Atlas Energy Inc., Pittsburgh, said it has identified more than 3,150 horizontal Marcellus shale drilling locations on its acreage from which it estimates the net incremental recovery is 13 tcf of gas equivalent.

An independent evaluation of Papua New Guinea explorer InterOil Corp.’s Elk and Antelope gas and condensate discoveries in the southern highlands has estimated contingent recoverable gas resources in excess of 8 tcf.

Consulting engineers doubled estimates of proved and probable oil reserves at Ombrina Mare field in the Adriatic off central Italy, where Mediterranean Oil & Gas PLC hopes to start production in late 2012.

Roc Oil Co., Sydney, has flagged a likely downward revision of remaining oil reserves in its Basker-Manta field development in Bass Strait.

Twelve environmental organizations and one Alaska Native group sued in federal court on Jan. 20 to block Shell Gulf of Mexico Inc.’s plan to drill three exploration wells in the Chukchi Sea off Alaska.

The volume of technically recoverable heavy oil in Venezuela’s Orinoco oil belt is 513 billion bbl, making it one of the world’s largest accumulations of recoverable oil, the US Geological Survey said Jan. 22.

The Society of Petroleum Engineers and the FGU State Commission on Mineral Reserves of Russia (GKZ) have entered into a memorandum of understanding to cooperate on programs to enhance the global understanding of petroleum reserves and resources.

Petroleo Brazileiro SA (Petrobras) reported that a new well drilled in the Tupi area of the Santos basin off Brazil further confirms reserves estimates of 5-8 billion boe of light oil and natural gas.

Estimated ultimate recovery of more than 100 million bbl of oil has been confirmed for OMV AG-operated Maari field and adjacent Manaia field in the offshore portion of New Zealand’s Taranaki basin, two of the field’s partners said.

Improved horizontal completion techniques in the North Texas Barnett Combo play have led EOG Resources Inc. to estimate that ultimate recoveries in one area will be 80% higher than the company’s early 2008 estimates in the play.

Proved US crude oil reserves fell by more than 10% in 2008, but there would likely have been a smaller drop or perhaps even an increase under new Securities and Exchange Commission rules.

The OMV-led joint venture at Maari oil field in the Taranaki basin off New Zealand has confirmed additional produceable oil reserves are contained within a separate reservoir, designated M2A, about 50 m above the main Moki formation.

Elm Coulee field, Montana’s primary Bakken shale oil producing field discovered in 2000, is a giant that is expected to recover more than 200 million bbl.

Trinidad and Tobago has proved gas reserves of 15.4 tcf and another 30 tcf in unrisked exploration potential, according to recent findings of Ryder Scott Consultants.

Questerre Energy Corp., Calgary, said consulting engineers estimated a range of 2.2 to 8 tcf of gas net to Questerre to be recoverable from Ordovician Utica shale in the deep fairway of Quebec’s St. Lawrence Lowlands.