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Oil and Natural Gas Projects North Marmara Underground Natural Gas Storage Facility

North Marmara Underground Natural Gas Storage Facility

An underground facility investment expanding Türkiye's natural gas storage capacity

Istanbul, Silivri, Marmara Sea coast

2019-2024

The Northern Marmara Underground Natural Gas Storage Facility Expansion Project, undertaken by Kalyon İnşaat, is being implemented on the Marmara Sea coast in Silivri, Istanbul.

General Information

Location

Istanbul, Silivri, Marmara Sea coast

Client/Employer

BOTAŞ (Boru Hatları ile Petrol Taşıma A.Ş.)

Project Scale

Europe's Largest Subsea Natural Gas Storage Facility: 4.6 billion m³. (Other examples: Rehden in Germany has capacity of 3.9 billion m³ and Bergermeer in the Netherlands, 4.1 billion m³.)

Infrastructure Components

Injection capacity: 30 million m³/dayWithdrawal capacity: 50 million m³/daySurface facilities and compressor stationsPipelines with diameters of 28” and 36”2 fixed offshore platforms in the Sea of Marmara18 new wells + decommissioning of 5 existing wells

Project Duration

Function

Natural gas storage, supply security and uninterrupted energy during peak demand

Key Feature

An international standard underground storage facility critical to Türkiye's energy strategy

Northern Marmara's storage capacity was increased from 3.2 billion Sm³ to 4.6 billion Sm³, and withdrawal capacity from 25 million Sm³/day to 75 million Sm³/day. A new surface facility with injection capacity of 30 million Sm³/day and withdrawal capacity of 50 million Sm³/day was constructed and commissioned. In addition to existing 20 and 24 inch pipelines, a 28 inch line was built between the Northern Marmara Gathering Station and the new surface facilities, and a 36 inch line between the new surface facility and BOTAŞ main transmission lines. The existing surface facility and 24 inch pipeline were also integrated with the new facilities, ensuring system integrity and operational efficiency.

Architectural and Engineering Details

General engineering services were provided for offshore and onshore facilities, including basic and detailed design, pipeline engineering, detailed equipment designs, layouts and system designs. Structural and architectural designs for equipment foundations and buildings were prepared. All civil, mechanical and electrical designs for compressor buildings, pig traps, pipe racks and auxiliary areas were completed within pipeline and structural engineering. Drilling and seismic data acquisition and monitoring systems were developed; reservoir modeling and simulation established the project's integrated engineering infrastructure.

Purchasing and Procurement Strategy

Process equipment was sourced from globally recognized manufacturers, while domestic solutions were preferred to the greatest possible extent. Principal equipment for the New Surface Plant (NSP) included inlet filters, metering systems, suction scrubbers, gas turbine compressor packages, a slug catcher, separators, startup heaters, condensate separators, silica gel adsorption units and air cooled gas coolers.

The project worked with global leaders including METANO (Italy), FORAIN (Italy), SIEMENS-G (Germany), KELVION (France), SPG (Germany) and DRY Cooling (Belgium). Local contributions included slug catcher units and a Slope vessel manufactured by TEKFEN (Türkiye) and DEHA-TECH (Turkey), which were integrated into the project.

Casing and liner pipes resistant to high pressure and deep drilling conditions were used for piping and well materials. Approximately:

2,920 m (13 3/8 inch casing)
900 m (10 3/4 inch casing)
7,500 m (9 5/8 inch casing)
24,950 m (7 inch casing and liner)

bringing the total casing material incorporated into the project to 36,270 meters.

Technologies and Innovations Used

Special high pressure steels, advanced welding procedures and automatic testing systems ensured pipeline durability. Subsea lines were laid using high capacity lay barges and installation vessels; horizontal directional drilling and microtunneling minimized environmental impacts at shore crossings. Explosion proof electrical equipment and automation were integrated on platforms, while SCADA at surface facilities enabled real time monitoring of all operations.

Project Stages and Solutions

Synchronized onshore and offshore operations accelerated implementation. Surface facility construction, pipeline laying, offshore platform installation and well drilling proceeded in sequential but integrated steps. Heavy lift vessels, special coating techniques and diver assisted installation successfully completed complex tie ins during construction, shortening the work period and minimizing operational risks.

Solutions

Solutions included welding and coating steel pipes with testing to international standards, and using high capacity cranes and specialist vessels for offshore platform installation. Occupational health and safety were prioritized throughout; complex tie ins were performed in a controlled manner with diver assistance.

Sustainability

Works followed environmental responsibility and energy security objectives. Efficient compressors and low emission vessels were used, while pipe laying was restricted during certain periods to protect marine life. Waste disposal complied with international standards and recyclable materials were preferred. Noise and vibration were monitored regularly; local resources reduced the carbon footprint. The resulting capacity increase makes an environmentally sensitive, long term contribution to Türkiye's energy supply security.

All offshore and onshore activities complied fully with national legislation, international environmental standards and legal requirements. Offshore operations observed global occupational health, safety, environmental protection and emission control standards, favoring methods that would not harm the Marmara Sea ecosystem. Transparent reporting, openness to inspections and international best practices governed the entire process.

Long Term Sustainability

Injection capacity of 30 million m³/day and withdrawal capacity of 50 million m³/day increased Türkiye's natural gas supply security.
Modern control systems minimized leakage risks and ensured environmental safety.
The project makes a critical contribution to the sustainability of the national energy strategy.

In the Marmara Sea, 28 inch subsea pipelines from fixed platforms DP-1 and DP-2 reach shore over approximately 1,605 m and 2,710 m respectively. They join at LFP-1 and LFP-2 connection points and connect to the onshore KMGS facility. Onshore, the 28 inch line extends approximately 4,000 m, with an additional 500 m, 28 inch line ensuring continuity. The existing 24 inch pipeline was integrated into the new surface plant (NSP) through a tie in. A 36 inch pipeline of approximately 4,200 m connects the new surface plant to BOTAŞ main transmission lines, integrating the system into the national grid.

Two fixed offshore platforms were built in the Marmara Sea, and 28 inch subsea pipelines laid between the onshore facility and the new platforms. The existing offshore platform and 8 and 2 inch pipelines were dismantled. Eighteen wells were drilled from the two new platforms, nine per platform, while five old wells on the existing platform were decommissioned. Completion increased working gas capacity from 3.191 billion Sm³ to 4.6 billion Sm³, daily withdrawal from 28 million Sm³ to 75 million Sm³ and daily injection from 21 million Sm³ to 45 million Sm³.