CA1292487C - Petroleum equipment tubular connection - Google Patents

Abstract

ABSTRACT

An anaerobic sealant composition is employed to seal a pipe joint between pin and box members intended for use in petroleum drilling operations.
The composition is applied to one or both of the members. The members are then joined and the composition cured into a 801 id form which bonds to the members and fills the space between them, The constituents of the composition can be selectively varied to control its lubricity which also affects the make up torque. Additionally, the concentration of the sealant composition can be selectively varied to control the break out torque of the joint to which it is applied, and preferably make the break out torque substantially greater than the make up torque.
Excellent seals can be obtained using lower grade pipe, and the pin and box members can be made up with the application of lower torque to the assembly without reducing the sealing capability of the connection. The preferred composition also serves as a rust and corrosion inhibitor for the joint.

Description

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PETROLFU~ EOUIP~ENT TUBULAR CONNECTION

BACKGROUND OF TH~ INVENTION

I. Field o~ the Invention The present invention relates to an anaerobic sealant composition and the use thereo~ to seal pipe joints between pin and box members intended ~or downhole ~z~

tubular goods used in petroleum drilling operations.
The invention encompasses the method of application of the sealant composition to the pipe joint structure, and the resulting connection.

For purposes of the invention, the term "petroleum operations" will be taken to include, but not necessarily be limited to, operations related to the exploration, drilling, the extraction from the earth of oil, gas, water, and geothermal materials as well as the disposal of nuclear and/or toxic wastes. Additionally the term "pipe" will be used for convenience to refer to all downhole tubular goods, whether it be tubing, drill pipe, casing, production pipe, or the like.

The term "drilling" will be taken to include the formation of a deep hole through which the materials are extracted or returned beneath the surface of the earth.
It will be understood, however, that pipe having the same characteristics of that used in petroleum operations can also be used in the opposite sense, that is, to return materials into the earth. Such a procedure is involved in the return of petroleum products to underground storage or the transfer of nuclear wastes to underground containment fields.

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The invention herein is concerned with the connection between two lengths of pipe. The ends to be joined of the two lengths of pipe are commonly referred to as a "pin" and as a "box". In this context, a "pin" may be a threaded end of pipe and a "box" may likewise be a threaded end of pipe and a coupling connected thereto with suitable threads for receiving a pin. However, these terms should be read sufficiently broadly to cover connecting mechanisms other than threads. Also, the term "make up" and variations thereof are taXen to mean assembly to two pin and box members, and the term "break out" and variations thereof, are taken to means disassembly of the pin and box members.

II. Description of the Prior Art The problems associated with petroleum drilling operations are many and extreme. The conditions experienced include extremes in kemperature, not only between polar regions and equakorial regions, but also of the products being extracted and the high temperature of the formations at depth. Pressures can be intense in the depths of the earth as well as exposure to the harse corrosiveness of such toxic materials as sulfur dioxide and hydrogen sulfide.

~ ~ ~Z~8~7 LC-184 ~4~

Particulary grueling are the stresses impo~ed on downhole tubular goods in the inætance of a string of pipe which may be many thou6and~ of f eet in 1 ength.

Couplings or tubular connection~ for lengths of pipe are of paramount importance in the drilling operation and serve two primary functions. In the first instance, they hold the weight of the pipe which can amount to two million pounds or more and they serve to seal the pipe both against incursions from its exterior as well as loss of the products being extracted. The customary type of pipe connections used in drilling operations are threaded joints and the industry standards which have been established by the American Petroleum Institute ~API) are known as ~API 8-round~
and as ~API buttress~ threads.

Leaking pipe connection~ have represented a significant problem to the petroleum indu~try, and the problem continues although recent research and development efforts by connection manufacturers and op~rators have made significant improvements in technology. Premium connection designs employing various combinations of ~2~Z4~

interference fit threads metal-to-metal seals, new generation of non-metallic seal materials, higher alloyed steels, and computer/numerical control machining technology have been developed and are very effective.
Typical of such premium connection designs ara those disclosed in U.S. patents to Blose No. 4,244,607 issued January 13, 1981 and Re. 30,647 reissued June 16, 1981.

Some of these designs include "Teflon"TM brand o-rings, or the like, as sealing aids. In this instance, sufficient material must be removed from the pipe end in the region of the joint to accommodate the o-ring.

Such removal necessarily weakens the joint and increases the stresses imposad on the joint. Furthermore, the o-ring material does not have sufficient plasticity to satisfactorily seal the interstices of the joint.

"A, lZ~2~

Nonetheless, failures continue to occur due in part to greater sensitivity of many of these designs to handling, running, and environmental factors. Single failures of production strings have cost millions of dollars and they continue to occur as industry continues to push back the technology frontier. One of the most pervasive causes of these connection failures is leakage. Aside from design problems, many new connections are easily damaged by a variety of common rig and handling procedures.

As a further effort to prevent leaking connections, sealing materials have been developed and are widely used by the industry. Numerous such sealing materials are available such as ShellTM high pressure thread compound produced by Shell Oil Corporation, EXXONTM 706 thread compound produced by EXXON Corporation, and "Liquid-O-Ring" brand thread compound manufactured by Oil Center Research, Inc. of Lafayette, Louisiana.
These material meet API standard and are referred to as "API modified". Typically, the components of these sealing materials include an oil based lubricant, and sealant components which may include, for example, .~
., .. ~

12~2413~

powdered graphite, lead powder, zinc dust, and copperflake. There is no chemical reaction between the sealant componen~s and the lubricant. The composition is merely a mixture and there is no curing step involved in its preparation or u~e. These sealing materials remain in a liquid form, seeking any voids which are present between the mating threads within the joint.

While such sealing materials have worked reaæonably well, they are, in composition, primarily a lubricant and only secondarily a sealant. The sealant components of the mixture seek out the voids within the threaded joint, but if a hole is large enough, the sealant lS material will extrude out and the sealant will no longer be effective for its intended purpose. It also often occurs in the harsh envlronment in which drilling operations take place that the li~uid component o the sealant material bakes of~ in the extreme heat to which it is exposed, leaving voids and the metallic sealant components behind. These components typically have particle sizes lying in a range o 50 to 500 microns.
This is not only undesirable during normal drilling operations, but becomes even more of a problem during disassembly of the pipe. Customarily, the same pipe can be used in a number of reinstallations in the same well or installations in successive wells. This, of course, is desirable because of the heavy expense of the piping.
However, in the instance in which the lubricant bakes off, the metallic particles left behind are of a gritty consistency and, upon disassembly, sometimes causes galling to occur on the threads of the pipe. This causes the pipe to be more difficult to disassemble and severely limits the reusability of the pipe.

SUMMARY OF TH~ INVENTION

It was with knowledge of the prior art and the problems existing which gave rise to the present invention.

The present invention in one aspect is directed towards a curable sealant composition which is employed to seal a pipe joint between pin and box members intended for use in petroleum drilling operations. In lts preferred form, 4~7 LC-184 ~9~

the composition is a single component anaerobic material which is applied to one or both of the members. The members are then joined and the composition cures into a 801 id form which bonds to the members and fills the space between them. The constituents of the composition can be ~electively varied to control its lubricity which also affects the make up torque. Additionally, the concentration of the constituents of the sealant composition can be ~electively varied to control the break out torque of the joint to which it is applied, and preferably make the break out torque substantially greater than the make up torque. Excellent seals can be obtained using lower grade pipe, and the pin and box members can be made up with the application of lower torque to the a~sembly without reducing the sealing capability of the connection. Tbe preferred composition also serves as a rust and corrosion inhibitor for the joint.

Subsequent discussion refers primarily to this preferred composltion. The curable sealant composltion o~ the invention (hereinafter ~sealantn), in its preerred form, ls a high viscosity anaerobic resin ~9;~l37 which may be combined with powders of PTFE
(polyte~rafluoroethylene~ and/or polyethylene having particles approximately 10 microns,in diameter for lubrication. Having a consistency between a ~hick liquid (e.g~ maple syrup) and a soft paste (e.g~
toothpaste), the sealant polymerizes between clo-~e fitted metal surfaces to provide sealing and resistance to loosening with a low break out strength. The sealant remains liguid indefinitely while exposed to the air~ Upon application to and make up of connections, however, complex reactions occur in the sealant which cause it to polymerize in the absence of air ts form a hard, high molecular weight, material with adhesive and sealant properties. These reactions lS are further catalyzed by the presence of iron, copper, nickel and o~her metal~.

The sealant has been specifically designed for use in sealing downhole petroleum drilling pipe joints. While such pipe joints have traditionally been of a ~hreaded nature, the application of the sealant need not be limited to threaded joints but can be applied with similar results to a variety to other types of joints .

as well. It may u~ed on slightly oiled, cadmium and zinc plated, black oxide, and phosphate and oil coated parts and still obtain satisfactory results. For a maximum benefit, parts should be wipe cleaned, but need no~ be solvent cleaned to remove an oil coating. This is for the reason that petroleum based oils by nature have an iron content sufficiently high to cause the resin or monomer in the anaerobic sealant to polymerize.
Some of the benefits of the sealant include the fact that it can be applied to the mating surfaces of the pin and box members either by machine or by hand. In the instance of threaded joints, the sealant seals between the thread~ to prevent spiral leak paths~
Indeed, the sealant seals all voids including microgrooves and other regions such as the metal to metal seal areas as found in premium connections. The sealant contains no lead (which is toxic to human being~ non-stringy ~and therefore easy to apply), and employs no flammable solvents ~which would be particularly hazardous on a petroleum drilling rig)O

lZ~24B`7 LC-184 ~12-Primary benefits of the invention, in addition to its excellent sealing ability, reside in it9 lubricity which improve the ability to make up and break out pipe joints, in it~ chemical stability and in the ability to adju~t it8 cohesive and adhesive strength so as to achieve a de~ired predetermined value of break out torque. As a result of some of these benef itB, the sealant will extend the life of production strings and will permit the upgrading of cheaper pipe for higher pressure applications.

A particularly important feature of the invention resides in the ability to provide a different break out torque for different members of a pipe joint.
Specifically, it i8 common practice to use lengths of pipe in the field which have a pin at one end and a box at the oppo~ite end. In thi~ instance, the box portion of the joint i8 usually assembled in a factory, then the pipe i8 shipped to the drilling site. As noted above, the con~tituents of the sealant composition can be controlled to thereby control the break out torque of the joint. According to this further embodiment of the invention, the concentration of the resin or ~Z~Z~17 ~13 monomer can be consistently different when applied to the mutually engageable surEaces of the hox than when applied to the pin such tha~, upon subsequent breakout, the same end of each ensuing length ~f pipe will be a pin and its opposed end will be a box. In this way, handling of the pipe is facilitated to a substantially extent. Prior art sealants customarily are not applied until make up as the pipe is descending into the well.
However, with this embodiment of the invention, the sealant having one concentration of the resin or monomer would preferably be applied at the factory at the time of assembly of the box portion of the joint. Then the sealant having a different concentration of the resin or monomer would be applied during make up in the field.

Various aspects of the invention are as follows:

In a pipe joint including pin and box members having opposed surfaces and intended for use in petroleum drilling operations, the improvement comprising:
a curable sealant composition of the anaerobic type applied in an uncured liquid state directly to said pipe joint prior to assembly and cured to a solid state following assembly so as to prevent fluid leakage through the joint, said sealant composition beiny of substantially equal constant volume both in the uncured liquid state and in the solid state.
A method of sealing a pipe joint including pin and box members having threaded ends with mutually engageable helical surfaces intended for use in petroleum drilling operations comprising the steps of:
applying a curable sealant composition of the anaerobic type in the uncured liquid state 2~87 ,~
13a directly to at least one of the helical surfaces;
assembling the threaded ends while the sealant composition remains in the uncured liquid state such that the sealant blocks all possible leak path~ including the helical flow path defined by the helical surfaces; and curing the curable sealant composition without substantial volume change from the uncured liquid state to whereby seal the pipe joint.
A sealed connection to two tubular members intended for use in petroleum drilling operations comprising:
a pin member;
a box member mechanically joined to said pin member to therPby form a joint therebetween; and a cured sealant of the anaerobic type containing no solvent within said joint to prevent leakage through said joint, said sealant being armed after said joirt is formed and composed partially of a polymerizable acrylake ester monomer the concentration of the acrylate ester monomer so chosen that the torque required for disassembly of said pin member and said box member is no less than the torque required for assembly of said pin member and said box member.
~ me~hod of sealing a pipe joint intended for use in petroleum drilling operations, the pipe joint including first and second opposed threaded pipe ends and a threaded coupling for threaded engagement with the pipe ends, the pipe ends and the coupling having mutually engageable helical surfaces, the method comprising the steps of:

~f~- ~2~2~ 7 13b applying a curable sealant composition of the anaerobic type in the uncured state directly to at least the helical surfaces of the pipe ends;
assembling the pipe ends and the coupling such that the sealant blocks all possible leak paths including the helical flow path defined by the helical surfaces;
curing the sealant composition; and controlling the concentration of ingredients in the sealant composition to thereby determine the torque required to disassemble the pipe joint.
A sealed connection of two tubular members intended for use in petroleum drilling operations comprising:
a box member including a first pin member having a threaded end and a threaded coupling member, said first pin member and said coupling member having mutually engageable helical surfaces, said first pin member and said coupling member being threadedly joined;
a cured sealant having a first concentration of ingredients applied in the uncured state to said helical surfaces of said box member to prevent leakage between said first pin member and said coupling member along a helical flow path de~ined by said helical surfaces, said irst concentration of ingredients resulting in a Eirst magnitude of torque required to disassemble said first pin member ~rom said coupling;
a second pin member having a threaded end, said second pin member and said coupling member having mutually engageable helical surfaces, said second pin member and said box member being threadedly joined;

,~ lX~9t8~

13c said cured sealant having a second concentration o~ ingredients applied in the uncured state to said helical surfaces between said second pin member and said coupling member to prevent leakage therebetween along a helical flow path defined by said helical surfaces, said second concentration of ingredients resulting in a magnitude of torque, different from said fir~t magnitude of torque, required to disassemble said second pin member from said box member.
In a pipe joint including in and box members having opposed surfaces and intended for use in petroleum drilling operations, the improvement comprising:
a curable sealant composition applied in an uncured liguid state to said pipe joint during assembly and cured to a solid state following assembly so as to prevent fluid leakage through the joint;
wherein, upon disassembly of said pin and box members when said sealant composition is in the fully cured states, said sealant composition is pulverized into a power form without causing galling of said opposed sur~aces.
A method of sealing pipe joint intended for use in petroleum drilling operations, the pipe joint including f.irst and second opposed threaded pipe ends and a threaded coupling for threaded engagement with the pipe ends, the pipe ends and the coupling having mutually engageable helical surfaces, the method comprisiny the steps of:
applying a curable sealant composition in the uncured state to at least the helical surfaces of the pipe ends;

_~ IL2~?Z~;8'7 13d assembling the pipe ends and the coupling such that the sealant blocks all possible leak paths including the helical flow path defined by the helical surfaces;
curing the sealant c~mposition; and controlling ~he concentration of ingredients in the sealant composition to thereby determine the tor~ue required to disas~emblP the pipe joint;
the step of applying a curable sealant composition including the steps of:
applving the sealant composition having a first concentration of ingredients resulting in a first magnitude of torque required to disassembly the first threaded pipe end and the coupling; and applying the sealant composition having a second concentration of ingredients resulting in a second magnitude of torque, different from said first magnitude of torque, required to disassemble the second threaded pipe end and the coupling.
A method of sealing a pipe joint intended for use in petroleum drilling operations, the pipe joint including first and second opposed threaded pipe ends and a threaded coupling for threaded engagement with the pipe ends, the pipe ends and the coupling having mutually engageable helical surfaces, the method comprising the steps of:
applying to a~ least the helical surfaces of the pipe ends a curable sealant composition of the anaerobic type composed of a polymerizable acrylate ester monomer and other inyredients in the uncured state;
choosing for application to the first threaded pipe end the sealant composition having a first predetermined concentration of ?2~ 7 13e the monomer such that the torque required to disassemble the first pipe end and the coupling will be of a first magnitude; and choosing for application to the second threaded pipe end the sealant composition having a second predetermined concentration of the monomer such that the torque required to disassemble the second pipe end and the coupling will be o~ a second magnitude different from the first magnitude;
assembling the pipe ends and the coupling such that the sealant blocks all possible leak paths including the helical flow path defined by the helical surfaces;
curing the sealant composition; and controlling the concentration of the acrylate ester monomer in the sealant composition to thereby determine the torque required to disassemble the pipe joint.
A method of sealing a pipe joint having a longitudinal axis and including adjoi~ing pin and box members having opposed surfaces and intended for use in petroleum drilling operations comprising the steps of:
applying a curable sealant composition of the anaerobic type in the uncured liquid state to at least one of the opposed surfaces to prevent leakage after curing occurs;
while the sealant composition remains in the uncured liquid ~tate, joining the two members together so that the sealant composition after curing adheres to the opposed surfaces of both the pin and box members and blocks the flow path in the longitudinal direction existing between the opposed surfaces; and curing the sealant composition to the solid state without substantial volume change 1~2~187 1~
from the uncured liquid state to thereby prevent fluid leakage through the joint.

Other and further features, o~jects, advantages, and benefits of the invention will become apparent from the following description. However, it is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory but are not restrictive of the invention.

DETAILED DESCRIPTION OF T~ PR~FERRED ~MBODIMENTS

The basic composition of the sealant used in the method of the invention is of a generally known formulation which has been used in a variety of other applications.
Examples of U.S. patents which have disclosed the use of monomer compositions having anaerobic properties are No.

3,625,875 to Frauenglass et al and No. 3,969,552 to Malofsky et al.

The monomers contemplated for use in the invention disclosed herein are polymerizable acrylate esters. As used herein, "acrylate esters" includes alpha-substituted acrylate esters, such as the methacrylate,ethacrylate, and chloroacrylate esters. Monomers of this type, when mixed with a peroxy initiator as described below, form desirable adhesives and sealants of the anaerobic type.

Anaerobic adhesives and sealants are those which remain stable in the presence of air (oxygen), but which when ~"

~9~ 7 removed from the presence of air will polymerize to form hard, durable re~ins. This type of adhesive and sealant is particularly adaptable to the bonding of metal 8 and other nonporous or nonair permeable S materials since they effectiYely exclude atmospheric oxygen from contact with the adhesive or sealant, and therefore the adhesive or sealant polymerizes to bond the surfaces together. Of particular utility as adhesiYe or sealant monomers are polymerizable di- and other polyacrylate ester~ since, because of their ability to form cross-linked polymers, they have more highly desirable adhesive or sealant properties.
However, monoacrylate esters can be used, particularly if the monacrylate portion of the ester contains a hydroxyl or amino group, or other reactive substituent which serves as a site ~or potential cross-linking.
Examples of monomers of this type are hydroxyethyl methacrylate, cyanoethyl acrylate, t-butylaminoethyl methacrylate, glycidyl methacrylate, cyclohexyl acrylate and furfuryl acrylate. Anaerobic propertiies are imparted to the acrylate ester monomers by combining with them a peroxy polymerization initiator as discussed more ~ully below.

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1~9248~

One of the most preferable groups of polyacrylate esters which can be used in the adhesives or sealants disclosed herein are polyacrylate esters which have the following qeneral formula:

[ (b`) b' ] ~

wherein Rl represents a radical selected from the group consistiny of hydrogen, lower alkyl of from one to about four carbon atoms, hydroxy alkyl of from one to about four carbon atoms, and o -C~-O-~-C~-C~I
t R2 is a radical selected ~rom the group consisting of hydrogen, halogen, and lower alkyl of from one to about four carbon atoms; ~3 is a radical selected from the ~roup consisting of hydrogen, hydroxyl, and _o_~_a-oFI.

2~37 m is an integer equal to a~ leas~ 1, e.g~, from 1 toabout 15 or higher, and preferably from 1 to about 8 inclusive; n is an in~eger equal to a~ lea~t 1, e.g., 1 to about 20 or more; and p is one of the following:
0, 1.

The polymerizable polyacrylate esters utilized in accordance with the invention and corresponding to the above general formula are exemplified by bu~ no~
restricted to the following materials: di-, tri- and tetraethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, polyethylene glycol dimethacrylate, di tpentamethylene glycol) dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol di(chloroacrylate), diglycerol diacrylate, diglycerol tetramethacrylate, tetramethylene dimethacrylate, ethylene dimethacrylate, neopentyl glycol diacrylate and trimethylol propane triacrylate. The foregoing monomers need not be in the pure state, but may comprise commercial grades in which inhibitors or stabilizers, such as polyhydric phenols, quinones, etc.
are included. As used herein the term "polymerizable polyacrylate ester monomerN includes not only the 41~7 foregoing monomers in the pure and impure state, butalso those other compositions which contain those monomers in amounts ~ufficient to impart to the compositions the polymerization characteristics of polyacrylate esters. It is also within the scope of the present invention to obtain modified charac~eristics for the cured composition by the utilization of one or more monomers within the above formula with other unsaturated monomers, such as unsaturated hydrocarbons or unsaturated esters.

The preferred peroxy initiators for use in combination with the polymerizable acrylate or polyacrylate esters described above are the hydroperoxy polymerization initiators, and most preferably the organic hydroperoxides which have the ~ormula R400M, wherein R4 generally is a hydrocarbon radical containing up to about 18 carbon atoms, preferably an alkyl, aryl or aralkyl radical containing rom one to about 12 carbon atoms. Typical examples of such hydroperoxides are cumene hydroperoxide, tertiary butyl hydroperoxide, methyl ethyl ketone hydroperoxide and hydroperoxides formed by the oxygenation of various hydrocarbons, such as methylbutene, cetane and cyclohexene. Other organicsubstances, such as ketones and e~ters, including the polyacrylate esters represented by the above general ~ormula, can be oxygenated to form hydroperoxy initiators. However, other peroxy initiators, such as hydrogen peroxide or materials such as certain organic peroxides or peresters which hydrolyze or decompose to form hydroperoxides frequently can be used. In addition, U.S. Patent No. 3,658,624 describes peroxides having a half-life of less then 5 hours at 100C. as suitable in somewhat related anaerobic systems.

The peroxy initiators which are used commonly comprise less than about 20 percent by weight of the combination of monomer and initiator since above tha~ level they begin to affect adversely the strength of the adhesive and sealant bonds which are Eormed. Prefera~ly the peroxy initiator comprises from about 0.1 percent to about 10 percent by weight of the comblnation.

Other materials can be added to the mixture of polymerizable acrylate ester monomer and peroxy ~ ~,a~

initiator, such a8 quinone or polyhydric phenolstabilizers, tertiary amine or imide accelerators, and other functional material~ such as thickeners, coloring agents, etc. These additives are used to obtain commercially desired characteristics, i.e., sui~able viscosity and shelf stability for extended periods ~e.g., a minimum of one month). The presence of these additives is particularly important when peroxy initiators other than organic hydroperoxides are used.
For a complete discussion of the anaerobic systems and anaerobically curing compositions, reference is made to the following U.S. Pat. Nos. 2,895,950 to Vernon K.
Rrieble, issued July 21, 1959; 3,041,322 to Vernon K.
Krieble, issued Junè 26, 1962; 3,043,820 to Robert K.
Krieble, issued Ju~y 10, 1962; 3,046,262 to Vernon K.
Krieble, issued July 24, 1962; 3,203,g41 to Vernon R.
Krieble, issued Aug. 31, 1965; 3,218,305 to Vernon~K.
Krieble, issued Nov. 16, 1965; and 3,300,547 to J.W.
Gorman et al, issued Jan. 24, 1967.
However, the aforesaid monomer compositions have been modlfied (e.g. by adjusting the strength, lubricity, etc.) for the purposes with which the LC-l 84 -21--present application is concerned, specifically, as a sealant or pipe joints, and more particularly, between pin and box members intended ~or use in petroleum drilling operations. Indeed, monomers S having anaerobic properties have been totally unknown in the role disclosed herein and provide highly desirable results of a nature previously unknownO

As noted above, the sealant is applied to mating metallic surfaces in a liquid state. It may be applied in any ~uitable manner as, for example, by brushing, by means of a mechanical applicator, by a ribbon applicator, or by sponge. So long as the parts so coated remain exposed to the air, the sealant remains in its liquid state. ~owever, when the parts are joined such that the internal interengaging surfaces are no longer exposed to the alr, then the sealant cures to the solid state. When thi~ occurs, it forms a physical bond to the outer surface of a metal on which it is coated. The presence of the metal to which the sealant is applied can also initiate and thereby accelerate the curing process. The sealant even ~ills the microgrooves whIch are formed in the metal ~2~2~87 resulting in elimination of leak paths for gases and liquids. The sealant provides an absolute, positive seal which works equally well with API 8-round, API
buttress, and with premium connections. ~ile the industry has had good experience with premium connections, the present invention provides a sound back up seal which is far more practical and reliable than "Teflon" brand o-rings, for example, that have come to be widely used. Effectively, the sealant of the invention provides a plastic seal throughout the area, without the need to machine expensive grooves (which weaken the pipe) as is required for the "Teflon"TM seal.

Physical properties of the preferred sealant of the invention include the following:

PHYSICAL PROPERTIES UNCURED SEALANT

Flash Point >100C (212F) Appearance pink viscous liquid .~.r~ "~, ~Z~ 87 LC-184 ~~3~

Pen~i~X 1.25 (~rookfield Viscometer type H~T 150-500 Pa'~
~6 Spindle, 2.5 rpm Q 23 + 2C) (150,000-500,000 cP) Composition2-1/2 RPM 20 RPM Thixotropic Ratio 11296 75 cP 30 cP 2.5 SL21 80 cP 26 cP 3.1 SL22 67 cP 20 cP 3,4 Note: Thixotropic ratio refer~ to the gap ~illing ability of the sealant and to its ability not to drip when applied. The above number~
re~lect this ability of the ~ealant;
speci~ically, the greater the thixotropic ratio is above 1.0~ the less it will drip.

Other deslrable properties of the sealant in ~2~48~

its uncured state include: its ability to be easily dispensed, as from a squeeze tube; $t~
stability, that i~, its long shelf life in a package prior to being used; its low toxicity, that is, lack of lead or other heavy metals among its constituents; itB non-flammability, that is, its flash point above 212F. Its lubricity is a measure of how much tension i8 applied to a joint with a given amount of torque.

Lub~ici~y Ten~ion (recorded in 100'9 of pounds) at the followiny torques:

Composition 100 200 300 400inch pounds 1129~ 1~ 25 3~ 51 SL21 15 33 49 6a i Z~7 5~ E~s Inch pounds breakfprevail mea~ured on 3/8 x 16 iron nut~ and bolt~ a~ter 24 hours ~ 70F

(Un6eated) Break2revail (180) 11296 1 in. lb.1 in. lb.
10 SL21 6 in. lb.2 in. lb.
SL22 8 in. lb.3 in. lb.

Vl~1m~Q ~t~çngth: As above but after 4 hours @ 2000F

1129650 in. lb. 0 in. lb.
SL2160 in. lb. 2 in. lb.
SL2260 in. lb. 5 in. lb.

Note:Un~eated break means that the nut is ree spinning on the bolt. Other desirable properties of the sealant in its cured and curing state include: its cured lubricity:
its resistance to heat: it has been -~, ~''}~9~&~7 LC-184 ~26-tested to 330~F in heat cycling te8t8; it~
resi~tance to chemical attack ~it i~
essentially chemically inert): and its hot strength - since it is a thermoset plastic composition, the sealant has a high hot strength.

It was previously noted that the sealant may contain PTFE and/or polyethylene additives in the form of a lQ powder for lubricity. Each of these additives may be provided in the range o~ 0 - 20% by weight. PTFE
increases lubricity slowly while polyethylene increases lubricity at a rapid rate per unit amount added.
In its liquid form, the sealant lubricates as well as or better than existing API thread compounds.
~urthermore, becau~e the sealant contains no solvent, there can be no "bake out~ or 1033 of volume under temperature or with time as with known thread compounds. ~ecause there is ~ubstantially no 10B8 of volume when it i~ cured, it prevents leak paths from developing. Furthermore, in its cured solid state~

~ 8 when the pipes are di~asfiembled, the ~ealant i~pulverlzed into a powder form wi~h lubricatlng qualities and continue~ to be a~ ef~eative a lubricant as it wa~ previously ln it8 liquid or uncured state.
This is because molecules of the sealant penetrate and remain in micro-burrs which exist on threads and other ~urfaces in the connection and reduce the galling effect caused by them.

The re~ulting threads are substantially clean and require little preparation for re-use. Thus, the sealant of the invention serves a~ a lubricant during both the make up and break out operations at the same time that it i8 an e~fectiYe seal.
Another prlmary benefit i~ that the sealant permit~
sealing at lower make up torque than currently used with non-curing sealants since the curing sealant will plug larger gaps throughout the joint. With known sealants, high torque i~ necessary in order to prevent leakage, even with premium connections. It will be appreciated that with lower tor~ue, there i~ less deformation of the pipe and hence a higher life z~

expectancy to be anticipated from the thread. Thi8 would enable the use of API 8-round thread and API
buttress thread in virtually all instances, thereby eliminating the need for the higher priced premium connectionsO This is important when one con~iders that a current price range for API 8-round connections is between ten dollars and twenty dollars per coupling whereas that for premium connection~ is between two hundred and five hundred dollars per coupling. In some specialized instances, the premium connections can cost even more than five hundred dollars per coupling Another benefit of a lower torque requirement is that less stress is imparted to the pipe connections assuring that the pipe will be more resistant to the corrosive effects of ~uch highly toxic subs~ances as hydrogen sulfide and sulfur dioxide which are common in petroleum well environments. Such toxic substances are known to corrode stressed regions in connections more rapidly than unstre~sed or lesser stressed regions.

Another significant benefit of the invention resides in the ability to control the strength of the sealant, by adjusting the percentage of its conetituents~ When translated into oil field terminologyA this means that the break out torque can be controlled. Specifically, the greater the percentage o resin or monomer, the greater the break out torque when the sealant is applied to a pipe joint, and vice versa. Strength may al~o be increased by increasing the amount of mineral fillers, although not to the extent of resin variation.
Typical mineral fillers are titanium dioxide used as a whitening agent and mica used as a strengthening filler.

Still another benefit of the invention is the ability to a~sure a substantially h~gher break out torque than make up torque in those connections where a low makeup torque i8 desirable. This is achieved by controlling the concentration of the ingredients in the sealan~
composition. In the preferred embodiment, the ingredient being controlled iB the polymerizable acrylate ester monomer. This will assure that an end will not break out inadvertently due to low make up torque.

4~3 ~he foregoing benef~t of controlling break ou'c torque by adjusting the concen~ration of the resin or monomer in the sealant composition leads to still another benefit of the invention~ Specifically, it is desirable from a materials handling standpoint to know which end of a reusable pipe being withdrawn from a well will be a pin and which end will be a box so that the pipe can be uniformly stacked pending further use.
This object can be achieved by applying sealant having one concentration of monomer to the box when it is assembled (most likely at the factory~, then applying sealant having a different concentration of monomer to the pin at the drill site. The concentration of the monomer would be known in each instance such tha~ the torque for break out of each portion of the joint would likewise be known. By maintaining the concentration of the monomer uniform in each instance, as the pipe is withdrawn from the well ~or subseqllent use, the same end of each subsequent length of pipe will be a pin and its opposite end will be a box. Heretofore, there was no way of knowing whether an end o pipe would be a box or a pin upon break out. This created difficulty with LC-1~4 -31-sub~equent operations which would be alleviated by the invention.

In addition to adjusting the percentage of the resin or monomer in the sealant compo~ition to adjust break out torque, by making further adjustments to the formulation, it can be be made certain that the prevailing strength is less than the break out strength. Prevalling strength i8 defined as the torque used to unscrew a pin from a box after the pin has been rotated through an arbitrary arc, for example, 180. If prevailing strength is not maintained to a value less than the break out strength, the torque may increase with continued un~crewing of the pin from the box wlth the result that the disassembly of the pin and the box will become extremely difficult.

In current practice, relatively high torques are used for make up and ~omething less than the make up torque is required for break out. This latter ~ituation i8 not desirable, but is a characteristic of a joint to which known sealants have been applied. The higher torques ; are required to ensure sealing in the connections. The 2~ 7 ~C-184 -32-following is an extract from Test Summary 4 below o~this disclosure~ It clearly shows how the connection wa~ made up to lower torques when the sealant was applied without compromising it8 sealing capabilities.
~ke-~~ IQ~9Ç~ =hk~ UUL~ ~5~
~1 2,500 Leak at 1,500 35,000 Leak at 8,000 10Sealant 2,500 ~eld at 8,000 Typically, using known sealant materials, break out torque is less than make up torque. However, by reason of the invention, break out torque can be made greater than make up torque by controlling the properties, specifically, the percentage of resin or monomer in the cured polymer. For example, in the above test, the cbnnectlon broke out at a torque somewhat less than make up torque when made up with API compound. When the sealant wa~ used, an~ the connection made up to 2,500 Ft-Lbs, the break-out torque was 14,000 Ft-Lbs.

. ~2~29L~37 Still another significant benefit of the invention i8 the chemical ~tability of the sealant. Specifically, its compo~ition is such that it i8 inert to the chemicals normally encountered in petroleum drilling operations. Furthermore, the sealant composition is non-toxic when properly used and will not pollute the environment as will the known sealants, which contain heavy metals such as lead, nickel and the like.
Substantial experimentation has indicated no adverse effects with expo~ure to chem~cals encountered in oil field use~ including hydrogen sulfide and sulfur dioxide.

Another significant feature of the invention i5 the self cleaning ability of the ~ealant. Speciically, upon break out, the solid polymeric material pulverizes and leaves a fine coating on the thread~. This fine coating doe~ not inter~ere with subsequent make up, but has been found to effectively prevent oxidation to an extent better than most known corrosion resistant protective coatings.

Exten~ive testing has been performed regarding the ~ Zf~7 sealant, and the following reflect some of the moresignificant tests which have been performed to date using both the anaerobic sealant composition of the invention and previously known compositions in a 5 variety of applications IQ~ mm~LY L

In thi~ group of tests, the connections used were standard ~VAM" single metal-to-metal seal connections with buttress thread~. ~VAM~ is a trademark of Vallourec, a corporation with headquarters in Paris, France, and one of the leading manufacturers of premium connections Leaks were created on the test sides of the connections by grooves filed into the seals. The connections were then tested to insure that they leaked readily when made up with API ~American Petroleum Institute) modified premium thread compounds, and then they were tested as followss ~a) 2-7/8 inch tubing. Pressure: 10,000 psi nitrogen. Heat cycling: ambient to 320F.

-12~Z~B7 Tension: 200,000 lbs.

tb) 3-1~2 inch casing. Pressure: 10l000 psi hydrostatic ~c) 7-5/8 inch casing. Pre~sure: 9,000 psi nitrogenO
Heat cycling: ambient to 300F.

In all instances, the connections sealed when the anaerobic sealing composition was applied to the crippled ~ide o~ the connection. The break out torques averaged approximately 150% of make up torques. There was no evidence of galling.

Pipe Size: 7-5/8 inch Connection types: "VAM~ premium connections with metal-to-metal seals and buttress threads.

Two pup ~oints and two end plugs were assembled with three couplings respectively interposed between the~pup 2~8~

LC-184 -3~

joints and the end plug~ One of the end plugs would not hold pressure above 4000 psi, preventing the testing of tha complete assembly. This connection was further crippled by notches filed into the seal to cause it to leak. The anaerobic sealant composition of the invention wa~ then applied to the thread area, and the connection was made up again and the entire assembly was subjected to heat and pressure cycling for several days. The connection held pressure through the threads ~or the entire test period, while leaks occurred in several o~ the healthy connections in the assembly. The maximum pressure was 9000 psi of nitrogen, and the temperature was cycled from ambient to approximately 300F.

Thi~ test u6ed 2~7/8 inch 8-round thread tubing and was designed to compare the anaerobic sealant composition o~ the invention with an ~PI modified high pressure thread compound manufactured by Shell Oil Corporation:

The sample comprised two threaded pins and a single -1~32fl~B~7 LC-184 ~37~

coupling. One pin contained a machined groove to simulate a field defect. 5he groove waæ cut to the root of ~he thread for the entire length of the thread.
~he groove was cut 0.060 inches wide at the nose of the pin and ~apered ~o 0.020 inche~ wide at the end of the thread.

The sample was made up to 2,300 ft-lbs. o torque using a light application of API Modified pipe dope manufactured by Shell Oil Corporation. The sample was pressure tested with nitrogen gas and a leak was noted immediately on the grooved end. It was disassembled and additional API Modified was applied to the grooved end to simulate ~ield conditions. The samp~e was remade to 1,900 ft-lbs. of torque using the same amount of turns used during the initial make up. Internal gas pressure was then applied and at 3,500 psiy pipe dope was noted extruding at the machined groove. A leak developed and the internal pressure bled down to zero psig.

The sample was dlsassembled, cleaned, and inspected.
The sealant o the invention was applied to the ;~ ?~8~

grooved end; while API Modified was applied to theother pin endO The sample was made up to 1,700 ft-lbs. and allowed to cure at ambient temperature ~approximately 95F) for five hours. Internal gas pre~sure of 7,~00 psig was applied and held for two hour~. No leakage was observed.

Subsequently, the sample was subjected to 235F
temperature for one hour. Internal gas pressure of 5,500 p~ig was applied for one hour while maintaining the elevated temperature and no leakage was observed, The sample was allowed to cool to ambient temperature while maintaining the 5,500 psig internal gas pressure.
No leakage was observed.
The sample was then disassembled, cleaned and inspected. Torque o 5,772 ft-lb~. was required to break out the pin with the machined groove and 5,382 ~t-lb~, of torque was required to break out the ~PI
Modified pin end, The grooved pin broke out ~moothly and without problems. No galling was obsexved on either pin end.

LC-184 -39~

~Q~ ~mm~L~ 4 Thread DeRign: 7-5/8 inch wedge ta)This test was de~igned to test a ~Teflon~ ring as a back-up seal in a known leaker. At 2,500 ft-lbs. of make up torque it leaked at 1,500 psi. At 35,000 ft-lbs. it leaked at 8,000 p8i. The inventive composition was applied and the connection was made up to 2,500 ft lbs. It held 8,000 ; psi. The break out torque was 14,000 ft-lbs.

IQ~ L This connection was made up to 35,000 ft-lbs. with API Modified dope and was ; sub~ected to a combined tension and internal pressure load o~ 588,000 lbs. It leaked at 10,000 psi7 The inventive composition was applied and under the same lZ~48~7 LC-l 84 - 4 0-conditions9 the connection held 13,000 p~i.

This connection was made up wikh API
dope to 40fOOO ft-lbs. It leaked at S,000 psi. In an effort to test performance of ~he inventive composition under adver~e conditl ons, the box end of the connection was completely filled with 16 lb drilling mudr and the joint was ~tabbed into the mud. It sealed to 13,000 psi with no adverse effects from the presence of the drilling mud,.

~L~f'3Z~

Test Summary 5 Thxeads/Mat'~ Test/~ot~ BeSults (a) Using preferred composition of invention:
pipe: 3-1/2 inch diameter 12.7~/ft-SM2550 Threads from a previous Made up connection to ~ No leaks test, but still in good approx. 4,000 ft-lbs condition. Pins were (whereas usual min-dry-honed with Moly Kote. imum torque for conn-Couplings phosphated. ection is 5,220 ft-lbs).
The torque shoulder and Made up connection s 30 seal area were allowed to cure for 2 crippled to thereby hours. Hydrostatic create a leak path. test Q lOk psi for 2 hrs. Connection broken apart:
~ 11 @ 5,~00 ft-lbs.
~ 12 @ 6,200 ft-lbs.

Test Summary 5 ~Cont.) Threads/~t'l Test/Notes ~ Resul~~

Same as above Another made up conn- No Test ection to check break out torque after short cure time: 1 hour. Conn-ection broken apart:
# 11 Q 4,500 ft-lbs.
lo $ 12 Q 4,500 ft-lbs. r Using API modified compound:

Same as above Same as above ~long $ 11 leaked cure time) except: @ 3,000 psi Connection broken ~ 12 leaked apart: @ 5,000 psi # 11 Q 3,600 ft-lbs.
~ 12 @.3,750 ft-lbs, 8t7 LC-134 ~3-Threads/~at'l $~5~c~ B~

~b) Using preferred composition of in~ention:
same as ~a) Made up connection toNo leaks approx. 4,000 ft-lbs.
Allowed to cure for 5 hours~ Hydrostatic test to lOk psi overnight.
Connection broken apart:
lA @ 6,000 ft-lbs.
~ 5B Q 6,300 ft-lbs.

same as ~a) Another made up connec-No test tion to check break ou~
torque after short cure time: 30 min~ Connection broken apart:
~ lA e 4,750 ft-lbs.
# 5B @ 4,750 ft-lbs.

gL137 Using API modified compound:

same as above Same as above ~long After 15 min.
cure time) except: ~ lA leaked No information re. @ 5,100 psi;
connection broken then, ~ 5B
apart. leaked when repressured to 7,000 psi ~c) Using preferred composition of invention:

same as ~a) Made up connection to No leaks ~15 except only approx. 4,000 Et-lbs.
pin # lB was Allowed to cure for crippled 20 hour~. Gas ~N2) test ~ 7,500 psi for 1 hour.
Then, pressure No leaks removed and connection heated to 300F;

LC-l84 -45-~ Su~ma~y S ~o~t.)_ Th~eads~Mat'l Test/~oteS Results Gas ~N2) test Q
lO,000 psi for l/2 hourO

Connections broken apart:
lB @ 5,700 ft-lbs.
~ 3B Q 6,300 ft-lbs.

Using API modified compound:

same as above Made up connection to No leaks approx. 4,000 ft~lbs. Q 5,000 psi Allowed to cure for ~ lB leaked 20 hours. Hydrostatic @ lOrOOO psi test to lO,000 psi ~ Threads/Mat'l TesttNotes , Results (d) Using Composition of Made up connection to ~o ~eak invention: Pi~e: 2 7l8 approx. 3,000 ft-lbs.
inch diameter.7.7 lbs/ft.; (Optimum torque) gas ~80 Treated same as (a) (nitrogen) test at above, only one side 3,600 psi overnight crippled Gas pressure increased Slight leak;
to 6,500 psi. External small steady 10 ~ tenslle ioad added for stream of total tensile load of bubbles coming - approx. 200K lbs. No in through temperature increase water in which yet assembly immersed.
. .
Assembly heated to 300F. ~eak appeared to (w/hot glycol); pressure stop; no more increased to 8,600 psi; bubbles visible ,hot cycle maintained approx. 2 hours.

Assembly cooled by flush- ~eak reappeared;
ing with cold water to small steady stream - approx. 120F; pressure of bubbles visible dropped to approx. 6,500 through water.
ps Another hot cycle No leak visible Another hot cycle Leak visible again LC-18~ ~~7 ~7 .

Threads/Mat'l Test/~otes Results (e~ Using Composition o~
Invention:
Pipe: 2-7/8 inch diameter ~ade up connection t~ No ~eaks i 7.7 lbs/ft; N80 approx. 4,000 ft-lbs.
VAM premium connec- External tensile load:
tion;Treated same as apprOx 170,000 lbs;
above: only one side gas preSsure (nitrogen) crippled to 9, 500 psi Temperature raised to No Leak visible approx. 300F (hot glycol); short time cycles at hot and cold Assembly cooled with Leak appeared; ' cold water flush s~all steady stream of bubbles Temp increased for No Leak visible second hot cycle Assembly'cooled for Leak visible again;
second cold cycle small steady stream Temp increased for No leak visible third hot cycle Assembly cooled for Lcak visible again;
third cold cycle small steady stream Two more hot and cold Small pa~tern of cycles leaking , lZ~2~137 LC-184 -48~

For ~hese tes~s, the connections used were VAM-PTS
2-7/8 inch N80 premium connections. ~o galling was evident in the connection or on the pin throughout the test. In order ~o understand the terminology, col. (1) represents the time of day; col. ~2) is tensile load created by the internal applied gas pre~sure (nitrogen); col. (3) is load applied by pulling frame;
col. (4) is combined load o cols~ (2) and (3); col.
~5) reflects heat cycling; and, with respect to col.
~6), leaks were recorded in estimated bubbl2s per : minute e~caping from a leaking connection and ed into a jar of water throu~h a ~mall diameter tube.
EiF~5 .Thermocycle: ~8~ somL~si5lQn ~2Q

~1) (2) (3) (4) (5) ~6) time int.press tensile load comb.load temp. remarks : 20 (LBS) (LBS) (LBS) (F) 10:05 373S3 162900. 200253 76 no leak 10:18 37737 164100 201837 301 no leak lZ~;~4~37 LC-184 -49- , 10:41 37900 162900200800 101 no leak 11:02 37980 163900201880 299 no leak llol9 38069 16399020205~ 101 120 ~.P.M.
11:27 38061 163800201861 306 no leak 11:57 38100 163200201300 108 leak &
end of test Results:
No leak on first 2 complete cycles Small leak on 3rd cold cycle Leak sealed on 3rd hot cycle ~Q~2 ~E~QÇ~-~ ~ ~OMPOSTTIO~

~ 2) (33 ~4) (5) ~6) Time Int.pres~ tensile load comb.load temp. remarks ~LBS) ~LBS)(LBS) (OF) 16:53 13787 1501391~3926 80 0 17:13 433~2 15~126198468 312 0 17:35 45278 159272204550 288 . 0 17:~1 45270 159597204867 281 0 17:47 38402 152183 190585 96 160 ~ 8 17:53 35329165291 200620 92 1~0 17:58 40500165157 205657 324 5 18:02 43491165443 208~34 307 5 ~8:11 369~5165539 202494 93 160 18:14 35661166036 201697 96 160 18:1~ 40683165997 2~6~0 323 0 18:20 43402156521 199923 310 0 18:26 37874156845 19~719 95 180 18:2~ 3651276235 112747 96 180 18:31 3586~3400 39265 97 180 18:33 3519770159 105356 98 180 18:35 34478169513 203991 99 180 Results:
No leak on initial cycle Leak on cold cycles Leak reduced or stopped during hot cycle Z~37 2~ ~3) (~) ~5) ~6) time int.pres~ tensload comb.load temp. remarks S ~r~Bs) ~LBS) ~LEIS) 10:16 1323 134625 135948 297 No Leaks 10:18 13604 134281 147885295 through-out 10523 18873 134376 153249 291 t~st 1010:26188~0 134109 152949290 10:30 19162 13~223 153385330 10:31 19169 134051 153220304 10 :37 17180 134223 151403103 10:40 19021 134242 153263105 1510:4520337 134281 15461~ 306 10 :48 211~7 133994 155181 312 10:54 19680 133765 153445 99 03 18079 133~60 151939 102 11 :24 17557 134739 152296 100 2011:2718830 134090 152920 266 11:31 ~01~6 1341~7 154333 286 11 :38 18927 ~33879 152806 92 11:42 18124 133994 15~118 ~7 :~Z~L87 11:4~ 2~465133~79156344 294 11:53 23~30133841157071 2g7 11:59 2146413391~ 15~82 99 12:~4 203351339561542~1 104 12.05 200û0180690 ~00770 103 12:14 19350180289199639 99 12:18 21302179850201152 276 12 :20 219851800602~2045 2O7 12:26 20622180213200835 98 12:30 196781~0060199738 100 12:31 1968014190~161584 99 12:32 195~61~8663148249 99 12:32 1960078470 98070 98 12:34 19487785~6 98053 98 12:36 1936778699 98066 97 12:36 1939848435 67833 97 12:37 19452 2770 22222 97 RESULTS: Seal held throughout test.

~Z~Z~7 API compound was applied to the test connections and it leaked profusely at low pressureO

A test downhole was run on an actual well on July 6, 1986. This comprised a string of 7-5/8 inch w~dge connec~ion, 1,200 ft in length in the form of a liner at the bottom of a 12,800 ft. well. The pipe made up very smoothly with no problems. The pipe stuck in the hole during the lowering of the string~ which neceRsitated the pulling of the string. This re~ulted in the unusual opportunity to break the pipe out after more than a week o exposure to down hole conditions. The connection broke out very smoothly, with a minimum of cleaning required as compared to normal conditions using API pipe dopes. The average make up torque was 20,000 ft.lbs, and the average break out ~92~7 LC-184 -54~

torque was 30,000 ft~/lbso There was no evidence of galling. The test can be summarized as having been completely success~ul.

The well is located about 10 miles ~outhwest of Lafayette, Louisiana.
Drilling rig - Glasscock 73 Operation - DaYis Oil Connection manufacturer - Tubular Corporation of America~ Rou~ton~ Texas While the preferred embodiments of the invention have been disclosed in detail, it should be understood by tho6e skilled in the art that various lS modifications may be made to those embodimen~s disclosed without departing from the scope thereof a~
described in the specification and deined in the appended claims.

Claims (28)

1. In a pipe joint including pin and box members having opposed surfaces and intended for use in petroleum drilling operations, the improvement comprising:
a curable sealant composition of the anaerobic type applied in an uncured liquid state directly to said pipe joint prior to assembly and cured to a solid state following assembly so as to prevent fluid leakage through the joint, said sealant composition being of substantially equal constant volume both in the uncured liquid state and in the solid state.

2. A pipe joint as set forth in Claim 1 wherein, upon disassembly of said pin and box members when said sealant composition is in the fully cured state, said sealant composition is pulverized into a powder form without causing galling of said opposed surfaces.

3. A pipe joint as set forth in Claim 1 wherein said curable sealant composition is composed partially of a polymerizable acrylate ester monomer, the concentration of the acrylate ester monomer so chosen that the torque required for disassembly of said pipe joint is no less than the torque required for assembly of said pipe joint.

4. A method of sealing a pipe joint including pin and box members having threaded ends with mutually engageable helical surfaces intended for use in petroleum drilling operations comprising the steps of:

applying a curable sealant composition of the anaerobic type in the uncured liquid state directly to at least one of the helical surfaces;
assembling the threaded ends while the sealant composition remains in the uncured liquid state such that the sealant blocks all possible leak paths including the helical flow path defined by the helical surfaces; and curing the curable sealant composition without substantial volume change from the uncured liquid state to whereby seal the pipe joint.

5. A method as set forth in Claim 4 wherein the curable sealant composition is composed of a polymerizable acrylate ester monomer and other ingredients; and includes the step of:
controlling the concentration of the acrylate ester monomer to thereby determine the torque required to disassemble the threaded ends.

6. A method as set forth in Claim 5 wherein the step of assembling the threaded ends includes the step of:
administering a predetermined torque to the pin and box members; and wherein the step of controlling the concentration of the acrylate ester monomer includes the step of:
choosing a predetermined concentration of the monomer such that the torque required to disassemble the threaded ends after curing is no less than that required to assemble the threaded ends.

7. A method as set forth in Claim 5 wherein the step of assembling the threaded ends includes the step of:
administering a predetermined torque to the pin and box members; and wherein the step of controlling the concentration of the acrylate ester monomer includes the step of:
choosing a predetermined concentration of the monomer such that the torque required to disassemble the threaded ends is no less than that required to assemble the threaded ends.

8. A method as set forth in Claim 4 wherein the curable sealant composition is composed partially of a polymerizable acrylate ester monomer and including the step of:
administering a torque to the pin and box members which thereby results in the application of a tension to the pipe joint;
and providing the sealant composition with a lubricating ingredient to thereby control the tension to the pipe joint resulting from administering a specific magnitude of torque to the pin and box members.

9. A method as set forth in Claim 8 wherein the lubricating ingredient is at least one of powders of polytetrafluoroethylene and polyethylene.

10. A sealed connection to two tubular members intended for use in petroleum drilling operations comprising:

a pin member;
a box member mechanically joined to said pin member to thereby form a joint therebetween; and a cured sealant of the anaerobic type containing no solvent within said joint to prevent leakage through said joint, said sealant being armed after said joint is formed and composed partially of a polymerizable acrylate ester monomer the concentration of the acrylate ester monomer so chosen that the torque required for disassembly of said pin member and said box member is no less than the torque required for assembly of said pin member and said box member.

11. A sealed connection as set forth in Claim 10 wherein a torque applied to said pin and said box members results in the application of a tension to said connection; and wherein a torque applied to said pin and said box members results in the application of a tension to said connection; and wherein said sealant includes a lubricating ingredient to thereby control the tension to said connection resulting from the application of a specific magnitude of torque to said pin and said box members.

12. A sealed connection as set forth in Claim 11 wherein said lubricating ingredient is at least one of powders of polytetrafluoro-ethylene and polyethylene.

13. A method of sealing a pipe joint intended for use in petroleum drilling operations, the pipe joint including first and second opposed threaded pipe ends and a threaded coupling for threaded engagement with the pipe ends, the pipe ends and the coupling having mutually engageable helical surfaces, the method comprising the steps of:
applying a curable sealant composition of the anaerobic type in the uncured state directly to at least the helical surfaces of the pipe ends;
assembling the pipe ends and the coupling such that the sealant blocks all possible leak paths including the helical flow path defined by the helical surfaces;
curing the sealant composition; and controlling the concentration of ingredients in the sealant composition to thereby determine the torque required to disassemble the pipe joint.

14. A method as set forth in Claim 13 wherein the step of applying a curable sealant composition includes the steps of:
applying the sealant composition having a first concentration of ingredients resulting in a first magnitude of torque required to disassemble the first threaded pipe end and the coupling; and applying the sealant composition having a second concentration of ingredients resulting in a second magnitude of torque, different from said first magnitude of torque, required to disassemble the second threaded pipe end and the coupling.

15. A method as set forth in Claim 13 wherein the curable sealant composition is composed of a polymerizable acrylate ester monomer and other ingredients; and wherein the step of controlling the concentration of ingredients in the sealant composition includes the step of:
controlling the concentration of the acrylate ester monomer therein.

16. A sealed connection of two tubular members intended for use in petroleum drilling operations comprising:
a box member including a first pin member having a threaded end and a threaded coupling member, said first pin member and said coupling member having mutually engageable helical surfaces, said first pin member and said coupling member being threadedly joined;
a cured sealant having a first concentration of ingredients applied in the uncured state to said helical surfaces of said box member to prevent leakage between said first pin member and said coupling member along a helical flow path defined by said helical surfaces, said first concentration of ingredients resulting in a first magnitude of torque required to disassemble said first pin member from said coupling;
a second pin member having a threaded end, said second pin member and said coupling member having mutually engageable helical surfaces, said second pin member and said box member being threadedly joined;
said cured sealant having a second concentration of ingredients applied in the uncured state to said helical surfaces between said second pin member and said coupling member to prevent leakage therebetween along a helical flow path defined by said helical surfaces, said second concentration of ingredients resulting in a magnitude of torque, different from said first magnitude of torque, required to disassemble said second pin member from said box member.

17. A sealed connection as set forth in Claim 16 wherein said sealant is of the anaerobic type.

18. A sealed connection as set forth in Claim 16 wherein said sealant is of the anaerobic type composed partially of a polymerizable acrylate ester monomer, said concentration of said acrylate ester monomer being chosen such that the torque required for disassembly of said first pin member and said coupling member is different from that required for disassembly of said second pin member and said box member.

19. In a pipe joint including in and box members having opposed surfaces and intended for use in petroleum drilling operations, the improvement comprising:
a curable sealant composition applied in an uncured liquid state to said pipe joint during assembly and cured to a solid state following assembly so as to prevent fluid leakage through the joint;
wherein, upon disassembly of said pin and box members when said sealant composition is in the fully cured states, said sealant composition is pulverized into a power form without causing galling of said opposed surfaces.

20. A method of sealing pipe joint intended for use in petroleum drilling operations, the pipe joint including first and second opposed threaded pipe ends and a threaded coupling for threaded engagement with the pipe ends, the pipe ends and the coupling having mutually engageable helical surfaces, the method comprising the steps of:
applying a curable sealant composition in the uncured state to at least the helical surfaces of the pipe ends;
assembling the pipe ends and the coupling such that the sealant blocks all possible leak paths including the helical flow path defined by the helical surfaces;
curing the sealant composition; and controlling the concentration of ingredients in the sealant composition to thereby determine the torque required to disassemble the pipe joint;
the step of applying a curable sealant composition including the steps of:
applying the sealant composition having a first concentration of ingredients resulting in a first magnitude of torque required to disassembly the first threaded pipe end and the coupling; and applying the sealant composition having a second concentration of ingredients resulting in a second magnitude of torque, different from said first magnitude of torque, required to disassemble the second threaded pipe end and the coupling.

21. A method of sealing a pipe joint intended for use in petroleum drilling operations, the pipe joint including first and second opposed threaded pipe ends and a threaded coupling for threaded engagement with the pipe ends, the pipe ends and the coupling having mutually engageable helical surfaces, the method comprising the steps of:
applying to at least the helical surfaces of the pipe ends a curable sealant composition of the anaerobic type composed of a polymerizable acrylate ester monomer and other ingredients in the uncured state;
choosing for application to the first threaded pipe end the sealant composition having a first predetermined concentration of the monomer such that the torque required to disassemble the first pipe end and the coupling will be of a first magnitude; and choosing for application to the second threaded pipe end the sealant composition having a second predetermined concentration of the monomer such that the torque required to disassemble the second pipe end and the coupling will be of a second magnitude different from the first magnitude;
assembling the pipe ends and the coupling such that the sealant blocks all possible leak paths including the helical flow path defined by the helical surfaces;
curing the sealant composition; and controlling the concentration of the acrylate ester monomer in the sealant composition to thereby determine the torque required to disassemble the pipe joint.

22. A method as set forth in Claim 21 including the step of:
providing the sealant composition with a lubricating ingredient to thereby control the tension to the pipe joint resulting from administering a specific magnitude of torque to the respective pipe ends.

23. A method as set forth in Claim 22 wherein the lubricating ingredient is at least one of polytetrafluoroethylene and polyethylene.

24. A sealed pipe joint intended for use in petroleum drilling operations produced in accordance with the method of Claim 13.

25. A method of sealing a pipe joint having a longitudinal axis and including adjoining pin and box members having opposed surfaces and intended for use in petroleum drilling operations comprising the steps of:
applying a curable sealant composition of the anaerobic type in the uncured liquid state to at least one of the opposed surfaces to prevent leakage after curing occurs;
while the sealant composition remains in the uncured liquid state, joining the two members together so that the sealant composition after curing adheres to the opposed surfaces of both the pin and box members and blocks the flow path in the longitudinal direction existing between the opposed surfaces; and curing the sealant composition to the solid state without substantial volume change from the uncured liquid state to thereby prevent fluid leakage through the joint.

26. A sealed connection between pin and box members of a pipe joint having opposed surfaces and intended for use in petroleum drilling operations produced in accordance with the method of Claim 25.

27. A connection as set forth in Claim 26 wherein said curable sealant composition is composed partially of a polymerizable acrylate ester monomer, the concentration of the acrylate ester monomer so chosen that the torque required for disassembly of said pipe joint is no less than the torque required for assembly of said pipe joint.

28. A connection as set forth in Claim 26 wherein a torque applied to said pin and said box members results in the application of a tension to said pipe joint; and wherein said sealant composition includes a lubricating ingredient to thereby control the tension to said pipe joint resulting from administering a specific magnitude of torque to said pin and said box members.