What - Why - HowThread Compounds
Mark MulvihillResearch & Development ManagerBestolife Corporation 2008
• Rotary shouldered connections
• Tubing and casing
• Threads in storage
— Thread Compounds —Important Jobs:
— Lubricate — ProtectSeal
Connections Should:
• Prevent metal to metal contact
• Provide a leakproof seal for fluids
• Limit make-up during drilling to prevent excessive stresses on threads
• Prevent corrosion of threads
• Ideally, breakout less torque than make-up
• Leave no residue or plating at breakout
— Rotary Shoulder Connections —
Compounds Need :
• Ingredients that should mould into threads, produce a seal, and reduce thread contact
• To be slick enough to lubricate threads during make-up but provide sufficient resistance to make-up under torque
— Rotary Shoulder Connections —
Compounds Seal:
• Additives that are spherical in shape. • As the joints are torqued, the additives are flattened & elongated
bonding together on the shoulders of the pipe, preventing metal to metal contact.
• The angular make-up at given torque controlled by the compound type
• Dispersed particles embrittle compact upon breakout and do not stick to it make-up under torque
— Rotary Shoulder Connections —
Compounds Should Have :
• Sealing and galling prevention are most important functions of a thread compound
• Metallic powdered compounds will deform to seal and reduce galling of threaded connections
• Non-metallic compounds rely on solids like Graphite, Talc, and others to seal and eliminate galling
— Rotary Shoulder Connections —
Make-Up of Connections:
• Sealing and galling prevention are most important functions of a thread compound
• Metallic powdered compounds will deform to seal and reduce galling of threaded connections
• Non-metallic compounds rely on solids like Graphite, Talc, and others to seal and eliminate galling
— Rotary Shoulder Connections —
Uncontrolled Make-Up:
• When the make-up torque of the tool joint is less than the drilling torque, it can make-up down hole and may be difficult to breakout
• Uncontrolled make-up down hole can damage a tool joint and cause a drill string to break down hole
— Rotary Shoulder Connections —
Make-Up Lubricity :
• Thread compounds need to decrease the friction between contacting surfaces
• For small diameter drill pipe, lubricity is not a major factor
• For large diameter drill pipe, high surface area, a low coefficient compound can reduce friction and help with make-up
• When joints are made up too far, severe damage can result
— Rotary Shoulder Connections —
Breakout:
• Ideally, breakout torque should be less than make-up torque
• If a joint makes up down hole, the breakout torque can be higher than the make-up torque and the original make-up equipment may not be able to breakout the joint
— Rotary Shoulder Connections —
Compound Properties:
• Lead based – Lead provides seal, and make-up stress energy is absorbed. Can be used on both collars and pipe.
• Zinc based – Zn is a reactive metal, and can have problems when temperature and moisture are present. Can be used on both collars and pipe.
— Rotary Shoulder Connections —
Compound Properties:
• Copper based – can be used on collars and pipe. Can withstand higher temperatures than Lead or zinc.
• Non-Metallic – additives take the place of metals to provide the seal, more environment & worker safe, non-reactive, non-hazardous for offshore.
— Rotary Shoulder Connections —
Environmental Compounds:
• No metals – Lead, Zinc, or Copper• Ingredients that cause no harm to environment• Biodegradable components• Non-toxic to marine organisms• No labels required for disposal• No Toxicity Characteristic Leaching Procedure
required
— Rotary Shoulder Connections —
Environmental Regulations:
• Offshore Drilling – Regulations are more strict
• Worldwide – many countries are regulating the use of hazardous materials
— Rotary Shoulder Connections —
Environmental Regulations:
• Land rig waste disposal is becoming more regulated
• Some companies are standardizing on the same thread compounds worldwide
— Rotary Shoulder Connections —
API Bulletin 7A1:
“Recommended Practice for Testing of Thread Compounds for Rotary Shouldered
Connections” - is used to determine the frictional properties of thread compounds
— Rotary Shoulder Connections —
API Bulletin 7A1:
• 7A1 is still being revised and a new tester & test method are being developed
• API SC 7 provides drillers with friction factors that help predict actual make-up and breakout torques required
— Types of Compounds —
Environmental Regulations:
• API Modified – Lead/Zinc/Copper product recommended by API for use API 5A2
• API 5A3 – allows for different compounds that meet performance specifications
— Tubing & Casing Thread Compounds —
Should Provide:
• a long term seal on the threads to prevent leaks
• protection against galling on the threads
• protection against corrosion to the threads
— Tubing & Casing Thread Compounds —
Environmental Regulations:
• API Modified 5A2 – reduced usage of this product due to heavy metal content. Alternative is API 5A3.
• More environmental products are used mainly, either copper or non-metallic
• Standardization by oil and tubular companies worldwide
• Move towards environmental products is strong
— Tubing & Casing Thread Compounds —
New Solutions
• Rusting threads in storage have been a major problem for all drillers
• Thread compounds are seldom compatible with currently available storage compounds
• Bestolife BSC provides 2000 hours of Salt Spray protection which is equivalent to 2 years of storage and is compatible with most thread compounds
Twenty-First Century Compound
• Rusting threads in storage have been a major problem for all drillers
• Thread compounds are seldom compatible with currently available storage compounds
• Bestolife BSC provides 2000 hours of Salt Spray protection which is equivalent to 2 years of storage and is compatible with most thread compounds
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