The US Geological Survey estimates that the world’s undiscovered, technically recoverable conventional oil and gas resources outside the US total 565 billion bbl of oil, 5,606 tcf of natural gas, and 167 billion bbl of natural gas liquids, it said on Apr. 18.

Resolute Energy Corp. and the Navajo Nation Oil & Gas Co. have acquired nonoperated assets in giant Greater Aneth oil field in the Paradox basin of Utah from Denbury Resources Inc., Plano, Tex., for $75 million.

Hilcorp Alaska LLC signed a definitive agreement to buy Marathon Oil Corp.’s assets in Alaska’s Cook Inlet, subject to required approvals, by the fall of 2012.

US natural gas reserves reached record levels in 2011 as producers found and produced more gas than was consumed, the American Gas Association said.

Buccaneer Energy Ltd., Sydney, will acquire a 25% working interest in and become operator of the Cosmopolitan project in southern Cook Inlet offshore Alaska.

Shell Gulf of Mexico Inc. and Nexen Inc. have demonstrated a contingent recoverable resource of 215 million bbl of oil equivalent in the Jurassic Norphlet formation in the northeast fault block of the Appomattox structure in the deepwater Gulf of Mexico, where they are conducting further exploration and appraisal activity and evaluating development concepts.

GeoPark Holdings Ltd. has made a second acquisition in Colombia with the $75 million purchase of Hupecol Cuerva LLC, a private explorer that holds two Llanos basin blocks.

An investment of $25 billion/year is needed to develop the existing prospective resource attributed to the Vaca Muerta shale formation in Argentina’s Neuquen basin, according to remarks attributed to Repsol YPF SA, Madrid.

The boards of Antrim Energy Inc. and Crown Point Ventures Ltd. have unanimously approved Crown Point’s acquisition of the assets of Antrim Argentina SA for $10.26 million cash and 35.7 million Crown Point common shares.

A Statoil ASA group has made a small oil discovery in PL053 in the Oseberg Area Unit in the North Sea offshore Norway.