초록 ▼

A method and fluid for selectively reducing the permeability of an oil-bearing subterranean formation is disclosed, wherein a cross-linkable polymer, a cross-linking agent and a spacer fluid are alternately injected. The spacer, such as sodium citrate, permits repeated injection cycles of the polyme

A method and fluid for selectively reducing the permeability of an oil-bearing subterranean formation is disclosed, wherein a cross-linkable polymer, a cross-linking agent and a spacer fluid are alternately injected. The spacer, such as sodium citrate, permits repeated injection cycles of the polymer and cross-linking agents without excessive polymer retention at or near the formation face. Such retention filters out polymers and inhibits polymer propagation throughout the formation. The present invention also permits controlled deep penetration of the cross-linked polymer into the formation to increase oil recovery.

대표청구항 ▼

A method of treating a subterranean formation, comprising the steps of sequentially injecting into the formation: (a) an aqueous solution of a cross-linkable polymer; (b) an aqueous solution of a cross-linking agent comprising multivalent cations suitable for cross-linking the polymer and sequesteri

A method of treating a subterranean formation, comprising the steps of sequentially injecting into the formation: (a) an aqueous solution of a cross-linkable polymer; (b) an aqueous solution of a cross-linking agent comprising multivalent cations suitable for cross-linking the polymer and sequestering anions; and (c) an aqueous solution of a salt comprising cations selected from the group consisting of alkali metal cations and sequestering anions.