Novel Class of Retarded, Newtonian, Single-Phase HCl-Based Stimulation Fluids: A Laboratory Characterization

Novel retarded acids were designed and evaluated by measuring their dissolution and corrosion rates in the laboratory at a temperature of 250°F. Results indicate that depending on the type of the retarder, the acid solutions containing 15 wt% HCl react 1.2–10.7 slower than 15 wt% straight HCl. In addition, novel retarded acids pass the industry standard for corrosion rate of L80, P110, T95, and 13Cr steel grades even with no corrosion inhibitor added to the formulation. Field application of the novel acid systems will provide a series of benefits, including ease to mix and pump, operational safety, deep stimulation of target zone, etc. Presented results are integral for designing the stimulation operations in carbonate reservoirs and the removal of carbonate scales in the oil and gas or geothermal energy industries.