Undeterred by this setback, Naftogaz is open to working with a foreign company, particularly Romanian, to develop the Dolphin block, in the Black Sea near the Danube delta and Romania’s maritime border. Working jointly with Romania to develop the shelf may be “more economically attractive” for Ukraine, and would create better security since Romania is a NATO member, Lana Zerkal, adviser to the Naftogaz CEO, said Friday at an online briefing. However, Exxon Mobil has been mulling selling its 50% stake in Romania’s Neptun Deep offshore project. Since 2008, it has shared this Black Sea block with Romania’s OMV Petrom, which is majority-controlled by Austria’s OMV.