The Sakarya gas field located in Black Sea is Turkey’s biggest ever natural gas discovery. Image courtesy of Schlumberger Limited.
Turkish Petroleum’s drillship Kanuni was deployed to perform flow test of the Turkali-2 appraisal well. Image courtesy of Sakhalinio.
First gas production from the Sakarya field phase one development is expected in 2023. Image courtesy of Bob White/Flickr.

The Sakarya gas field located in the Turkish waters of the Black Sea is the first deepwater gas field discovery in Turkey. It also represents the biggest natural gas reserves in the country.

State-owned Turkish Petroleum Corporation (TPAO) discovered the Sakarya field in August 2020 and performed additional exploration and appraisal drilling in the field area in 2021.

Sakarya is estimated to hold 540 billion cubic metres (bcm) of gas reserves. TPAO awarded the key contract for phase one development of the deepwater gas field in October 2021. First gas is expected in 2023.

Sakarya field location and discovery

The Sakarya gas field lies the Turkish exclusive economic zone (EEZ) in the Black Sea, approximately 175km off the coast of Eregli.

The field was discovered by drilling the Tuna-1 exploration well in 2,117m-deep waters in August 2020. TPAO’s deepwater drillship Fatih drilled the Tuna-1 well to a total depth of 4,775m, which encountered more than 100m of gas-bearing reservoir in Pliocene and Miocene sands.

Further, TPAO drilled the Amasra-1 discovery well in 1,938m-deep waters in the North Sakarya field using the same drillship in June 2021. Drilled to a total depth of 3,850m, the Amasra-1 well indicated the presence of 135bcm of natural gas reserves in the North Sakarya field.

Turkali-2 appraisal well flow test results

The Turkali-2 deepwater appraisal well was drilled by the Fatih drillship to a total depth of 3,950m, while the flow tests are being conducted by TPAO’s drillship Kanuni.

The flow test conducted on the first reservoir section of the Turkali-2 appraisal well in July 2021 delivered a net gas pay of 0.75 million cubic metres (Mcm) a day.

The flow test on the second reservoir section of Turkali-2 well delivered 0.63Mcm of gas a day In August 2021. The flow tests data is being used by Turkish Petroleum to optimise the field development.

Sakarya field development details

The Sakarya gas field development involves the installation of a subsea gas production system, construction of a gas processing terminal in Filyos, and laying a 170km-long subsea pipeline to export gas from the field to the gas terminal.

Phase one of the field development comprises the drilling of ten wells, of which six were completed as of October 2021.

The field will export up to 10Mcm of gas a day to the Filyos gas processing facility in phase one. The ground-breaking ceremony of the Filyos gas processing facility was held in June 2021, with its commissioning expected in 2023.

Contractors involved in Turkey’s biggest gas field development

A consortium of Schlumberger and Subsea 7 was awarded an integrated engineering, procurement, construction and installation (EPCI) contract for phase one of Sakarya gas field development in October 2021.

The contractual scope covers subsea solutions to onshore production, including well completions, subsea production systems (SPS), subsea umbilicals, risers, flowlines (SURF), and an early production facility (EPF).

Schlumberger will be responsible for well completions, as well as design, construction, and commissioning of the EPF with a capacity to handle up to 350 million cubic feet (Mcf) of gas a day.

OneSubsea, a subsidiary of Schlumberger, together with Subsea 7, will carry out the SPS and SURF scope of the project.

The value of Subsea 7’s share of the contract is more than £548m ($750m). The company will be responsible to design and install the infield flowlines, control umbilicals, tie-in connections, associated subsea equipment, gas export pipeline, and a monoethylene glycol (MEG) injection pipeline to the EPF.