Decline in world crude reserves is first since '92

Dec. 20, 1999
Worldwide reserves of crude oil declined slightly while natural gas reserves rose in 1999.

Worldwide reserves of crude oil declined slightly while natural gas reserves rose in 1999. For oil, it was the first decline since 1992.

Reserves of crude oil fell by 18.2 billion bbl during the year, and natural gas reserves were 1.5 tcf higher, according to Oil & Gas Journal estimates based on an annual survey of companies, government ministries, and other reporting entities.

The world totals as of Jan. 1, 2000: 1.016 trillion bbl of crude oil and 5.15 quadrillion cu ft of gas.

Average worldwide production of crude oil and lease condensate fell 2.4% from the 1998 level to 64.55 million b/d, according to OGJ's estimate.

Tracking trends

The individual country reserves totals are not as important as the trends they indicate. The published reserves figures rely on survey responses and pertain to quantities of hydrocarbons that are subject to wide interpretation even under strict parameters of estimation.

OGJ's survey form requests data on proved reserves, but responses inevitably include volumes that strict systems for estimation would classify as "indicated." Some countries neither update their reserves estimates every year nor respond annually to OGJ. In those cases, year-to-year changes (or lack thereof) may be misleading.

OGJ's world reserve estimate as of Jan. 1, 2000, is almost 17 billion bbl higher than it was on Jan. 1, 1991 even though more than 205 billion bbl of production occurred in the interim.

OPEC's share of world oil reserves has grown to 78.9% now from 77.5% in 1991.

Natural gas reserves are 22.3% greater than they were in 1991, while crude oil reserves are only 1.7% higher.

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Maintaining the reserves has been largely a matter of improving recovery from existing fields. However, the tables that follow are an indication that this has not occurred in every country. Furthermore, exploration successes have added important volumes during the decade, some of the more recent of which are not yet reflected in the most recent reserves figures.

Big reserves changes

Mexico and the US reported big declines in oil reserves, while reserves attributable to numerous discoveries off Angola in 1998-99 are not yet reflected in the tables.

OGJ estimated Mexico's reserves on Jan. 1, 2000, at 28.4 billion bbl of oil, down 40.6% on the year, and gas at 30.1 tcf, down 52.6%. Pemex in April released figures effective Jan. 1, 1999, from a re-assessment that reflected similar declines.

Crude oil reserves in the US, subject to strict definitions, were reported to be 21.034 billion bbl at yearend 1998. The US Energy Information Administration termed the 6.7% drop "the largest percentage decline in 53 years." Proved reserve additions replaced only 24% of 1998 production, EIA reported.

Figures for India reflect a 22% increase in oil reserves to 4.8 billion bbl and a 21% hike in gas reserves to 22.9 tcf.

Egypt's oil reserves fell 16% to 2.9 billion bbl, but its gas reserves are up 12% to 35.2 tcf. Algeria's oil reserves held at 9.2 billion bbl, but gas reserves climbed 23% to 159.7 tcf.

Argentine oil reserves of 2.75 billion bbl showed a 5% increase.

US reserves

EIA noted that crude oil reserve additions in the US in 1998 were less than one fifth those in 1997, a sharp reversal after several years of increases.

Additions would have been even smaller except that operators continued several large, long-term development projects, mainly in California, in the face of low oil prices.

Another major reversal from 1997 was a new-field-discovery addition of 152 million bbl, less than a quarter of the 1997 level and well below the prior 10-year average, EIA reported.

Rebounding crude oil prices from March 1999 until late in the year had not resulted in marked increases in drilling.

The gas reserves decline ended a 4-year trend of increases in the US. Again low drilling results caught the blame. Volumes added from new field discoveries were down 27% from 1997, and volumes added from new reservoir discoveries were off 9%.

The number of gas wells drilled was up, but the amount of discoveries per exploratory gas well was down 32% in 1998, EIA said.

Proved gas reserves were down in both of the two leading US producing areas, Texas and the Gulf of Mexico federal offshore. Small gains in the deepwater gulf did not offset the decline of proved gas reserves on the shallow shelf.

Coalbed methane reserves accounted for 7% of 1998 proved dry gas reserves in the US.

Production trends

The figures show a 4.7% decline in OPEC oil production in 1998 vs. 1997 but only a 2.4% drop worldwide.

OGJ estimated production declines on the year of 4.3% in the Western Hemisphere, 4% in Africa, and 3.1% in the Middle East.

The tables show a year-to-year gain of less than 1% in oil production in eastern Europe and the Former Soviet Union. Among the larger producers there, Russia's production was off slightly and Kazakhstan's increased a little more than 1%. Middle Eastern output was 3% lower as intentional production cuts in most countries more than offset Iraq's 26% hike.