Overview of Storage Facilities


The Storage Facilities that were commissioned in 2007 is established in the vicinity of Alipasa Village (near TEM Kinali toll booths) in Silivri in the west of Istanbul at a distance of 65 km. The total amount of working gas of Kuzey Marmara and Degirmenkoy Fields is 2,841,000,000 (two billion and eight hundred and fourty one million) STDm3. Maximum withdrawal amount of the Storage Facilities is  25 million STDm3/day and maximum injection amount is 16 million STDm3/day (maximum daily amounts may decrease depending on the reservoir pressure, National Transmission Network pipeline pressure, gas temperature and other operating parameters).

The Injection Gas to be received from main transmition pipeline and injected to Kuzey Marmara and Degirmenkoy Fields for storage purposes shall be provided at a pressure of 50 (fifty) bar(g) or higher and uninterruptedly depending on the operating conditions of BOTAŞ, at the flow rates given below at the Delivery and Reception Point throughout the Injection Period.

Injection of the gas in to the reservoirs after being received from the National Transmission Network (Injection)

The natural gas is received through a pipeline installed between the Natural Transmission Network and Storage Facilities with a diameter of 24” and a length of approximately 4500 m. The pressure and temperature of the National Transmission Network vary in the ranges 50-75 bar(g) and 5-23oC, respectively. Gas measurement is done by means of orifice type flow meters and the gas is filtered with a filter separator before it is transmitted to the metering units. The piping of the metering station is designed to be used in the withdrawal phase as well, but to allow only unidirectional flow.  The flow rate measurements are collected and recorded separately for injection and withdrawal. The data needed for gas flow rate calculations is obtained by means of the gas chromatograph. Since the pressure of the National Transmission Network is less than the reservoir pressures, the Storage Facility is equipped with four centrifugal compressors, one of which is redundant. The compressors used for injection can also be used for withdrawal.

Two 10 MW compressors are used for the Kuzey Marmara Field and one 5 MW compressor for Degirmenkoy Field, and one 10 MW compressor is designed to serve both of the fields.

Once the gas is pressurized at the compressors, it is transmitted to the Kuzey Marmara Field through the 20” pipeline with a length of 3.2 km and to Degirmenkoy Field through the 16” pipeline with a length of 13.2 km. Both fields are equipped with a pig launcher system and the Storage Facility has pig receiver systems.

The natural gas arriving at the gathering manifold in the sites is injected into the reservoirs by means of 11 wells in the Kuzey Marmara Field and 9 wells in Degirmenkoy Field.

Transmission of the gas withdrawn from the reservoirs to the National Transmission Network (Withdrawal)

The natural gas received at the gathering manifold from the wells is subject to pre-separation at Degirmenkoy but not at the Kuzey Marmara Field and then transmitted to the Storage Facility through the 16” and 20” pipelines, respectively.

The gas is passed through slug catchers after it arrives at the Storage Facility. Slug catchers are used to collect liquid, formation of which is due to two-phase flow regime and the pipeline profile. At the earlier stages of withdrawal from the wells in the Kuzey Marmara and Degirmenkoy Fields and in those periods when withdrawal is at lower flow rates of gas (especially at low soil temperatures) in Degirmenkoy Field, the natural gas transmitted from the wells is heated in water-bath heaters after passing through the slug catchers. Three heaters are used for this purpose.

The gas pressure is reduced to a level above the pressure of the Natural Transmission Network. Liquids (hydrocarbon and water) formed at the end of pressure reduction depending on the temperature decrease and condensation properties of the gas are subject to phase separation by means of high-pressure separators.

After pressure reduction and high-pressure separator operation, the gas is dried in the gas dehydration unit so that it can meet the water dew point specification of the pipeline, which is -8 oC at a pressure of 39 bar(g).

The water which is vapor in the gas is absorbed by triethylene glycol (TEG) that is 98.8% pure in the glycol dehydration tower. TEG, which is dissolved in the water separated from the gas is made ready for reuse by evaporating the water throughout the processes in the regeneration system.

The dried gas is then forwarded to the hydrocarbon dew point adjustment unit (cooling unit). The adjustment unit is designed to meet the hydrocarbon dew point specification of the pipeline, which is 0 oC at a pressure of 67.5 bar(g).

The drying unit and hydrocarbon dew point adjustment unit are located before the compressor units. The gas exiting from these units is forwarded to the compressor units if necessary and transmitted to the National Transmission Network after the metering.

Please click for the presentation about our gas storage facilities.

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