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Risk: expected value and chance of success (view source)
Revision as of 21:35, 17 June 2014
, 21:35, 17 June 2014→Probability of completion
==Probability of completion==
==Probability of completion==
The key question for most development geologists is, "What is the probability that this well will be completed?" Thus, the ''probability of success,'' or ''P''<sub>s</sub>, is really the ''probability of completion.'' The probability of geological success (as defined and derived above) can be made to approximate the probability of completion (or the probability of success) by two linked measures:
The key question for most development geologists is, "What is the probability that this well will be completed?" Thus, the ''probability of success,'' or ''P''<sub>s</sub>, is really the ''probability of completion.'' The probability of geological success (as defined and derived above) can be made to approximate the probability of completion (or the probability of success) by two linked measures:
# Minimum but finite dimensions are required for all reserves parameters, such as area, net pay, and hydrocarbon recovery factor. The concept here is that a small but finite volume of oil or natural gas, and some minimum reservoir thickness and quality, must be present for an accumulation even to be ''detected'' by an operator. In other words, the lower limit of an ''accumulation'' thus defined is substantially larger than 1 bbl of oil!
# Minimum but finite dimensions are required for all reserves parameters, such as area, net pay, and hydrocarbon recovery factor. The concept here is that a small but finite volume of oil or [[natural gas]], and some minimum reservoir thickness and quality, must be present for an accumulation even to be ''detected'' by an operator. In other words, the lower limit of an ''accumulation'' thus defined is substantially larger than 1 bbl of oil!
# The four geological chance factors are defined so as to include the concept of the ''practical'' lower limit, that is, a modicum of [[porosity]], [[permeability]], and thickness of reservoir rock; a closure sufficient to contain an accumulation large enough to sustain a production test (or even a prudent drill stem test); and a hydrocarbon charge and sealing capability sufficient for at least 50% hydrogen saturation.
# The four geological chance factors are defined so as to include the concept of the ''practical'' lower limit, that is, a modicum of [[porosity]], [[permeability]], and thickness of reservoir rock; a closure sufficient to contain an accumulation large enough to sustain a production test (or even a prudent drill stem test); and a hydrocarbon charge and sealing capability sufficient for at least 50% hydrogen saturation.