Mechanical sticking can be caused by junk in the hole, wellbore geometry anomalies, cement, keyseats or a buildup of cuttings in the annulus.

机械卡钻可能由井眼内的碎屑、井眼内几何形状异常、水泥、键槽或者岩屑在环空中的积聚等引起。

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Many pressure dominated testing valve is through pumping of relieving annulus pressure to realize open or shut down hole test valve and keep annulus pressure for certain all the time.

许多种压控测试阀均是通过环空加泵压打开，泄掉泵压关闭，开井过程中环空始终保持一定的开启压力。

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And the bottom hole pressure in different depths is predicted, which can be found that the casing annulus velocity declines with the depth increasing at different hole depth.

并对不同井段处的井底压力进行了预测，发现在不同的井身深度条件下，其环空流速随井身深度的增加而降低。

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Cementing fills and seals the annulus between the well casing and the drilled hole.

FORBES: The Fracking Solution Is A Good Cement Job