Economic analysis of hydrocarbon exploration by simulation with geological uncertainties

Abstract

This research continues the work of Chungcharoen (1994) to extend the benefit of Manly's Approximation Method in the area of hydrocarbon discovery process modeling, to incorporate the uncertainties in geologic parameters in order to provide an assessment of the distributions of total hydrocarbon discoveries that are expected to be recovered as a result of exploration activity, and to combine economic parameters into the evaluation of the economic worth of the results of multiple-wells exploration activity. This research is separated into two parts. In the first part, the uncertainties involved in the geological parameters are included in the initial field size distribution and the number of fields distribution. The Monte Carlo approach is used to sample data from the field size distribution with each number of fields selected from the number of fields distribution. A frequency-size distribution is constructed based on sampled data. Dry hole data are also added into the initial frequency-size distribution in order to reflect the exploration risk. After obtaining frequency-size distributions that define the uncertainties in geological parameters, the distributions of total hydrocarbon discoveries for a selected number of exploratory wells are constructed. The second part involves incorporating economic parameters, such as the price of oil/gas, and the costs of exploration, development, and production, into the distribution of the number of discoveries and the distribution of total hydrocarbon discoveries in order to produce a probability distribution of the net present value (NPV) of a proposed exploration program. The distributions of NPV are used as input to the expected utility analyses for determining multiple-wells exploration strategies. The offshore Nova Scotia Shelf basin is selected for implementing the methodology. Several scenarios regarding changes in economic parameters are illustrated. The effect of increasing variability in field size in a basin on the forecast is also discussed.

This methodology could be used by a company as a part of a planning system for projecting exploration programs. It would provide insight into how a company makes a forecast of future discovery volumes that includes uncertainties in geological parameters and how the results are used in long-term planning to determine future development programs for these hydrocarbon reserves. In addition, results from this methodology could assist government departments by supporting their efforts to establish the potential of hydrocarbons discoveries and to aid in their analyses of policies concerning exploration programs regarding taxes and royalty regimes in any basin with various stages of exploration activity.