U.S. patent application number 10/943575 was filed with the patent office on 2006-03-23 for method for extending the life of thin walled tubing and austempered weld stress relieved thin walled tubing.
Invention is credited to Dan Thomas Benson.
Application Number | 20060060267 10/943575 |
Document ID | / |
Family ID | 36072658 |
Filed Date | 2006-03-23 |
United States Patent
Application |
20060060267 |
Kind Code |
A1 |
Benson; Dan Thomas |
March 23, 2006 |
Method for extending the life of thin walled tubing and austempered
weld stress relieved thin walled tubing
Abstract
The present invention is directed to a method of extending the
life of thin walled tubing by austempering the tubing in a
controlled continuous run process involving heating, quenching, and
cooling the tubing pursuant to predetermined process parameters.
The invention is also directed to a process for austempering tubing
having a welded seam and for relieving residual stress in the weld.
The invention is further directed to the product of the above
processes as well as an austermpered weld stress relieved thin
walled tubing and such tubing in combination with other apparatus
with which it is suitable for use in the production of
hydrocarbons.
Inventors: |
Benson; Dan Thomas;
(Tomball, TX) |
Correspondence
Address: |
DUANE, MORRIS, LLP
3200 SOUTHWEST FREEWAY
SUITE 3150
HOUSTON
TX
77027
US
|
Family ID: |
36072658 |
Appl. No.: |
10/943575 |
Filed: |
September 17, 2004 |
Current U.S.
Class: |
148/570 ;
148/575; 148/594; 266/112 |
Current CPC
Class: |
C21D 1/607 20130101;
Y02P 10/25 20151101; Y02P 10/253 20151101; C21D 1/42 20130101; C21D
1/30 20130101; C21D 9/08 20130101 |
Class at
Publication: |
148/570 ;
148/575; 148/594; 266/112 |
International
Class: |
C21D 1/42 20060101
C21D001/42; C21D 9/08 20060101 C21D009/08 |
Claims
1. A method for austempering thin walled tubing, comprising: a.
heating a section of metallic tubing having a wall thickness of
less than 0.25 inches to a high temperature in the range of
1300-1600.degree. F. in a heater; b. moving the section of metallic
tubing from the heater to a low temperature reservoir as part of a
continuous run process; c. quenching the section of metallic tubing
in the low temperature reservoir to reduce the temperature of the
section of metallic tubing to a first low temperature in the range
of 500-1000.degree. F. in a time period of less than 3 seconds; d.
allowing the section of metallic tubing to transform to bainite; e.
moving the section of metallic tubing transformed into bainite out
of the low temperature reservoir as part of the continuous run
process; and f. cooling the section of metallic tubing to a second
low temperature below 100.degree. F.
2. The method of claim 1, wherein the heater used for heating is an
induction heater.
3. The method of claim 1, wherein the low temperature reservoir
used for quenching is a molten salt bath.
4. The method of claim 1, wherein the moving is accomplished in
part by using rollers.
5. The method of claim 1, wherein the cooling is accomplished by
forced convection.
6. The method of claim 1, wherein the section of metallic tubing
comprises a steel alloy with a carbon content greater than or equal
to 0.25 and less than or equal to 0.45.
7. The method of claim 6, wherein the section of metallic tubing
comprises 4130 alloy steel.
8. The method of claim 1, wherein the section of metallic tubing
comprises a time-temperature-transformation curve where the start
of conversion to austentite-ferrite is at least 0.75 seconds after
quenching in the low temperature reservoir.
9. The method of claim 1, wherein the heater comprises a flame.
10. A method for austempering thin walled coiled tubing,
comprising: a. extending a section of thin walled metallic tubing
having a wall thickness of less than 0.25 inches from a reel
mounted coil into a heater as part of a continuous run process; b.
heating the section of metallic tubing to a high temperature in the
range of 1300-1600.degree. F. in the heater; c. moving the section
of metallic tubing from the heater to a low temperature reservoir
as part of the continuous run process; d. quenching the section of
metallic tubing in the low temperature reservoir to reduce the
temperature of the section of metallic tubing to a first low
temperature in the range of 500-1000.degree. F. in a time period of
less than 3 seconds; e. allowing the section of metallic tubing to
transform to bainite; f. moving the section of metallic tubing
transformed into bainite out of the low temperature reservoir as
part of the continuous run process; and g. cooling the section of
metallic tubing to a second low temperature below 100.degree.
F.
11. The method of claim 10, further comprising the step of coiling
the section of metallic tubing after it reaches the second low
temperature.
12. The method of claim 10, wherein the low temperature reservoir
used for quenching is a molten salt bath.
13. The method of claim 10, wherein the cooling is accomplished by
forced convection.
14. The method of claim 10, wherein the thin walled metallic tubing
wall has a thickness of around 0.120 inches.
15. An austempered thin walled tubing produced by the method of
claim 10.
16. A method for austempering and stress relieving a thin walled
coiled tubing, comprising: a. extending a section of thin walled
metallic tubing having a welded seam and a wall thickness of less
than 0.25 inches from a reel mounted coil into a heater as part of
a continuous run process; b. heating the section of metallic tubing
to a high temperature in the range of 1300-1600.degree. F. in the
heater; c. moving the section of metallic tubing from the heater to
a low temperature reservoir as part of the continuous run process;
d. quenching the section of metallic tubing in a low temperature
reservoir to reduce the temperature of the section of metallic
tubing to a first low temperature in the range of 500-1000.degree.
F. in a time period of less than 3 seconds; e. allowing the section
of metallic tubing to transform to bainite; f. moving the section
of metallic tubing transformed to bainite out of the low
temperature reservoir as part of the continuous run process; and g.
cooling the section of metallic tubing to a second low temperature
below 100.degree. F.
17. The method of claim 15, wherein the section of metallic tubing
comprises a steel alloy with a carbon content greater than or equal
to 0.25 and less than or equal to 0.45.
18. The method of claim 16, wherein the section of metallic tubing
comprises 4130 alloy steel.
19. The method of claim 15, wherein the low temperature reservoir
used for quenching is a molten salt bath.
20. An austempered thin walled and stress relieved welded tubing
produced by the method of claim 15.
21. A thin walled welded tube, comprising: a. an austempered
cylindrical body created as part of a continuous run process, the
austempered cylindrical body comprising a first seam edge, a second
seam edge, and a wall having a thickness of less than 0.25 inches;
and b. a stress relieved welded seam joining the first and second
seam edges.
22. The tubing of claim 20, wherein said tubing has a length of at
least 200 feet.
23. The tubing of claim 21, wherein said tubing is coiled on a
reel.
24. The tubing of claim 23, wherein the tubing comprises a first
end region attached to at least one of (i) a motor, (ii) an
overshoot jar, (iii) an intensifier, (iv) a landing nipple, (v) a
plug catcher, (vi) a casing scraper, (vii) a snake pin, (viii) a
downhole tool, or (ix) a valve.
25. The tubing of claim 24, wherein the tubing comprises a second
end region opposite the first end region connected to a pump.
26. An apparatus for austempering thin walled tubing, comprising:
a. a heater adapted to accept a section of metallic tubing that has
a wall thickness of less than 0.25 inches and heat the section of
metallic tubing to a high temperature in the range of
1300-1600.degree. F. in a continuous run process; b. a low
temperature reservoir adapted to accept a moving section of the
metallic tubing as part of a continuous run process and to reduce
the temperature of the section of metallic tubing to a first low
temperature in the range of 500-1000.degree. F. in a time period of
less than 3 seconds; and c. a cooler adapted to cool the section of
metallic tubing to a second low temperature below 100.degree.
F.
27. The apparatus of claim 27, wherein the heater comprises at
least one of (i) an induction heater or (ii) a flame
28. The apparatus of claim 28, wherein the heater is located at
least one of (i) proximate the low temperature reservoir or (ii)
within the low temperature reservoir.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is directed to a method of extending
the life of thin walled tubing by austempering the tubing in a
controlled process involving heating, quenching, and cooling the
tubing pursuant to predetermined process parameters. The invention
is also directed to a process for austempering tubing having a
welded seam and for relieving residual stress in the weld. The
invention is further directed to the product of the above processes
as well as an austempered weld stress relieved thin walled tubing
and such tubing in combination with other apparatus with which it
is suitable for use in the production of hydrocarbons.
[0003] 2. Description of the Prior Art
[0004] Each instance tubing is rolled on or off a coil tubing reel,
it is permanently elongated. The elongation accumulates until
exhausted and the tubing breaks. Hence, elongation is a significant
property of the tubing material.
[0005] The second significant property of tubing material is
strength or hardness. This quality resists dialation stesses of
pressure and tension stresses of deployments in deep wells.
[0006] A characteristic of steel is decreasing elongation with
increasing hardness. Metallurgically, an ideal coil tubing is a
paradox: hard for strength in deep or high pressure wells, ductile
for repetitive reeling.
[0007] Present technology coil tubing steels have a martensitic
structure. Martensite has unfavorable hardness versus elongation
trade-off. On the other hand, austempered steels have a bainitic
structure. Bainitic structured steels are not only hard, but also
retain commendable elongation.
[0008] Austempering of steel is known in the prior art, however it
is typically accomplished in a non-continuous batch process which
is unsuitable for coil tubing milling.
[0009] Represented by FIG. 1 is the current technology to
continuously mill steel tubing: metal strip is introduced to a tube
formation device, the seam welded and scarfed, and the formed
tubular annealed, e.g., by heating. The tubing is chilled by
cooling apparatus, and then travels through additional formation
devices, e.g., sizing rolls. The tubular may then be heated and
cooled again and taken up, e.g., on a reel. By welding the butts of
the strip stock at the front end of the process, very long lengths
of tubing can be milled.
[0010] In the continuous tube milling process, the sizing operation
in FIG. 1 work-hardens the tubing increasing the strength. The
thermal processes depicted in FIG. 1 are either palliatives for
problems caused by welding, or to soften tubing to the desired
grade after work-hardening. The thermal processes used in present
tubing milling technology do not harden the tube.
SUMMARY OF THE INVENTION
[0011] The present inventions are directed toward an apparatus and
methods useful for increasing the strength of the tubing while
maintaining the elongation of thin walled tubing by austempering
the thin walled tubing. The present invention is further directed
toward a method for austempering thin walled tubing comprising a
welded seam and for stress relieving the welded seam. The present
invention is also directed toward a product produced by the methods
and/or processes described above. The present invention is also
directed toward a thin walled austempered tubing comprising a
stress relieved welded seam.
DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic overview of a prior art system.
[0013] FIGS. 2 and 2a are schematic overviews of an exemplary
apparatus for practicing the present inventions' methods.
[0014] FIG. 3 is a view in partial perspective of a section of
austempered tubing.
[0015] FIG. 3 is a schematic view of an exemplary deployment of
austempered tubing in a well.
[0016] FIG. 5 is a block diagram of a first method of the present
invention.
[0017] FIG. 6 is a block diagram of a second method of the present
invention.
[0018] FIG. 7 is a block diagram of a third method of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Referring now to FIG. 2, exemplary apparatus 10 for
austempering thin walled tubing according to the methods of the
present inventions comprises heater 20, low temperature reservoir
30, and cooler 40. Apparatus 10 is adapted to be used with
continuous runs of tubing 12 while practicing the methods of the
present invention. As used herein, a continuous run is one which
processes a length of around 200 feet or more in a single
processing procedure.
[0020] Metallic tubing 12 has a wall thickness of less than 0.25
inches, preferably around 0.120 inches. In an embodiment, metallic
tubing 12 comprises a steel alloy with a carbon content greater
than or equal to 0.25 and less than or equal to 0.45 and may
comprise 4130 alloy steel. Metallic tubing 12 may be supplied from
source 15 of a substantially continuous supply of metal, e.g. a
rolled strip, and formed in to a tubular at tube former 90. Seams
created by tube formation may be welded at seam welder 91 and the
formed seam scarfed at scarfer 92.
[0021] Heater 20 is adapted to accept a section of metallic tubing
12 and heat the section to a high temperature in the range of
1300-1600.degree. F. Heater 20 may comprise an induction heater
and/or a flame or the like, or a combination thereof. Heater 20,
e.g. an induction heater, may be located proximate to or within low
temperature reservoir 30.
[0022] Low temperature reservoir 30 is adapted to accept a moving
section of metallic tubing 12 as part of a continuous run process
and to reduce the temperature of the section of metallic tubing to
a first low temperature in the range of 500-1000.degree. F. in a
time period of less than 3 seconds. Low temperature reservoir 30 as
used for quenching may comprise a molten salt bath. Moving may be
accomplished by numerous equivalent means including by using
rollers.
[0023] Cooler 40 is adapted to cool a section of metallic tubing 12
to a second low temperature below 100.degree. F. Cooling may be
accomplished by numerous equivalent means including by forced
convection. Additional coolers may be present, e.g. water cooler
93, as is practiced in the art.
[0024] Additional processing may occur after the second cooling.
For example, austempered metallic tubing 12 may be sized at sizing
rollers 94 and cooled further by coolers 96 and 97.
[0025] Austempered metallic tubing 12 may then be taken up, e.g. at
takeup reel 17.
[0026] Austempered thin walled welded tube 12 may be coiled on a
reel, e.g., takeup reel 17, which may be further mounted on ship 16
(FIG. 2a).
[0027] Referring to FIG. 3, austempered thin walled welded tube 12
may comprise first end region 12a adapted to be attached to device
19, e.g. a motor, an overshoot jar, an intensifier, a landing
nipple, a plug catcher, a casing scraper, a snake pin, a downhole
tool, a valve, or the like. Austempered thin walled welded tube 12
may further comprise second end region 12b opposite first end
region 12a which may be adapted to be further connected to device
18, e.g. a pump.
[0028] Austempered, thin walled, and stress relieved welded tubing
12 may be produced by any of the exemplary methods described
herein. Moreover, thin walled welded tube 12 produced by any of the
exemplary methods described herein may comprise an austempered
cylindrical body created as part of the continuous run processes of
those methods where the austempered cylindrical body comprises
first seam edge 12c, second seam edge 12d, and a wall having a
thickness of less than 0.25 inches. Thin walled welded tube 12 may
further comprise stress relieved welded seam 12e joining the first
and second seam edges.
[0029] Referring now to FIG. 4, in an exemplary embodiment thin
walled welded tube 12 is unspooled from takeup reel 17. One end of
thin walled welded tube 12 is connected to pump 18 and the other
end deployed through well casing 90 and/or production tubing 91,
terminating in tool 19.
[0030] In the operation of exemplary embodiments, referring now to
FIG. 5, in a first exemplary method for austempering thin walled
tubing, a section of metallic tubing 12 (FIG. 2a) is heated to a
high temperature in the range of 1300-1600.degree. F. in heater 20
(FIG. 2a). The section of metallic tubing 12 has a wall thickness
of less than 0.25 inches, preferably around 0.120 inches.
[0031] After being heated, the section of heated metallic tubing 12
(FIG. 2a) is moved from heater 20 (FIG. 2a) to low temperature
reservoir 30 (FIG. 2a) as part of a continuous run process. While
in low temperature reservoir 30, the section of metallic tubing 12
is quenched to reduce the temperature of the section of metallic
tubing 12 to a first low temperature in the range of
500-1000.degree. F. in a time period of less than 3 seconds.
Processing the section of metallic tubing 12 may comprise a
time-temperature-transformation curve where the start of conversion
to austentite-ferrite is at least 0.75 seconds after quenching in
low temperature reservoir 30.
[0032] The section of metallic tubing 12 (FIG. 2a) is allowed to
transform to bainite and then moved out of low temperature
reservoir 30 (FIG. 2a) as part of the continuous run process and
cooled to a second low temperature below around 100.degree. F.
Cooling may be by forced convection, e.g. at cooler 40 (FIG.
2a).
[0033] In a second exemplary method, referring to FIG. 6, a further
exemplary method for austempering thin walled coiled tubing 12
(FIG. 2a) comprises extending a section of thin walled metallic
tubing 12 having a wall thickness of less than 0.25 inches from a
coil mounted about reel 15 (FIG. 2a) into heater 20 (FIG. 2a) as
part of a continuous run process. The section of metallic tubing 12
is heated to a high temperature in the range of 1300-1600.degree.
F. in heater 20 and then moved from heater 20 to low temperature
reservoir 30 (FIG. 2a) as part of the continuous run process. In
low temperature reservoir 30, the section of metallic tubing 12 is
quenched in low temperature reservoir 30 to reduce the temperature
of the section of metallic tubing 12 to a first low temperature in
the range of 500-1000.degree. F. in a time period of less than
around 3 seconds.
[0034] The section of metallic tubing 12 (FIG. 2a) is allowed to
transform to bainite and then the section of metallic tubing 12
transformed into bainite is moved out of low temperature reservoir
30 (FIG. 2a) as part of the continuous run process and cooled to a
second low temperature below around 100.degree. F., e.g. at cooler
40 (FIG. 2a).
[0035] After it reaches the second low temperature, the section of
metallic tubing may be coiled, e.g. about reel 17 (FIG. 2a).
[0036] In a third exemplary method, referring now to FIG. 7, a
section of thin walled metallic tubing 12 (FIG. 2a) having a welded
seam and a wall thickness of less than 0.25 inches is extended from
a coil mounted about reel 15 (FIG. 2a) into heater 20 (FIG. 2a) as
part of a continuous run process. The section of metallic tubing 12
is heated to a high temperature in the range of 1300-1600.degree.
F. in heater 20 (FIG. 2a) and then moved from heater 20 to low
temperature reservoir 30 (FIG. 2a) as part of the continuous run
process. In low temperature reservoir 30, the section of metallic
tubing 12 is quenched to reduce the temperature of the section of
metallic tubing 12 to a first low temperature in the range of
500-1000.degree. F. in a time period of less than around 3
seconds.
[0037] The section of metallic tubing 12 (FIG. 2a) is then allowed
to transform to bainite. The section of metallic tubing 12
transformed to bainite is then moved out of low temperature
reservoir 30 (FIG. 2a) as part of the continuous run process cooled
to a second low temperature below around 100.degree. F., e.g. at
cooler 40 (FIG. 2a).
[0038] The foregoing disclosure and description of the inventions
are illustrative and explanatory. Various changes in the size,
shape, and materials, as well as in the details of the illustrative
construction and/or a illustrative method may be made without
departing from the spirit of the invention.
* * * * *