Changes

==Probability of geological success==

==Probability of geological success==

Every expression in the expected value equation requires a responsible geotechnical estimate. We have already addressed procedures for estimating reserves (the primary component of revenue) and costs (both of success as well as failure) in the previous chapter ("Uncertainties Impacting Reserves, Revenue, and Costs"). Here we address the problem of assessing the chance of geological success.

Every expression in the expected value equation requires a responsible geotechnical estimate. [[Uncertainties Impacting Reserves, Revenue, and Costs]] addresses procedures for estimating reserves (the primary component of revenue) and costs (both of success as well as failure). Here we address the problem of assessing the chance of geological success.

For exploratory prospects (including shallow pool, deeper pool, and extension wildcats, commonly managed by development geologists), the recommended procedure is for the geotechnical professional to express his or her confidence independently in four critical geological aspects of any prospect:

For exploratory prospects (including shallow pool, deeper pool, and extension wildcats, commonly managed by development geologists), the recommended procedure is for the geotechnical professional to express his or her confidence independently in four critical geological aspects of any prospect:

#: 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?

#: This geological chance factor is formulated to apply to stratigraphic as well as structural traps, and in tacit acknowledgment that the structural map is ordinarily the single most important map involved in most prospects and many development projects. Also, structural "busts" are a common reason for dry holes (Rose, 1987)<ref name=Rose_1987>Rose, P. R., 1987, Dealing with risk and uncertainty in exploration--how can we improve?: AAPG Bulletin, v. 71, n. 1, p. 1-16.</ref>.

#: This geological chance factor is formulated to apply to stratigraphic as well as structural traps, and in tacit acknowledgment that the structural map is ordinarily the single most important map involved in most prospects and many development projects. Also, structural "busts" are a common reason for dry holes<ref name=Rose_1987>Rose, P. R., 1987, Dealing with risk and uncertainty in exploration--how can we improve?: AAPG Bulletin, v. 71, n. 1, p. 1-16.</ref>.

#: The geological structure chance factor, in combination with the reservoir requirement, focuses on the geometry of the envisioned oil or gas accumulation and on the volumes of fluids necessary to sustain a production test or prudent drill stem test.

#: The geological structure chance factor, in combination with the reservoir requirement, focuses on the geometry of the envisioned oil or gas accumulation and on the volumes of fluids necessary to sustain a production test or prudent drill stem test.

# ''What is the probability (or confidence) that hydrocarbons are present in the subsurface geological environment such that the prospect has had access to them in some quantity to provide at least some modicum of '''''''hydrocarbon charge?'''''

# ''What is the probability (or confidence) that hydrocarbons are present in the subsurface geological environment such that the prospect has had access to them in some quantity to provide at least some modicum of '''''''hydrocarbon charge?'''''