What is the differance between Differential sticking and Mechanical stucking?

[B][COLOR=red]what is the differance between Differential sticking and Mechanical [/COLOR][COLOR=red]?stucking[/COLOR][/B]

Differential sticking one of the most common problem occure during drilling as aresult of differential pressure between hydrostatic pressure of mud and formation pressure of mud ie when the hydrostatic pressure is greater than the formation pressure which cause pushing adrill string into afilter cake of permeable formation


when the Differential sticking occure moving the pipe string

in the upward and downward direction is impossible


free circulation is easily established

What should i do for this situation ?

Reducing of hydrostatic pressure by circulation and reducing mud weight

Reducing the contact area by reducing the thickness of filter cake by using the solids in mud to the minimum and use mud of low water loss

Most pipe sticking problems are associated with drill collars and the ideal solution is to use drill collars with minimum surface area by using [COLOR=blue]aspirally grooved drill collar[/COLOR] and [COLOR=blue]heavy weight drill pipe[/COLOR]

The contact area can also be reduced by using [COLOR=blue]stabiliser[/COLOR] which centralise the drill collars within the hole

Displacing the choke

Maintain drill string rotation at all times if possible

Dont use high mud weight

to free mechanical stucking we should be

rotating and reciprocating the drill string and increase flow rate


increasing the mud weight if mechanical stucking caused as arusult of plastic shale


Mechanical stuck pipe

When drill cutting or sloughing formation pack off the annular

space around the drill string as aresult of improper cleaning


The settling of alarge amount of suspended cutting to the bottom when the pump is shut down

When drill string is run too fast it hits abridge or tight spot

[CENTER]Tight spots can result from drilling undersized holes due to the use

of worn drill bits

Drilling at excessive Rates Of Penetration (ROP) for a given circulation rate. This generates cuttings faster than they can be circulated mechanically from the annulus

The usual method used to free mechanical stuck pipe is to work the drill string either by rotation and pulling it or by activating adrilling jar

[B]Differential sticking there is acirculation but there is no a rotation [/B]
[B] Mechanical sticking there is no acirculation and arotation[/B]

source of this article from

egy petroleum engineer