Changes

# ''What is the probability (or confidence) that '''reservoir rock '''is present, of sufficient [[porosity]] and [[permeability]] to be productive, and in some minimal thickness and extent sufficient to contain detectable (i.e., measurable) quantities of mobile hydrocarbons, or to tempt a prudent onshore domestic operator to attempt a completion?''

# ''What is the probability (or confidence) that '''reservoir rock '''is present, of sufficient [[porosity]] and [[permeability]] to be productive, and in some minimal thickness and extent sufficient to contain detectable (i.e., measurable) quantities of mobile hydrocarbons, or to tempt a prudent onshore domestic operator to attempt a completion?''

#: One approach is to estimate the minimum required flow rate and relate this flow rate to thickness and [[permeability]]. In any case, what we seek is the geologist's confidence in the existence of at least a minimal reservoir—thickness, extent, [[porosity]], and effective [[permeability]]. Under this approach, encountering a wet, commercial-quality sandstone would not be a failure in the reservoir category, but rather in one of the other categories, such as an unexpected structural low, an absence of hydrocarbon charge, or a leaky trap. However, the presence of a 1-ft-thick tight siltstone where a 10-ft-thick porous sandstone objective had been predicted would be a reservoir failure!

#: One approach is to estimate the minimum required flow rate and relate this flow rate to thickness and [[permeability]]. In any case, what we seek is the geologist's confidence in the existence of at least a minimal reservoir—thickness, extent, [[porosity]], and effective [[permeability]]. Under this approach, encountering a wet, commercial-quality sandstone would not be a failure in the reservoir category, but rather in one of the other categories, such as an unexpected structural low, an absence of hydrocarbon charge, or a leaky trap. However, the presence of a 1-ft-thick tight siltstone where a 10-ft-thick porous sandstone objective had been predicted would be a reservoir failure!

# ''What is the probability (or confidence) that the '''geological structure''' of the reservoir objective is, in reality, essentially as represented on maps and cross sections?''

# ''What is the probability (or confidence) that the '''geological structure''' of the reservoir objective is, in reality, essentially as represented on maps and [[cross section]]s?''

#: It is important to note here that we do not require an actual "structure," such as a domal anticline or a fault closure, only that prospect maps and sections accurately depict the structural configuration. For example, if only regular monoclinal south dip is required in the case of a stratigraphic trap prospect, then the geologist should express confidence—as a probabilistic estimate—that the structure in the vicinity of the prospect actually is indeed regular monoclinal south dip.  

#: It is important to note here that we do not require an actual "structure," such as a domal anticline or a fault closure, only that prospect maps and sections accurately depict the structural configuration. For example, if only regular monoclinal south dip is required in the case of a stratigraphic trap prospect, then the geologist should express confidence—as a probabilistic estimate—that the structure in the vicinity of the prospect actually is indeed regular monoclinal south dip.  

#: If the map shows an antithetic fault closure, then what is the probability that such a structural configuration will actually turn out to be present?

#: If the map shows an antithetic fault closure, then what is the probability that such a structural configuration will actually turn out to be present?