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Small changes mask big swings for US reserves

By OGJ editors
HOUSTON, Oct. 14 -- Proved reserves of natural gas in the US were up nearly 2% in 2004, while proved oil reserves fell more than 2%, the Energy Information Administration said.

Proved dry gas reserves at the end of 2004 were 192.5 tcf, and proved crude oil reserves were 21.37 billion bbl. Proved natural gas liquids reserves were 7.9 billion bbl, up 6.3% on the year.

Gas figures
Gas reserve additions onshore in the Lower 48 exceeded 21 tcf, pushing 2004 total US reserves replacement to 118% of 2004 dry gas production.

The onshore performance more than made up for an unusually large 15% drop in Gulf of Mexico proved reserves that was due mainly to a dearth of new discoveries and partly to relatively large negative revisions, EIA said.

"Twenty percent of US dry natural gas production is from the Gulf of Mexico federal offshore, and (Hurricane) Ivan caused infrastructure damage that impacted oil and gas production in the gulf in the last quarter of 2004," the agency said. "Ivan's damage will also reduce 2005 gulf production from what it could have been."

The 21 tcf added in the Lower 48 came mostly in known fields. On the other hand, additions from new gas field discoveries were the lowest in 12 years. Field extensions accounted for 18.2 tcf of the 21 tcf added, 11% more than 2003 extensions and 66% above the prior 10-year average.

New field discoveries added 759 bcf, and new reservoir discoveries in existing fields added 1.2 tcf.

Coalbed methane reserves fell 2% to 18.4 tcf, almost 10% of US dry gas proved reserves. The last reported decline was in 1994.

CBM output, 1.72 tcf or 9% of US dry gas production in 2004, was 7% higher than in 2003.

Exploration and developmental gas completions were 15% higher than in 2003.

States that more than replaced their 2004 gas production were Alaska, Arkansas, California, Louisiana (North only), New Mexico, Oklahoma, Texas, Utah, Virginia, West Virginia, and Wyoming.

Oil statistics
Oil reserves additions in Wyoming, Montana, North Dakota, and Texas edged Lower 48 reserves to a 0.1% increase, but Gulf of Mexico oil reserves fell 9%.

"Three of the four largest crude oil reserves areas, the Gulf of Mexico, Alaska, and California, registered reserves declines," EIA said. "US new field discoveries were the lowest in 12 years, and as a result operators only replaced 71% of crude oil production with reserves additions."

The fourth large crude oil area, Texas, reported a 1% gain.

The 782 million bbl of additions from 2004 oil discoveries of all types was 29% less than the prior 10-year average and 37% less than the 2003 figure.

As with gas, the majority of crude oil discoveries came from extensions to fields in Texas, Alaska, and the gulf federal offshore.

New field discoveries totaled 33 million bbl, and new reservoir discoveries in existing fields were 132 million bbl. Most of the new field discoveries were small finds in gulf federal waters.

Deepwater reserves fell to 4.1 billion bbl of oil, down 9%, and 19.3 tcf of gas, down 14%.

States that more than replaced their 2004 oil production were Alabama, Arkansas, Colorado, Kansas, Kentucky, Mississippi, Montana, North Dakota, Texas, and Wyoming.


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