MXPA00001446A - Apparatus for amorphous bonding of tubulars - Google Patents

Abstract

An apparatus for amorphous bonding of tubulars (110, 111) comprises a double skin jacket (2, 113, 114) which can be placed around said tubulars (110, 111), which skins define a sealed inner fluid space (11, 121) which contains shield gas and a heating element (1, 129) and a sealed outer fluid space (9, 119) surrounding the inner fluid space (11, 121) to reduce the risk of explosion during the amorphous bonding process.

Description

AN APPARATUS FOR THE AMORFA UNION OF TUBULAR ELEMENTS Field of the invention This invention relates to an apparatus for the amorphous union of tubular elements.

BACKGROUND OF THE INVENTION During the construction of oil and gas wells it is usual to connect a large number of tubular elements. Conventionally this is done by means of threaded couplings. One of the disadvantages of this construction is that the couplings are subject to corrosion with the result that a complete column of tubular elements may have to be replaced every couple of years, particularly in high pressure, high temperature wells containing corrosive vapors.

It has been suggested that the useful life of such tubular elements could be greatly increased, perhaps up to 25 years, if couplings could be dispensed with.

One proposal to address this problem was to weld tubular elements together. However, this is REF .: 32613 extremely dangerous in the mouth of an oil or gas well. In addition, normal manual welding does not produce a homogeneous metallurgical structure and the problem of corrosion remains.

A metal-bonding technique known as "amorphous bonding" was successfully used in the automotive industry. The surfaces of the components to be joined are molded to achieve parallelism. A sheet of a metal alloy is then placed between the components, which are mechanically pressed together. The joint is then subjected to local heating by means of an inductive heater. The resulting structure is approximately metallurgically homogeneous.

It will be appreciated that it would be extremely desirable to be able to join tubular elements by amorphous bonding. However, the technical difficulties are discouraging in that it is necessary to transfer an ideally suitable procedure for a precision factory to an area where mixtures of flammable and frequently explosive gases are present and where the stiffness of a factory floor is replaced by a drilling rig that may well be offshore and that may be in continuous motion in rough seas and bad weather.

It is noted that British Patent Specification No. 540,519 discloses a welding device comprising an annular burner that is surrounded by an annular water cooling jacket to reduce the explosion hazards during the welding process.

European Patent Application No. 157131 discloses a double chamber sealing system for welding pipe ends, which injects protective inert gas in radial and axial directions towards unsealed areas around the welding zone to prevent air pollution from said area.

European Patent Application No. 418606 discloses an amorphous bonding apparatus in which protective nitrogen gas is injected into a jacket surrounding the joined tubular ends and nitrogen gas is also injected into the interior of the tubular elements to create a virtually free atmosphere of oxygen in the region of the union.

Although the known devices provide some protection against explosion hazards, they do not provide sufficient protection in the hazardous environment at the mouth of an oil or gas well.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates mainly to the reduction of the risk of explosion while the amorphous union occurs.

According to the present invention there is provided an apparatus for the amorphous connection of the ends of tubular elements that are aligned in a substantially axial manner and surrounded by a protective gas, said apparatus comprising a sleeve which during use is located around said ends. adjacent tubular ends, said jacket having an inner layer, which during use, defines a sealed interior fluid space containing a heating element and a protective gas and an outer layer surrounding the inner layer so that during use an outer fluid space sealed between said inner and outer layers is defined.

It is preferred that said jacket be formed by two parts mounted in a sliding manner on a support structure and that they can be brought to form said jacket and that the inner layer be provided with a fluid communication means that allows the fluid to circulate during the use of the fluid. a controlled manner from the interior fluid space to the exterior fluid space or vice versa.

In one embodiment the apparatus comprises an element for introducing a protective gas into the interior fluid space and an element for introducing water into the outer fluid space and the fluid communication element comprises a conduit which during use can lead said shielding gas within said outer fluid space at a selected depth below the water level in the outer fluid space so that a selected pressure difference between the inner and outer fluid spaces is maintained.

In an alternative embodiment the apparatus comprises an inlet tube for introducing a shielding gas into the outer fluid space, a hole in the inner layer to allow the shielding gas to circulate from the outer fluid space to the fluid space inside and an outlet tube to allow the shielding gas to exit the interior fluid space; wherein pressure control elements are preferably provided which during use control the pressure in the interior and exterior fluid spaces so that the pressure in the interior fluid space is greater than the ambient pressure and that the pressure in the interior space is greater than the ambient pressure. outer fluid is greater than in the interior fluid space. In this way a high pressure gas shield is created in the outer fluid space which prevents air from flowing into the interior fluid space and the hot protective gases escaping from the interior fluid space into the atmosphere.

Conveniently, the apparatus further comprises a sealant which during use is inserted into the interior of the tubular ends that are joined by the apparatus, which obturator comprises an elongate mandrel having an elastic obturator element adjacent to each end thereof, an element that allows the introduction of an inert protective gas at one end of said elongated mandrel and that allows it to leave said elongate mandrel between said elastic obturator elements, and an element to allow water to enter said end of said elongated mandrel and that allows it to leave said elongated mandrel between said elastic shutter elements.

It will be understood that the outer bilayer jacket and the inner seal provide adequate protection against explosion hazards during the amorphous bonding process as they prevent explosive gases from reaching the area of the heating element and the tubular elements heated in this way, and also avoid that hot protective gases or other fluids escape into the surrounding atmosphere.

For a better understanding of the present invention reference will now be made, by way of example, to the accompanying drawings, wherein: Fig. 1 is a vertical section through an amorphous apparatus according to the present invention; Fig. 2 shows in enlarged scale a view according to line II-II of Fig. 1; and Fig. 3 shows a schematic sectional view of an apparatus according to the present invention wherein pressurized protection gas is injected through the outer fluid space in the interior fluid space and then vented to the atmosphere.

With reference to Fig. 1, an amorphous attachment apparatus is shown which is generally identified with the reference number 101.

The amorphous connecting apparatus 101 comprises a support structure 102 which is provided with wheels 103 running in channels (not shown).

Two jaws 104 and 105 are disposed towards the bottom of the support structure 102 while two other jaws 106 and 107 are mounted near the top of the support structure 102 and can be moved vertically by two piston and cylinder assemblies 108 and 109 .

During use, a lower tubular member 110 is secured in wedges (not shown). The support structure 102 is displaced towards the lower tubular member 110 and the jaws 104 and 105 are secured thereto.

An upper tubular member 111 is then moved to the position using a lifter or positioning device and clamped in the jaws 106 and 107.

The piston and cylinder assemblies 108 and 109 are then actuated to bring the lower end of the upper tubular end 111 close to the upper end of the lower tubular member 110. The adjacent ends of the upper and lower tubular elements are then aligned and machined from each other. so that the adjacent ends are substantially flat and parallel to each other.

An alloy sheet is then placed on the upper surface of the lower tubular member 110 and the upper tubular element 111 is forced down the piston and cylinder assemblies 108, 109 with a predetermined pressure that varies according to the composition of the elements tubular and the composition of the sheet.

At this point the sealable heating apparatus 112 is mounted on the tubular elements by placing the sheet thereon. The sealable heating apparatus 112 comprises two halves 113 and 114 which can be advanced and retracted by hydraulic jacks. In particular, the half 112 can be advanced and retracted by hydraulic jacks 115 while the half 113 can be advanced and retracted by hydraulic jacks 116.

As can be seen in Fig. 2 the half 113 comprises an inner layer 117 and an outer layer 118 defining an outer fluid space 119 therebetween. The faces of the inner layer 117 and the outer layer 118 are each provided with elastic seals 120 which engage on sealing surfaces in the middle 114 and together define a jacket surrounding the lower tubular element 110 and the upper tubular element 111. The seals elastics 120 also extend around the lower tubular element 110 and the upper tubular element 111, respectively. As indicated above, after the ends of the lower tubular member 110 and the upper tubular member 111 were prepared for joining, a film of a suitable alloy is placed therebetween and the upper tubular member 111 is pressed against the lower tubular member. 110 The halves 113 and 114 are then moved to the position on each side of the tubular elements 110, 111 and pressed together with the hydraulic jacks as to form an inner chamber 121 enclosed by the inner layer 117. The two halves 113 and 114 they are subjugated to each other with six mechanical fasteners (not seen) to ensure that the others do not inadvertently stop.

The outer fluid space 119 is then filled with water (H20) from the inlet tube 122. The water fills the outer fluid space 119 and leaves it through the outlet tube 123. The water is pumped continuously through the space of external fluid 119 and its presence is detected by a sensor 124 which is designed to inhibit the rest of the process if no water is present or the water temperature exceeds a predetermined temperature.

The outer fluid space 119 can be emptied through a drain line 125. An emergency water tank 126 and a surge water supply 127 are provided so that the exterior fluid space 119 can be flooded with water in an emergency , for example, a catastrophic failure of a seal resulting in a loss of water from the exterior fluid space 119.

The interior fluid space or chamber 121 is cooled by a flow of shielding gas which is introduced through a manifold 128 located under an induction heating ring 129. The shielding gas is supplied through a supply pipe. of gas 130 which in turn is connected to a source of compressed air through an air line 131 and a source of argon gas protection through an argon line 132.

The inner chamber 121 is also provided with two gas outlet tubes 133, 134 which are connected to an outlet manifold 135. The outlet manifold 135 is connected to an argon circulation line 136 and a line 153 that opens to the outer fluid space 119 well below the outlet tube 123.

A sampling tube 137 is provided to allow gas samples to be taken and analyzed continuously from inside the inner chamber 121.

The induction heating ring 129 is independently cooled by water (HO) by means of a water supply which is pumped through the inlet tube 138 and exits through the outlet pipe 139. The induction heating ring 129 it is provided with energy by means of heavy metal conduits which are symbolized by conductors 140 and 141.

While the heating apparatus 112 is prepared, an inner shutter 142 is lowered into the upper tubular element 111. The objective of the inner shutter 142 is threefold: 1) to prevent flammable and possibly explosive vapor from rising through the lower tubular element 110; 2) prevent air from flowing down the upper tubular element 111; and 3) allow the creation of a desired atmosphere in the vicinity of the union.

For such purposes the inner obturator 142 comprises an elongate mandrel 143 with an elastic obturator element 144, 145 at each end thereof. Each elastic shutter element 144, 145 is connected to a pressurized water source through a shutter element control line 146. When pressurized water is supplied through the shutter member control line 146 the two elements of obturator 144, 145 expand and form a seal between elongated mandrel 143 and upper tubular element 111 and lower tubular element 110, respectively, thereby forming an insulated chamber 147.

The center of the elongated mandrel 143 is provided with an elongated hole 148 which is connected to a water inlet tube (H20) 149 and is provided with numerous radial outlet tubes 150 that open inside the insulated chamber 147. A tube of supply of argon.151 also passes downwardly through the elongated mandrel 143 and opens in the insulated chamber 147 immediately above the elastic shutter member 145.

After the apparatus 112 was correctly positioned, the inner shutter 142 was positioned and the elastic shutter elements 144, 145 were fixed, the amorphous bonding procedure is performed as follows: 1. A flow of water is established through the outer fluid space 119. 2. The inner chamber 121 is purged with air for a set time and in any case until the gas sampled through the safety device 137 does not register an unacceptable level of hydrocarbons. 3. The air supply is disconnected and argon is passed through the inner chamber 121 to form an argon protective gas atmosphere towards the outside of the joint. 4. When the gas sample taken through the sampling tube 137 indicates that the atmosphere in the inner chamber 121 is substantially pure argon, the inner chamber 121 is ready. During steps 3 and 4 the argon leaves the system through the argon circulation line 136 and can, if desired, be recovered for use in another application. 5. During steps 2, 3 and 4 the insulated chamber 147 is purged by the introduction of argon shielding gas through an argon supply tube 151. The argon purges the insulated chamber 147 and escapes through a tube of exit (that is not seen). A sensor in the outlet tube controls the argon content of the gas passing through the outlet pipe and inhibits activation of the induction heating ring 129 until the gas passing through the outlet pipe is substantially pure argon. Air is also introduced into the upper tubular member 111 through the tube 152 to purge any combustible gas within the upper tubular member. 6. In this step, energy is applied to the induction heating ring 129 to heat the metal in the area of the junction to a temperature in the range of about 1000-1300'C for a predetermined period. However, safety requirements require that the surrounding area be kept as cold as possible. With this in mind, argon is pumped through inner chamber 121 and insulated chamber 147 through the heating process. In addition, air is pumped through the tube 152.

The argon leaving the inner chamber 121 through the gas outlet pipes 133, 134 is directed through the line 153 by closing valves 154 and opening 155. The argon bubbles through the water and is cooled in this way before being vented to the atmosphere. In addition, the argon pressure in the inner chamber 121 can be controlled by varying the depth of the outlet of the line 153 below the water level. This provides a simple and effective method of pressure control in the inner chamber 121.

After the required period the induction heating ends and the union is allowed to cool while the argon flow continues.

When the junction is sufficiently cooled, the supply of argon is terminated through the argon supply line 151 and cooling water is introduced through the water inlet pipe 149. The water supply continues until the tubular elements 110 and 111 were conveniently cooled by interrupting the supply of argon to the inner chamber 121 through the gas supply tube 130. The water supply to the outer fluid space 119 is also interrupted and the outer fluid space 119 is drained by opening a valve 156 on the drainage line 125.

The halves 113 and 114 are then removed.

Only when it is determined that it is safe to do this, the water supply to the shutter 142 is terminated through the water inlet pipe 149. The elastic shutter elements 144, 145 are then deflated and the shutter 142 is removed.

The tubular elements 110 are then released from the jaws 104, 105, 106, 107 and the amorphous union apparatus 101 is removed.

* The union is then tested. If the test is successful the tubular elements are hoisted to allow the wedges to be released and to be lowered into the hole. Then the wedges are applied and the procedure is repeated.

Various modifications to the described embodiment are contemplated, for example, air, or preferably, as described with reference to Fig. 3, an inert shielding gas such as nitrogen, may be circulated through the exterior fluid space. instead of water. Instead of purging the insulated space 147 with argon it may be initially purged with air, subsequently argon in the heating step. If desired, after the induction heating was completed and cooling started, the elastic shutter member 144 (but not the elastic shutter member 145) could be released prior to the introduction of cooling water. This would allow any steam found to escape quickly and then purge the interior of the upper tubular element.

Turning now to FIG. 3, an amorphous-binding heating coil with the reference number 1 is identified.

The amorphous bonding heating coil 1 surrounds a tubular element 110 and is surrounded by a jacket sleeve 2 having a first half 3 and a second half 4.

Each half 3, 4 comprises an inner layer 7 and an outer layer 8 defining an annular outer space 9 therebetween. The halves 3 and 4 are provided with seals which engage each other when the halves 3 and 4 are fastened together and which are intended to form the sealed sleeve jacket 2. However, to facilitate the understanding of the present invention it will be considered that there is a small separation 5 between the halves 3, 4.

During use, an inlet tube 6 carries a protective inert gas to an annular outer space 9 between the inner layer 7 and the outer layer 8. The outer annular fluid space 9 is maintained at a pressure Pl which is slightly greater than the pressure of the environment PO. An orifice 10 allows part of the protective inert gas to pass into an interior fluid space 11 within the inner layer 7. The inert gas can then pass from the interior fluid space 11 to an isolated outlet tube 12 through a hole 13 which is for maintaining pressure P2 in chamber 11 between Pl and PO.

During use, cold inert gas is passed through the inlet pipe 6. Part of the cold inert gas passes into the annular outer fluid space 9 while the rest flows through the interior fluid space 11 through the hole 10 and the orifice 13. When the induction heater 1 is in operation the inert gas in the interior fluid space 11 is heated and the heated inert gas escapes through the isolated outlet pipe 12 which vents to the atmosphere in a safe area optionally after being chilled indirectly.

As can be seen from the arrows 14, 15, in the case of a leak in the inner layer 8, cold inert gas from the annular outer fluid space 9 passes through the separation to the ambient air since the pressure Pl in the space 9 is greater than the pressure of the PO environment. Similarly, in the case of a leak in the inner layer 7 cold inert gas will pass from the space 9 through the inner layer 7 to the inner fluid space 11.

It will be appreciated that with the disclosed configuration, the probability that hot protective gases escape into the atmosphere surrounding the envelope 2 is small.

Various modifications of the claimed embodiment are contemplated, for example, the inlet tube 6 and the orifice 10 could be arranged to help ensure that the annular outer fluid space 9 is constantly filled with cold inert gas thus reducing the possibility of accumulation of small pockets of hot inert gas in the outer fluid space 9. If desired, several inlet pipes 6 and several holes 10 may be provided.

It will be appreciated that the holes 10 and 13 may be formed by adjustable valves or pressure relief valves.

If desired, flow and temperature sensors that are located to stop the amorphous bonding process and soak the entire area with water may be provided if a signal indicating a large loss is detected.

Such sensors could comprise flow sensors in the inlet pipe 6 and the isolated outlet pipe 12.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (9)

1. An apparatus for the amorphous joining of ends of tubular elements that are in a substantially axial alignment and surrounded by protective gas characterized in that said apparatus comprises a sleeve which during use is placed around the ends of adjacent tubular elements, said sleeve having an inner layer defining during use a sealed inner fluid space containing a heating element and protective gas, and an outer layer surrounding the inner layer so that during use a sealed outer fluid space is defined between said inner and outer layers.

2. An apparatus according to claim 1, characterized in that said liner is formed by two parts that are slidably mounted on a support structure and that can be joined together to form said liner.

3. An apparatus according to claim 1, characterized in that the inner layer is provided with fluid communication elements that allow during use that the fluid circulates in a controlled manner from the interior fluid space towards the exterior fluid space or vice versa.

4. An apparatus according to claim 1, characterized in that it includes elements for introducing protective gas into the interior fluid space and elements for introducing water into the outer fluid space and wherein the fluid communication element comprises a conduit which during the Use can drive said protective gas within said outer fluid space to a selected depth below the water level in the outer fluid space.

5. An apparatus according to any of the preceding claims, characterized in that it includes a sensor that operates during use to inhibit the amorphous union of said tubular elements if there is not enough water or other fluid in the outer fluid space.

6. An apparatus according to claim 1, characterized in that it comprises an inlet pipe for introducing a shielding gas into the outer fluid space, a hole in the inner layer to allow the shielding gas to circulate from the outer fluid space towards the interior fluid space and an outlet tube to allow the shielding gas to exit the interior fluid space.

7. An apparatus according to claim 1 or 6, characterized in that it further comprises pressure control elements which during use control the pressure in the interior and exterior fluid spaces so that the pressure in the interior fluid space is greater than the pressure in the interior fluid space. ambient pressure and that the pressure in the outer fluid space is greater than in the interior fluid space.

8. An apparatus according to claim 2, characterized in that at least two jaws are mounted on said support structure; one of said jaws being adapted to grip a lower tubular element and the other of said jaws for gripping an upper tubular element; and elements are provided to move one of said jaws relative to the other so that said tubular elements can be brought toward each other.

9. An apparatus according to claim 8, characterized in that it further comprises a shutter which during use is inserted into the interior of the tubular ends that are joined by the apparatus, a shutter comprising an elongate mandrel having an adjacent elastic obturator element at each end thereof, an element that allows a shielding gas to be introduced at one end of said elongated mandrel and that leaves said elongated mandrel between said elastic shutter elements, and an element that allows water to be introduced into said end of said elongate mandrel. said elongated mandrel and leaving said elongated mandrel between said elastic obturator elements.