U.S. patent application number 13/379087 was filed with the patent office on 2012-06-28 for method and apparatus for monitoring fluids.
This patent application is currently assigned to Paradigm Flow Solutions Limited. Invention is credited to Robert Bain, Hugh MacKenzie.
Application Number | 20120160329 13/379087 |
Document ID | / |
Family ID | 40972774 |
Filed Date | 2012-06-28 |
United States Patent
Application |
20120160329 |
Kind Code |
A1 |
MacKenzie; Hugh ; et
al. |
June 28, 2012 |
METHOD AND APPARATUS FOR MONITORING FLUIDS
Abstract
A method and apparatus for monitoring a fluid that is to be
transported through a fluid conduit within a hydrocarbon
exploration and production installation is described. A monitoring
zone is established upstream of the fluid conduit configured such
the fluid supply to the fluid conduit is introduced via the
monitoring zone. The fluid supply within the monitoring zone is
monitored for the occurrence of events detrimental to the flow of
the fluid supply through the fluid conduit. Monitoring the fluid
supply prior to entering the fluid conduit allows for the early
detection of an event detrimental to the flow of the fluid supply
e.g. a chemical reaction indicative of corrosion of the fluid
conduit or the formation of a potential blockage within the fluid
conduit. In this way the risk of costly blockages or structural
failure occurring within the fluid conduit is reduced.
Inventors: |
MacKenzie; Hugh; (Aberdeen,
GB) ; Bain; Robert; (Aberdeen, GB) |
Assignee: |
Paradigm Flow Solutions
Limited
Aberdeenshire
GB
|
Family ID: |
40972774 |
Appl. No.: |
13/379087 |
Filed: |
June 18, 2010 |
PCT Filed: |
June 18, 2010 |
PCT NO: |
PCT/GB2010/051014 |
371 Date: |
March 8, 2012 |
Current U.S.
Class: |
137/1 ; 137/511;
340/608; 356/326; 702/50; 73/53.01; 73/61.43; 73/61.71;
73/61.76 |
Current CPC
Class: |
Y10T 137/0318 20150401;
E21B 47/001 20200501; Y10T 137/7837 20150401; E21B 43/01
20130101 |
Class at
Publication: |
137/1 ; 73/53.01;
73/61.71; 73/61.43; 73/61.76; 356/326; 702/50; 340/608;
137/511 |
International
Class: |
F17D 1/00 20060101
F17D001/00; G01N 15/06 20060101 G01N015/06; G01N 37/00 20060101
G01N037/00; F16K 15/00 20060101 F16K015/00; G01J 3/28 20060101
G01J003/28; G06F 19/00 20110101 G06F019/00; G08B 21/00 20060101
G08B021/00; G01N 11/00 20060101 G01N011/00; G01N 25/00 20060101
G01N025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 25, 2009 |
GB |
0910978.6 |
Claims
1. A method for monitoring a fluid supply to be transported through
a fluid conduit located within a hydrocarbon exploration and
production installation, the method comprising the steps of:
providing a monitoring zone upstream of the fluid conduit;
introducing the fluid supply to the fluid conduit via the
monitoring zone; and monitoring the fluid supply within the
monitoring zone so as to detect the occurrence of one or more
events detrimental to the flow of the fluid supply through the
fluid conduit.
2. A method for monitoring a fluid supply as claimed in claim 1
wherein the step of monitoring the fluid supply within the
monitoring zone comprises the step of detecting solids or
solidification within the fluid supply.
3. A method for monitoring a fluid supply as claimed in claim 2
wherein the method further comprises the step of shutting off the
fluid supply to the fluid conduit when solidification is
detected.
4. A method for monitoring a fluid supply as claimed in claim 2
wherein the step of detecting solids or solidification within the
fluid supply comprises monitoring a pressure differential across a
filter located within the monitoring zone.
5. A method for monitoring a fluid supply as claimed in claim 4
wherein the step of shutting off the fluid supply to the fluid
conduit occurs when the pressure differential across the filter is
outside of a predetermined tolerance value for the fluid
supply.
6. A method for monitoring a fluid supply as claimed in claim 4
wherein the step of monitoring the pressure differential across the
filter further comprises the step of correlating the monitored
pressure differential with a temperature of the fluid supply.
7. A method for monitoring a fluid supply as claimed in claim 2
wherein the step of detecting solids or solidification within the
fluid supply comprises the step of monitoring the water content of
the fluid supply.
8. A method for monitoring a fluid supply as claimed in claim 7
wherein the step of shutting off the fluid supply to the fluid
conduit occurs when the water content of the fluid supply is
outside a predetermined tolerance value for the fluid supply.
9. A method for monitoring a fluid supply as claimed in claim 2
wherein the step of detecting solids or solidification within the
fluid supply comprises the step of monitoring a particulate or
debris content of the fluid supply.
10. A method for monitoring a fluid supply as claimed in claim 9
wherein the step of shutting off the fluid supply to the fluid
conduit occurs when a density or mass of the particulate or debris
content within the fluid supply is outside a predetermined
tolerance value for the fluid supply.
11. A method for monitoring a fluid supply as claimed in claim 3
wherein the method further comprises the step of activating an
alarm to notify an operator that the fluid supply to the fluid
conduit has been shut down.
12. A method for monitoring a fluid supply as claimed in claim 3
wherein the method further comprises the step of sending an
electronic notification to a preselected person notifying them that
the fluid supply to the fluid conduit has been shut down.
13. A method for monitoring a fluid supply as claimed in claim 1
wherein the step of monitoring the fluid supply within the
monitoring zone further comprises the step of analysing the quality
or purity of the chemical composition of the fluid supply.
14. A method for monitoring a fluid supply as claimed in claim 13
wherein the method further comprises the step of notifying an
operator of the risk of a blockage occurring within the fluid
conduit when the quality or purity of the chemical composition of
the fluid supply is outside a predetermined tolerance value.
15. A method for monitoring a fluid supply as claimed in claim 1
wherein the step of monitoring the fluid supply within the
monitoring zone further comprises the step of monitoring the rate
of flow of the fluid supply.
16. A method for monitoring a fluid supply as claimed in claim 1
wherein the method further comprises the step of recording
information relating to one or more of the monitored
parameters.
17. A fluid monitoring unit for monitoring a fluid supply to a
fluid conduit, the fluid monitoring unit comprising a monitoring
zone and a sensor, the sensor providing a means for detecting the
occurrence of one or more events within the monitoring zone
detrimental to the flow of the fluid supply through the fluid
conduit, wherein the monitoring zone is configured to provide
upstream fluid cooperation with an entrance of the fluid
conduit.
18. A fluid monitoring unit as claimed in claim 17 wherein the
sensor comprises a filter located within the monitoring zone and a
pressure detector arranged to monitor the pressure differential of
the fluid supply across the filter.
19. A fluid monitoring unit as claimed in claim 17 wherein the
sensor further comprises a thermometer arranged to provide a means
monitoring a temperature of the fluid supply.
20. A fluid monitoring unit as claimed in claim 17 wherein the
sensor comprises a hygrometer arranged to monitor the water content
of the fluid supply.
21. A fluid monitoring unit as claimed in claim 17 wherein the
sensor comprises a particulate sensor arranged to monitor the fluid
supply transmitted through the monitoring zone for the presence of
particulate or debris.
22. A fluid monitoring unit as claimed in claim 21 wherein the
particulate sensor comprises an optical particulate sensor.
23. A fluid monitoring unit as claimed in claim 21 wherein the
particulate sensor comprises a passive-induction particulate
sensor.
24. A fluid monitoring unit as claimed in claim 17 wherein the
sensor comprises a UV spectrometer arranged to monitor the chemical
composition of the fluid supply transmitted through the monitoring
zone.
25. A fluid monitoring unit as claimed in claim 17 wherein the
sensor comprises a flow meter arranged to monitor the rate of flow
of the fluid supply.
26. A fluid monitoring unit as claimed in claim 17 wherein the
fluid monitoring unit further comprises a computer processing unit
that provides a means for controlling the sensor.
27. A fluid monitoring unit as claimed in claim 26 wherein the
computer processing unit provides a means for the fluid monitoring
unit to transmit and receive data.
28. A fluid monitoring unit as claimed in claim 26 wherein the
computer processing unit generates an output signal if the pressure
differential of the fluid supply across the filter is outside of a
predetermined tolerance value.
29. A fluid monitoring unit as claimed in claim 26 wherein the
computer processing unit generates an output signal if the water
content within the fluid supply is outside of a predetermined
tolerance value.
30. A fluid monitoring unit as claimed in claim 26 wherein the
computer processing unit generates an output signal if a density or
mass of the particulate or debris content within the fluid supply
is outside a predetermined tolerance value.
31. A fluid monitoring unit as claimed in claim 26 wherein the
computer processing unit generates an output signal if the quality
or purity of the chemical composition of the fluid supply is
outside a predetermined tolerance value.
32. A hydrocarbon exploration and production installation, the
installation comprising at least one supply conduit that provides a
means for fluid communication between a fluid source and a fluid
conduit, and a fluid monitoring as claimed in claim 17, wherein the
fluid monitoring unit is located within the supply conduit upstream
of the fluid conduit.
33. A hydrocarbon exploration and production installation as
claimed in claim 32 wherein the installation further comprises a
pump located between the fluid source and the fluid monitoring
unit.
34. A hydrocarbon exploration and production installation as
claimed in claim 32 wherein the installation further comprises a
shut off valve located between the fluid monitoring unit and the
fluid conduit.
35. A hydrocarbon exploration and production installation as
claimed in claim 32 wherein an output signal from the fluid
monitoring unit is employed as a feedback signal to activate a shut
down of the pump.
36. A hydrocarbon exploration and production installation as
claimed in claim 34 wherein an output signal from the fluid
monitoring is employed as a feedback signal to activate closure of
the shut off valve.
37. A hydrocarbon exploration and production installation as
claimed in claim 32 wherein the installation further comprises an
operations control module connected to the fluid monitoring unit so
as to provide a means for monitoring and recording output data from
the fluid monitoring unit.
Description
[0001] The present invention relates to a method and apparatus for
use in the hydrocarbon exploration and production industry and in
particular to a method and apparatus for monitoring a fluid that is
to be transported through a fluid conduit. The monitoring of a
fluid to be transported through a fluid conduit provides a dynamic
indication of the occurrence of detrimental effects for the fluid
flow within the conduit. The described method and apparatus have
particular application for preventing blockages within fluid
umbilicals, although the methods and apparatus may also be adapted
for monitoring fluids for the occurrence of detrimental effects
within pipelines, wellbores and risers.
[0002] During the production and transportation of hydrocarbons, it
is common for the interiors of fluid conduits, including pipelines,
wellbores, risers and umbilicals, to become fouled. This fouling
can lead to the build up of layers of debris or particulate matter
on the inside of conduits, which reduces the effective inner
diameter (ID) of the conduit and thus reduces the flow rate.
Fouling can also produce blockages in the fluid conduits which
completely prevent fluid flow.
[0003] A fluid umbilical is a bundled collection of steel and/or
thermoplastic tubing and electrical cabling. Typically they are
employed to transmit chemicals, hydraulic fluids, electric power,
and two-way data communication and control signals between surface
production facilities and subsea production equipment. Umbilicals
typically range up to 10 inches (254 mm) in diameter, with internal
tubes ranging from 0.5 inch to 1 inch (12.7 mm to 25.4 mm) in
diameter. A dynamic umbilical is the portion of the umbilical that
is suspended from a semi-submersible vessel to the seabed, where it
is coupled to a static section of the umbilical. In a typical
umbilical, the multiple internal conduits are twisted together into
a helical rope-like structure in order to increase the tensile
strength. This is a particularly important consideration for the
dynamic umbilical section since it must withstand stresses due to
its own weight and the dynamic loading from currents.
[0004] Examples of some of the most frequently transmitted
chemicals through umbilicals within the hydrocarbon exploration and
production industry include: scale inhibitors; corrosion
inhibitors; methanol, ethanol, ethylene glycol, mono ethylene
glycol, MEG (examples of hydrate inhibitors); industrial methylated
spirits; wax inhibitors and pour point depressants (PPD); low
dosage hydrate inhibitors (LDHIs); asphaltene inhibitors and
dispersants; flow improvers and surfactants; biocides; H.sub.2S
scavengers; and demulsifiers.
[0005] The relatively small diameters of the internal tubes within
the subsea umbilical, in combination with the fact that their
helical path arrangement significantly increases the frictional
drag experienced by objects inserted into the internal tubes, means
that umbilicals are particularly prone to blockages. Such blockages
completely prevent fluid transmission through the umbilical and so
can cause considerable disruption to production activities.
Furthermore, the helical path arrangement of the internal conduits
means that conventional cleaning equipment is often prohibited from
being inserted to attempt to clear a blockage. If a blockage cannot
be removed then this results in obvious time and cost implications
for the operator. It is estimated that the costs incurred in
replacing a typical subsea fluid umbilical run into several
millions of pounds.
[0006] In order to mitigate the risk of blockages forming within
umbilicals it is known in the art to provide the internal tubes
with a filter at its entrance. Such filters do help prevent certain
particulates and other debris from entering the internal tubing.
However, in practice it is found that the major contributing factor
to the formation of blockages within a fluid umbilical is human
error, either through the poor design of the chemical bunkering
systems, unsuitable methodologies being employed in offshore
environments or even faulty chemical compatibility testing being
carried out. For example, if an operator accidentally allows
incompatible fluids to be transmitted down the same internal tube
then coagulation or flocculation may take place so resulting in
blockages within the umbilical. Some examples of known incompatible
fluid combinations include: [0007] 1) Scale inhibitors and methanol
or glycols. If the scale inhibitor is water based (as is normally
the case) then methanol or a glycol will precipitate the inhibitor;
[0008] 2) Pour point depressants and methanol or glycols. When the
level of methanol or glycol is above a certain level then
precipitation of some polymer PPDs occurs; [0009] 3) Asphaltene
inhibitors and methanol; [0010] 4) Asphaltene dispersants and polar
solvents (e.g. alcohols, glycols or water); [0011] 5) Flow
improvers for water and polar solvents; [0012] 6) Flow improvers
for oil and any of the other above listed transmitted chemicals;
[0013] 7) H.sub.2S scavengers and methanol or organic solvents; and
[0014] 8) Biocides and methanol.
[0015] A further detrimental effect that occurs within fluid
conduits is the onset of corrosion. The effects of corrosion can be
exacerbated by the chemical nature of the fluid supply being
transported through the conduit. Corrosion can ultimately lead to
structural failures within a fluid conduit and therefore it is
obviously beneficial to be able to monitor the detrimental effects
of corrosion within a fluid conduit.
[0016] It is therefore an object of an aspect of the present
invention to provide a method and apparatus for monitoring a fluid
that is to be transported through a fluid conduit so as to provide
a dynamic indication of the occurrence of detrimental effects for
the fluid flow within the conduit.
[0017] It is a further object of an aspect of the present invention
to provide a method and apparatus for monitoring the formation of a
blockage within a fluid conduit system.
[0018] A yet further object of an aspect of the present invention
to provide a method and apparatus for monitoring the level of
corrosion within a fluid conduit system.
[0019] The described method and apparatus is applicable to a wide
range of fluid conduit systems used in the hydrocarbon exploration
and production industry, and in particular to fluid umbilicals.
SUMMARY OF INVENTION
[0020] According to a first aspect of the present invention there
is provided a method for monitoring a fluid supply to be
transported through a fluid conduit located within a hydrocarbon
exploration and production installation, the method comprising the
steps of: [0021] providing a monitoring zone upstream of the fluid
conduit; [0022] introducing the fluid supply to the fluid conduit
via the monitoring zone; and [0023] monitoring the fluid supply
within the monitoring zone so as to detect the occurrence of one or
more events detrimental to the flow of the fluid supply through the
fluid conduit.
[0024] It is advantageous to monitor the fluid supply prior to
entering the fluid conduit as this allows for the early detection
of an event detrimental to the flow of the fluid supply e.g. a
chemical reaction indicative of corrosion of the fluid conduit or
the formation of a potential blockage within the fluid conduit. In
this way the risk of costly blockages or structural failure
occurring within the fluid conduit is significantly reduced.
[0025] Most preferably the step of monitoring the fluid supply
within the monitoring zone comprises the step of detecting solids
or solidification within the fluid supply.
[0026] Preferably the method further comprises the step of shutting
off the fluid supply to the fluid conduit when solidification is
detected. Shutting off the fluid supply to the fluid conduit allows
an operator to check the installation to see if a non-compatible
chemical supply has been introduced to the fluid supply.
[0027] Optionally the step of detecting solids or solidification
within the fluid supply comprises monitoring a pressure
differential across a filter located within the monitoring zone. A
change in the pressure differential across the filter is indicative
of a change in the viscosity within the fluid supply and hence a
possible contamination of the fluid supply.
[0028] Preferably the step of shutting off the fluid supply to the
fluid conduit occurs when the pressure differential across the
filter is outside of a predetermined tolerance value for the fluid
supply.
[0029] Most preferably the step of monitoring the pressure
differential across the filter further comprises the step of
correlating the monitored pressure differential with a temperature
of the fluid supply. By correlating the pressure differential
across the filter with the temperature of the fluid supply reduces
the risk of erroneous contamination events being detected.
[0030] Optionally, the step of detecting solids or solidification
within the fluid supply comprises the step of monitoring the water
content of the fluid supply.
[0031] Preferably the step of shutting off the fluid supply to the
fluid conduit occurs when the water content of the fluid supply is
outside a predetermined tolerance value for the fluid supply.
[0032] Optionally, the step of detecting solids or solidification
within the fluid supply comprises the step of monitoring a
particulate or debris content of the fluid supply.
[0033] Preferably the step of shutting off the fluid supply to the
fluid conduit occurs when a density or mass of the particulate or
debris content within the fluid supply is outside a predetermined
tolerance value for the fluid supply.
[0034] If the fluid supply to the fluid conduit is shut down then
an alarm may be activated to notify an operator of the shut down
event. Optionally an automated electronic notification may also be
sent to an appropriate preselected person notifying them of the
shut down event.
[0035] Preferably the step of monitoring the fluid supply within
the monitoring zone further comprises the step of analysing the
quality or purity of the chemical composition of the fluid
supply.
[0036] Optionally the step of monitoring the fluid supply within
the monitoring zone further comprises the step of monitoring the
rate of flow of the fluid supply.
[0037] Preferably the method further comprises the step of
notifying an operator of the risk of a blockage occurring within
the fluid conduit when the quality or purity of the chemical
composition of the fluid supply is outside a predetermined
tolerance value.
[0038] Optionally the method further comprises the step of
recording information relating to one or more of the monitored
parameters. Recording information regarding fluid cleanliness,
viscosity, water content, differential pressure, absolute pressure,
temperature and fluid flow rates allows for historical data reviews
to be generated.
[0039] According to a second aspect of the present invention there
is provided a method for monitoring a fluid supply to be
transported through a fluid umbilical, the method comprising the
steps of: [0040] providing a monitoring zone upstream of the fluid
umbilical; [0041] introducing the fluid supply to the fluid
umbilical via the monitoring zone; and [0042] monitoring the fluid
supply within the monitoring zone so as to detect the occurrence of
one or more events detrimental to the flow of the fluid supply
through the fluid umbilical.
[0043] Embodiments of the second aspect of the invention may
comprise preferred and optional features of the first aspect of the
invention and vice versa.
[0044] According to a third aspect of the present invention there
is provided a fluid monitoring unit for monitoring a fluid supply
to a fluid conduit, the fluid monitoring unit comprising a
monitoring zone and a sensor, the sensor providing a means for
detecting the occurrence of one or more events within the
monitoring zone detrimental to the flow of the fluid supply through
the fluid conduit, wherein the monitoring zone is configured to
provide upstream fluid cooperation with an entrance of the fluid
conduit.
[0045] By having the monitoring zone configured to provide upstream
fluid cooperation with an entrance to the fluid conduit allows the
fluid monitoring unit to dynamically monitor the fluid supply prior
to entering the fluid conduit. This allows for the early detection
of potential blockage forming scenarios and so significantly
reduces the risk of costly blockages occurring within the fluid
conduit.
[0046] Most preferably the sensor comprises a filter located within
the monitoring zone and a pressure detector arranged to monitor the
pressure differential of the fluid supply across the filter.
[0047] Preferably the sensor further comprises a thermometer
arranged to provide a means for the fluid monitoring unit to
correlate changes in the monitored pressure differential across the
filter with temperature changes of the fluid supply.
[0048] Alternatively, or in addition, the sensor comprises a
hygrometer arranged to monitor the water content of the fluid
supply.
[0049] Alternatively, or in addition, the sensor comprises a
particulate sensor arranged to monitor the fluid supply transmitted
through the monitoring zone for the presence of particulate or
debris.
[0050] The particulate sensor may comprise an optical particulate
sensor. The particulate sensor may comprise a passive-induction
particulate sensor.
[0051] Alternatively, or in addition, the sensor comprises a UV
spectrometer arranged to monitor the chemical composition of the
fluid supply transmitted through the monitoring zone.
[0052] Alternatively, or in addition, the sensor comprises a flow
meter arranged to monitor the rate of flow of the fluid supply.
[0053] Most preferably the fluid monitoring unit comprises a
computer processing unit that provides a means for controlling the
sensor. The computer processing unit also provides a means for the
fluid monitoring unit to transmit and receive data.
[0054] Preferably the computer processing unit generates an output
signal if the pressure differential of the fluid supply across the
filter is outside of a predetermined tolerance value.
[0055] The computer processing unit may also generate an output
signal if the water content within the fluid supply is outside of a
predetermined tolerance value.
[0056] The computer processing unit may also generate an output
signal if a density or mass of the particulate or debris content
within the fluid supply is outside a predetermined tolerance
value.
[0057] The computer processing unit may also generate an output
signal if the quality or purity of the chemical composition of the
fluid supply is outside a predetermined tolerance value.
[0058] According to a fourth aspect of the present invention there
is provided a fluid monitoring unit for monitoring a fluid supply
to a fluid umbilical, the fluid monitoring unit comprising a
monitoring zone and a sensor, the sensor providing a means for
detecting the occurrence of one or more events within the
monitoring zone detrimental to the flow of the fluid supply through
the fluid umbilical, wherein the monitoring zone is configured to
provide upstream fluid cooperation with an entrance of the fluid
umbilical.
[0059] Embodiments of the fourth aspect of the invention may
comprise preferred and optional features of the third aspect of the
invention and vice versa.
[0060] According to a fifth aspect of the present invention there
is provided a hydrocarbon exploration and production installation,
the installation comprising at least one supply conduit that
provides a means for fluid communication between a fluid source and
a fluid conduit, and a fluid monitoring unit in accordance with the
third aspect of the present invention, wherein the fluid monitoring
unit is located within the supply conduit upstream of the fluid
conduit.
[0061] Preferably the installation further comprises a pump located
between the fluid source and the fluid monitoring unit.
[0062] Optionally the installation further comprises a shut off
valve located between the fluid monitoring unit and the fluid
conduit.
[0063] Preferably an output signal from the fluid monitoring unit
is employed as a feedback signal to activate a shut down of the
pump. The output signal may also be employed as a feedback signal
to activate closure of the shut off valve.
[0064] Preferably the installation further comprises an operations
control module connected to the fluid monitoring unit so as to
provide a means for monitoring and recording output data from the
fluid monitoring unit.
[0065] According to a sixth aspect of the present invention there
is provided a hydrocarbon exploration and production installation,
the installation comprising at least one supply conduit that
provides a means for fluid communication between a fluid source and
a fluid umbilical, and a fluid monitoring unit in accordance with
the fourth aspect of the present invention, wherein the fluid
monitoring unit is located within the supply conduit upstream of
the fluid umbilical.
[0066] Embodiments of the sixth aspect of the invention may
comprise preferred and optional features of the third fourth and
fifth aspects of the invention and vice versa.
BRIEF DESCRIPTION OF DRAWINGS
[0067] Aspects and advantages of the present invention will become
apparent upon reading the following detailed description of example
embodiments and upon reference to the following drawings in
which:
[0068] FIG. 1 presents a schematic diagram of a surface production
facility, that provides fluid communication with an umbilical, and
which incorporates fluid monitoring units in accordance with an
embodiment of the present invention; and
[0069] FIG. 2 presents a schematic diagram of the fluid monitoring
units of FIG. 1.
[0070] In the description which follows, like parts are marked
throughout the specification and drawings with the same reference
numerals. The drawings are not necessarily to scale and the
proportions of certain parts have been exaggerated to better
illustrate details and features of embodiments of the
invention.
DETAILED DESCRIPTION
[0071] In order to provide understanding of the various aspects of
the present invention a schematic diagram of a surface production
facility, generally depicted by the reference numeral 1, is
presented in FIG. 1, while FIG. 2 presents a schematic diagram of a
fluid monitoring unit 2 employed with the surface production
facility 1.
[0072] The surface production facility 1 can be seen to comprise
four supply conduits 3 that provide a means for fluid communication
between a corresponding fluid source 4 and an umbilical 5 via a
topside umbilical termination unit (TUTU) 6. In the presently
described embodiment the fluid sources comprise a corrosion
inhibitor 4a (one such suitable corrosion inhibitor being that sold
by Champion Technologies under the trade mark Scortron.RTM.
G10000), a scale inhibitor 4b (one such suitable scale inhibitor
being that sold by Champion Technologies under the trade mark
Gyptron.RTM. SA110N), methanol 4c and a wax inhibitor 4d (one such
suitable wax inhibitor being that sold by Champion Technologies
under the trade mark Flexoil.RTM. WM1840).
[0073] Within each supply conduit 3 is located a metering pump 7, a
fluid monitoring unit 2 and a shut-off valve 8. Each metering pump
7 is employed to regulate the pressure flow of the fluid within its
respective supply conduit 3 and hence into an internal tube of the
umbilical 5. The fluid monitoring units 2 are located between the
metering pumps 7 and the TUTU 6 and are employed to monitor one or
more parameters associated with the transported fluid before it is
pumped into the umbilical 5. A feedback connection 9 provides a
means for the fluid monitoring unit 2 to stop its respective
metering pump 7 and/or to close the respective shut-off valve 8
when the occurrence of a detrimental effect for the fluid flow
within the umbilical 5 is detected e.g. a potential blockage
forming scenario is detected or significant levels of corrosion are
detected, further details of which are provided below.
[0074] An electricity supply 10 provides a dedicated power source
for each of the fluid monitoring units 2. Each fluid monitoring
unit 2 is also connected to an operations control module 11 which
may be located within the surface production facility 1.
Optionally, the operations control module 11 is connected to a
remote operations control module 12 that provides a means for
remotely monitoring and controlling the fluid supplies into the
umbilical 5. Communication to and from the facility and within the
facility itself may be by RS232, Ethernet or wireless means.
[0075] From FIG. 2 each fluid monitoring unit 2 can be seen to
comprise a monitoring zone in the form of a conduit 13 through
which the fluid supply is transmitted such that the monitoring zone
provides a means for upstream fluid cooperation with an entrance of
an internal tubing of the umbilical 5. Located within the
monitoring zone 13 is a filter 14 which provides an initial means
for preventing particulates and other debris from entering the
internal tubing of the umbilical 5. The fluid monitoring unit 2
further comprises a pressure sensor 15 that provides a means for
measuring the pressure differential of the fluid supply across the
filter 14 or the absolute pressure of the fluid supply within the
monitoring zone 13 (an Able Instrumentation Differential Pressure
Gauge Model 126 being one such suitable pressure sensor), a
thermometer 16 that provides a means for measuring the temperature
of the fluid supply (an Able Instruments eight wire, one series
temperature switch being one such suitable thermometer), and a
hygrometer 17 that provides a means for measuring the water content
within the fluid supply (an Able Instruments HTF dewpoint sensor
being one such suitable hygrometer). Optionally, the fluid
monitoring unit 2 further comprises a particulate or flocculation
sensor 18 (an Able Instruments Model 980 series dual beam
Photometer being one such suitable particulate sensor); a UV
spectrometer 19 (an Able Instruments Model 960 UV-Analyzer being
one such suitable UV spectrometer); and a flow meter 20 that
provides a means for accurately monitoring the rate of flow of the
fluid before it enters the internal tubing of the umbilical 5. The
flow meter may be a positive displacement flow meter, for example a
helical screw flow meter or a rotary piston flow meter since both
meter types provide accurate readings at relatively low flow
rates.
[0076] Each of the sensors 15, 16, 17, 18, 19 and 20 are connected
to a CPU 21 which provides a means for controlling the sensors 15,
16, 17, 18, 19 and 20, processing the measured data and relaying
the data on to the control modules 11 and/or 12.
[0077] In the presently described embodiment the filter 14
comprises a two micron absolute filter, however the filter size may
be changed depending on expected flow rates within the system. For
the presently described surface production facility 1 the fluid
supply flow rates range from a minimum flow rate of 40 ml/min to a
maximum flow rate of 1000 ml/min. Corresponding pressures through
the system range from 0 to 5000 psi.
[0078] It is preferable for the distance between the fluid
monitoring unit 2 and the shut-off valve 8 to be sufficient that on
the fluid monitoring unit 2 detecting the occurrence of a
detrimental effect for the fluid flow within the umbilical the
shut-off valve 8 can be closed before the fluid supply passes its
physical location.
[0079] The above described fluid monitoring units 2 allow for
various ways to detect the occurrence of solidification within
supplied fluids and for analysing the quality of supplied fluids.
The onset of solidification within the fluid supply can be
indicative of coagulation or flocculation caused by chemical
reactions between different fluids or the use of low quality or
purity fluids, and/or the formation of solid particulates or debris
as a result of corrosion within the umbilical itself. The various
techniques will now be described in further detail.
Monitoring Pressure Deferential
[0080] The first method employs the pressure sensor 15 to monitor a
pressure differential across the filter 14. The pressure
differential is correlated with the temperature of the fluid, as
measured by the thermometer 16. This correlation may take place
directly within the pressure sensor 15, the CPU 21 or more
preferably within the control modules 11 or 12. A change in the
viscosity within the fluid supply is detected as a corresponding
change in the pressure differential across the filter 14. If the
change in pressure differential is outside of a predetermined
tolerance value for that particular fluid, and does not correlate
with a corresponding temperature change, as detected by the
thermometer 16, then this is indicative of a chemical reaction
causing coagulation or flocculation, for example the inadvertent
mixing of a scale inhibitor and methanol. Coagulation or
flocculation can lead to the onset of a blockage within the
umbilical 5 and so in such circumstances the fluid monitoring unit
2 would activate an alarm within the control module 11 and/or 12
and preferably provide for the automatic shut down of the metering
pump 7 in conjunction with the closing of the corresponding
shut-off valve 8. This would allow the operator to check the
facility 1 to see if a non-compatible chemical combination had been
set up in error sufficiently early in the process so as to avoid
the occurrence of a costly blockage.
Monitoring Water Content
[0081] The second method for detecting potential on set of a
blockage is achieved via the employment of the hygrometer 17. The
hygrometer 17 is set to detect the presence of water within the
fluid supply between 0% and 100% using a small electrical current.
A predetermined value, with acceptable tolerance levels, is
provided for a particular fluid supply. Activation of the alarms
and/or the shutting down of the fluid supply, as previously
described, again results if the detected water level moves out with
the predetermined tolerance levels. For example, the water content
for a water-based fluid supply e.g. a biocide may be of the order
of 80% with an accepted tolerance level of .+-.0.5%. If a solvent,
for example a wax inhibitor, were to be introduced to the
water-based fluid supply then the water content may fall to around
78% thus triggering the alarms and/or the shutting down of the
supply line. Alternatively, the water content for a solvent-based
fluid supply e.g. an ashphaltene inhibitor may be of the order of
0% with an accepted tolerance level of +0.5%. If a water based
fluid, for example an H.sub.2S scavenger or even simply rain water
were to be introduced to the solvent-based fluid supply then the
water content may rise to above 0.5% thus triggering the alarms
and/or the shutting down of the supply line.
[0082] What is important for the operation of the above
solidification diagnostic is the establishment of a base water
level content for a fluid supply and an appropriate tolerance
level. The hygrometer 17 then allows for changes in the water
content of the fluid supply to be monitored and appropriate action
taken if this exceeds the predetermined tolerance value.
[0083] It is preferable for the fluid monitoring unit 2 to also be
capable of measuring and recording the absolute pressure,
temperature and rate of fluid flow of the fluid supply. The
pressure sensor 15, the thermometer 16 and the flow meter 20 in
conjunction with the control modules 11 and/or 12 can facilitate
all of these diagnostics.
Particle Analysis
[0084] The employment of the particulate sensor 18 provides a means
for detecting the presence of particulates or debris with the fluid
supply. The particulates or debris may be of a type that is
transmitted directly into the monitoring zone 13 or are formed as a
result of a chemical reaction within the monitoring zone 13 e.g.
via corrosion.
[0085] The particulate sensor 18 preferably comprises an optical
sensor whereby one or more light sources and a photodetector are
arranged to provide sensing points within the monitoring zone 13
e.g. an Able Instruments Model 980 series dual beam Photometer.
Particulates or debris passing through sensing points then acts to
scatter the light from the light source onto the photodetector
which is thereafter transformed into a pulsed signal. The number of
pulses per unit time is proportional to the density of particulates
or debris presents. The pulse signal is then converted into a
voltage output for relaying to the control modules 11 and/or
12.
[0086] Alternatively, or in addition to the optical particulate
sensor, the particulate sensor 18 may comprise a type that employs
a combination of passive-induction and protected-probe technologies
(a Baumer Process Instrumentation conductivity sensor ISL05x being
one such suitable sensor). As particles or debris flow near and
around the probe, minute currents are dynamically induced within
the probe. These currents can then be processed to provide an
absolute output that is substantially linear to the mass of the
particulates or debris present.
[0087] Optical particulate sensors are preferable for use with oil
based fluids or solvents e.g. wax inhibitor while they are less
effective when used with water based fluids e.g. biocides. In such
fluids it is preferable to employ the passive induction type of
sensors.
[0088] In a similar manner to that described above a predetermined
particulate or debris level is defined for a particular fluid
supply. If the mass of the particulate or debris exceeds this
predetermined value then the fluid monitoring unit 2 activates the
corresponding alarms and/or shuts down the fluid supply.
[0089] As well as the fluid monitoring units 2 being configured to
operate or trigger an alarm and/or shut down the fluid supply upon
exceeding one or more predetermined parameters, the control modules
11 or 12 may also be configured to automatically e-mail an
appropriate preselected person about the potential problem within
the facility 1. This facility has particular application in the
following circumstances.
UV Spectroscopy
[0090] During the operation of the surface production facility 1
there are times when it is required to be shut down. On occasion
this shut down period may last several weeks. On restarting the
surface production facility 1 it can be found to have developed a
blockage even although no obvious contamination of the fluid has
occurred.
[0091] It has been recognised by the inventors that the source of
the formation of such blockages lie within the inherent quality or
purity of the fluid being transported i.e. if the fluid quality or
purity is below a predetermined value and then the fluid is allowed
to remain static within the umbilical then a blockage may form.
[0092] The employment of the UV spectrometer 19 provides a means
for analysing the chemical composition of a fluid within the
monitoring zone 13 and thus provide an indication if it falls below
a predefined quality or purity level. In such circumstances the
fluid monitoring unit 2 notifies the control modules 11 and/or 12
that the fluid should not be allowed to remain static within the
umbilical 5.
[0093] If a shut down event of the surface production facility 1
occurs during this period then subsequent periodic reminders may be
sent to the operator of the surface production facility 1 notifying
them that unless pumping of the fluid is re started then they are
heading for the occurrence of a blockage within the umbilical
5.
[0094] The above described method and apparatus provide a means for
protecting the integrity of a fluid conduit and in particular a
fluid umbilical. The method and apparatus allow for a reduction in
the vulnerability of these expensive assets due to human error by
providing a means for continuous dynamic monitoring of the injected
fluid supplies and providing for automated pump shut down when
potential detrimental effects for the fluid flow within the fluid
umbilical are detected e.g. blockage forming circumstances.
Significantly, the fluid monitoring units provide a proactive
method that prevents the formation of blockages rather than
allowing for a reactive method to be employed in response to the
detection of a blockage, as is the case for known prior art
systems.
[0095] By performing real time particle analysis and monitoring
chemical compatibilities, via pressure, temperature, water and
particle content measurements, and UV spectroscopy round the clock
analysis can be performed. This allows for trends within the
facility to be built up for individual umbilicals, or other fluid
conduits, and so enables the activation of alarms or automated shut
downs, as and when appropriate.
[0096] The adapted facility also allows for periodic integrity
reviews to be carried out wherein information regarding fluid
cleanliness (NAS rating), viscosity, water content, differential
pressure, absolute pressure, temperature and flow rates can be
displayed in real time or downloaded for historical data
reviews.
[0097] The foregoing description of the invention has been
presented for purposes of illustration and description and is not
intended to be exhaustive or to limit the invention to the precise
form disclosed. The described embodiments were chosen and described
in order to best explain the principles of the invention and its
practical application to thereby enable others skilled in the art
to best utilise the invention in various embodiments and with
various modifications as are suited to the particular use
contemplated. Therefore, further modifications or improvements may
be incorporated without departing from the scope of the invention
as defined by the appended claims.
* * * * *