U.S. patent application number 09/782769 was filed with the patent office on 2002-08-15 for method and apparatus to detect faults in conduits.
Invention is credited to Kohli, Harjit, Pessin, Jean-Louis, Rhein-Knudsen, Erik.
Application Number | 20020108449 09/782769 |
Document ID | / |
Family ID | 25127130 |
Filed Date | 2002-08-15 |
United States Patent
Application |
20020108449 |
Kind Code |
A1 |
Kohli, Harjit ; et
al. |
August 15, 2002 |
Method and apparatus to detect faults in conduits
Abstract
Conduit integrity monitors enable the detection of defects or
faults in conduits. One type of the conduit integrity monitor
measures the bending stiffness of the conduit. A load cell device
is used to detect a force applied by a bent conduit. Defective or
damaged portions may cause an increase or decrease in bending
stiffness that can be detected by the conduit integrity monitor.
Another type of the conduit integrity monitor includes proximity
sensors each measuring its distance to a predetermined layer of the
conduit, such as a metallic reinforcement layer. Defects or damage
in the conduit may cause the conduit to change shape, which can be
detected by the proximity sensors.
Inventors: |
Kohli, Harjit; (Sugar Land,
TX) ; Pessin, Jean-Louis; (Houston, TX) ;
Rhein-Knudsen, Erik; (Houston, TX) |
Correspondence
Address: |
SCHLUMBERGER TECHNOLOGY CORPORATION
IP DEPT., WELL STIMULATION
110 SCHLUMBERGER DRIVE, MD1
SUGAR LAND
TX
77478
US
|
Family ID: |
25127130 |
Appl. No.: |
09/782769 |
Filed: |
February 13, 2001 |
Current U.S.
Class: |
73/849 |
Current CPC
Class: |
G01N 2203/028 20130101;
G01N 2203/0023 20130101; G01N 2203/0274 20130101; G01M 5/0075
20130101; G01N 3/26 20130101; G01M 5/0033 20130101; G01N 3/20
20130101; G01M 5/0025 20130101 |
Class at
Publication: |
73/849 |
International
Class: |
E21B 047/00 |
Claims
What is claimed is:
1. An integrity monitor for use with a conduit, comprising: a
receiving mechanism adapted to receive the conduit, the receiving
mechanism adapted to further bend the conduit by a predetermined
amount; and a detector device adapted to measure a force applied by
the bent conduit.
2. The integrity monitor of claim 1, wherein the measured force
represents a bending stiffness of the conduit to indicate physical
integrity of the conduit.
3. The integrity monitor of claim 1, wherein the receiving
mechanism is adapted to receive a hose, the flexible conduit
comprising the hose.
4. The integrity monitor of claim 1, wherein the receiving
mechanism is adapted to receive a composite coiled tubing, the
flexible conduit comprising the composite coiled tubing.
5. The integrity monitor of claim 1, wherein the receiving
mechanism is adapted to receive a flexible conduit formed at least
in part of a flexible material.
6. The integrity monitor of claim 1, wherein the receiving
mechanism comprises a plurality of rollers arranged to bend the
conduit.
7. The integrity monitor of claim 1, wherein the detector device
comprises a load cell.
8. The integrity monitor of claim 1, further comprising a
positioning device adapted to position the conduit.
9. The integrity monitor of claim 1, wherein the detector device is
adapted to measure a force applied by the bent conduit when a
relatively high internal pressure is applied in the conduit.
10. A system to determine integrity of a conduit, comprising: a
plurality of integrity monitors, each integrity monitor comprising:
a receiving mechanism adapted to receive a portion of the conduit,
the receiving mechanism adapted to further bend the portion of the
conduit by a predetermined amount; and a detector device adapted to
measure a bending stiffness of the bent portion of the conduit,
wherein the plurality of integrity monitors are spaced apart along
a length of the conduit and angularly offset from each other.
11. The system of claim 10, wherein a first integrity monitor is
positioned to detect bending stiffness along a first
cross-sectional axis of the conduit, and a second integrity monitor
is positioned to detect bending stiffness along a second
cross-sectional axis of the conduit.
12. The system of claim 11, wherein the first and second axes are
substantially perpendicular to each other.
13. The system of claim 10, further comprising a positioning device
adapted to detect a position of the conduit.
14. The system of claim 10, wherein the receiving mechanism
comprises a plurality of rollers arranged to bend the conduit.
15. The system of claim 14, wherein the receiving mechanism further
comprises a retainer, at least one of the rollers being rotatably
mounted on the retainer.
16. The system of claim 15, wherein the detector device is in
contact with the retainer.
17. The system of claim 16, wherein the detector device comprises a
load cell.
18. The system of claim 17, wherein the load cell has a loading
surface, and wherein the retainer is in contact with the loading
surface.
19. A method of determining integrity of a conduit, comprising:
passing the conduit through an integrity monitor; bending a portion
of the conduit by a predetermined amount in the integrity monitor;
and measuring a bending stiffness of the conduit portion.
20. The method of claim 19, further comprising determining if the
conduit portion is faulty based on the measured bending
stiffness.
21. The method of claim 19, further comprising: mounting the
conduit on a reel assembly; and unwinding the reel assembly to
release the conduit.
22. An apparatus for use with a conduit, comprising: a plurality of
proximity sensors positioned proximal the conduit, the conduit
having plural layers, the plural layers comprising a structural
layer; each proximity sensor adapted to sense a distance to the
structural layer, the plurality of proximity sensors adapted to
detect a shape of the conduit.
23. The apparatus of claim 22, wherein the proximity sensors
comprise inductive proximity sensors.
24. The apparatus of claim 22, wherein the proximity sensors are
arranged circumferentially around a portion of the conduit.
25. The apparatus of claim 24, wherein the proximity sensors are
arranged in pairs, each pair of proximity sensor adapted to detect
a diameter of one section of the conduit.
26. The apparatus of claim 25, wherein the proximity sensors are
arranged in plural sets spaced apart along a longitudinal axis of
the conduit.
27. The apparatus of claim 24, wherein the proximity sensors are
arranged at at least the following positions around the conduit:
0.degree., 30.degree., 60.degree., 90.degree., 120.degree.,
150.degree., 180.degree., 210.degree., 240.degree., 270.degree.,
300.degree., and 330.degree..
28. The apparatus of claim 22, wherein the structural layer
comprises metal, each proximity sensor adapted to interact with the
metal to sense the distance.
29. The apparatus of claim 22, wherein the plural layers comprise
an outer layer formed of a non-electrically conductive layer, each
proximity sensor adapted to sense the distance to the structural
layer through the non-electrically conductive layer.
30. A method of determining integrity of a conduit, comprising:
providing a plurality of proximity sensors; measuring a distance of
each proximity sensor to one of plural layers of the conduit, the
one of plural layers comprising a structural layer; and determining
a shape of the conduit based on the distance measurements, the
shape indicating the integrity of the conduit.
31. The method of claim 30, wherein providing the plurality of
proximity sensors comprises providing a plurality of sets of
proximity sensors, the method further comprising spacing the sets
apart along a longitudinal axis of the conduit.
32. An apparatus for determining integrity of a conduit having an
inner liner formed of a predetermined material, comprising: a
housing defining a bore; a retainer mechanism arranged inside the
housing; and a test liner retained by the retainer mechanism and in
communication with the bore, the retainer mechanism adapted to be
removed from the housing to enable removal of the test liner for
visual inspection of wear.
33. The apparatus of claim 32, wherein the retainer mechanism
comprises first and second sleeves removably connected to each
other.
34. The apparatus of claim 32, wherein the test liner is formed of
a material that is the same as the material of the conduit
liner.
35. The apparatus of claim 32, further comprising a connection
assembly adapted to be connected to the conduit.
36. A method of detecting wear of a liner in a conduit, comprising:
providing a test structure having an inner bore and a test liner in
communication with the inner bore; flowing a fluid through the
inner bore; and inspecting the test liner to determine wear of the
conduit liner.
37. The method of claim 36, further comprising flowing the same
fluid through a bore of the conduit.
38. A method for use with a connector assembly for a conduit,
comprising: connecting the conduit to the connector assembly;
placing a first mark on a portion of the connector assembly
adjacent the conduit; marking a second mark on a portion of the
conduit adjacent the connector assembly; and inspecting for a gap
between the first and second marks to detect for possible failure
of a connection between the conduit and the connector assembly.
Description
TECHNICAL FIELD
[0001] The invention relates to methods and apparatus to detect
faults in conduits, such as hoses and the like.
BACKGROUND
[0002] To operate a well, various operations are performed. For
example, after a wellbore has been drilled, casing can be installed
in the wellbore by cementing the casing to the walls of the
wellbore. To perform the cementing operation, cement slurry is
pumped into the wellbore to fill the annulus between the casing and
the wellbore. Mixing and pumping equipment, which can be carried on
a truck, is brought out to the well site for performing cement
mixing and for pumping cement slurry into the wellbore. The common
way for delivering cement slurry from the cement mixer to the well
site is by use of treating iron. However, treating iron, which is
typically made of a metal such as steel, is relatively heavy. As a
result, equipment used to deploy treating iron is often large and
unwieldy. Thus, it may be desirable to use flexible conduits formed
of materials that are lighter weight than metal tubing. One example
of a flexible conduit is a multi-layered hose with rubber layers
and reinforcement metal wires.
[0003] Conduits can also be used to pump other types of fluids into
a wellbore, such as gravel packing fluids, fracturing fluids,
clean-up fluids, and so forth. For enhanced flexibility and ease of
use, conduits are mounted on a reel, with the reel rotated to
deploy and retrieve the conduit. After the well operation has been
completed, the reel can be rewound to reload the conduit. However,
after multiple uses of the conduit, deterioration of the conduit
and other damage may occur. A damaged conduit may fail and cause
injury to well site personnel, as well as damage to the well. If a
damaged conduit is encountered at a well site, then operations at
the well site may have to be halted until a replacement conduit can
be found and brought to the well site, which may cause substantial
delays. Delays in well operations can result in substantial costs
to the well operator.
SUMMARY
[0004] In general, according to one embodiment, an integrity
monitor for use with a conduit comprises a receiving mechanism
adapted to receive the conduit. The receiving mechanism is adapted
to further bend the conduit by a predetermined amount. A detector
device is adapted to measure a force applied by the bent
conduit.
[0005] Other features and embodiments will become apparent from the
following description, from the drawings, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 illustrates an embodiment of equipment used to deploy
a conduit into a wellbore.
[0007] FIG. 2 is a cross-sectional view of an example conduit.
[0008] FIGS. 3A-3G illustrate various possible defects in the
conduit of FIG. 2.
[0009] FIG. 4A is a rear-view of a truck carrying a reel assembly
and a conduit integrity monitor, in accordance with one embodiment,
to detect defects in the conduit of FIG. 1.
[0010] FIG. 4B is a schematic view of the conduit integrity
monitor.
[0011] FIG. 5 illustrates a bending stiffness detector that is part
of the conduit integrity monitor of FIG. 4B.
[0012] FIG. 6 illustrates an example load cell for use in the
bending stiffness detector of FIG. 5.
[0013] FIG. 7 illustrates a conduit axial position detection device
that is part of the conduit integrity monitor of FIG. 4B.
[0014] FIG. 8 is a graph that illustrates the bending stiffness of
a conduit, with some portions of the conduit having defects.
[0015] FIG. 9 illustrates a conduit integrity monitor according to
another embodiment.
[0016] FIGS. 10A-10C illustrate, respectively, positions of three
sets of inductive sensors in the conduit integrity monitor of FIG.
9.
[0017] FIG. 10D illustrates the collective positions of the
inductive sensors of FIGS. 10A-10C.
[0018] FIG. 11A is a graph representing the minimum and maximum
diameters of a conduit along its length as measured by the conduit
integrity monitor of FIG. 9.
[0019] FIG. 11B is a graph representing the ovality of a conduit
along its length as measured by the conduit integrity monitor of
FIG. 9.
[0020] FIGS. 12A-12B are graphs showing changes in the shape of a
conduit in response to a pressure test.
[0021] FIG. 13 is a vertical sectional view of a connection
assembly for connecting to a conduit.
[0022] FIGS. 14A-14B are a vertical sectional view of a liner wear
detector, in accordance with an embodiment.
[0023] FIG. 15 illustrates a mechanism to detect separation of a
conduit from a connection assembly.
DETAILED DESCRIPTION
[0024] In the following description, numerous details are set forth
to provide an understanding of the present invention. However, it
will be understood by those skilled in the art that the present
invention may be practiced without these details and that numerous
variations or modifications from the described embodiments may be
possible.
[0025] As used here, the terms "up" and "down"; "upward" and
"downward"; "upstream" and "downstream"; "above" and "below"; and
other like terms indicating relative positions above or below a
given point or element are used in this description to more clearly
describe some embodiments of the invention. However, when applied
to equipment and methods that are deviated or horizontal, such
terms may refer to a left to right, right to left, or other
relationship as appropriate.
[0026] Referring to FIG. 1, in accordance with one example
embodiment, a truck 12 carrying equipment including a reel assembly
14 is located at a well site that includes a well 10 and wellhead
equipment 16. Although not shown, the truck 12 also includes pump
equipment and mixing equipment (e.g., cement mixer). The reel
assembly 14 carries a conduit 20 that can be unreeled from the reel
assembly 14 for connection to the wellhead equipment 16. A cement
head 24 and manifold 22 are connected at the upper portion of
wellhead equipment 16, with the hose 20 connected to the manifold
22. In other embodiments, other arrangements for connecting the
hose 20 to the wellhead equipment can be employed.
[0027] In accordance with some embodiments of the invention, the
conduit 20 is a flexible hose that is formed of various layers. As
shown in the cross-sectional view of FIG. 2, the conduit 20
includes an inner liner 102, a reinforcement layer 104, another
layer 106, and an outer jacket 108. The conduit 20 defines an inner
bore 100 through which fluids can flow. In one example embodiment,
the liner 102 and the layer 106 can be formed of a flexible
material such as rubber. The outer jacket 108 is formed of a
durable or wear-tolerant material, such as high-density
polyethylene. The reinforcement layer 104 can be formed of metal
wires arranged at different angles to provide support for the
conduit 20. In other embodiments, the conduit 20 can have other
arrangements (whether single-layered or multi-layered) and can be
formed of other materials. The conduit 20 is designed to withstand
high pressures (e.g., greater than about 1,000 psi) during
operation when a fluid or slurry is pumped through the conduit 20.
Also, the reinforcement layer 104 provides relatively high tensile
strength for the conduit 20. More generally, the reinforcement
layer 104 is considered a "structural layer" of the conduit, since
it provides the structural strength of the conduit 20.
[0028] The conduit 20 can be subjected to various types of
deterioration and damage over time. This occurs when the conduit 20
is repeatedly reeled and unreeled from the reel assembly 14 and
connected to the wellhead equipment 16 Also, handling by personnel
at the well site may also cause damage, such as when the conduit 20
collides with other equipment, is run over by vehicles, and so
forth.
[0029] Alternatively, instead of a flexible hose, the conduit 20
can be a composite coiled tubing. Typically, a composite coiled
tubing includes an inner liner (which can be formed of a
thermoplastic material in one example) and one or more structural
reinforcement layers (made of graphite fiber or fiberglass, as
examples). Other example composite coiled tubings are described in
U.S. Pat. No. 5,828,003. Composite coiled tubing is deployed into
the wellbore 10 through wellhead equipment 16, rather than to an
attachment as in the case of the flexible hose.
[0030] FIGS. 3A-3G illustrate examples of deterioration or damage
that may be experienced by the conduit 20. FIG. 3A shows the
conduit 20 being flattened so that deformation occurs at portions
200 and 202. The effect is a substantially non-circular conduit.
FIG. 3B shows a conduit 20 in which corrosion 204 has removed or
weakened a portion of the layers of the conduit 20. FIG. 3C shows a
kink 206 in the conduit 20, where one part along the circumference
of the conduit 20 has been deformed. Generally, bending stiffness
is lowered at the kinked portion 206, and bending stiffness may
increase at other portions of the conduit in the same
cross-section, making it hard to bend in a different direction.
[0031] FIG. 3D shows wear of the inner liner 102, as indicated by
208. When fluids are run through the bore 100 of the conduit 20,
such fluids can wear away the liner 102 of the conduit 20 over
time.
[0032] FIG. 3E shows external damage at a portion 210 of the
conduit 20. FIG. 3F shows a manufacturing defect at location 212,
where the metal reinforcement layer 104 is not properly formed.
FIG. 3G illustrates damage to an inner part of the reinforcement
layer 104 due to an over-pressure condition within the bore 100 of
the conduit 20.
[0033] Except for the liner defect shown in FIG. 3D, the other
defects shown in FIGS. 3A-3C and 3E-3G affect the bending stiffness
of the conduit at various portions. In accordance with some
embodiments of the invention, a conduit integrity monitor is used
to monitor the bending stiffness of the conduit along its length so
that the presence of such defects can be identified. Because the
conduit 20 is relatively flexible, the shape of the conduit 20 is
changed when pressure is increased in the conduit 20. In another
embodiment, a proximity sensor can be used to detect for changes in
the shape of the conduit, with and without pressure within the
conduit 20. Both these devices are explained in greater detail
below.
[0034] FIG. 4A illustrates a rear view of the truck 12 and reel
assembly 14 of FIG. 1. A conduit integrity monitor 300 is mounted
on the truck 12, with the conduit 20 run through the integrity
monitor 300. As the conduit 20 is unreeled, the conduit 20 extends
through the integrity monitor 300 so that the integrity of the
conduit 20 is monitored along its length. While the conduit 20 is
being run through the integrity monitor 300, one or more
characteristics of the conduit 20 along the length of the conduit
can be detected by the integrity monitor 300. This can be
communicated to an operator console that is located either on the
truck 12 itself or at some other location.
[0035] As represented in FIG. 4B, the integrity monitor 300
includes a conduit axial positioning device 304 and first and
second bending stiffness detectors 302 and 304 positioned on either
side of the positioning device 304. In other embodiments, other
arrangements of positioning device(s) and bending stiffness
detector(s) can be employed. The bending stiffness detector 302 is
mounted to detect bending stiffness along an X axis (FIG. 2), which
corresponds to the 0.degree. cross-sectional axis of the conduit
20. The second bending stiffness detector 306 is mounted generally
perpendicularly to the first bending stiffness detector 302, and is
capable of detecting bending stiffness of the conduit 20 along a Y
axis (FIG. 2), which corresponds to the 90.degree. cross-sectional
axis of the conduit 20. Thus, the integrity monitor 300 is capable
of detecting bending stiffness along two different cross-sectional
axes. In other embodiments, only one bending stiffness detector or
more than two bending stiffness detectors can be used.
[0036] Referring to FIG. 5, the bending stiffness detector 302 or
306 is illustrated in greater detail. In one embodiment, the
bending stiffness detector includes three rollers 402, 404, and 406
(which can be knurled rollers). The roller 402 includes a portion
408 that is shaped to receive the generally tubular conduit 20. The
rollers 404 and 406 similarly include corresponding receiving
portions 410 and 412. The rollers 402 and 406 are generally at a
first level while the roller 404 is positioned at another level
below the first level. The rollers 402, 404 and 406 are arranged to
bend the conduit 20 by a predetermined bending radius. For example,
for a conduit having a diameter of about 2.8 inches, the bending
radius can be selected to be greater than the minimum specified
bend radius of the conduit 20 (e.g., about 30 inches).
[0037] First and second alignment clasps 414 and 416 are used to
position the rollers 402 and 406. The adjustment to achieve the
desired bending radius of the conduit 20 passing through the
bending stiffness detector is through the position of the
roller-load cell assembly 404, 420.
[0038] The roller 404 is mounted on a load cell device 420 that
measures a downwardly vertical force applied by the roller 420 due
to interaction of the conduit 20 and the rollers 402, 404, and 406.
The roller 404 is rotatably mounted in a retainer 430 having a
bottom plate 432 that is in contact with the load cell device
420.
[0039] Referring to FIG. 6, the load cell device 420 according to
one example embodiment has a loading surface 450 and circuitry (not
shown) that is capable of detecting a force applied along the
direction L. The loading surface 450 is in contact with the bottom
plate 432 of the retainer 430. An electrical connector 452 is
attached to the side of the load cell device 420 to enable the load
cell device 420 to be electrically connected to another component,
which receives signals generated by the load cell device 420
indicating the force applied due to bending of the conduit 20, from
which the bending stiffness of the conduit 20 at different portions
can be derived. In one embodiment, the load cell device 420 is a
pancake load cell from Futek Advanced Sensor Technology, Inc. In
other embodiments, other devices for detecting forces applied by
the conduit 20 subjected to predetermined bending can also be
employed.
[0040] The arrangement in FIG. 5 shows a first orientation of the
bending stiffness detector with respect to the conduit 20. In the
arrangement shown in FIG. 5, the bending stiffness detector is
positioned to measure the bending stiffness of the conduit 20 along
the Y direction (FIG. 2). However, if the bending stiffness
detector is rotated about 90.degree. with respect to the conduit
20, then the bending stiffness detector is positioned to measure
the bending stiffness of the conduit 20 along the X direction,
which is perpendicular to the Y direction (FIG. 2).
[0041] Referring to FIG. 7, the conduit axial positioning device
302 is illustrated. The axial positioning device 302 includes a
first roller 502 that is rotatably mounted to a housing 504 of the
axial positioning device 302. The axial positioning device 302 also
includes a second roller 506 that is rotatably mounted to a
spring-loaded retainer 508. The roller 502 is generally fixed in
position with respect to the housing 504, but the spring-loaded
retainer 508 allows up and down movement of the roller 506 to
enable positioning of the conduit 20. The rollers 502 and 506
include respective receiving portions 503 and 507 to receive the
conduit 20.
[0042] The roller 502 is mounted on a pin (not shown) that is
rotatably attached to the housing 504. The pin is also operably
coupled to a counter 510 that counts the number of times that the
roller 502 rotates. This enables the operator of the reel assembly
14 to determine the position of the conduit 20 with respect to the
conduit integrity monitor 300. Thus, if damage is detected, the
operator can determine where along the conduit 20 the damage has
occurred.
[0043] Referring to FIG. 8, a graph shows the bending stiffness of
the conduit 20 along its axial position as measured by the conduit
integrity monitor 300. Curves 602 and 604 represent the bending
stiffness of the conduit (along the X and Y directions) before
first use of the conduit (job 0). Curves 606 and 608 represent the
bending stiffness of the conduit 20 along its axial position in the
X and Y directions after a predetermined number of uses (e.g., 500
jobs). Bumps in the curves 606 and 608 proximal position P1 of the
conduit 20 represent the change in bending stiffness due to a kink
(such as that shown in FIG. 3C). Because of the kink, the bending
stiffness along one direction (X or Y) increases while the bending
stiffness along the perpendicular direction decreases. Further
along the conduit 20, a over-pressure defect in the conduit 20
causes the bending stiffness along both the X and Y directions to
be decreased.
[0044] As shown in FIG. 8, a curve 610 represents an acceptable
minimum bending stiffness of the conduit 20. As bending stiffness
drops, other important physical properties of the conduit are
affected, such as the burst pressure of the conduit. Thus, bending
stiffness is a key indicator of wear and physical damage. In the
example of FIG. 8, the kink and over-pressure defects are not
enough to cause the bending stiffness to fall below the acceptable
level. However, this may not always be true, since with further
uses, the kink and over-pressure defects may deteriorate to a point
that the bending stiffness along one of the X and Y directions
would fall below the acceptable level. If that occurs, then some
type of a warning may be issued to the operator of the reel
assembly 14 so that use of the conduit 20 can be stopped.
Alternatively, before a reel assembly 14 is delivered to a job
site, the operator of the reel assembly can check the bending
stiffness of the conduit to ensure that the conduit is not close to
failure. If so, then the operator can choose another reel assembly
to take to the job site.
[0045] In accordance with another embodiment, instead of using a
conduit integrity monitor system that monitors the bending
stiffness of the conduit 20, a proximity monitoring system 700 uses
analog inductive proximity sensors 702, as shown in FIG. 9. Each
inductive proximity sensor 702 is designed to detect its proximity
with an electrically conductive layer (in this case the metal
reinforcement layer 104) in the conduit 20. The inductive proximity
sensor 702 detects for induced magnetic fields in the electrically
conductive layer, and based on the strength of the induced magnetic
fields, is able to determine a distance between the inductive
proximity sensor and the electrically conductive layer. The
inductive proximity sensor is able to measure the distance through
non-electrically conductive layers (108 and 106) of the conduit 20.
Calibration data is stored in a memory module on each sensor, with
the calibration data used to enable an accurate measurement of the
distance. The calibration data calibrates for individual sensor
distance response as well as for variations of the response with
temperature. Optionally, temperature in the vicinity of the sensors
can be measured, with the measured temperature used to select the
appropriate calibration data to use.
[0046] Multiple sensors 702 are arranged along the circumference of
the conduit 20. Thus, if the conduit 20 is not damaged, the conduit
will be substantially circular, and the inductive proximity sensor
702 will detect a distance between the sensor and the reinforcement
layer 104 of the conduit 20 that is within a predetermined range.
However, if any portion of the conduit 20 is damaged, then that
portion may be substantially further away or closer to one or more
of the inductive proximity sensors than the other sensors. Further,
when internal pressure is applied in the conduit 20, substantial
shifts are seen in the distances to the sensors (due to deformation
of the conduit) when compared to an undamaged conduit. The
substantial shifts in detected distances are used to identify
damaged locations of the conduits. Thus, going back to the defect
shown in FIG. 3A, the conduit 20 at locations 200 and 202 will be
closer to the proximity sensors positioned proximal those
locations, and a substantial shift in detected distances will occur
under internal pressure. This is also the case for defects shown in
FIGS. 3B, 3C, 3E, 3F, and 3G; however, the proximity sensor may not
be able to pick up defects shown in FIG. 3D, which is a
non-structural defect that does not affect the overall shape of the
conduit 20.
[0047] The proximity monitoring system 700 includes a first set 704
of positioning rollers 706 and 708 and a second set 710 of
positioning rollers 712 and 714. The first set 704 of rollers 706
and 708 are arranged generally along direction 750 to center the
conduit 20 along that direction, while the second set 710 of
rollers 712 and 714 are arranged generally along direction 752 to
center the conduit 20 along that direction. The conduit 20 is
passed through an opening formed in a "scraper" 718. The scraper
718 has a housing in which the inductive proximity sensors 702 are
mounted around the conduit 20.
[0048] There are three sets of inductive proximity sensors: a first
set 702A, a second set 702B, and a third set 702C. In one
embodiment, as illustrated, the three sets of inductive proximity
sensors 702 are offset longitudinally along the conduit 20. This
offsetting enables more inductive proximity sensors 702 to be
arranged around the conduit 20 without affecting the accuracy of
the detection of distances.
[0049] Referring to FIGS. 10A-10C, the positions of the three sets
of proximity sensors referenced to the conduit 20 are illustrated.
In FIG. 10A, the first set of proximity sensors 702A are arranged
at 0.degree., 90.degree., 180.degree., and 270.degree.. The second
set of proximity sensors 702B are arranged at 30.degree.,
120.degree., 210.degree., and 300.degree.. As shown in FIG. 8C, the
third set of proximity sensors 702C are positioned at 60.degree.,
150.degree., 240.degree., and 330.degree.. The collection of all
three sets of proximity sensors 702A, 702B, and 702C are
illustrated in FIG. 8D. The proximity sensors work in pairs (about
180.degree. apart) to enable measurement of the diameter of the
conduit between each pair of sensors.
[0050] FIGS. 11A-11B illustrate how the proximity monitoring system
700 can be used to monitor the integrity of the conduit 20. FIG.
11A is a graph that plots the maximum and minimum diameters of the
conduit 20 (as detected by each of the six pairs of proximity
sensors 702) along the axial length of the conduit 20. A first
curve 800 represents the maximum acceptable diameter, and a second
curve 802 represents the minimum acceptable diameter. A curve 804
represents the maximum diameter among the diameters detected by the
twelve sensors at each point along the conduit 20. A curve 806
represents the minimum diameter among the diameters detected by the
twelve proximity sensors. A first upward spike 808 on the curve 804
represents an increase in diameter at a first position of the
conduit 20, and a first downward spike 810 on the curve 806
represents a decrease in diameter at a second position of the
conduit 20. A second downward spike 812 occurs at a later position
along the conduit 20. In the illustrated example, the tip of the
first downward spike 810 reaches the minimum acceptable diameter,
while the tip of the second downward spike 812 falls below the
minimum acceptable diameter, which indicates that the conduit 20
has experienced a substantial change in shape. Thus, the conduit 20
in the example of FIG. 11A would be unacceptable for use.
[0051] The curves are shown to an operator (on a display, such as
one on the truck 14) when the hose 20 is reeled out at the
beginning of a job, and also when the hose 20 is reeled back in at
the end of a job.
[0052] FIG. 11B illustrates a graph that plots ratio of the minimum
diameter to the maximum diameter (D.sub.min/D.sub.max) along the
axial axis of the conduit 20. The graph represents the ovality at
each point along the conduit 20. A curve 820 represents the minimum
acceptable ovality. A curve 822 represents the ovality along the
length of the conduit before the first job, while a curve 824
represents the ovality of the conduit 20 after 500 jobs. The
downward spikes in each of the curves 822 and 824 show where
defects cause the ovality to drop. In the example, after 500 jobs,
the ovality of the conduit 20 is unacceptable at two locations, a
first location corresponding to downward spike 826 and a second
location corresponding to downward spike 828.
[0053] Referring to FIGS. 12A-12B, in conjunction with use of the
proximity monitoring system 700 of FIG. 9, a pressure test can be
performed to determine the integrity of the conduit 20. Pressure is
built up in the bore 100 of the conduit 20 to a predetermined
level, with the idea that portions of the conduit that are
defective would change their shapes more than other portions of the
conduit 20. In FIG. 12A, the change in shape at each position along
the conduit 20 due to the pressure test is plotted before first use
of the conduit 20. The curve 850 represents no change in response
to the pressure test. The curve 852 represents the maximum change
detected by one of the twelve proximity sensors, while the curve
854 represents the minimum change detected by another one of the
twelve proximity sensors.
[0054] FIG. 12B illustrates the change in shape of the conduit 20
in response to the pressure test after the conduit has been used in
500 jobs. The curve 852A represents the maximum change in shape
detected by one proximity sensor (an increase in distance from the
sensor), while the curve 854A represents the minimum change in
shape detected by another proximity sensor (a reduction in distance
from the sensor). As shown in FIG. 12B, the portions of the conduit
20 that are defective experience the greatest shape change, as
evidenced by spikes 860 and 862 on curve 852A and spike 864 on
curve 854A.
[0055] Thus, in accordance with some embodiments of the invention,
conduit integrity monitors are provided to detect for certain types
of faults, defects, or damage. One conduit integrity monitor
monitors the bending stiffness of the conduit, while another
integrity monitor detects the change in shape of the structural
layer of the conduit. Shape changes (e.g., a conduit becoming more
oval or other shape changes as discussed above) indicate a
reduction in physical strength of the conduit at the cross-section,
which may cause the conduit to fail at an unacceptably low internal
pressure or in response to other forces. By detecting for faults in
the conduit, defective or damaged conduits can be replaced before
they are brought to the well site, where conduit failure may cause
substantial delays in well operation and add substantial costs.
Also, conduits that fail suddenly and unexpectedly may pose serious
safety concerns to well personnel.
[0056] Another concern associated with connecting a flexible
conduit, such as the multi-layered composite conduit 20 shown in
FIG. 2, to another structure is the integrity of the connection
mechanism. If an unreliable connection mechanism is used, then it
is likely that the conduit 20 will separate from a connector during
operation.
[0057] Referring to FIG. 13, a connection mechanism 1100 in
accordance with one embodiment for connecting the conduit 20 to a
connector 1102 is illustrated. The conduit 20 has multiple layers,
with the external layer 108 and the internal liner 102. To achieve
a more reliable connection between the conduit 20 and the connector
1102, an insert 1104 and a crimp are used to more securely engage
the flexible conduit 20. One end of the insert 1104 has a flange
1106 that sits on a connector ring 1108. The other end of the
insert 1104 has an outer sawtooth profile 1110 for engaging the
inner surface of the liner 102. Also, the crimp 1112 is provided
around the outside of the insert 1104, with the crimp 1112 having
inner protrusions 1114 that engage the outer surface of the
external conduit layer 108. A first end of the crimp 1112 has an
engagement member 1116 that fits into a groove 1118 formed on the
outer surface of the insert 1104. The inner diameter of the inner
protrusions 1114 of the crimp 1112 progressively increases the
further they are from the first end of the crimp 1112. This enables
easier engagement of the conduit 20 into an annular space between
the sawtooth profile 1110 of the insert 1104 and the inner
protrusions of the crimp 1112. The crimp 1112 is compressed onto
the conduit 20 while the crimp 1112 is on the insert 1104.
[0058] Referring to FIG. 15, once the conduit 20 is connected to
the connection mechanism 1100, one portion of the connection
mechanism 1100 and the adjacent end portion of the conduit 20 can
be painted with some predetermined color or otherwise marked. Thus,
a first mark 1122 is provided on a portion of the connection
mechanism 1100 adjacent the conduit, and a second mark 1124 is
provided on a portion of the conduit 20 adjacent the connection
mechanism 1100. If slippage occurs between the conduit 20 and the
connection mechanism 1100, a gap 1120 will develop between the
marked portion 1124 of the conduit 20 and the marked portion 1122
of the connection mechanism 1100. This gap provides a visual
indication to the operator that the connection of the conduit 20 is
about to fail. Such a slippage detection mechanism and method can
be applied to a flexible hose. Alternatively, the slippage
detection mechanism and method according to other embodiments can
be applied to a composite coiled tubing.
[0059] Another issue associated with use of the conduit 20 is that
the liner is prone to wear after repeated use. However, it is
usually difficult to determine when the liner 102 has been damaged
to a level that makes it unsafe or unreliable to use. As noted
above, wear of the liner 102 is difficult to detect with the
bending stiffness detector (FIG. 5) or the proximity integrity
monitor (FIG. 9). To enable detection of liner wear, a liner wear
detector device 1200 in accordance with some embodiments is used,
as shown in FIGS. 14A-14B. One end of the conduit 20 is connected
by a connection mechanism 1202 that is similar to the connection
mechanism 1100 of FIG. 13. The connection mechanism 1202 is in turn
connected by a connector mandrel 1204 to another connection
mechanism 1206 that is part of the wear detector device 1200. The
wear detector device 1200 has a housing 1208 that is threadably
connected to the connection mechanism 1206. Inside the housing 1208
is arranged a first sleeve 1210 that is threadably connected to a
second sleeve 1212. The first sleeve 1210 has a narrowed portion
1214 that ends at a shoulder 1216. The second sleeve 1212 similarly
has a narrowed portion 1218 that ends in a shoulder 1220. In
accordance with some embodiments, a liner insert 1222 can be placed
between the shoulders 1216 and 1220. The liner insert 1222 is
formed of the same material as the liner 102 in the conduit 20. The
first and second sleeves 1210 and 1212 form part of a retainer
mechanism for the liner insert 1222 (also referred to as a "test
liner").
[0060] The wear detector device 1200 can be periodically detached
from the connection mechanism 1202 so that the sleeves 1210 and
1212 can be pulled out of the wear detector device 1200. The
sleeves 1210 and 1212 can then be unscrewed so that the liner 1222
can be pulled out for examination. Wear in the liner insert 1222
can be visually detected. If the liner insert 1222 is deteriorated,
then it can be assumed that the liner 102 in the conduit 20 may
also be similarly deteriorated since the same fluid flows through
at the same rate. When that occurs, the conduit 20 is replaced with
a new conduit. A test liner can be used with either a conduit
system containing a flexible hose or a composite coiled tubing. For
use with a composite coiled tubing, the wear detector device 1200
is modified to connect to the composite coiled tubing.
[0061] While the invention has been disclosed with respect to a
limited number of embodiments, those skilled in the art will
appreciate numerous modifications and variations therefrom. It is
intended that the appended claims cover such modifications and
variations as fall within the true spirit and scope of the
invention.
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