Abstract
Tilting of a structure after it has been filled with hydrocarbons has the potential to allow leakage of either oil or gas depending on the original fill volume, the location of the spill point, and the degree of tilt. Here we concentrate on assessing what the economic consequences are for decisions to explore such structures when there is uncertainty on the volumes of oil and gas retained, uncertainty on the unit costs of production, the total infrastructure costs, the unit selling price of product, and on the probability that, when titled, the structure did indeed lose hydrocarbons or not. Both deterministic examples as well as stochastic illustrations are given to show how one allows for the uncertainties in attempts to assess better the worth of proceeding, to undertake exploration. The dominant contributions to the uncertainty of the expected worth of the tilted structure are also examined with simple illustrations to show how one goes about determining where more effort is needed to narrow the range of uncertainty of those parameters causing the greatest relative fraction of the uncertainty on the exploration assessment value.