28-01-09 Proved US oil reserves rose by 345 mm bbl, or 2 %, during 2007 to 21.32 bn bbl from 20.97 bn bbl at the beginning of the year, reported the US Energy Information Administration on Jan. 28.
The increase was a contrast to the rapid decrease in domestic crude reserves that began in 1970 but which have moderated in the past decade, EIA said as it released final yearend numbers for 2007. The federal energy research and statistical service will begin gathering 2008 numbers in February when it distributes proved reserves data survey forms to more than 1,400 US well operators.

It takes about 12 months to collect the data, resolve anomalies, and develop a final report, EIA said. The latest figures do not reflect 2008's market fluctuations, when crude oil prices reached a peak of about $ 150/bbl before dropping to around $ 40/bbl, it added.
During 2007, EIA said, US producers added nearly 2.04 bn bbl of new reserves while producing more than 1.69 bn bbl, resulting in the 345 mm bbl net addition. About 40 % of the reserve additions were discoveries, either from discovered reservoirs and fields or by extending the boundaries of existing fields, it said. Almost all the remaining additions, or about 1.2 bn bbl, came from more intensive development of known producing fields, it added.

EIA said Alaska, Texas, and North Dakota accounted for a majority of the year's new reserves with a combined 605 mm bbl of net additions. Eight other states showed relatively small increases while 13 states and the Gulf of Mexico reported declines, it said.
Alaska reported the largest net increase, 284 mm bbl or 7 %, according to EIA. Most of its new reserves were revisions, but the state also had the nation's largest volume of new field discoveries during the year, it said.

It said Texas had the second largest net increase-251 bbl or 5 %. A majority of its 601 mm bbl of reserves additions were revisions, but 30 % or 183 mm bbl came from new discoveries in already known fields. The state led the nation in such extensions during 2007, with most occurring in West Texas, EIA said.
North Dakota reported the nation's third largest net addition of proved oil reserves during 2007 with 70 mm bbl, 17 % more than its 2006 total. The increases came primarily from the unconventional Bakken formation, a deep, predominantly shale formation that produces light, sweet crude when fractured, EIA said.