Perforationeffect is seriously affected by the clearance between perforator and casing.
射孔枪与套管之间的间隙过大会影响射孔效果，太小容易出现工程事故。
2
Formulae were derived to predict additional pressure drops due to mechanical skin and non-Darcy effect in the perforation radial flow and wellbore radial flow.
在射孔径向流和井筒径向流中，推导出了机械表皮因子和非达西流影响引起的附加压力降的表达式。
3
As a main completion pattern in current oil and gas Wells, the perforation has a large effect on their productivity.