Gridless Simulation for Assessment of Volumetric Uncertainty

It is possible to assess volumetric uncertainty using a gridless geostatistical simulation method that directly simulates the shape of contour lines of continuous variables, such as thickness, net-to-gross or porosity. This method is not as fast as global Monte Carlo methods, which can easily produce millions of realizations of global averages; but the number of realizations it can produce in a reasonable amount of time is considerably more than conventional geostatistical conditional simulation, which is typically limited to hundreds of realizations. It is an improvement on global Monte Carlo methods because it honours well data, and can incorporate soft or indirect information. It is an improvement on conventional conditional simulation because it more easily honour complex information on the geometry of the oil-water contact.