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The AAPG/Datapages Combined Publications Database

Houston Geological Society Bulletin


Houston Geological Society Bulletin, Volume 22, No. 3, November 1979. Pages 4-4.

Abstract: How Many Wildcats Must We Previous HitDrillTop?


John D. Haun

Decline of U.S. oil and gas reserves could be moderated by increased exploratory drilling. In 1978 U.S. production was 3.0 x 109 bbl crude oil, 0.7 x 109 bbl natural-gas liquids (NGL), and 19.3 x 1012 cu ft natural gas (=3.3 x 109 bbl oil equivalent-BOE), for a total of 7.0 x 109 BOE. To continue production at this rate until 1990 (12 years) would require discovery of 84 x 109 BOE.

Annual estimates of ultimate recovery (past production + reserves) are made for each year since 1920 by API and AGA. To each of these estimates must be added an estimate of reserve growth from revisions, extensions, new-pool discoveries, in-field drilling and enhanced recovery. From the derived annual totals and AAPG estimates of footage drilled annually in new-field wildcat wells, the oil and natural gas discovered/foot were estimated. In the late 1940s the average discovery/foot was more than 350 BOE. By the late 1970s the average discovery/foot had dropped to 52 BOE. Projections of these decline curves determined the number of feet of new- wildcats needed to find 2 x 109 BOE/yr, approximately the present rate of discovery in the U.S. Projected average drilling depth permits calculation of the number of needed wildcats/yr (12-yr total= 388,514 wells). Estimated discoveries are 7% oil and 8% gas.

Projected increases in drilling and completion costs (JAS) indicate a total cost of $179 billion. Not included are lease, geological and geophysical, development-well, and overhead costs.

A projected increasing role of natural gas and NGL in the total energy mix results from the relatively large proportion of gas, on a Btu equivalent basis, being discovered/foot of new-field wildcat drilled. At present finding rates it is not possible to replace the 7.0 x 109 BOE annual production.

Projected costs are so large that attainment of these limited goals does not seem possible. Total cost of the necessary new-field wildcats ($179 billion), however, is in the same order of magnitude as President Carter's estimated federal income from the "windfall" profits tax for 1980 to 1990. In any case, estimates of available oil and gas resources indicate that it is possible to moderate the decline in reserves and production.

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