The Mediterranean Sea has provided some of the world’s largest hydrocarbon finds in recent times, transforming the energy scene in environments that have been geologically and, at times economically and politically, challenging.
Yet the region continues to draw oil and gas companies, with major finds such as the Leviathan and Tamar discoveries in the Eastern Mediterranean serving as promising signs of lasting potential. Still considered a frontier area, most of the region’s possible lush deepwater areas have yet to be tapped, but companies are pushing forward with plans in the Mediterranean from the Israeli coast to Spanish shores.
In some cases, businesses are facing challenges before the drillbit reaches the seafloor. Fearing drilling could harm beach tourism, the fishing industry and sea life, some residents in the Balearic Islands offshore Spain have taken to the streets in opposition to drilling in the Gulf of Valencia, as others support the move and the economic benefits such efforts could bring. In other parts of the region, geopolitical risks continue to threaten the regulatory progress of projects. Yet other regions are poised for growth with few of the aforementioned barriers.
But just as in other parts of the world, there are geological challenges, which vary, as regional energy demand grows, providing incentive to proceed with developments.
Mediterranean-focused Energean Oil & Gas has taken the lead offshore Greece, having revived production from the Prinos Field as it pursues further exploration opportunities in Greece and other parts of the Mediterranean region.
“Many areas in the offshore and onshore Adriatic have proven hydrocarbon systems but have not been available to the international exploration community for a quarter century and more for a variety of mostly political reasons,” Hank David, new business development manager for Energean, was quoted as telling E&P magazine. “During this time, these areas have laid fallow or have been subject to exploration and exploitation efforts almost exclusively by state-run oil companies, most of which were underfunded and lacked up-to-date technology and tools. Consequently, this large area remains today underexplored. Suddenly, and simultaneously, massive amounts of this acreage are now hitting the market.”
These include acreage offshore Greece, Croatia and Montenegro—all of which have recently had or have tender procedures underway. Studies have shed light on possible petroleum systems in these areas, with billions of barrels of oil in place on the Italian side of the Adriatic and the potential for just as much on the eastern side.
“Oil companies have taken great risk, and at great expense, venturing into the deep waters of the south Atlantic and east Africa over the last several years to test unproven plays, with mixed results,” David continued. “Here is an area of political stability, in the heart of the European market, with abundant new acreage availability not only in deepwater but also in shallow water and onshore, where oil is proven and seeping out of the ground. Energean sees this as a great opportunity and is uniquely positioned to take full advantage.”
Energean CEO Mathios Rigas said the Prinos Field’s potential was initially estimated at 60 million barrels. However, production since 1981 has nearly doubled, exceeding 115 million barrels of oil with 850 MMcm (30 Bcf) of gas having been produced. In addition, the Katakolo block has initial estimates of between three million to six million barrels of oil.
The stock tank oil-initially-in-place (STOIIP) for the Prinos oil field is 289 MMboe, while it’s 16 MMboe in Prinos North and 39 MMboe in Epsilon, with recovery factors at 38%, 24% and 1%, respectively.
The company, which has more than 30 years of offshore operator experience, has unveiled a $225 million development plan that aims to recover 30 million barrels of 2P reserves and increase production to 10 Mbbl/d within the next couple of years, according to Rigas. The program includes drilling seven wells in the main Prinos Field, one well in the currently producing satellite oil field of Prinos North and seven more wells in the undeveloped Epsilon satellite field.
“Energean investments and scientific surveys have proven that there is significant scope for extracting additional production by means of drilling of new wells and through the extended use of enhanced oil recovery techniques,” Rigas said. “In order to execute the new drilling program, Energean has purchased the tender assist drilling rig Glen Esk from KCA Deutag and will be utilizing its own drilling crews to drill the wells.”
Plans are for the new rig to be renamed Energean Force, which will begin drilling early next year. Two new unmanned self-installed platforms will be placed in the Prinos North and Epsilon oil fields, which will be connected to each other and to the existing Prinos platform complex through pipelines, he said.
Energean is evaluating data and considering whether to pursue additional blocks offered as part of Greece’s licensing round, he added, calling the offshore region south of Crete “a real frontier with deep and ultradeep waters, requiring high-risk exploration investment that could potentially prove a new hydrocarbon play” and the Ionian Sea part of the Adriatic region with producing oil fields offshore.
Fold and thrust belts worldwide have proven to be prolific hydrocarbon provinces, but these rewards have not come easy, David added.
“Tortuous terrains and contorted stratum make for difficult and expensive seismic acquisition and processing, which historically have failed to provide a quality image of the subsurface,” David said. “Add hard rocks into the mix (carbonates), and the situation becomes even more challenging and expensive with regards to imaging and drilling through a fractured and cavernous substrate. The Alpine Dinaride/Hellenide system will be no less challenging. But these challenges are partly why the remaining potential is still there.”
Exploration success onshore nearby Albania has led to hope of the play’s southern extension into western Greece, he added, turning to the onshore Ioannina Block in northwest Greece. Here, the exploration program will include geophysical subsurface imaging including seismic acquisition and processing and the acquisition of a full-tensor gravity gradiometry survey over the entire block.