Recovering enhanced oil recovery surfactants by temperature cycling
AssigneeTexaco Inc.
InventorGabriel Prukop
Life of this patent
Estimating the term…
Abstract
A method for recovering surfactants from produced fluids by mixing with produced fluids about 0.1% to about 5% of a nonionic surfactant having a phase inversion temperature above the temperature of the produced fluids, heating the mixture above the phase inversion temperature, mixing the phase containing oil and the surfactants with water, and cooling the mixture below the phase inversion temperature to extract the surfactants into an aqueous phase, provided that if a sufficient concentration of the nonionic surfactant is already in the produced fluids, it need not be added.
Claims13
A method for recovering enhanced oil recovery surfactants from produced fluids, which comprises:
- mixing about 0.1% to about 5% by weight of an extracting surfactant with fluids produced from an enhanced oil recovery surfactant flood, said extracting surfactant having a phase inversion temperature above the temperature of the produced fluids and selected from the group consisting of nonionic surfactants and ionic surfactants having a nonionic hydrophile;
- heating the mixture of produced fluids and said extracting surfactant above the phase inversion temperature of said extracting surfactant to extract enhanced oil recovery surfactants into a phase containing oil;
- separating the phase containing oil, the enhanced oil recovery surfactants and said extracting surfactant from other produced fluids;
- mixing water with the phase containing oil and the surfactants;
- cooling the mixture of water and the phase containing oil and surfactants below the phase inversion temperature of said extracting surfactant to extract the enhanced oil recovery surfactants and said extracting surfactant into an aqueous phase;
- and
- separating the aqueous phase containing the enhanced oil recovery surfactants and said extracting surfactant from other fluid phases.
A method for recovering enhanced oil recovery surfactants from produced fluids, which comprises:
- separating relatively most of produced oil from fluids produced from an enhanced oil recovery surfactant flood to leave remaining produced fluids;
- mixing about 0.3% to about 1% by weight of an ethoxylated alkylphenol surfactant with the remaining produced fluids, said alkylphenol surfactant having about 4 to about 12 ethylene oxide groups, about 5 to about 12 carbon atoms in its alkyl chain, and a phase inversion temperature above the temperature of the produced fluids;
- heating the mixture of produced fluids and said alkylphenol surfactant above the phase inversion temperature of said alkylphenol surfactant to extract enhanced oil recovery surfactants into a phase containing oil;
- separating the phase containing oil, the enhanced oil recovery surfactants and said alkylphenol surfactant from other produced fluids;
- mixing water having a salinity below about 1000 ppm TDS with the phase containing oil and the surfactants;
- cooling the mixture of water and the phase containing oil and surfactants below the phase inversion temperature of said alkylphenol surfactant to extract the enhanced oil recovery surfactants and said alkylphenol surfactant into an aqueous phase;
- and
- separating the aqueous phase containing the enhanced oil recovery surfactants and said alkylphenol surfactant from other fluid phases.
A method for recovering enhanced oil recovery surfactants from produced fluids wherein the enhanced oil recovery surfactants include a nonionic surfactant or ionic surfactant having a nonionic hydrophile, said surfactant having a phase inversion temperature above the temperature of the produced fluids, which comprises:
- heating produced fluids comprising water, oil and enhanced oil recovery surfactants including about 0.1% to about 5% by weight of said surfactant having a phase inversion temperature above the temperature of the produced fluids, said heating continued until the temperature of the produced fluids is above the phase inversion temperature of said surfactant to extract enhanced oil recovery surfactants into a phase containing oil;
- separating the phase containing oil and the enhanced oil recovery surfactants from other produced fluids;
- mixing water with the phase containing oil and the surfactants;
- cooling the mixture of water and the phase containing oil and the surfactants below the phase inversion temperature of said surfactant to extract the enhanced oil recovery surfactants into an aqueous phase;
- and
- separating the aqueous phase containing the enhanced oil recovery surfactants from other fluid phases.
Dependencies are inferred from the claim text.