packers

1.The probability of packer sticking is increased because of the casing deformation and crustation in casing failure well.

在套损井中,由于套管变形、结垢等因素,进一步加大了卡钻的可能性。

2.In order to prevent failure of packer and provide theoretical basis for selection of unsetting shear pin, the unsetting force of packer must he calculated in design.

了防止在工作程中失，解剪钉（或剪环）的选择提供理论依据，必须进行解力的设计计算。

3.The causes are presented as follows: packer unloading pressure, formation damage, oil tool plugging, formation voidage, the worst formation physical properties and the effect from vicinage wells.

地层污染或工具堵塞;地层欠压;地层物性极差;邻井影响等。