Turkey is slightly larger than the state of Texas geographically, yet the country has only seen 4,400 wells drilled since 1940. While Texas’ oil history goes back much further, the state has seen more than 1.5 million wells drilled through 2013. “Turkey is largely unexplored,” said Lee Muncy, vice-president, geosciences at TransAtlantic Petroleum Ltd., during the AAPG International Conference and Exhibition on Sept. 15.
Muncy described Turkey as having a complex geology that is widely unknown since “exploration is in its infancy,” he said.
It is estimated that merely 20% of Turkey’s onshore basins and 1% of its offshore basins have been explored. In addition, deep tests also are relatively few with less than 75 wells penetrating through the Paleozoic.
In the southeastern part of the country, the Dadas formation has seen much drilling activity within the last several years. Originally discovered by Royal Dutch Shell PLC in the mid-1960s, the Dadas 1 was thought to be a source rock. Both of the deep tests are prolific gas producers, primarily supplying fuel for additional field operations in the region.
Since 2010, several operating companies have produced oil from the Dadas with modern drilling and completion technologies. According to TransAtlantic Chief Executive Officer N. Malone Mitchell, the company bought into the region in 2008, drilled its first deep tests in 2010, and attempted to land its first horizontal in the Dadas in 2012 (OGJ Online, Sept. 26, 2012).
According to Mitchell, the average well drilled in the region—TransAtlantic produces from several horizons—flows 400 b/d of oil unstimulated; although modern stimulation technologies—multistage fracturing and sliding sleeves—will provide access to 20 times as much oil. Mitchell added that the company has deployed North American completion technology on more than 200 fracture stages in Turkey with enhanced results for most of its wells.
Located on the Arabian plate, the Dadas comprises two zones (1 and 2), and the formation’s geologic structure is analogous to the Oklahoma Woodford shale gas play in North America. Also speaking at AAPG, OMV group Chief Geologist Gabor Tori described the Dadas shale as upper Silurian, lying at a depth of 7,000-10,000 ft. The formation, which is 300-800-ft thick, is organically rich with total organic carbon (TOC) between 3-12%, Ro of 0.5-1%, and a porosity of 0.5-10%.
Turkish Petroleum Corp. (TPAO) deputy director of exploration department Coskun Namoglu said the company is currently working with Shell on four licenses in the Dadas formation. The joint venture partners have yet to release the results of this campaign; however, a source close to drilling activity in southeastern Turkey said partners are now completing a third well in the JV’s four-well program.
In addition to increased drilling, new 3D seismic data stands to enhance development in the region. TransAtlantic has just completed the largest onshore 3D seismic survey in Turkey to date, and the company expects to begin horizontally drilling into the Dadas within the next year.
To date, there are few operators actively drilling for unconventional resources in southeastern Turkey. “That was an early part of our regional learning when we began drilling in Turkey,” said TranAtlantic’s Mitchell. “Unlike plays in the US, with so few operators working in the region there is very little data to be shared.” In addition, limited drilling in the region outside of producing fields also leaves very little well control data to lend information on the subsurface.
New, modern seismic data combined with increased research and development should continue to improve Dadas performance. Besim Sisman, TPAO chief executive officer, said, “The United States has been successful in unconventional development partly due to its leading research and development investments.” Turkey has tripled its research and development in the last 10 years. “We expect to triple this spending again in the next decade through 2023,” Sisman said.
Turkey’s fiscal regime should also benefit further development. The country currently carries a 12.5% royalty with a flat 20% corporate tax. Turkey is also a full-payer, and operators receive Brent prices on produced oil and about $9/Mcf of gas. “A barrel of oil in Turkey will go much farther than any in any of its neighboring countries,” Mitchell said.