The project would tie a pipeline system near Corlu, in Thrace, with one in the south near Mersin and the Incirlik Air Base, said the people, speaking on condition of anonymity to discuss sensitive information. Doing so would increase the size of the North Atlantic Treaty Organization’s Cold War-era pipeline system, which supplies alliance forces during military conflict. It would also bolster Turkey’s own energy infrastructure, the people said, adding that Ankara would cover the cost of any part of the project intended for civilian use.