HYDROCARBON ASSESSMENT USING SUBJECTIVE PROBABILITY AND MONTE CARLO METHODS

Publisher Summary This chapter describes the hydrocarbon assessment using subjective probability and Monte Carlo methods. It discusses the problems encountered in deciding on the best methods to evaluate oil and gas potential. It also discusses the philosophy behind the methodology and the mechanics of the assessment scheme. Estimates of hydrocarbon resources are made primarily as a basis for planning. A major problem in assessing Canada's hydrocarbon potential is evaluation of the frontier areas where, in many cases, little drilling has been done and data are sparse. The assessment is done by a committee of geologists from the staffs of the Department of Energy, Mines, and Resources, Canada, and the Department of Indian and Northern Affairs. Data are collected, analyzed, and presented by geologists and geophysicists working in the areas to be assessed. After consideration of the available information, the committee decides on the approach to take and makes the assessment. The assessment methods used are as follows: (1) break the estimating procedure into component parts in order that the assumptions and decisions made at each step can be critically examined by the committee and, if necessary, by others, (2) incorporate into the estimate the probability, that is, the risk, that any factor related to the hydrocarbon occurrence has a value less than or equal to some minimum value, and (3) express the estimate of potential as a range of values of potential and the probability of occurrence of any value in the range. The estimate of potential can be considered as a solution to an equation relating a series of variables to hydrocarbon potential. The marginal probability, the probability that pooled hydrocarbon occurs in any given prospect, is obtained by consideration of the oil occurrence factors in light of available data.