Paper: A New Solids-free Acid Diverting Agent - Case History

"Conventional acidizing has ignored relative permeability effects by attempting to inject aqueous fluids into zones filled with crude." Since most oil wells in the Permian Basin today are on water flood or produce large quantities of water, relative permeability is an issue. Therefore in zones where the water saturation is high due to depletion of the higher permeability zones and/or natural fractures, acid tends to enter these zones instead of the oil zones where the acid is needed and wanted. This in turn leads to higher water cuts instead of increased oil cuts. A new non-particulate, non-gaseous material has been developed to effectively divert acid away from highly water saturated zones. This new material's diversion capabilities are dictated by the relative permeability of the formation as with foam, but it offers a simplicity and accuracy to the treatment that foam and other diverting agent can not. This paper discusses a case history that utilized this material for acid diversion in a water flood.