Coating processes – Applying superposed diverse coating or coating a coated base – Synthetic resin coating
Reexamination Certificate
2002-05-31
2003-09-16
Cameron, Erma (Department: 1762)
Coating processes
Applying superposed diverse coating or coating a coated base
Synthetic resin coating
Reexamination Certificate
active
06620460
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods for protecting and lubricating threaded connections such as, oil field tool joints, drill collars, casing, tubing, line pipe, flow lines, subsurface production tools and other threaded connections that are exposed or subjected to extremes of stress, temperature, and/or pressure. More particularly, the present invention relates to methods for adhering an anti-seize metallic film onto the surface of threads of threaded connections and for coating the anti-seize protected threads with an environmentally friendly lubricating composition providing an environmentally friendly anti-seize/lubricating system.
BACKGROUND OF THE INVENTION
Oil field thread forms require products with high film strength and a certain range in coefficient of friction. Because thread faces are often subjected to bearing stresses in excess of 50,000 psi, excessive rotation could result in bearing stresses capable of rupturing the protective film and leading to subsequent galling and damage to the pipe. Anti-seize compounds are used to protect against the damage that high bearing stresses may otherwise cause by providing a dissimilar metal or other material between like substrates. Such a compound inhibits the “welding” that may otherwise occur from the temperatures, pressures, and stresses normally incurred during proper make-up.
Conventionally used anti-seize thread compounds include greases which contain substantial amounts of heavy metals or their oxides, carbonates, or phosphates. Such metals include: copper, zinc, lead, nickel, molybdenum, and aluminum. Recent environmental regulations have begun to discourage, and in some cases prohibit, the use of anti-seize compounds that contain such materials. Organic fluid additives containing antimony, zinc, molybdenum, barium, and phosphorus have become the subject of environmental scrutiny as well.
Although it is becoming increasingly unacceptable to include such materials in anti-seize compounds, compounds that do not include them generally do not, by themselves, provide the film strength needed to protect threaded connections from galling or other damage, when subjected to high bearing stresses.
One of the reasons why such compounds are disfavored results from the way they are used. Oil field threaded connections are usually coated with an excess amount of the thread compound to ensure complete connection coverage. The excess compound is sloughed off and ends up downhole. It is then included with the other materials pumped out of the wellhole and into a containment area. From there, material contaminated with heavy metals must be removed to a hazardous waste disposal site.
There is a need for methods that protect threaded connections by adhering and coating an environmentally friendly anti-seize/lubricating system to the thread surfaces so that there is provided adequate protection against galling and other damage to threaded connections subject to high bearing stresses, such as those on oil field tool joints and drill collars and adequate lubrication for controlled make-up and break-out of the threaded connections. Such methods should provide environmentally friendly, yet adequate anti-seize film strengths and adequate lubrication to protect such threaded connections from galling or failure, to reduce additional downhole make-up, to reduce heavy metals leached, and to reduce the classification of the drilling fluids as hazardous waste due to heavy metal or other hazardous material contamination from the anti-seize/lubrication system. The methods of the present invention provide just such a system.
SUMMARY OF THE INVENTION
The present invention provides methods for protecting threaded connections including:
adhering a protective metallic, anti-seize film coating to threads, prior to make-up; and
coating the film protected threads with an environmentally friendly lubricating composition prior to make-up.
The present invention also provides methods for protecting threaded connections including:
depositing a bonding metallic film to the threads, prior to make-up;
depositing a protective metallic, anti-seize film on top of the bonding film, prior to make-up; and
coating the film protected threads with an environmentally friendly lubricating composition prior to make-up;
where the bonding film is adapted to be interposed between the threaded surface and the anti-seize film and to simultaneously bond to the thread surface and to the anti-seize film.
The present invention further provides a method for protecting threaded connections comprising:
coating the threads, prior to their make-up, with a solvent thinned resin based coating and bonding composition comprising a suspending agent, a bonding agent, a thinning agent, and a metallic flake;
drying the coated threads for a time sufficient to bond the coating and bonding composition to the threads; and
coating the threads, prior to their make-up, with an excess amount of an environmentally friendly lubricating composition.
With such methods, an anti-seize metallic film is adhered to the thread surface to provide anti-seize protection while minimizing the amount of metal released into the environment. In such methods, thread wear alone discharges metal into the environment. Metal contamination is thus substantially reduced, when compared to present methods that coat the threads with excess amounts of metal containing oil based lubricants, a significant amount of which may be leached into drilling mud and other fluids used in drilling operations. The use of anti-seize metallic films in conjunction with environmentally friendly lubricating compositions will further reduce the potential for environmental damage, yet provide optimum protection in very critical operations, thus, reducing drilling down time.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
The inventors have found that oil field tool joints, drill collars, casing, tubing, line pipe, flow lines, subsurface production tools, and the like can be protected from seizing and abrading during make-up by first applying an anti-seize metallic coating to the thread surfaces where the anti-seize film is adapted to be in a bonded relationship to the surface of the threads and by second coating the anti-seize film protected thread surfaces with an environmentally friendly lubricating composition.
The methods of the present invention are particularly well suited for use in oil drilling operations. Although, the present invention is directed By primarily to oil field threaded tool, the methods of the present invention are broadly applicable to any threaded joint which is subjected to extremes of either stress, temperature, and/or pressure. Such other applications include, without limitation, chemical reactors, distillation towers, cracking towers, fluid bed reactors systems, and other equipment that has threaded connections that are subjected to extremes of stress, temperature, and/or pressure.
In its most basic form, the methods of the present invention include adhering a metallic anti-seize film to the thread surfaces and coating the film protected thread surfaces with an environmentally friendly lubricating composition to form an environmentally friendly anti-seize/lubricating system. This system is designed to protect and lubricate the threads during make-up and break-out and, yet, substantially reduce environmental contamination from both the anti-seize metal and the lubricant.
The step of adhering the anti-seize metallic film to the surface of the threads can be accomplished by a number of processes including, without limitation, burnishing, plating, sputtering, implanting, depositing, and bonding the anti-seize metallic film to the surface the threads. The adhering step can include at least one of these film forming processes. However, any combination of these processes also has usefulness in the methods of this invention.
Burnishing is a physical technique whereby a dissimilar metallic film is deposited onto a metallic surface. Additional information on burnishing can be found in U.S. Pat. Nos. 4,105,812; 4
Joseph Anthony W.
Oldiges Donald A.
Cameron Erma
Jet-Lube, Inc.
Strozier Robert W.
LandOfFree
Methods for using environmentally friendly... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods for using environmentally friendly..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods for using environmentally friendly... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3102960