| 摘要 |
Improved sweep efficiency is obtained in an oil recovery process wherein oil is recovered from a subterranean, viscous oil containing formation having relatively highly permeable zones and relatively low permeability zones penetrated by at least one injection well and at least one spaced apart production well in fluid communication with a substantial portion of the formation. First, a predetermined amount of gel solution is injected into the formation at high pressure to deeply penetrate and plug the fracture face and highly permeable zones of the formation. Thereafter, a breaker material such as hydrochloric acid is injected into the formation at a low pressure to break the gel and displace it from the fracture face and highly permeable zones in the vicinity of the injection well thereby reestablishing injectivity into the formation in the vicinity of the injection well. Thereafter, a flooding agent such as carbon dioxide, steam or water is injected into the formation that displaces oil through the low permeability unswept zones of the formation and fluids including oil are recovered from the formation through the production well.
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