E&P NOTE: The rebirth of the Leduc-Woodbend Nisku oil pool in Alberta, Canada, by Mengwei Zhao and David Tian. Horizontal drilling has led to the rebirth of the Leduc-Woodbend Nisku oil pool and substantial economic returns. The original vertical-well develop-ment produced 91.4 MMBO in 64 yr, whereas horizontal-well development has produced 17 MMBO of oil in the past 12 yr and will produce at least 41.5•51.9 MMBO in the future. If other oil-field operators thoroughly review the sedimentary settings, lithofacies, and petrophysical parameters in their old oil pools developed only by vertical wells and compare them with those in this pool, they may identify potential for horizontal drilling and extending production life.

Giant submarine fans in a greenhouse world--The Paleogene Wilcox Group of the northern Gulf of Mexico, by Michael L. Sweet, Tim Whiteaker, Annie Walker, Marcie Purkey, Jazmin Villeda, and John Snedden. The Paleocene•Eocene Wilcox Group in the northern Gulf of Mexico Basin records the history of very large and long-lived submarine fans that formed during global greenhouse conditions (i.e., no continental ice sheets). These sand-rich, submarine-fan deposits are up to 8000 ft thick and cover an area of at least 66,000 sq mi. They were deposited over 14.5 m.y. and are important oil and gas reservoirs. The authors mapping of sediment across different depositional environments suggests that up to half of the sand routed to the basin was deposited in these submarine fans.

Deep hydrothermal dolomitization in a superimposed basin that experienced multiple tectonic-thermal events, by Zhiqian Gao, Duan Wei, Kaikai Li, Hairuo Qing, Shoutao Peng, Jingbin Wang, Ruisi Li, and Tailiang Fan. Hydrothermal dolomite, due to its significant impact on reservoir quality and complex mineralization, has received significant attention for many decades. Regional studies in many superimposed basins have produced extensive petrographic and geochemical data sets, and, together with recent technological advancements, provide a robust framework for comparative analysis. This study confirms that the interpreted hydrothermal dolomite in the Tarim Basin primarily originated from deep-sourced hydrothermal fluids that underwent extensive water-rock reaction.

Rare earth elements in latest Famennian Woodford Shale phosphate nodules, Oklahoma, United States: Land-driven phosphorus overloading and evolving organic carbon preservation, southern Laurentia, by Andrew Cullen and David Hull. The Upper Devonian•lower Carboniferous Woodford Shale, Oklahoma, United States, is a world-class oil-prone source rock with a thick (9.5 m average) regionally extensive (>42,000 sq km) phosphatic interval at the top of its upper member. Inductively coupled plasma mass spectrometry analyses of 27 phosphate nodules from 9 upper Woodford outcrops defining a 120-km transect into increasing paleowater depths show that the concentrations of rare earth elements and other “continental” trace elements have a strong negative correlation with distance from the paleoshoreline.