A gas and condensate discovery west of Istanbul in the Thrace basin of European Turkey is believed capable of rates far higher than the stabilized 12.4 MMcfd tested through small tubing, said the operator, Amity Oil NL, Perth.
Amity, in 50-50 partnership with Turkish Petroleum AO on PEL AR/AOI/3589, said more zones remain to be tested. It began a 6-day continuous test through a separator to gather condensate and reserves data.
The company said reserves would be 70 bcf recoverable if the tested zone blankets the Gocerler structure and would be substantially higher if the untested units prove productive.
Amity planned to spud Velimese-1 in mid-November on a structure similar to Gocerler.
Amity is also evaluating existing seismic data in the Adana basin on Turkey's Mediterranean coast, where it holds 9 exploration licenses. The blocks contain several undeveloped gas discoveries, but no well has been drilled for 10 years.
Test results
Gocerler-1 flowed through a 42/64-in. choke and 27/8-in. tubing at 1,110 psi flowing tubing pressure from the upper 22 m of Tertiary Lower Danismen sandstone with the top perforation at 1,271 m.
Amity said the Danisman test zone is 46 m thick. Overlying the tested zone are shales and two other sandstone units 14 m and 13 m thick, respectively, separated by shales. Wireline log responses and mud log gas shows from those two sandstones are similar to those of the tested inteval.
The well's primary target, deeper Oligocene Osmancik, was tight.
Danisman, which has flowed hydrocarbons in other parts of the basin, appears from logs to have close to 25% porosity in Gocerler-1. Amity said explorers have tended to drill through the Danismen with high mud weights without bothering to run tests to quickly reach the Osmancik.
The Gocerler structure is a seismically defined dome north of the Marmara Sea and about midway between Istanbul and Greece's eastern border. The well site is 15 km northwest of Yulaf* gas field, tapped by a TPAO pipeline.
Zarara Oil & Gas Ltd. recently said it took a 25% participation on the 25,000-acre Kandamis production license 90 miles west of Istanbul. The block contains an undeveloped 1958 gas discovery and five delineation wells. The partners plan to drill shortly for gas in Osmancik at 4,500 ft (OGJ, Mar. 9, 1992, p. 45).
