Risk Assessment of Petroleum Prospects in Kansas

DAVIS, JOHN C., Kansas Geological Survey, Lawrence, KS

Probabilistic techniques have been employed for many years to evaluate petroleum prospects and to forecast the likely outcomes of drilling ventures. These methods are used most widely by major oil companies in high-cost (and high-risk) offshore, foreign, and frontier areas but can be beneficial for evaluating more modest prospects in mature petroleum provinces such as Kansas. Probabilities can be estimated from public production data, and models of prospects can be based on the characteristics of fields in the same or comparable plays. Inexpensive, general-purpose programs running on personal computers are adequate to model and evaluate most prospects.

A simple forecast of sizes of fields likely to be discovered can be made by extrapolating any trends in graphs of discovered field sizes vs. order of discovery. Models of individual prospects can be made using Monte Carlo methods to estimate the likely distribution of oil in place, using distributions of porosity and water saturation based on the characteristics of nearby fields and distributions of area and height of closure from prospect maps. Difficult-to-evaluate factors such as source, timing, and migration are not required for a prospect in a mature basin since these are already known to be adequate. The resulting distribution of probable volume should be comparable to the field-size distribution predicted for the region. Dry-hole risks can be derived from current industry perfo mance or the performance of the individual company. These simple assessment techniques are demonstrated for an area in western Kansas.

AAPG Search and Discovery Article #91008©1991 AAPG Mid-Continent Section Meeting, Kansas Geological Society, Wichita Kansas, September 22-24, 1991 (2009)