We present a method to integrate log, core, and well-test pressure data to describe reservoir heterogeneities. The conditional simulation method of simulated annealing is used to incorporate diverse sources of data. We use analytical solutions for radially heterogeneous reservoirs to define an equivalent radial permeability and a corresponding region of investigation. By numerical experimentation on drawdown well-test simulations in heterogeneous permeability fields, we determine that a weighted-area-based geometric average of the grid-block permeabilities within the region of investigation best defines the equivalent radial permeability. This information, along with the spatial statistics from core/log data, are coded into the overall objective function of the simulated annealing algorithm to yield a consistent reservoir description.