Oil and gas in offshore tracts: Bias in estimates of reserves

  • L. A. Thomsen
  • Matt Joggerst


Two independent data sets show that current means of estimating reserves of oil and gas in offshore fields are biased. The bias which is established here is that small fields (with less than about 10 million barrels of oil equivalent) are overestimated, and larger fields (at least up to 200 MMBOE) are underestimated. This systematic bias occurs with or without a significant overall bias, and in addition to a large scatter. Because bias (as opposed to scatter) has serious implications for national energy policy, and in particular for conduct of offshore lease sales, these results indicate that evaluation methods should be revised, or that ad hoc adjustments (based on historical data) should be applied.

Key words

Oil gas reserves estimate bias 


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Copyright information

© Plenum Publishing Corporation 1985

Authors and Affiliations

  • L. A. Thomsen
    • 1
    • 2
  • Matt Joggerst
    • 1
  1. 1.Department of Geological Sciences and Environmental StudiesState University of New YorkBinghamtonUSA
  2. 2.TulsaUSA

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