From Outcrop to Flow Simulation: The Effects of Shallow Marine Clinoforms on Simulated Production from Outcrop Analogs in Utah

John Howell¹, Åsmund Vassel¹, Tanja Aune¹, Simon Buckley², and Håvard H. Enge^2
1 University of Bergen, Bergen, Norway
² Centre for Integrated Petroleum Research, University of Bergen, Bergen, Norway

A key application of outcrop analogs is to provide data on geobody properties for stochastic modeling of subsurface reservoirs. While such an approach is extremely useful, it does not provide accurate geometric information on the actual effects that bodies such as deltaic clinoforms have on fluid flow. In recent years there has been an increasing focus on the direct building of models that provide an accurate 3D representation of the outcrop. To date much of this work has concentrated on capturing and visualising the outcrop in 3D; there has been less focus on building 3D geomodels and dynamically interrogating them.

Outcrop data have been collected from the well-exposed, Cretaceous, Panther Tongue and Ferron deltaic systems of Utah with the aim of investigating the effects of clinoform geometry on fluid flow. A variety of data collection and modeling techniques have been used, including laser scanning (LIDAR) of the outcrops. Workflows for taking the outcrop data through to 3D simulation model involve the production of virtual outcrops; the interpretation and correlation of key surfaces and the design and population of grids.

Dynamic interrogation of the models from the two systems indicates that the choice of griding strategy can account for up to 30% difference in the simulated production. Horizontal grids appear to produce significantly better and fail to capture the geometry of the clinoforms. These models also enable comparison of highstand and lowstand deltas systems and testing flow simulation sensitivity to factors such as shale object length and water flood direction.