Shale samples of Silurian Longmaxi Formation in the Changning area of the Sichuan Basin, SW China, were selected to carry out scanning electron microscopy, CT imaging, high-pressure mercury injection, low-temperature nitrogen adsorption and imbibition experiments to compare the hydration characteristics of montmorillonite and illite, analyze the main factors affecting the water block removal of shale, and reveal the mechanisms of pore structure evolution during shale hydration. The hydration characteristics of shale are closely related to the composition of clay minerals, the shale with high illite content is not susceptible to hydration and thus has limited room for pore structure improvement; the shale with high montmorillonite is susceptible to hydration expansion and thus has higher potential of pore structure improvement by stimulation; the shale with high illite content has stronger imbibition in the initial stage, but insufficient diffusion ability, and thus is likely to have water block; the shale with high montmorillonite content has weaker imbibition in the initial stage but better water diffusion, so water blocking in this kind of shale can be removed to some degree; the shale reservoir has an optimal hydration time, when it is best in physical properties, but hydration time too long would cause damage to the reservoir, and the shale with high illite content has a shorter optimal hydration time; inorganic cations can inhibit the hydration of clay minerals and have stronger inhibition to illite expansion, especially K⁺; for the reservoir with high content of montmorillonite, the cation content of fracturing fluid can be lowered to promote the shale hydration; fracturing fluid with high K⁺ content can be injected into reservoirs with high illite content to suppress hydration.

选取四川盆地长宁地区志留系龙马溪组页岩样品，进行扫描电镜、CT成像、高压压汞、低温氮气吸附和渗吸实验，比较其水化特征。蒙脱石和伊利石，分析影响页岩水堵去除的主要因素，揭示页岩水化过程中孔隙结构演化的机制。页岩水化特征与黏土矿物组成密切相关，伊利石含量高的页岩不易发生水化作用，孔隙结构改善空间有限；高蒙脱石页岩易发生水化膨胀，具有较大的增产改善孔隙结构潜力；伊利石含量高的页岩初期吸水能力强，但扩散能力不足，容易出现水堵；蒙脱石含量高的页岩初期吸水能力较弱，但水的扩散性较好，可在一定程度上解除此类页岩的水堵；页岩储层具有最佳水化时间，在物性最佳时，但水化时间过长会对储层造成破坏，伊利石含量高的页岩最佳水化时间较短；无机阳离子能抑制粘土矿物的水化作用，对伊利石膨胀有较强的抑制作用，尤其是K 蒙脱石含量高的页岩初期吸水能力较弱，但水的扩散性较好，可在一定程度上解除此类页岩的水堵；页岩储层具有最佳水化时间，在物性最佳时，但水化时间过长会对储层造成破坏，伊利石含量高的页岩最佳水化时间较短；无机阳离子能抑制粘土矿物的水化作用，对伊利石膨胀有较强的抑制作用，尤其是K 蒙脱石含量高的页岩初期吸水能力较弱，但水的扩散性较好，可在一定程度上解除此类页岩的水堵；页岩储层具有最佳水化时间，在物性最佳时，但水化时间过长会对储层造成破坏，伊利石含量高的页岩最佳水化时间较短；无机阳离子能抑制粘土矿物的水化作用，对伊利石膨胀有较强的抑制作用，尤其是K 但水化时间过长会对储层造成破坏，伊利石含量高的页岩最佳水化时间较短；无机阳离子能抑制粘土矿物的水化作用，对伊利石膨胀有较强的抑制作用，尤其是K 但水化时间过长会对储层造成破坏，伊利石含量高的页岩最佳水化时间较短；无机阳离子能抑制粘土矿物的水化作用，对伊利石膨胀有较强的抑制作用，尤其是K⁺ ; 对于蒙脱石含量高的储层，可降低压裂液的阳离子含量，促进页岩水化；高K ⁺含量的压裂液可注入伊利石含量高的储层，抑制水化。