Effect on Water Breakthrough When a Near-Critical Fluid Reservoir Reaches Saturation Pressure

Abstract

Many factors affect water movement within the reservoir; it's already known that petrophysical characteristics of the porous media, reservoir fracture networks and exploitation rhythm are some of them. In naturally fractured reservoirs containing near-critical fluids (oil systems) there is evidence that fluid properties have a direct effect in the strong water breakthrough at the time that the saturation pressure is reached in the reservoir.These reservoirs undergo substantial changes in volume and composition, due to its high oil formation volume factors that cause a sudden advance oil water contact that is aided by the presence of fracture networks. This semi-instantaneous variation can be up to 40% loss of liquid saturation and it will depend on the characteristics of the fluid itself. This effect is usually confused by channeling or water coning when conventional techniques are used to diagnose water breakthrough.This work was developed in order to demonstrate the effects and consequences of reaching the saturation pressure in the advancement of water oil contact in naturally fractured reservoirs (NFR) that contains near-critical fluids, using traditional reservoir engineering analysis, novel diagnostic plots and numerical simulation.