Acid Encapsulated Wax Particles Potentially Useful to Speed up Drilling in Carbonate Formations

Abstract

Encapsulated acids can increase the rate of penetration (ROP) during drilling operations by reacting with carbonate formations while avoiding corrosion of the metallic equipment parts. Drilling fluids can carry particles containing acid to the drilling tip where they will be mashed, and the acid released. The paraffin encapsulation is used in the processing of food ingredients, flavors, chemicals, drugs, protection of cosmetics, and in the oil industry. The novel solution presented in this paper is to use paraffin in the strong acid encapsulation to be added to the drilling fluid. Acid containing wax particles is prepared by the double emulsion technique. The results indicate that encapsulation efficiency is dependent on the wax to acid solution ratio and on acid concentration. Acid leakage is a significant concern; it is found to be directly dependent on acid concentration in the particle and on the particle wax fraction.