Perpustakaan Digital ITB

Acid fracturing is an important method to stimulate oil and gas wells in carbonate reservoirs. The main purpose of acid fracturing is to create a high-speed channel for oil and gas flow, and conductivity is an important factor that determines the effect of acid-fracturing construction pressure. Studying the variation trend of the fracture friction coefficient is important to explain the variation in the acid-fracturing construction pressure and the formation of conductivity of acid-etched fracture. According to the fracture-roughness theory and friction-coefficient calculation method, the roughness, aperture width, and friction coefficients of carbonate rocks before and after acid etching were calculated using the surface morphology and conductivity results of gelled acid-etched carbonate fractures. The average friction coefficients of the fractures were found to be 3088529 and 49857.4 before and after the acid etching after acid etching, respectively, i.e., approximately 1.61% of that before acid etching. With the increase in the reaction rate, reaction time, and acid flow rate, the fracture friction coefficient significantly reduced after the acid etching. Similar to the variation law in the friction coefficient of a pipe flow, the smaller the fracture roughness and the larger the hydraulic aperture are, the smaller is the friction coefficient of the fracture. The smaller the friction coefficient is, the higher is the conductivity and the better is their correlation.