Page 18 - OGA-Sept-2015
P. 18
S MONTH
OIL & GAS AUSTRALIA
New ways of thinking for hydrate dilemma
BY ANDREW HOBBS
CHANGES to risk assessment methods could
change the way process engineers plan for
Gas Hydrates – the ice-like solids that can
shut down subsea systems when they form.
Speaking with Oil & Gas Australia, Associate Members of the UWA research team, from left: A high-pressure sapphire autoclave developed
Professor of the University of Western Research Associate Bruce Norris, Professor Paul at UWA allows researchers to visualise hydrate
Australia’s (UWA) School of Chemical and Stanwix, Professor Eric May, Masoumeh Akhfash, particle deposition to study the rate and severity
Mechanical Engineering Zachary Aman said and Associate Professor Zachary Aman. Image of hydrate formation. Image courtesy UWA.
many of the methods used to assess the risk of courtesy UWA.
hydrate formation were out of date. and Woodside, heard from lead PhD students
“The simplest way to put it is to say – how involved in the project, giving their feedback on
Early developers of risk assessment had much of that expendable energy to drive the the approaches taken, he said.
looked for a way for process engineers to find fluids are you going to burn through because
the risks of hydrate formation on a desktop of hydrate? If that number reaches 100 per cent “[We look at] what we need to be doing
computer in a short space of time, he said. you have a problem.” differently that informs our outputs that then
changes the model outcomes and the direction
To enable these calculations to be made more “If you need more pressure differential of the development.”
quickly, risk modellers had over-simplified than you have, that is when it becomes a flow
the way that the risk of hydrate formation was assurance risk and that is the basis on which we Work on the project was ongoing, Dr Aman
calculated – making broad assumptions about are moving forward to try and produce these said, with the broad partnerships researchers
how hydrates were formed. risk based models for industry,” he said. enjoy enabling them to develop stronger models.
“So one of the simplifications was to assume These models could be used to develop a “We have made a phenomenal amount of
that the hydrate particles, when they’re in oil, design tool – enabling process engineers to progress in the past 24 months,” Dr Aman said.
are distributed much like sand in the ocean… develop a system of flowlines well within the
when in reality we know that these particles are limits of acceptable risk for hydrate formation. “But every time we unlock a new level, new
erratic – that they form these large aggregate obstacles emerge to get to the next one, so
structures,” he said. It could also be used as a diagnostic tool, Dr it is kind of this unfolding story that we are
Aman said. only beginning to understand.” l
“It is not something that we can just dismiss.”
Dr Aman said the problem had historically “This is part of the flow assurance engineer’s
been an academic one – with risk modellers toolkit that we hope will enable them to do
saying that a system was at risk of hydrates deeper analysis from a diagnostic perspective.”
forming when a critical boundary was crossed.
“Where in reality we don’t have enough data In turn, this could help project developers
to inform those boundaries,” he said. determine flowline running times and
Today computers have advanced to the point insulation requirements, as well as the types
where more data can be mapped and better and quantities of chemicals which may need to
models formed, but Dr Aman said despite these be injected into the flowlines.
advances, it was still impossible to assess how
much hydrate was in a pipeline at any one time. Dr Aman said all data used in project
As a result, researchers from UWA and calculations was available for scrutiny by any
the Commonwealth Scientific and Industrial member of the engineering community – giving
Research Organisation (CSIRO) had put efforts them the ability to form their own judgements
to calculate the presence of hydrates themselves about the quality of the model.
to one side, Dr Aman said.
Instead, they were looking at the differential Researchers’ perspectives had also been
pressure of flowlines and pipelines at any given shifted through UWA’s Flow Assurance
moment, he said. Workshop for industry, where up to 40 industry
“If you have an oil and gas system, everything personnel, including experts from Chevron
is driven by pressure – you have some kind
of upstream capability of pressure you can
deliver and you have some kind of downstream
requirements,” he said.
But if hydrates are present in the mixture, the
amount of energy required to move the mixture
through the pipeline goes up, he said.
“So what it is trying to do is model how that
fluid and that very complex mixture behaves
relative to the pressure drawing force you have
available to move it,” Dr Aman said.
“If it is so sticky or so viscous that it doesn’t
want to move, that is when you cross the risk
boundary.”
16 ENERGY PUBLICATIONS CELEBRATING 34 YEARS OF PUBLISHING IN AUSTRALIA
OIL & GAS AUSTRALIA
New ways of thinking for hydrate dilemma
BY ANDREW HOBBS
CHANGES to risk assessment methods could
change the way process engineers plan for
Gas Hydrates – the ice-like solids that can
shut down subsea systems when they form.
Speaking with Oil & Gas Australia, Associate Members of the UWA research team, from left: A high-pressure sapphire autoclave developed
Professor of the University of Western Research Associate Bruce Norris, Professor Paul at UWA allows researchers to visualise hydrate
Australia’s (UWA) School of Chemical and Stanwix, Professor Eric May, Masoumeh Akhfash, particle deposition to study the rate and severity
Mechanical Engineering Zachary Aman said and Associate Professor Zachary Aman. Image of hydrate formation. Image courtesy UWA.
many of the methods used to assess the risk of courtesy UWA.
hydrate formation were out of date. and Woodside, heard from lead PhD students
“The simplest way to put it is to say – how involved in the project, giving their feedback on
Early developers of risk assessment had much of that expendable energy to drive the the approaches taken, he said.
looked for a way for process engineers to find fluids are you going to burn through because
the risks of hydrate formation on a desktop of hydrate? If that number reaches 100 per cent “[We look at] what we need to be doing
computer in a short space of time, he said. you have a problem.” differently that informs our outputs that then
changes the model outcomes and the direction
To enable these calculations to be made more “If you need more pressure differential of the development.”
quickly, risk modellers had over-simplified than you have, that is when it becomes a flow
the way that the risk of hydrate formation was assurance risk and that is the basis on which we Work on the project was ongoing, Dr Aman
calculated – making broad assumptions about are moving forward to try and produce these said, with the broad partnerships researchers
how hydrates were formed. risk based models for industry,” he said. enjoy enabling them to develop stronger models.
“So one of the simplifications was to assume These models could be used to develop a “We have made a phenomenal amount of
that the hydrate particles, when they’re in oil, design tool – enabling process engineers to progress in the past 24 months,” Dr Aman said.
are distributed much like sand in the ocean… develop a system of flowlines well within the
when in reality we know that these particles are limits of acceptable risk for hydrate formation. “But every time we unlock a new level, new
erratic – that they form these large aggregate obstacles emerge to get to the next one, so
structures,” he said. It could also be used as a diagnostic tool, Dr it is kind of this unfolding story that we are
Aman said. only beginning to understand.” l
“It is not something that we can just dismiss.”
Dr Aman said the problem had historically “This is part of the flow assurance engineer’s
been an academic one – with risk modellers toolkit that we hope will enable them to do
saying that a system was at risk of hydrates deeper analysis from a diagnostic perspective.”
forming when a critical boundary was crossed.
“Where in reality we don’t have enough data In turn, this could help project developers
to inform those boundaries,” he said. determine flowline running times and
Today computers have advanced to the point insulation requirements, as well as the types
where more data can be mapped and better and quantities of chemicals which may need to
models formed, but Dr Aman said despite these be injected into the flowlines.
advances, it was still impossible to assess how
much hydrate was in a pipeline at any one time. Dr Aman said all data used in project
As a result, researchers from UWA and calculations was available for scrutiny by any
the Commonwealth Scientific and Industrial member of the engineering community – giving
Research Organisation (CSIRO) had put efforts them the ability to form their own judgements
to calculate the presence of hydrates themselves about the quality of the model.
to one side, Dr Aman said.
Instead, they were looking at the differential Researchers’ perspectives had also been
pressure of flowlines and pipelines at any given shifted through UWA’s Flow Assurance
moment, he said. Workshop for industry, where up to 40 industry
“If you have an oil and gas system, everything personnel, including experts from Chevron
is driven by pressure – you have some kind
of upstream capability of pressure you can
deliver and you have some kind of downstream
requirements,” he said.
But if hydrates are present in the mixture, the
amount of energy required to move the mixture
through the pipeline goes up, he said.
“So what it is trying to do is model how that
fluid and that very complex mixture behaves
relative to the pressure drawing force you have
available to move it,” Dr Aman said.
“If it is so sticky or so viscous that it doesn’t
want to move, that is when you cross the risk
boundary.”
16 ENERGY PUBLICATIONS CELEBRATING 34 YEARS OF PUBLISHING IN AUSTRALIA
