine one or more foam properties of the test solution.

A method for evaluating the foamability of a test solution. The method includes forming foam in a vertical measurement column including an open top end and a fritted plate proximal to a bottom end by passing a gas stream through the fritted plate and through the test solution present in the vertical measurement column at a gas volume rate (GVR) and a gas flow rate (GFR). The foam travels upwards in the vertical measurement column while the gas stream is passing through the test solution. The method further includes measuring the viscosity of the foam with a vibration viscometer disposed proximal to the top end of the vertical measurement column, and further recording a plurality of vibration viscometer measurement results and storing the results (a surfactant amount C.sub.surf, the GVR, and the GFR) in memory to determine one or more foam properties of the test solution.