Overlapping faults and their effect on fluid flow in different reservoir types: A LIDAR-based outcrop modeling and flow simulation study

In this article we focus on the potential of fault-overlap zones as conduits for fluid flow in a variety of reservoir types. Light detection and ranging (LIDAR) technology were applied to collect a three-dimensional, spatially constrained data set from a well-exposed fault-overlap zone that crops out in the Devil's Lane area of the Canyonlands National Park in Utah. A virtual outcrop was generated and used to extract structural and stratigraphic data that were taken into a reservoir modeling software and reconstructed. The outcrop-based model was flow simulated and used to test fluid flow through a real-world fault-overlap zone. A structural framework was built based on collected outcrop data and combined with a series of nine different facies models. The different facies models included an eolian model based on the outcrop and a range of synthetic fluvial and shallow marine systems. Results show that, for certain depositional models, cross-fault reservoir communication may be poor despite the geometric connectivity of the relay beds. This was the case for low net/gross fluvial models and shore-face models. Conversely, high net/gross fluvial systems and eolian systems show good communication through the same relay zone. Overall, the results show that, in the presence of a fault-overlap zone, pressure communication across a relay ramp may still be poor depending on the scale of the faults and relay ramp as well as the geometry and volume of the sands.