On 8 March, Houston-based Noble Energy said that an independent estimate, published earlier last week, of the natural gas resources within its Block 12 concession were consistent with its own assessments, Cyprus Mail reported.

The estimated amount of natural gas reserves within the Block 12 concession, operated by the Noble Energy Inc., has been revised downwards by a foreign independent consulting company, "Netherland Sewell & Associated Ltd", which works with the American firm "Noble Energy".

Netherland Sewell & Associates Ltd (NSAI), a Texas-based oil and gas consulting firm, gives a best estimate of 5.1 trillion cubic feet of gas with a probability of 50%.

In a statement, Noble said NSAI's estimate was in fact "consistent with and confirms Noble Energy's 28 December 2011 announcement of an estimated gross resource range of five to eight trillion cubic feet, with a gross mean of seven trillion cubic feet."

Noble went on to explain that NSAI had employed a different method of calculation. It said that, in conformance with the Israeli Securities Authority requirements, "NSAI utilised a 'deterministic' calculation of resources, the results of which are not directly comparable to the 'probabilistic' calculation employed by Noble Energy.

"Both are accepted methodologies for characterising resources; however, the oil and gas industry more commonly reports results of an initial, unappraised discovery based on a probabilistic calculation," the statement said.

Noble said the differing methodology used by NSAI "yielded a broader estimated resource range than the probabilistic calculation conducted by Noble Energy, and in fact included a high side estimate of 10.2 trillion cubic feet. Because deterministic and probabilistic resource calculations are not directly comparable, NSAI's estimate does not refute Noble Energy's resources estimate."

Noble Energy owns 70% of Block 12, and Delek Group energy exploration subsidiaries Avner Oil and Gas LP and Delek Drilling LP each own 15%. The Cypriot field sits close to a huge Israeli gas find and the two countries are currently in talks on ways of jointly exploiting the mineral wealth. And last month, Cyprus launched a second licensing round for more offshore exploratory drilling. Turkey, which doesn't recognise Cyprus as a sovereign state, claims it has rights to a large swath of the island's exclusive economic zone and has threatened the EU-member state.

In related news, China National Offshore Oil Corp (CNOOC) is among several firms showing interest in investing in Cyprus' offshore natural gas field, Cyprus Interior Minister Neoklis Sylikiotis said on 4 March. "It's significant that after Noble confirmed its findings in Bloc 12, interest in the other blocs is growing," Sylikiotis said.