Investigating the Effects of Fracture Network Complexity on EOR Performance in Naturally Fractured Reservoirs (Published)
Naturally fractured oil reservoirs have complicated flow dynamics that play a significant role in the enhanced oil recovery (EOR). This paper examines how the complexity of fracture networks, i.e. fracture density and connectivity, impact on oil recovery, sweep efficiency, and breakthrough behavior of a porous medium, in this case, a dual-porosity numerical model. The outcome of the simulation indicates that fracture density has a high effect to recover performance with moderate fracture density producing the best oil recovery of 68%, as opposed to low and high fracture density which gave 62% and 55% respectively. The fracture density that resulted in early breakthrough of 60 days and low density resulting in late breakthrough of 120 days showed slower fluid propagation. In the same way, the fracture connectivity affected sweep efficiency with moderate connectivity having the highest value of 72%, as compared to the 60% and 50% values of low and high connectivity respectively. Time-dependent recovery profiles also indicated that fracture networks with high complexity led to high initial production but lower ultimate recovery as they channel and the fluid will pass by passageways, but low complexity fracture networks lead to slower but stable recovery. In general, relatively complex fractures offer the best balance between fluid transport and matrix interaction leading to a high recovery efficiency. The results underscore the need in maximizing fracture properties in the development of efficient EOR plans and show that numerical modeling can be used to forecast the behavior of the reservoir when distinctions of fracture are introduced. The research has useful information to enhance oil recovery in naturally fractured reservoirs.
Keywords: Enhanced Oil Recovery (EOR)., breakthrough time, dual-porosity model, fracture connectivity, fracture density, naturally fractured reservoirs, numerical simulation, oil recovery., sweep efficiency