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Modelling Peak-load Exploitation of Underground Gas Storage in Salt Caverns Turkish and Polish Case |
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Modelling Peak-load Exploitation of Underground Gas Storage in Salt Caverns Turkish and Polish Case Studies Author: E. Cetinkaya
The natural gas storage plays an important role in countries gas supply system as it manages fl uctuation
of demand and prices by matching seasonal or peak supply-demand. Moreover, it composes a supplydemand
security and optimizes the network capacity. Underground Gas Storage (UGS) in salt caverns
holds several advantages over the other types of storage methods, such as higher deliverability (gas can
be withdrawn and refi lled very quickly), larger fraction of working gas relative to total gas (provided by
lower cushion gas requirement) and effi ciency in operational cycling.
Turkey and Poland, owing to their strategical location on the route of the natural gas transmission
pipelines, have big strategic importance. There are six domestic underground gas storage facilities currently
in use in Poland, situated both in depleted natural gas fi elds and salt caverns. Mogilno Cavern Underground
Gas Storage (CUGS) is the only salt cavern gas storage fi eld among them.
Despite the fact that, there are no underground storage units currently in operation in Turkey, alterations
in natural gas market push the Authorities to make signifi cant precautions. Furthermore, UGS Facilities
should be brought out as an urgent task bearing in mind a long-term construction schedule of an UGS
facility which would be able to answer the future consumption.
The major objective of this study is to examine and to compare two differently located underground
salt caverns; one in Mogilno CUGS Facility-currently operated in Poland- and the other one in Tarsus
P-UGS Facility Project, a potential storage fi eld to be operated in Turkey. In order to enable simulation
operations, a suitable location of imaginary pattern cavern will be chosen.
For optimization, a pattern cavern model which has a constant cavern volume is used for each depth
localization applications. Having decided a size of the cavern and its geometrical volume, in order to
compare and optimize which depth is suffi cient for the cavern localization, KAGA introduces run for
different supply-demand scenarios throughout the given depths.
In Mogilno CUGS simulations, two real gas caverns are examined, one in shallow location and the
other in considerably deep location. The results obtained from Polish storage case study are compared
with a pattern cavern hypothetically located in three different depths of a candidate UGS Facility which
will be developed in salt deposits near Tarsus.
In this aspect, KAGA1 computer model was used to simulate the thermo-hydrodynamical processes
occurred during the operation of underground natural gas storage. A detailed cavern study and model
development optimized by the KAGA software enables effi cient operation during the max. and min.
demand scenarios and subsequently it allows the operator to successfully optimize cavern operations. In
order to obtain an effi cient cavern development in Tarsus P-USG the cavern should not only have possibly
big volume but also it should be located in the considerably deepest depth. KAGA simulation model is
also used in herein study to select an optimal cavern location for hypothetically planned Tarsus P-UGS
Facility. Subsequently, the information provided by KAGA can be used in further cavern optimizing
operations for Tarsus P-UGS.
Therefore, simulation results for Tarsus case prove, both from technical and cavern point of view,
that the most suitable location for cavern development are the depths between 1150-1200 meters with an
optimum fl ow rate between 100.000 mn
3/h and 150.000 mn
3/h.These results are presented and extensively
discussed in this study. What is more, the results also indicate that in case of the inability to improve
the geological parameters of depth or temperature conditions of the rock massif there is a possibility to
increase the production string diameter, which in this study is taken as 7”. |
2011