초록 ▼

There is disclosed a method of recovering oil from a subterranean oil formation having the vertical thickness of 40 ft or more. The method exploits the effect of gravity on the various slugs of diverse materials injected into the oil column of the formation. The method comprises injecting a surfacta

There is disclosed a method of recovering oil from a subterranean oil formation having the vertical thickness of 40 ft or more. The method exploits the effect of gravity on the various slugs of diverse materials injected into the oil column of the formation. The method comprises injecting a surfactant slug into the lower 50-75% of the vertical thickness of the oil column, then injecting a slug of a mobility control polymer into the upper 50-75% portion of the thickness of the oil column, followed by the injection of a slug of a drive fluid over substantially the entire vertical thickness of the oil formation. Optionally, a low-salinity pre-flush slug may be injected to reduce contact of high salinity water with the surfactant slug, and an alkaline pre-treat solution may be injected to precipitate divalent cations prior to the injection of the surfactant slug.

대표청구항 ▼

A method of recovering oil from an offshore subterranean oil formation having the vertical thickness of at least about 40 feet, comprising an oil column which is a portion of the formation containing the oil, the formation containing at least one injection well and at least one production well space

A method of recovering oil from an offshore subterranean oil formation having the vertical thickness of at least about 40 feet, comprising an oil column which is a portion of the formation containing the oil, the formation containing at least one injection well and at least one production well spaced-apart from said injection well, comprising the consecutive steps of: (1) injecting a surfactant slug formulated with sea water into the lower 50 to 75% vertical thickness of the oil column; (2) injecting a slug of a mobility control polymer formulated with sea water into the upper 50 to 75% portion of the vertical thickness of the oil column; (3) injecting a slug of a drive fluid formulated with sea water over substantially the entire vertical thickness of the oil column; and, (4) recovering oil from the production well.