Drilling problems 2

Differential Pipe Sticking... Differential Pipe Sticking eae nà ne pra: ed GraphicPanic.com... Differential Pipe Sticking e Precaution ¢ Maintain the lowest continuous fluid loss ¢

TAP DOAN DAU KHI VIET NAM TRUONG ĐẠI HỌC DẦU KHÍ VIỆT NAM

PETROVIETNAM

Drilling Problems

Seminar on April

KEYSEAT

* xã n

GraphicPanic.com

Differential Pipe Sticking

Differential Pipe Sticking

eae

nà

ne pra: ed

GraphicPanic.com

Differential Pipe Sticking

e Precaution

¢ Maintain the lowest continuous fluid loss

¢ Maintain the lowest level of drilled solids in the mud system or remove all drilled solid

Use the lowest differecial pressure with allowance of swab and surge

pressures during tripping operation Select a mud system will yield a smooth mudcake ( low coefficient of friction)

¢ Maintain drillstring rotation at all time if possible

¢ If sticking does occur

¢ The driller first tries to free pipe by jarring with a jar in drillstring

¢ Freeing stuck pipe i oil spotting aro

achanical Pipe Sticking

Mechanical Pipe Sticking

Mechanical Pipe Sticking

Mechanical Pipe Sticking

chanical Pipe Sticking

Solution: depending on what caused pipe sticking

¢ If hole narrowing as a result of salt is the cause, then circulating fresh water can free the pipe

¢ If the pipe is stuck in a key-seat area, the most likely successful solution is backing off below the key seat and going back into the hole with an opener to drill out the key section This will lead to a | etrieve the Jish

¢ Drillpipe failures: contain the following categories:

off, parting, burst or collapse, fatigue

¢ Twist-off caused by excessive torque

¢ Parting caused by excessive tensile

¢ Burst or collapse due to excessive internal or external pressure, respectively

¢ Fatigue as a result of mechanical cyclic loads with or without

Bore Hole Instability

* Types and associated problems: There are 4 types of

bore hole instability: hole closure, hole enlargement, fracturing, collapse

¢ Hole closure or narrowing: occurs in shale or salt section

Associated problems are an increase in torque and drag, potential pipe sticking, difficulty of casing landing

=

GraphicPanic.com

potential hole deviation, hydraulic equipment for effective hole cleaning and potential problem during logging

operations

¢ Fracturing: occurs when the wellbore drilling-fluid pressure exceeds the formation fracture pressure The associated problems are lost circulation and possible kick occurrence

¢ Collapse Borehole collapse occurs when the drilling-fluid pressure is too low to maintain the structural Integrity of the

GraphicPanic.com

611612 1ay0i nụ Partial lost s Greater thanh 10bbl/hr,

Pressure

© Equipment &

- Personnel —

GraphicPanic.com

Damage weak formations 7

Contamination pressure and fracture gradients

Lost Circulation

© Pipe Failure 2 ¢ Keep drilling if the geological condition allow

JSC sốc gui e In the case of severe lost circulations, use lost-

Hole Deviation

° Causes:

° Heterogeneous nature of formation and dip angle

Drillstring characteristics, specifically the BHA makeup

Stabilizers (location, number, and clearances)

Applied weight on bit (WOB)

Hole-inclination angle trom vertical

Drill-bit type and its basic mechanical design

Hydraulics at the bit

Improper hole cleaning

Fiowing Pressure

GraphicPanic.com

microorganisms forrmation fluids

Mechanical Sidevwall cores Hydraulic

evaluation Grovrth of E>va luiat<e ‘Treat drilling,

cormpletion fluids

Hydraulic compression

Theoretical

flow stidies

Under development

Mud comtamination

° Definition: A mud is said to be contaminated when a foreign material enters the mud

system and causes undesirable changes in mu properties, such as density, viscosity, and filtration

GraphicPanic.com

ud Contamination

solution:

use mechanical separating equipment: shakers, desanders, desilters, and centrifuges

shakers remove solids in the size of cuttings

(approximately 140u or larger)

Desanders remove solids in the size of sand (down to SOU)

Desilters remove solids in the size of silt (down to 20U)

Mud Contamination

contaminant to freshwater-based sodium-clay treated mud systems

ud Contamination

Biocarbonate and Carbonate Contamination

¢ Definition: The contaminant ions (CO;,—, HCO,°) are from

drilling a CO,-bearing formation, thermal degradation of organics in mud, or over treatment with soda ash and bicarbonate

¢ Causes: cause the mud to have high yield and gel strengt and a decrease in pH

¢ Solution: Treating the mud system with gypsum or lime

Mud Contamination

¢ Hydrogen Sulfide Contamination

¢ Definition: drilling mud involve the contaminant ions (HS-, cee

¢ Causes:

¢ danger for human

¢ extremely corrosive to steel used during drilling operations

¢ Solution: Scavenging H,S by using zinc, copper, or iron

Mud Contamination

¢ Salt/Saltwater Flows

¢ Definition: The ions, Na + Cl —- enter drilling mu

¢ Cause: high yield strength

¢ Solution:dilution with fresh water

the use of dispersants fluid-loss chemicals

conversion to a mud that tolerates the roblem if the cost a

GraphicPanic.com

Abnormal High Pressure

Equipment &

Personnel

GraphicPanic.com

Abnormal High Pressure

drilling mud by a kick

¢ Solution

detect the kick:

pit volume totalizer

base on the principle that shale should become more dense or less porous with depth as It is

compacted

ontrol the kick:

wait and weigh methoo

Sa ¢ Cause: all problems we ©

Contamination

AbGoanal Hon ¢ Solution: replace unsafe

Pressure equipment always check

® Equipment & systems during worki :

Personnel

Equipment And Personnel Related

¢ Personnel

Given equal conditions during drilling/completion operations, personnel are the key to the success or failure of those operations

Overall well costs as a result

of any drilling/completion problem can be extremely high; — therefore, continuing

education and training for personnel directly or indirectly involved is essential to

successful drilline

GraphicPanic.com