Geo-modeling and fluid flow simulation in paleokarst reservoirs

Abstract

This master thesis focuses on modeling and simulation of fluid flow in collapsed paleocave systems, also known as paleokarst. Petroleum reservoirs all around the world exhibit karst structures. The latest ones on the Norwegian Shelf are the discoveries Gohta (7120/1-3) and Alta (7220/11-1), the wells were drilled by Lundin Norway AS and completed respectively October 2013 and 2014. Reservoirs of this kind have substantial heterogeneity because of the karst features, which has big impact on fluid flow behavior. This thesis presents a procedure for modeling paleokarst reservoirs in RMS. Furthermore, the effect of the radius of the cave after collapse is tested by comparing production curves derived from simulation of fluid flow in the paleokarst reservoir with Eclipse. Upscaling of the paleokarst reservoir model is also tested to save simulation time, while minimizing the loss of vital information about the reservoir petrophysical properties. Finally, this thesis presents several simulation results that can be used as reference curves for future simulation of either synthetic- or real paleokarst reservoirs. The study in this thesis may provide a better understanding of worldwide petroleum reservoirs that fall in the same category.