Abstract
To find oil, drill near an oil field - the cheapest and lowest risk reserves are commonly found as extensions of existing fields, or updip from "near-miss" exploration wells, or simply in prospective acreage which has had many prior discoveries. In these cases, there is more well control and some risks have already been eliminated or minimised compared to the traditional wildcat. The most attractive prospects may also have stacked pay or other multiple targets. In either case, to best estimate the risks and rewards involved in developing these resources, attention to detail is required. Proper accounting for dependencies among different risk factors is required, in order to evaluate the overall risk, the risked reserves distribution, and thus the economic value. The techniques can be extended to value a prospect portfolio, accounting for common or related risk elements.
