ACIDIZATION WELL STIMULATION—SALTWATER DISPOSAL (SWD), PRODUCING & WATER FLOOD WELLS
Acidization well stimulation has been a common practice for years. Iron sulfide and biomass are coating the wellbore, blocking perforations and plugging formation. During conventional acidizing HCL is pumped downhole. The HCL only touches the surface of the scale. It may not penetrate the perfs or formation unless it can break through the scale. FeS is converted to Fe2+, 2Cl- and H2S. The Iron Chloride only remains soluble as long as pH remains low. Biomass is virtually untouched. A water flush removes scale but Fe2+, 2Cl- and H2S remain present in solution. When the well goes back online the pH shifts back to normal and the FeS precipitates and scale formation begins again. Scheduling of another acidizing job is just around the corner.
PureLine’s enhanced acidization well stimulation incorporates chlorine dioxide (ClO2), solvent, and nano surfactant in addition to the traditional HCL. Chlorine dioxide oxidizes the H2S in solution to form HCL and soluble SO4-2 ions. Fe2+ and Cl- are present in solution. Chlorine dioxide then penetrates the biomatrix. The iron sulfide is oxidized to soluble Fe+3, Cl- and SO4-2. Because the iron sulfide is oxidized all the way to iron sulfate (FeSO4), it remains soluble when pH normalizes and will not precipitate. Thus, breaking the traditional acidizing cycle. H2S has been completely oxidized by the chlorine dioxide. When the well is put back online the sulfur compounds have been converted from insoluble sulfides to soluble sulfates and the biofilm is gone.
