U.S. patent application number 13/531239 was filed with the patent office on 2013-01-10 for method and module for determination of erosion in systems.
Invention is credited to Nicholas Josep Ellson, Astrid Kristoffersen, Gaute Yddal Vestbostad, Inge Wold.
Application Number | 20130008649 13/531239 |
Document ID | / |
Family ID | 44195015 |
Filed Date | 2013-01-10 |
United States Patent
Application |
20130008649 |
Kind Code |
A1 |
Vestbostad; Gaute Yddal ; et
al. |
January 10, 2013 |
METHOD AND MODULE FOR DETERMINATION OF EROSION IN SYSTEMS
Abstract
A method of providing information regarding erosion in an oil
and/or a gas production system, which system includes at least one
equipment/piping, the method including the steps of obtaining CFD
results regarding hot spots in the equipment/piping from a CFD
analysis of the equipment/piping for a range of pressures, flow
rates and sand rates; and to, during production, obtaining data
regarding erosion rates in a particular location in the system; and
combining the data regarding erosion rates and CFD results to
estimate and monitor sand erosion rates in the hot spots of the
system. Further disclosed is a module performing the method steps
as well as a computer program.
Inventors: |
Vestbostad; Gaute Yddal;
(Asker, NO) ; Kristoffersen; Astrid; (Lier,
NO) ; Ellson; Nicholas Josep; (Bristol, GB) ;
Wold; Inge; (Kjeller, NO) |
Family ID: |
44195015 |
Appl. No.: |
13/531239 |
Filed: |
June 22, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/IB2010/003334 |
Dec 22, 2010 |
|
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13531239 |
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Current U.S.
Class: |
166/250.05 |
Current CPC
Class: |
G01N 3/56 20130101; E21B
47/10 20130101; E21B 47/08 20130101 |
Class at
Publication: |
166/250.05 |
International
Class: |
E21B 47/00 20120101
E21B047/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2009 |
NO |
20093580 |
Claims
1. A method of providing information regarding erosion in an oil
and/or a gas production system, which system comprises at least one
equipment/piping, the method comprising the steps of: obtaining CFD
results regarding hot spots in the equipment/piping from a CFD
analysis of the equipment/piping for a range of pressures, flow
rates and sand rates; and to, during production obtaining data
regarding erosion rates in a particular location in the system;
combining said data regarding erosion rates and CFD results to
estimate and monitor sand erosion rates in the hot spots of the
system.
2. The method according to claim 1, wherein also data regarding
flow rates, sand rates and pressures are obtained.
3. The method according to claim 1, wherein unadjusted,
interpolated or extrapolated CFD results are used for obtaining an
erosion pattern depending on the obtained data.
4. The method according to claim 1, wherein said obtained data
regarding erosion rates is derived from previously obtained and
stored data.
5. The method according to claim 4, wherein said estimated sand
erosion rates are correlated and adjusted against actual erosion
results.
6. The method according to claim 1, wherein said data regarding
erosion rates also is obtained from sensors arranged in said
equipment/piping.
7. The method according to claim 6, wherein said sensors include at
least one of physical sensors and virtual sensors.
8. The method according to claim 1, wherein said erosion rates are
estimated instantaneously.
9. The method according to claim 1, wherein accumulated erosion
rates are estimated.
10. The method according to claim 7, wherein data from sensors
comprise data from sand detectors, erosion probes, pressure
sensors, flow sensor, temperature sensors.
11. The method according to claim 1, wherein data further is
obtained from at least one of production management tools and
simulation tools.
12. The method according to claim 1, wherein it further comprises
the step of correlating available data with analytical models based
on models from said CFD results of the actual geometry of said
system.
13. A module for providing information regarding erosion in an oil
and/or a gas production system, which system comprises at least one
equipment/piping, the module comprising: means for obtaining CFD
results regarding hot spots in the equipment/piping from a CFD
analysis of the equipment/piping for a range of pressures, flow
rates and sand rates; means for, during production, obtaining data
regarding erosion rates in a particular location in the system;
means for, during production, combining said data regarding erosion
rates and CFD results to estimate and monitor sand erosion rates in
the hot spots of the system.
14. The method according to claim 1, wherein also data regarding
flow rates, and pressures are obtained.
15. The module according to claim 13, wherein also data regarding
flow rates, sand rates and pressures are obtained.
16. The module according to claim 13, wherein unadjusted,
interpolated or extrapolated CFD data are used for obtaining an
erosion pattern depending on the obtained data.
17. The module according to claim 13, wherein said module is
connected to and receives data from at least one of virtual sensors
and physical sensors such as sand detectors, erosion probes,
pressure sensors, flow sensor, temperature sensors.
18. The module according to claim 13, wherein data further
comprises data from production at least one of management tools and
simulation tools.
19. The module according to claim 13, wherein it further comprises
means for correlating available data with analytical models based
on models from said computational fluid dynamics of the actual
geometry of said system.
20. A computer program product comprising software code portions
for making a processor perform the steps of claim 1.
21. The computer program product according to claim 20 supplied via
a network, such as Internet.
22. A computer readable medium containing a computer program
product according to claim 19.
23. A computer program comprising software code portions for making
a processor perform the steps of claim 1.
24. The computer program according to claim 23 supplied via a
network, such as Internet.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of pending
International patent application PCT/IB2010/003334 filed on Dec.
22, 2010 which designates the United States and claims priority
from Norwegian patent application 20093580 filed on Dec. 22, 2009,
the content of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to production systems for
fluids such as oil and gas, which could contain particles that
cause erosion inside the system.
BACKGROUND OF THE INVENTION
[0003] The modern off-shore production of oil and gas comprises
complex production systems from the wells to platforms and also
further to shore. Apart from oil and/or gas the systems also
contain water, solid particles such as sand and other unwanted
matter that negatively affects the function and life of the
system.
[0004] Sand and other abrasive materials are one major concern
regarding the function and life of the system where erosion is a
key problem. Thus, in a system/equipment geometry like a valve tree
or a manifold there may be a number of critical points where
erosion affects the system/equipment. Computational Fluid Dynamics
(CFD) is one of the branches of fluid mechanics that uses numerical
methods and algorithms to solve and analyze problems that involve
fluid flows. Computers are used to perform the millions of
calculations required to simulate the interaction of liquids and
gases with surfaces defined by boundary conditions. Even with
high-speed supercomputers only approximate solutions can be
achieved. The fundamental basis of almost all CFD problems is the
Navier-Stokes equations, which define any single-phase fluid
flow.
[0005] In order to try to handle the situation the production
systems are often arranged with a number of sensors that provide
information regarding the system, such as sand detectors that are
capable of detecting the presence of sand, and erosion probes that
can measure directly the erosion rate. Sensor placements are
restricted to a few locations. Erosion hot spots may occur in other
locations than the sensor placements. Further the accuracy of the
sensors may be limited, providing inaccurate information about the
condition of the system.
[0006] Thus, in a complex production system there may be many
erosion hot spots that are not monitored. Further erosion rates
might also change based on measured sand rates and the actual flow
pattern through these geometries.
[0007] Some methods that utilize CFD analysis in order to find
erosion, corrosion or wear have been developed. The document WO
2009/073495 A1 discloses a method where one or more computational
fluid dynamics (CFD) simulations may be conducted based on the
results of a comparison step. CFD simulations may provide velocity
vectors corresponding with various portions of a well tool with
high fluid flow rates.
[0008] One evaluation may be to determine if exterior portions of a
rotary drill with high fluid velocity correspond with areas of high
abrasion, erosion and/or wear. Comparing an "as built" 3D data file
with an associated after use 3D data file and an associated 3D
design data file may show areas of abrasion, erosion and/or wear
with a high degree of precision and accuracy. Such evaluations and
comparisons may result in changing the location and/or orientation
of one or more nozzles on rotary drill bits.
[0009] The geometrical configuration and dimensions associated with
blades and/or junk slots may also be changed. The design of
associated cutting elements and other cutting structures may also
be modified to minimize abrasion, erosion and/or wear.
[0010] The document US 2008/0257782 A1 discloses a method that
includes assessing corrosion in a refinery operation having a
piping network. Assessing can include identifying in a petroleum
sample a presence and an amount of a species determined to be
potentially corrosive to equipment in a refinery. A corrosion risk
presented by the presence, the amount, and the boiling point of the
species is determined. The corrosion risk is evaluated in view of
piping network information.
[0011] A system for implementing the method is also provided. An
advanced flow model is a computational fluid dynamics model. The
information from a corrosion model and the advanced flow model is
fed into a corrosion simulation model to predict the corrosion
rate. The corrosion simulation model basis its prediction on the
particular corrosive species, such as for example naphthenic acid
and sulphur compositions.
[0012] Document Andrews, J et al.: Production Enhancement From Sand
Management Philosophy. A case study from Staifjord and Gullfaks.
SPE European Formation Damage Conference, Scheveningen, Holland,
25-27 May 2005. SPE 94511 discloses a method of handling sand
contained in piping networks in order to increase production and
the reduce down-time due to erosion. The document discloses
monitoring the sand production by sensors, preferably a dual
acoustic sensor system, and by well samples collected from a sand
trap during well testing.
[0013] Production data such as well rates, pressures, choke
positions and uptime is collected daily. This data is then used for
calculating an erosion potential at various locations assuming a
base sand load. The erosion potential can then be related to sand
measurements such as from the above mentioned acoustic sensor
system and well samples in order to distinguish wells with high or
negligible sand erosion potential.
[0014] It is mentioned in the document that an on-line monitoring
is provided for an operator, but in reality, no information or data
is processed during actual production and provided to the operator
directly. On the contrary data collected and processed is related
to off-line measurements and given to the operator on a day to day
basis not instantly but well after occurrence. It is also to be
noted that it is only an erosion potential that is obtained, no
actual or current conditions on the production piping due to
erosions.
SUMMARY OF THE INVENTION
[0015] The aim of the present invention is to provide a method and
a module for accurately determining erosion in oil and/or gas
production systems.
[0016] This aim is obtained by a method and a module according to
the features of the independent patent claims. Preferable
embodiments form the subject of the dependent patent claims.
[0017] According to a main aspect of the invention, it is
characterised by a method of providing information regarding
erosion in an oil and/or a gas production system, which system
comprises at least one equipment/piping, the method comprising the
steps of:
[0018] obtaining CFD results regarding hot spots in the
equipment/piping from a CFD analysis of the equipment/piping for a
range of pressures, flow rates and sand rates; and to, during
production
[0019] obtaining data regarding erosion rates in a particular
location in the system; and
[0020] combining said data regarding erosion rates and CFD results
to estimate and monitor sand erosion rates in the hot spots of the
system.
[0021] According to another aspect of the invention also data
regarding flow rates and pressures are obtained.
[0022] According to yet another aspect of the invention,
unadjusted, interpolated or extrapolated CFD data results are used
for obtaining an erosion pattern depending on the obtained
data.
[0023] According to a further aspect of the invention, said
obtained data regarding erosion rates is derived from previously
obtained and stored data.
[0024] According to yet a further aspect of the invention, said
estimated sand erosion rates are correlated and adjusted against
actual erosion results.
[0025] According to another aspect of the invention, said data
regarding erosion rates also is obtained from sensors arranged in
said equipment/piping.
[0026] Said sensors may include physical and/or virtual
sensors.
[0027] According to another aspect of the invention, said erosion
rates are estimated instantaneously. Alternatively accumulated
erosion rates are estimated. Future erosion rates can also be
estimated.
[0028] According to a further aspect of the invention, data from
sensors comprise data from sand detectors, erosion probes, pressure
sensors, flow sensor, temperature sensors.
[0029] According to yet an aspect of the invention, data further is
obtained from production management tools, simulation tools and/or
soft sensor methods.
[0030] According to yet another aspect of the invention, the method
further comprises the step of correlating available data with
analytical models based on models from said computational fluid
dynamics of the actual geometry of said system.
[0031] The present invention also comprises a module, an erosion
adviser, that is capable of performing the method steps mentioned
above, where preferably the method steps are comprised in a
computer program that is run by the erosion adviser.
[0032] The advantages with the present invention are several and
there are several uses for the present invention. Some examples for
are:
[0033] the erosion adviser, preferably working on-line, can
supervise the erosion in all the system and give warnings if the
erosion is higher than an acceptable level. This level is set by
the user.
[0034] an operator wants to minimize erosion on equipment/piping.
Using a look-ahead functionality of the erosion adviser, it is
possible to see how the erosion changes with the production rates.
The erosion adviser will in this way be an input to the production
planning.
[0035] for maintenance purposes, the adviser can take into account
the production history of the field and tell the operator how much
is eroded away and, for a certain production profile, how long time
it will take before the equipment has to be changed because of
erosion. The results from the adviser will probably be different
from what the design base tells, as the adviser uses more realistic
data than the design base, which must be a worst-case.
[0036] a valve, such as a choke valve, erodes during its lifetime,
and the flow capacity (Cv) changes. If sufficient CFD analysis has
been done for the valve (choke), the erosion adviser can tell the
current Cv of the choke and hence act as guidance for intervention
frequency.
[0037] These and other aspects of, and advantages with, the present
invention will become apparent from the following detailed
description of the invention and from the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] In the following detailed description of the invention,
reference will be made to the accompanying drawing,
[0039] FIG. 1, which schematically shows the structure of a module
according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0040] An embodiment of the present invention as shown
schematically in FIG. 1 comprises an erosion adviser or module
capable of handling and running computer programs, which computer
programs are provided with data that are either stored in memories
of the module as well as external data provided via input means,
where the external data may come from a plurality of different
types of sensors, data from other modules, and data entered by a
user via keyboards, touch panels and the like.
[0041] The module may further comprise filters for filtering
signals from sensors, A/D-converters for converting and sampling
the signals and a micro processor. The micro processor comprises a
central processing unit CPU performing the functions according to
the present invention that will be described by way of example. The
micro processor further comprises a data memory and a program
memory. The result from the functions may be stored in appropriate
memory means, displayed to a user via display means and/or
transmitted via wired or wireless network connections to other
suitable receivers of data and/or results of the processing unit.
Data and information may also be transmitted to the module via
network connections.
[0042] A computer program for carrying out the method according to
the present invention is stored in the program memory. It is to be
understood that the computer program may also be run on a general
purpose computer instead of a specially adapted computer.
[0043] The module requires several different data depending on the
functionality requirements of a user. This input data may comprise
a list of equipment/piping names or geometry names that are
included in the production system to be analyzed, a design base and
equipment/piping geometry, i.e. on the first hand wall thickness
and equipment/piping geometry, CFD analyses, sand rate measured by
sensors, sand detector design data, sand particle size, flow and
historical flow, pressure, temperature, valve (choke) capacity Cv,
valve footprint, historical data and erosion probes etc. The
sensors may be both physical (hard) sensors positioned in the
equipment/piping as well as virtual (soft) sensors. The soft
sensors, for example edpm or a virtual flowmeter, are algorithms
capable of estimating quality indexes when no physical sensors are
available due to e.g. mounting costs. They make use of secondary
variables, easily measured in real time, such as pressure,
temperature, flow rates etc. and a mathematical model that
correlates these parameters and the variables that must be
monitored.
[0044] Further input data, as data files, may be stored in memory
means in the module, which data contain information regarding the
system to be analyzed and maybe also information regarding the
current state of the system. These files may contain geometry of
the equipments/piping and/or system, design base data, CFD
analyses, sensor or OPC (OLE (Object linking and embedding) for
Process Control) tag names, recorded or constructed system state
and look-ahead scenario, see further description below.
[0045] With this input data the module will have different
functionalities:
1) On-line functionality. A real time system that monitors and
analyzes the current system during production. With this
functionality, the system may work with any data collection system
like Master Control Station from GE Oil & Gas or modelling
systems like edpm (eField Dynamic Production Management System)
from SPT Group. Such systems are known to the person skilled in the
art and will not be described in detail. 2) Off-line functionality.
a) Design case functionality. The worst case possible is always
used when designing the system (equipment/piping). This
functionality shows the worst case scenario. b) Look ahead
functionality. Starts with current situation or user defined case.
It then calculates results of future erosion rates according to
user input.
[0046] Thus the module is capable of estimating both instantaneous
and accumulated erosion rates at all spots in the analyzed system,
based on i.a. measured sand and erosion rates at the sensor
locations and the actual flowing configuration. The module can
further use future estimated production conditions to calculate
future erosion rates, provide estimates on the changes in valve
(choke) characteristics due to erosion and give advice on
intervention strategies, correlate valve (choke) wear estimate to
either measured or modelled valve (choke) characteristics as well
as estimation of sand production rate based on monitoring erosion
at erosion probes in correlation with CFD simulation.
[0047] The erosion adviser is preferably based on detailed CFD
modelling of entire valve trees (X-mas trees), jumpers, connectors
and manifolds under a range of conditions, but may also use other
erosion models like Tulsa.RTM. from University of Tulsa or
Veritas.RTM. from Det Norske Veritas. It can function either as a
standalone unit, or together with an on-line system.
[0048] It is at present not possible to use CFD on-line in the
system, due to computing power limitations, so it is the results of
the CFD work for the geometry that are used by the module. For each
geometry, several CFD scenarios will have to be performed, for a
range of different parameters.
[0049] Here follows two examples of how the adviser will perform a
calculation. In the first example all parameters are fixed except
the flow rate and no measurements from erosion probes are
available.
[0050] CFD results for the analyzed geometry are available for
three different flow rates (result a, b and c). These flow rates
cover the expected operational envelope for the field.
[0051] All necessary information is read, either from set-up files,
scenario files, system instrumentation or a modelling system. Also
the actual production flow rate is obtained.
[0052] If the actual production flow rate, i.e. the flow rate for
which the module will calculate the erosion, is between the flow
rate for a and b, the module will interpolate between the results a
and b and get an erosion pattern for the actual flow rate. This
step as well as the following are done during production, i.e.
on-line.
[0053] In this erosion pattern the module will find the maximum
erosion value.
[0054] The module then uses an experimentally verified erosion
correlation to calculate the value for the maximum erosion.
[0055] The module will then adjust the whole erosion pattern to fit
the maximum erosion value calculated and will present this adjusted
erosion pattern to the user together with the calculated value for
the maximum erosion.
[0056] In the second example the CFD results will be adjusted to
the measurements of an erosion probe:
1) CFD results are available for several different combinations of
parameters, e.g. for variations of flow rate, sand particle size
and sand rate. 2) All necessary information is read, either from
set-up files, scenario files, system instrumentation or a modelling
system. The data from the erosion probe is also read. This is done
during production, i.e. on-line, as well as the following steps. 3)
The module will now interpolate (or extrapolate if necessary)
between the CFD results to get an erosion pattern for the actual
values read from the different sensors (or from a modelling
system). 4) The module then uses an experimentally verified erosion
correlation to calculate the value for the maximum erosion. 5) The
module will then adjust the whole erosion pattern from 3) to fit
the maximum erosion value calculated. 6) The module will then from
the new erosion pattern from 5) find the predicted erosion in the
location of the erosion probe and compare this erosion with the
data read from the erosion probe. The values in the erosion pattern
will then be adjusted according to the findings in this comparison.
E.g. if the erosion probe tells us that the erosion is only half of
what was predicted by the CFD-results, the values in the erosion
pattern can be divided by two (this is a simplification, an erosion
correlation will probably be used for this). 7) The adjusted
erosion pattern resulting from 6) will be presented, preferably
directly to the user together with the value for the maximum
erosion from this erosion pattern.
[0057] In the first example, the parameter flow rate is the one
that varies. In reality most parameters in a system will vary: sand
rate, sand particle size, flow rate, pressure and others. So the
module will have to interpolate (or in some cases also extrapolate)
between several CFD results. In fact, in many cases none of the
parameters will be exactly the same as the CFD simulations have
used.
[0058] A short description of how the system can work with two
varying parameters follows:
[0059] Varying parameters are sand particle size and flow rate. For
sand particle size three values have been studied, a, b and c. For
the flow rate the three rates x, y and z has been studied. In this
example we can have CFD results for the following combinations: ax,
ay, az, bx, by, bz, cx, cy, cz.
[0060] If the actual sand particle size is between a and b and the
actual flow rate is between y and z, the module has to
combine/interpolate the CFD results ay, az, by and bz to get the
erosion pattern for actual values of the parameters. If more
parameters vary, interpolation between even more CFD results has to
be done. The algorithms and equations used will depend on the
parameters that vary.
[0061] When the module is working according to any of the three
functionalities mentioned above (last paragraph of page 7), the
output or returned/shown results may be:
1) Erosion rate, which may be either or all of instantaneous
erosion, accumulated erosion and look-ahead erosion. 2) Erosion
amount, i.e. how many millimetres are, or will have been, eroded
away. 3) Wall thickness left. 4) Choke Cv, i.e. flow capacity. 5)
Production sand rate. 6) Service intervals, i.e. time to wall
thickness limit or valve (choke) intervention.
[0062] The module or adviser can work on both one or more pieces of
equipment/piping or a whole system. The adviser must have the
geometry of the equipment/piping in the memory. When working with a
whole system the adviser has to have a set of geometries stored in
the memory.
[0063] When a specific equipment/piping is analyzed the output
could be presented as values for the worst hot spot and a visual
presentation of the whole piece of equipment/piping. When a whole
geometry or list of equipment/piping are analyzed the output could
be presented as values for worst hot spot, a list of the worst hot
spot for each equipment/piping and a visual presentation of the
most eroded piece of equipment/piping.
[0064] The module will have several ways to present the results. It
will be a module that can be used separately with its own user
interface, or it can be used together with other control or on-line
systems.
[0065] The module will have its own interface to the user, where it
will be possible to make several choices, such as e.g.
functionality (on-line, design case, look-ahead), set-up files,
presentation form (graphical or not), which results should be
presented.
[0066] The results will be shown in this interface, as numerical
data and graphically when that is possible. The graphical
presentation will typically be a 2-D presentation of the
equipment/piping analyzed where the degree of erosion is presented
with different colours. The input to the graphical presentation
will be the CFD results. The relevant cases will have to be
analyzed and the results will have to be in the input files of the
module. The module will then interpolate between CFD results to be
able to present the results for the current situation. If the input
data is outside the range for the CFD analysis, e.g. outside valid
operation window, the user should be warned about this. The user
may also be provided with recommended service intervals.
[0067] It is also possible to present the results as 3-D graphics,
but there are at present not many cases where this will add value
for the user. In some cases, no CFD analyzes are available and the
module will perform the analysis with the chosen erosion
correlation. The result will not be presented graphically, only
numerically.
[0068] The module will in many cases be used together with other
control or on-line systems. It will communicate with the connected
system via wired or wireless networks through appropriate
communication protocols. The module can be called from the other
systems, get the input from them and send the results back. Which
input the calling system will give to the module will vary from
case to case. It should be possible to send over all the needed
inputs, except geometry and CFD analyzes. The input the calling
system does not provide, should be available from set-up files.
[0069] The module is intended to be able of primarily working
during production, i.e. on-line as described above, but it may also
be used off-line. When used off-line the module loads the files
with input data needed for doing the analysis from its memory
means. Further, the module can also create such input files from
current scenarios to be used off-line. All this information is
stored in the history database.
[0070] The methods according to the present invention may be
implemented as software, hardware, or a combination thereof. A
computer program product implementing the method or a part thereof
comprises software or a computer program run on a general purpose
or specially adapted computer, processor or microprocessor. The
software includes computer program code elements or software code
portions that make the computer perform the method. The program may
be stored in whole or part, on, or in, one or more suitable
computer readable media or data storage means such as a magnetic
disk, CD-ROM or DVD disk, hard disk, magneto-optical memory storage
means, in RAM or volatile memory, in ROM or flash memory, as
firmware, or on a data server. Such a computer program product can
also be supplied via a network, such as Internet.
[0071] It is to be understood that the embodiments described above
and shown in the drawing are to be regarded only as non-limiting
examples of the invention. The invention may thus be modified in
many ways within the scope of the patent claims.
* * * * *