Cupet said geological studies of the exploratory well drilled by the Scarabeo 9 offshore platform show the presence of "an active petroleum system" but in rocks too dense to release oil and gas in commercial quantities.
Russia's Gazprom Neft and PC Gulf of Malaysia "continue to evaluate the information" gathered from the four blocks it contracted to explore.
But the Scarabeo 9 platform has been passed to Venezuela's state oil giant PDVSA to drill in its assigned block.
The Spanish oil company Repsol, which used the Scarabeo platform to drill for oil in a block assigned to it off Havana, abandoned its efforts in June after failing to find oil.
Cuba's economic zone in the Gulf of Mexico was divided into 59 blocks, 22 of which were put under contract to companies from Angola, India, Malaysia, Norway, Russia, Spain, Venezuela and Vietnam.
Some studies estimate that the 112,000-square-kilometer (43,243-square-mile) area has probable reserves of between five and nine billion barrels of crude oil, although Cuban authorities say there could be as much as 20 billion barrels.
Cuba produces oil from wells on land and in shallow water, but they are reaching their capacity limits.
It also imports 100,000 barrels of oil a day from Venezuela, a close ally that supplies oil to Cuba on easy terms.
