### Abstract

Evaluation of the possible range of reserves associated with a prospect is a key part of risk taking in hydrocarbon exploration. The challenge of presenting a range of geologically possible models for a range of prospect reserve estimates is addressed using Swanson's 30-40-30 rule. Swanson's rule defines the mean as 0.3P(10) + 0.4P(50) + 0.3P(90), and provides a good approximation to the mean values for modestly skewed distributions. Pragmatic and mathematical justifications for this rule are given. Applications of the rule to a historical field size distribution and a specific prospect evaluation demonstrate its efficacy in handling routine problems in hydrocarbon exploration, with particular reference to use with the lognormal distribution.

Original language | English |
---|---|

Pages (from-to) | 1883-1891 |

Number of pages | 9 |

Journal | AAPG Bulletin |

Volume | 84 |

Publication status | Published - 2000 |

### Keywords

- UNCERTAINTY
- RISK

### Cite this

*AAPG Bulletin*,

*84*, 1883-1891.

**Swanson's 30-40-30 rule.** / Hurst, A ; Brown, G C ; Swanson, R I .

Research output: Contribution to journal › Article

*AAPG Bulletin*, vol. 84, pp. 1883-1891.

}

TY - JOUR

T1 - Swanson's 30-40-30 rule

AU - Hurst, A

AU - Brown, G C

AU - Swanson, R I

PY - 2000

Y1 - 2000

N2 - Evaluation of the possible range of reserves associated with a prospect is a key part of risk taking in hydrocarbon exploration. The challenge of presenting a range of geologically possible models for a range of prospect reserve estimates is addressed using Swanson's 30-40-30 rule. Swanson's rule defines the mean as 0.3P(10) + 0.4P(50) + 0.3P(90), and provides a good approximation to the mean values for modestly skewed distributions. Pragmatic and mathematical justifications for this rule are given. Applications of the rule to a historical field size distribution and a specific prospect evaluation demonstrate its efficacy in handling routine problems in hydrocarbon exploration, with particular reference to use with the lognormal distribution.

AB - Evaluation of the possible range of reserves associated with a prospect is a key part of risk taking in hydrocarbon exploration. The challenge of presenting a range of geologically possible models for a range of prospect reserve estimates is addressed using Swanson's 30-40-30 rule. Swanson's rule defines the mean as 0.3P(10) + 0.4P(50) + 0.3P(90), and provides a good approximation to the mean values for modestly skewed distributions. Pragmatic and mathematical justifications for this rule are given. Applications of the rule to a historical field size distribution and a specific prospect evaluation demonstrate its efficacy in handling routine problems in hydrocarbon exploration, with particular reference to use with the lognormal distribution.

KW - UNCERTAINTY

KW - RISK

M3 - Article

VL - 84

SP - 1883

EP - 1891

JO - AAPG Bulletin

JF - AAPG Bulletin

SN - 0149-1423

ER -