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Annual Report 2015
Dynamic simulation model library
The operation of most subsea installations today
require very little automatic (feedback) control ac-
tion. However, to recover hydrocarbons also under
increasingly challenging reservoir conditions, the
subsea installations may contain one or several
modules for separation, pumping and boosting. As
the subsea processes become more complex, also
more advanced control and monitoring solutions
are required to operate these safely and optimally.
The research area Systems Control covers the development of new meth-
ods and tools related to safe and optimal operation of such complex subsea
processes. In particular, it focuses on the development of:
• Models
- Models designed for process control purposes
- Modelling techniques for subsea process control purposes
• Methods
- Control and optimal operation strategies for subsea processes
Research area manager,
Prof. Sigurd Skogestad
SYSTEM CONTROL
Project manager,
Prof. Sigurd Skogestad
In the area of subsea processing and produc-
tion there is a big need for simple, yet efficient
mathematical models describing complex phe-
nomena and behaviours of different equipment.
These models can be used for example for con-
ceptual design of subsea processes and dynamic
simulation of (interconnected) equipment as well
as model-based controller design and the test of
control structures in an overall (high level) setup.
A major part of the subproject will be to coordi-
nate model development performed in the other
activities in System control area and to cooperate
with other subprojects, such as for example “Mul-
tiphase booster models” in the Field architecture
area. These modelling activities will cover equip-
ment in the whole chain from reservoir to the prod-
uct export. The biggest area is thereby the model-
ling of separators such as phase splitters, gravity
separators, cylindrical cyclones and in-line (swirl)
separators. Furthermore, the large area of boost-
ing devices, such as compressors (dry- and wet-
gas) as well as pumps (single- and multi-phase),
can be investigated, although this is not a main
research area in the SUBPRO project. In addi-
tion, heat transfer phenomena and heat exchang-
ers, membranes as well as valves/chokes and
pipes are potential areas for modelling activities.
Furthermore, the choice of a simulation environ-
ment / programming language is crucial in order to
test and verify the obtained mathematical models.
In the first stage, the models will be designed and
tested in the tools MATLAB/SIMULINK. However,
also Modelica will be used, in cooperation with
Statoil. At later stages, it should be possible to
implement the mathematical models in commer-
cial software, such as OLGA. This can possibly be
achieved by interconnecting different simulation
environments, for example MATLAB with OLGA, in
order to test sophisticated control structures.
The ultimate goal will be to build a model library for
subsea processes including models for the most
crucial equipment mentioned above, but also for nov-
el control structures based on the obtained models.
- State and parameter estimation methods for
estimating unmeasured process conditions
The main application focus of the research
area Systems Control is on subsea separation
processes. In addition, other processes, such as
pumping or compression may be included. The
goal is to develop tools and methods that are sim-
ple and robust enough for use in real subsea ap-
plications.
Sub-projects of Systems control
The research area Systems Control consists of five
sub-projects:
• Dynamic simulation model library
• Modelling and multivariable control of subsea
systems
• Control of subsea processes
• Estimation of un-measureable variables
• Control for extending component life
Postdoc, Christoph Backi