Acid System and Stimulation Efficiency of Multistage Acid Fracturing in Porous Carbonate Reservoirs

With little to no natural fracture development and the high calcite content in porous carbonate reservoirs, for multistage acid fracturing, different fluids are used form a viscous fingering fracture, thus enhancing degree of nonuniform etching. However, existing studies on fracturing mainly focused combination fluid acid, which is less specific rocks. Here, rheological properties five fluids, including guar-based fluid, cross-linked guar, gelled diverting were studied at each temperature condition, viscosity relationship between was clarified. Based properties, differences seven liquid combinations etched morphology walls analyzed. The conductivity acid-etched fractures under closure stress simulated. experimental results showed that relationships temperatures guar > (spent acid) (fresh acid). Because has higher than it can more obvious with variety liquids, suitable stimulation reservoirs. In addition, acids screened out. alternate injection this could tortuous complex etching channels, its acid-etching significantly other stress. study, we optimized carbonates clarified effect mechanism provide guidance selection process