Neptun Deep gas field development project is located in water depths between 100m and 1,700m offshore Romania in the Black Sea. Credit: Klaas Slot on Shutterstock.
Deepwater Champion drilling rig drilled the Domino -1 exploration well in Neptun Block in 2012. Credit: Michael Elleray on Flickr.
The tax and energy legislation changes in Romania delayed the project. Credit: Cepconsult s.r.o.

Neptun Deep is a deep-water offshore gas field development project located in the Romanian deep-water sector of the Black Sea, in water depths between 100m and 1,700m.

The gas field is being jointly developed by OMV Petrom (50%) and ExxonMobil Exploration and Production Romania (50%, operator).

In 2000, the Romanian Government made a concession agreement with OMV Petrom and ExxonMobil to explore and develop the Neptun Deep natural gas perimeter in the Black Sea until 2030. The government extended the agreement until 2045 in January 2019.

OMV Petrom formed a joint venture with ExxonMobil for the exploration of Neptun Deep in November 2008. A final investment decision on the project is yet to be made and the project is facing delays caused by changes in the tax and legal structure of Romania.

ExxonMobil announced its decision to exit the project in 2019 citing the regulatory changes in the country and low oil and gas prices globally. The company invested approximately $700m in project development.

Neptun Deep gas field project location and reserves

The Neptun Deep project lies in the Neptun Block, which spans approximately 7,500km² of the deep-water region of the Black Sea. The Neptun Deep natural gas perimeter extends across 9,900km² in the Black Sea.

Exploration activities in the Romanian continental region of the Black Sea commenced in 1969 while first hydrocarbons were discovered in 1980.

The block is estimated to contain natural gas resources of approximately 42 to 84 billion cubic metres (bcm), which is equivalent to three to six times the annual Romanian consumption.

Exploration details of Neptun Deep gas field project

ExxonMobil acquired over 3,000km² of three-dimensional (3D) seismic data over Neptun Deep Block between 2009 and 2010. The drilling activities in the Neptun Block began by the end of 2011.

In 2012, the Domino-1 exploration well was drilled in 1,000m deep water approximately 170km off the coast of Romania.

"Drilled to a total depth of around 3,000m below the sea bed using the Deepwater Champion double-hull drilling rig, the well was the country’s first deep-water well."

The well encountered 70.7m of net gas pay and confirmed the presence of natural gas in the deep-water sector of the block.

Based on initial estimates, the Domino-1 well was expected to produce approximately 630 million cubic feet per day (Mmcfd) of gas. A seven-month 3D seismic study covering an area of 6000km² in the block was completed in 2013.

In 2014, the second well, Domino-2, was drilled in a water depth of approximately 800m, nearly 200km offshore Romania using Ocean Endeavor rig. The rig also drilled the Pelican South-1 wildcat well approximately 155km offshore to evaluate a new geological structure on the Neptune Block.

A second exploration drilling programme was completed in January 2016. A total of seven wells were drilled during the campaign and most of them encountered gas. Extensive engineering work was performed in 2017.

OMV and ExxonMobil invested more than $1.5bn in exploration and appraisal activities in the block during the period between 2008 and 2016.

Exploration activities of OMV Petrom in Romanian Black Sea

OMV Petrom is exploring shallow, as well as deep waters in the Black Sea. In the Neptun Shallow Perimeter, the company has a 100% interest in a shallow-water exploration project.

In addition to the Neptun Block, the company is performing exploration and production operations in the shallow water of Istria perimeter in the Black Sea. OMV Petrom produces hydrocarbons from five reservoirs, including Lebada East, Pescarus, Sinoe, Lebada West and Delta in the Istria perimeter.

The cumulative oil and gas production from the five fields stands at approximately 25,000 barrels of oil equivalent per day (boepd).

The company produced 156 million barrels of oil (Mboe) from its global upstream operations in 2018. OMV Petrom (42.5%), along with ExxonMobil (42.5%) and GasPlus (15%), is also engaged in deep-water exploration in the Midia Deep Perimeter.