| 摘要 |
A process and composition are provided for permeability reduction in a treatment region to improve hydrocarbon recovery from a hydrocarbon-bearing formation. The process includes placement of a crosslinked polymer gel in the treatment region preceded by surface preparation of a gelation solution which is the gel precursor. The gelation solution contains a crosslinkable polymer, a chromium(III)/carboxylate complex crosslinking agent, a carboxylate salt delaying agent and an aqueous solvent. The gel is placed in the treatment region by injecting the gelation solution into a well bore in fluid communication with the treatment region, displacing it into the desired treatment region and gelling the solution to completion forming the permeability-reducing gel in situ. The gelation rate is retarded in a controlled manner by adjusting the composition or concentration, and correspondingly the pH, of the delaying agent in the gelation solution.
|
