NPRA factsheet2

“Whereas there are large seepages of petroleum along the Arctic Coast of Alaska and conditions favorable to the occurrence of valuable petroleum fi elds on the Arctic Coast . . .” President Warren G. Harding used those words in 1923 to describe the apparent petroleum potential of a tract of land on the western North Slope of Alaska, when he issued a one-page executive order establishing the 23-million acre (36,000 square miles) Naval Petroleum Reserve No. 4. During the following six decades, the U.S. Government conducted two petroleum exploration programs in the reserve, one in the wake of World War II and the second in the wake of the 1970’s oil embargo. These programs found only a handful of oil and gas fi elds, none of them commercial. The name of the reserve was changed to the National Petroleum Reserve in Alaska (NPRA) in 1976 (fi g. 1). Four lease sales were held in the 1980’s, but only two exploration wells were drilled by industry within the NPRA boundary—one on a Federal lease and another on Native land—and neither resulted in development of petroleum resources. Following a 10-year hiatus in exploration activity, NPRA again became a focus of interest with the 1996 announcement of the discovery of the Alpine oil fi eld, located just outside NPRA (fi g. 1). A Federal lease sale was held in northeastern NPRA in 1999, and a number of exploration wells in that lease sale area were completed by industry during the 2000 and 2001 winter drilling seasons. Five of those wells were announced in 2001 to have encountered oil and gas, and additional wells were drilled during 2002 to delineate those discoveries and to test additional prospects (fi g. 2). The U.S. Geological Survey (USGS) has reexamined the petroleum geology of NPRA and has prepared a new petroleum resource assessment. This new assessment was prompted by (1) the rapidly evolving exploration activity focused on the “Alpine trend,” (2) the growing interest in natural gas resources of the Arctic, and (3) the dated perspective of previous resource estimates (the last USGS assessment of NPRA was completed in 1980). Although none of the data from 3-D seismic surveys or new wells drilled in NPRA since the 1999 lease sale was available for this study, the results nevertheless refl ect a comprehensive examination of all public domain data and a consideration of new exploration and development strategies currently being applied on the Alaska North Slope. This new study complements the 1998 assessment of the Arctic National Wildlife Refuge (ANWR), 1002 Area (see USGS Fact Sheet 028-01).