The leakoff in acid fracturing kinetics control mechanism

Abstract

To study the compacted carbonate leakoff mechanism during acid fracturing process, we introduced a new characterization method. Realized acid reaction violently with carbonate reservoirs, concentration within the natural crack, larger pores or natural fractures are excessive corrosion firstly and grow rapidly, to a certain extent, form a wormhole, acid leakoff area increases sharply, cause wormhole control mechanism; But in the process of compacted carbonate acid fracture, the wormhole will not generate in scale, main controlling factors of the leakoff by acid rock reaction kinetics parameter. Acid rock reaction kinetics parameters determined by experiments, and the acid leakoff experiments under different rock attracts many kinetic parameters obtained difference, put forward in the dense carbonate acid, acid rock reaction kinetics parameter controlling the leakoff. While fracturing in tight carbonate rocks, acid rock reaction rate can form larger acid intrusion area, so the wormhole connection rate will be higher. However, excessive CO2 will preventing uniform dissolution. Therefore, these two parameters should not be less than a certain value. When the Qibt is higher than 1, the purpose of enhance permeability will be reach.