Fluid Diversion and Sweep Improvement With Chemical Gels in Oil Recovery Processes – 1992

Final year of the three-year fluid diversion study. Four gel types are characterized: resorcinol-formaldehyde, colloidal silica, Cr3+(chloride)-xanthan, and Cr3+(acetate)-polyacrylamide. Chromium propagation is significantly faster with acetate counterions than with chloride — unbuffered Cr-Cl gelants likely cannot propagate through carbonate reservoirs. Strong gels reduce permeability to near-microdarcy values across all rock types. DPR is confirmed for monomer-based and polymer-based gels, but NOT for colloidal-silica gels. Tracer studies suggest strong gels encapsulate residual oil, rendering it inaccessible during subsequent oil flooding. WAG cycling causes gel breakdown, but DPR persists for most gel types. Guidelines are established for gel candidate selection in injection and production wells.