Simulation experiment and analysis of acid wormhole in dolomite

Acid wormhole can greatly improve the flow conditions of dolomite reservoir and increase the effect of acidizing stimulation, while the wormhole development is the key issue related to the optimization of acid system and construction parameters for this type of formation. This article compares the corrosion inhibition property of thickening acid with hydrochloric through experiment; aiming at the characteristics of natural fractures of dolomite reservoir, artificial fracture is made to simulate the flow and reaction feature in natural fracture, and the impact of acid injection flowrate, acid viscosity, temperature and acid amount on acid wormhole development is analyzed. The results show that the higher viscosity of thickening acid helps to increase the effective reaction distance and the expansion of acid wormhole; high reaction temperature limits the acidizing effect of improving formation permeability; there is an optimal value of acid volume, the excess amount of acid injection will only result in the waste of acid.