白云岩储层酸压过程中酸液的滤失控制

白云岩储集层酸压改造中的酸液滤失是影响施工效果的关键，常规室内测试结果不能反映入地酸液流体的真实滤失行为。从酸液滤失模式分析入手，结合酸与白云岩石反应动力学特征，探讨了白云岩储层的点蚀密集型、溶蚀孔洞型、溶蚀穿透型酸液滤失行为，认为储集层天然裂缝、白云岩自身物性特征、H+传质系数和反应速度的影响是主要控制酸液滤失的内在因素，并以此为依据提出了现场酸压控制酸液滤失的对策：对于天然裂缝较发育的白云岩储集层，实际酸液滤失程度不及石灰岩，但总体上建议采用黏滞性前置液诱发裂缝（必要时可考虑追加少量粉陶），尽可能地采用低H+传质系数和低反应速率的高黏酸液体系，交替注酸和附加前置液段塞也能很好地控制地层中酸液的滤失。

Behavior of acid fluid filtration in dolomite acid-fracturing

The acidizing fluid filtration is one of the key factors for the acid fracturing effects in dolomite reservoirs. Conventional laboratory tests can not reflect the real filtration behaviors of pumping fluids. According to the analysis of acid-fracturing fluid filtration pattern combined with the reaction kinetics of acid/dolomite, three acidizing fluid filtration behaviors, i.e., intensive pitting, corrosion hole, and corrosion and break-through,were discussed. Furthermore, three main intrinsic factors were presented controlling fluid filtration, such as natural fracture, petrophysical property of dolomites and H~+ mass transfer coefficient and reaction rate, and based on this, corresponding countermeasures were also put forward. Actually, the acid fluid filtration in dolomite reservoirs with developed natural fractures is less than that in limestone reservoirs, however, it was suggested that viscosity pad (if necessary, some pulverized haydite can be added into use), high viscosity acid system with low H~+ mass transfer coefficient and low reaction rate be adopted as far as possible, and either the alternating acidizing fluids injection or additional pad slug is beneficial to control acid filtration in dolomite acid-fracturing.