A method, system and computer program product is disclosed for utilizing proxy models to evaluate a subterranean reservoir. The method includes constructing a proxy model from a set of sampling points to approximate simulation outputs of a reservoir model. The set of sampling points is updated by adding at least one new sampling point that is selected from a location associated with surface non-linearities such as gradients, curvature, and bending energy. Response surface values at new sampling points and distances to existing sampling points can also be used to evaluate new sampling points. Proxy models are refined with the updated set of sampling points until the proxy model satisfies a predetermined stopping criterion, such as when a predetermined number of iterations are reached or when changes to the response surface are below a predetermined threshold.