In some designs, they are flat at the mating surfaces to enable them to seal over an open wellbore.
某些设计中，表面是平坦的，以便使其能够对裸眼井眼进行密封。
Large bypass ports open automatically as drill pipe is run into the vertical or horizontal wellbore, diverting mud into the annulus above any restrictions.
当钻杆进入垂直或水平井段时，大孔径旁通自动打开，将泥浆无阻碍导入环空。
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