Initial fracture morphology and variation of acid-rock reaction temperature caused by alternate stages were ignored in the traditional alternate multistage acid-fracturing experiments, so a new design method of experiment simulation was proposed with these considerations in this paper. Alternate multistage acid-fracturing experiments were carried out based on this new method through using self-generating acid and gelled acid, while the influence of alternate stages on acid-etching fracture morphology and conductivity were also investigated. The study shows that acid smoothing the peaks are stronger than deepening the valleys on rough fracture during alternate acid-fracturing and the tortuosity of fracture surface also increased after acidizing. Injection time of self-generating acid at high temperature caused by alternate stages is the main influences on the acid-etching pattern, while that of gelled acid has little effect. Excessive dissolved-rock of one alternate stage is beneficial to creating high initial conductivity, but the retention rate of conductivity is the lowest under medium and high closure stress. Although rough initial fracture has a little contribution to generation high conductivity, two alternate stages with moderate acid-etching creates high conductivity and improves the retention rate of conductivity under medium and high closure stress. It is useful to select reasonable alternate stages for self-generating acid and gelled acid in multistage acid-fracturing treatment.

在传统的交替多阶段酸压裂实验中，忽略了初始阶段的断裂形态和交替引起的酸岩反应温度变化，为此，提出了一种新的实验模拟设计方法。在此新方法的基础上，利用自生酸和胶凝酸进行了交替的多阶段酸压裂实验，同时研究了交替阶段对酸蚀断口形貌和电导率的影响。研究表明，在交替酸压裂过程中，酸蚀峰比粗糙裂缝的酸化峰强于深谷，酸化后裂缝表面的曲折度也增加。交替阶段引起的高温下自生酸的注入时间是影响酸蚀模式的主要因素，而胶凝酸的注入时间影响很小。一个交替阶段过多的溶解岩石有利于产生高的初始电导率，但在中等和高闭合应力下，电导率的保持率最低。尽管粗糙的初始断裂对产生高电导率的贡献很小，但是在中等和高闭合应力下，具有适度酸蚀的两个交替阶段可产生高电导率并提高电导率的保持率。在多级酸压裂处理中，选择合理的自生酸和胶凝酸交替步骤是有用的。一个交替阶段过多的溶解岩石有利于产生高的初始电导率，但在中等和高闭合应力下，电导率的保持率最低。尽管粗糙的初始断裂对产生高电导率的贡献很小，但是在中等和高闭合应力下，具有适度酸蚀的两个交替阶段可产生高电导率并提高电导率的保持率。在多级酸压裂处理中，选择合理的自生酸和胶凝酸交替步骤是有用的。一个交替阶段过多的溶解岩石有利于产生高的初始电导率，但在中等和高闭合应力下，电导率的保持率最低。尽管粗糙的初始断裂对产生高电导率的贡献很小，但是在中等和高闭合应力下，具有适度酸蚀的两个交替阶段可产生高电导率并提高电导率的保持率。在多级酸压裂处理中为自生酸和胶凝酸选择合理的替代步骤是有用的。具有适度酸蚀的两个交替阶段可产生高电导率，并在中等和高闭合应力下提高电导率的保持率。在多级酸压裂处理中，选择合理的自生酸和胶凝酸交替步骤是有用的。具有适度酸蚀的两个交替阶段可产生高电导率，并在中等和高闭合应力下提高电导率的保持率。在多级酸压裂处理中，选择合理的自生酸和胶凝酸交替步骤是有用的。