Simulation of Reservoirs with Multiple Scale Fracturing

Abstract

The share of the world's hydrocarbon reserves, related to fractured reservoirs is over 20%. Some studies have shown based on the Nelson criterion that reservoirs in Western Siberia with the terrigenous reservoir type are characterized by a significant influence of fractures on production. Tectonic disturbances have multiple scale features: there are non-conductive and conductive fractures as well as the decompression zone with small fractures. This raises the question of adequate reservoir modeling with multiple scale fracturing. The point is that a simulation of large fractures within the continuum mechanics framework is incorrect and a simulation of small fractures within the discrete fracture model is time consuming and impractical. It is also important to consider the relationship between fracture conductivity and pressure, and to be able to specify both conductive and nonconductive fractures. Therefore, it is important to develop an appropriate and productive software for this task. A new software was developed for simulating water flooding in reservoirs with multiple scale fracturing using novel numerical method. The relationship between fracture opening and water flooding performance was studied in fractured porous reservoirs accounting for the relationship between fracture permeability and pressure. The relationship between injection rate and production performance in fractured porous reservoirs was studied. Analytical and numerical study of the relationship between the well placement system and the oil recovery in fractured zonally heterogeneous reservoirs and porous reservoirs was performed.