BOGOTA, Colombia, June 30 /PRNewswire-FirstCall/ -- Ecopetrol S.A. ("Ecopetrol" or the "Company") (NYSE: EC; BVC: ECOPETROL; BVL: EC) will assume direct operation of the Cupiagua and Cupiagua Sur fields as of midnight, June 30. The fields are located in the municipality of Aguazul in the Casanare pr