m1,1-p17 drilling problems2[2]

8/3/2019 M1,1-P17 Drilling Problems2[2]

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TCP M1.1 P17 Vers 1 Rev 1 090313 page 1 ©2009

Stuck pipe and fishing




Stuck pipe

Stuck pipe is a very good example of “prevention is better

than cure".

The recovery from a stuck pipe situation can be very timeconsuming, hence expensive, and in the limit may lead to theloss of the well with the resultant necessity to redrill it.

It may alternatively result in what in the long term may beeven worse - a poor quality well.

The routine application of normal good practice while drillingthe well also goes a long way towards avoiding problems.

Stuck pipe will usually lead to fishing operations, but it is onlyone type of fish. Fishing may carried out to recover any typeof undesirable material from the borehole, stuck or free.




Fishing

A "fish" in oilfield terminology is a piece of equipment, orother material, which is in the well and which satisfies two

conditions: it was not placed deliberately in its current situation

it does not extend all the way to surface

Fishing is the name given to the process of getting hold of,and removing, such material.




Fishing Operations

Cardinal Rules Pipe Sticking

Determining the Stuck Point Mechanical sticking Keyseat Cement sticking Pipe sticking Differential sticking Blow out sticking Lost circulating sticking

Parting the Pipe String Catch Tools Jarring Wash-over Loose-Junk Mills and Rotary Shoes Wireline Fishing Stuck Packers Fishing in Cavities


http://slidepdf.com/reader/full/m11-p17-drilling-problems22 5/23TCP M1.1 P17 Vers 1 Rev 1 090313 page 5 ©2009

Cardinal Rules

Evaluate the situation Communicate

Collect complete information Notify the fishing tool company

All parties understand the situation

Keep all parties informed

Gather information OD, ID, length of fishing string

Know limitations of fishing string

Accurate weight indicator

Locate the top of the fish

Determine freepoint

Leave one to two joints above freepoint

Keep track of pipe tallies Do not rotate fishing string

Do not pull out of the rope socket



Pipe sticking

Mud Sticking: dehydration of mud, barite and solids cansettle out

Sand sticking: hole in the casing

Barite and solids settle out in the annulus causing pipe to become stuck



Mechanical Sticking

Stuck packers:

Casing Collapse Crooked pipe

Junk in the hole



Keyseat

Keyseats are often associated with deviationand variation of formation hardness

A small-diameter channel worn into the sideof a larger diameter wellbore.

When larger diameter drilling tools such astool joints, drill collars, stabilizers, and bitsare pulled into the channel, their largerdiameters will not pass and the larger

diameter tools may become stuck in thekeyseat.

Preventive measures include keeping anyturns in the wellbore gradual and smooth.The remedy to keyseating involves enlargingthe worn channel so that the larger diameter

tools will fit through it.



Cement sticking

The cement makes the pipe to be stuck



Pipe sticking

Under gauge hole



Differential sticking

These cross-sectional views show a drillcollar embedded in mudcake and pinned to

the borehole wall by the pressure differentialbetween the drilling mud and the formation.As time passes, if the drillstring remainsstationary, the area of contact can increase(right) making it more difficult to free thedrillstring.



Blow out sticking

Sand, shake or other formation

debris and pipe stabilisers, could

be blown up the hole. This debris

can bridge over and stick the

string of pipe.




Lost circulating sticking

Occurs when highly permeable or unconsolidated

formations are fractured by the hydrostaticpressure of the drilling fluid.

In this situation drilling fluid van flow freely into theformation.




Parting the pipe string

Back off

Chemical Cut

Jet Cut

Mechanical Cut




Back off

The term back-off defines the operation ofseparating the free pipe from the stuck

pipe at a pipe joint. Blind back off

Back off tool Inside

Outside

Sometimes it is impossible to effect aback-off and another method of separatingthe free portion of the string must be used.Pipe cutting is then the solution. Pipe canbe cut mechanically, chemically or by jet.




Chemical cut

The term chemical cut refers to radically severed pipe thathas been cut with a special chemical forced under high

pressure through a severing head orifice. The primary advantages of this tool over explosive methods

are its ability to sever tubing without: Damaging the well casing or adjacent tubing

Enlarging or leaving a burr on the OD of the cut pipe.




Jet cut

The jet pipe cutter uses the shaped charge principle.




Mechanical cut




Catch Tools

Overshot

Basket Grapple

Spiral Grapple

SpearOvershot w/ Basket Grapple

Spiral GrappleBasket Grapple




Jarring assembly




Wash over




Junk Baskets

Mill d R Sh




Mills and Rotary Shoes

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