Bit balling up often occurs and results in serious sticking of drill stem during drilling operation, in which adhersion caused by montmorillonite is considered to be the main reason.

• 在钻井过程中经常发生钻头泥包,造成严重的卡钻事故,经现场和实验室观察认为蒙脱土在钻井泥包中起粘附作用。