Abstract: Saline-tolerant surfactant is utilized in tertiary recovery of oil. The surfactant is concentrated in a portion of the produced oil and water and is recovered by the use of a cosolvent and fresh water. Both the cosolvent and surfactant are reclaimed for reuse, while the oil is released for sale.

Abstract: A vessel in the form of a vertically-extended cylindrical tank receives oil well production containing a difficult-to-treat component. An elongated path for the production is formed within the tank with which to stratify production fluids. The upper stratum is oil containing some percentage of emulsion, the lower stratum is water containing some percentage of emulsion, and the intermediate stratum is a concentration of the remaining difficult-to-treat emulsion. A subsystem is provided for the liquids of each stratum. The subsystem processing the intermediate stratum extracts surfactant which has been used in facilitating production from the earth, and isopropanol utilized to break the bond of oil with the surfactant and water of the emulsion.

Abstract: A steel-reinforced concrete gravity structure mounts a support framework with which to elevate a production deck above sea level. The structures are separately fabricated on shore, assembled in bordering shallow water, transported as a unit to the subsea well site, and subsequently installed on the sea floor.