Liner hanger

In most air and gas drilling operations, open-hole well completions are common. This type of completion is consistent with low pore pressure and the desire to avoid formation damage. It is often used for gas wells where nitrogen foam fracturing stimulation is necessary to provide production. In oil wells drilled with natural gas as the drilling fluid, the well is often an open hole completed with a screen set on a liner hanger to control sand influx to the well. 

An example of the typical safety problem that can occur when completing these wells is when a 6 in. open hole has been drilled below the last casing (or liner) shoe. The open section of the borehole is usually to be cased with a 4 in. liner. The liner is to be lowered into the open hole on a liner hanger that is made up to 3- in. drill pipe. It is assumed that prior to the liner operation, drilling had been under way thus the stripper rubber in the rotating... 

Liner hanger. This special tool is installed on the top of the liner string. The top of the liner hanger makes up to the drillpipe on which the entire liner assembly is lowered into the well. Liner hangers can be either mechanically or hydraulically actuated. 

The determination of the excess cement slurry should be carefully calculated too little and the cement seal at the liner hanger is contaminated with drilling mud too much and there are problems removing it. 

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