A New Material and Novel Technique for Matrix Stimulation in High-Water-Cut Oil Wells

Abstract

Abstract A new process has been developed that effectively diverts acid away from zones with high water saturation into hydrocarbon zones. This process is designed to increase the success in matrix acidizing treatments. Because of the relative permeability effect, aqueous acid predominantly enters the zone with highest water saturation, resulting in stimulation of the water zones and an increase of water cut. Although foam can be used to divert acid from the "aquifer" to the damaged oil zones, nitrogen is not readily available in some areas and additional handling equipment is required. A new non- particulate, non-gaseous material has been developed to effectively divert acid away from highly water saturated zones. The material forms a highly viscous plug when it contacts water in the matrix yet degrades when mixed with oil in the matrix of the formation. This paper discusses in detail the diversion technique and laboratory results. Laboratory tests conducted in a dual-core flow apparatus showed excellent diversion from a water-rich zone to an oil-rich zone, as well as from a high-permeability formation to a low-permeability formation. P. 675