1. A method of predicting the likely behavior of a system by constructing a model of the system and processing the model. 2. Estimating the distribution of a physical property based on an interpolation scheme that involves a random approach. A point selected at random is first calculated based on the known data, then another point based also on the points already determined, and so on until values are determined for all points. The calculation of many simulations allows a measure of the probability of the statistical result. Two types of data (often well and seismic data) are used in co-simulation. 3. Specifically, a computer model of a hydrocarbon-field production that allows one to predict what will happen given various scenarios.