Impact of Diversion on Acid Fracturing of Laminated Carbonate Formations: A Modeling Perspective

Acid-fracturing treatment schedules usually contain diversion stages either to reduce fluid loss or equally stimulate pay zones. Near-wellbore diversion employs solid or mechanical diverters to direct acid to less-stimulated zones. This study focuses on the impact of near-wellbore diversion on the acid fracturing of calcite/dolomite laminated formations. The study was performed using an integrated acid fracture and productivity model. Simulations showed that when acid preferentially etches more reactive lamina, channels with infinite conductivity can be achieved. Nevertheless, deploying diverters to equally stimulate pay zones can result in less conductive but equally stimulated zones. The productivity model showed that the preferential etching that naturally occurs when injecting acid results in better well performance, if a continuous pay zone is assumed. This study also shows that the optimum acid fracture design conditions in laminated formations are similar to those of calcite-dominated formations.