stuckp~1

Agip KCO Well Area OperationsDrilling Supervisor Training Course Drilling Technology 2nd part RPW2021A 1

STUCK PIPE


STUCK PIPE

Main causes of Pipe Stuck

KEY SEAT

DIFFERENTIAL PRESSURE

UNDERGAGE HOLE- during run in- during pull out

CAVE IN due to:- total loss of circulation- mobile formation- accumulation of debris in collapsed holes


STUCK PIPE KEY SEAT


STUCK PIPE DIFFERENTIAL PRESSURE STICKING


COMPOSITION OF HEAVY OIL CUSHIONS

Composition of 1 m3 of mix:

Density Water CaCl2 Diesel oil Emulsion Gel BariteKg/l litres Kg litres Kg Kg Kg

1.4 275 170 515 45 3 550

1.5 250 155 515 45 3 650

1.6 225 140 520 45 4 760

1.7 200 125 515 40 4 910

1.8 175 110 510 40 4 1050

1.9 155 95 505 40 5 1180

2.0 135 85 500 35 5 1330

2.1 115 75 490 35 5 1460

2.2 100 65 480 35 5 1600


DETERMINING THE FREE POINT

The method is based on the elongation of the drill string subject to a given tensile load.

method based on the elasticity of steel:

Elongation = (T x L)/(E x A) where:

T = tensile load (difference in Kg of load that produced the elongation)L = length of the free pipes (m)E = Youngs modulus 21,000 Kg/mm2A = section area body of pipes (mm2)

example:A tensile load of 20 t is applied and the DP point is marked on the TR. An additional 20 t load is applied and the lengthening is measured.L is calculated (repeated 2/3 times to confirm result)


DETERMINING FREE POINT FROM ELECTRIC LOGS

Electrode lowered into well through the pipes, measures deformation (axial and torsion), with results transmitted to surface by electric cable.

At the drill string is applied overpull and torsion:as long as both deformations are observable, the drill string is free; otherwise it is

considered stuck at that point.


STUCK PIPE OPERATIONS

Depending on the cause of stuck, it can be released as follows:

Mechanically, by applying force to the drill string andusing the JAR and BUMPER

By pumping cushions into the well:- made of oil- HCl- etc.


PIPE STUCK OPERATIONS UNSCREWING OF THE DRILL STRING

MECHANICAL unscrewing, with torsion of the drill stringunder pull load.

Unscrewing with the aid of an explosive charge(Back-off). The shock wave of the explosive charge deforms the joint to be disconnected,

leading to enlargement that favours disconnection.

Cutting of the drill string.


BACK-OFF

Abbreviated description of back-off operation:

Screwing of drill string by increments, with gradually increasing weights and turns. Example: Pipe stuked at 3000 m

0 tons 3 turns 12 tons 5 turns 24 tons 6 turns36 tons 7 turns 48 tons 8 turns 60 tons 10 turns

72 tons 11 turns 84 tons 12 turns 96 tons 14 turns

Apply tension to the drill string (weight of the drillstring in mud) sothat the neutral point falls at the desired unscrewing depth.

Rotate the drill string left (the number of turns is based on length anddiameter of the drill string; roughly = 60-80% of the number of turns done tothe right).

Run in the explosive charge to the desired tool joint.

Fire the explosive charge..


PARTED DRILL STRING


PARTED DRILL STRING

Z = SECTION MODULUS (pin and box)

Balanced BSR = 2.5

BSR < 2,5 Weakest box

BSR > 2.5 Weakest pin

Note: external wear reduce the BSR

RdR

DbD

ZZBSR

pin

box44

44

==


DRILL COLLARS

Recommendations to avoid breaking:

Recommended BSR = 2.5

Consider reducing the O.D. due to wear.

Inventory of materials for planning(BSR, control certificates).

Inspection of BHA at site every 300 hours.



Eliminate (as much as possible) the number ofcrossover in the drill string.

Visual inspections and NDT on body and threads (BHA)and identification of markings.

Apply the correct make-up torque.

Control of certificates:- Original material- Processing in shop- Shop NDT

CROSSOVERCROSSOVER


STABILISERS


Identification, marking and inspections by the service companies (NDT inspection documentation)

Site inspections (BHA).

Tightening operations (make-up).



Identification, marking and inspections by the service companies (NDT inspection documentation)

Site inspections (BHA).

Tightening operations (make-up).

Certified revisions of bodys mechanical parts.

JAR BUMPER SHOCK ABSORBER


HEAVY WALL DRILL PIPES


Preliminary inspections of new and sitematerials.BHA: Control of threads every 300 hourscontrol of body every 3500 hours.

Marking - Identification.


DRILL PIPES


Control first 20 pipes above HW every 300 hours (threading and body). Control all other pipes every 1500 hours.

Equipment for ultra-sonic control on site.

Marking - Identification.

Automatic controls of threading.


PROCEDURE FOR MONITORING DRILLING STRING AND BHA (DEEP WELLS)

Indelible marking of drill string and BHA Creation of database to manage tubular materials

(code, hours of rotation, date of insertion in drill string). Control all the DP and HW with ultra-sonic prior to

lowering into well. Control threading of all BHA elements, initially every 300

hours, by magnetic particle inspection (MPI). Control every 300 hours with ultra-sonic the pipe body

size, threads with MPI for first 20 DP above the HW. Ultra-sonic control of DP after 1500 hours, in lots of 100. Ultra-sonic control every 3000 hours of pipe body of the

HW.


FISHING JOB


OVERSHOT


TAPER TAP AND DIE COLLAR


KUNCKLE JOINT


ROTARY SHOES (WASHOVER SHOES)


WASH PIPE


FISHING JAR


SAFETY JOINT


FISHING MAGNET


WIRELINE SPEAR


POOR BOY JUNK BASKET


CORE TYPE JUNK BASKET


REVERSE CIRCULATION JUNK BASKET


JUNK BASKET


MILLS


INTERNAL CASING CUTTERS


RELEASING SPEAR


CASING ROLLER


CASING SCRAPER


CASING WHIPSTOCK

stuckp~1

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