In-Situ Foam Generation: A Superior Method for Enhanced Oil Recovery in Unconventional Fractured Reservoirs

Abstract

Unconventional reservoirs, like shale gas, shale oil, tight gas sands, and coalbed methane deposits, pose unique challenges due to their low permeability, low porosity, and complex geological structures. These factors hinder the natural flow of hydrocarbons, necessitating advanced extraction techniques. Hydraulic fracturing is commonly used to increase permeability and enhance hydrocarbon recovery. However, this creates a challenge during gas injection due to significant permeability differences between fractures and matrix. Foam flooding is an innovative enhanced oil recovery method in heterogeneous systems. It reduces fracture transmissivity and improves matrix-fracture interactions, thus enhancing oil sweep efficiency. Yet, foam stability depends on the method of generation. Traditional foam pre-generation at the surface is ineffective in fractured systems as foam loses its properties during transport under high pressure and temperature. This study’s primary objective is to develop in-situ foam generation under reservoir conditions within fractured systems to enhance oil displacement. Achieving this involves optimizing factors like surfactant formulation, concentration, injection rate, and gas fraction. Additionally, the reservoir’s petrophysical properties like wettability, permeability, and mineral composition, are considered. As a result of these efforts, the foam generated in situ will possess the capability to adapt to prevailing conditions and boost hydrocarbon production from such reservoirs.