Research Progress on Supercritical Carbon Dioxide Fracturing Technology

Abstract:

For the exploitation of low-permeability oil shale deposits, supercritical carbon dioxide (SC-CO2) fracturing technology avoids the formation damage, possible induced earthquakes and environmental pollution caused by hydraulic fracturing effectively and becomes a hot waterless fracturing technology because of its advantages of reducing initiation pressure, communicating micro cracks and developing complex fracture network. This paper introduced in detail the technical characteristics and the experimental and mathematical model studies of SC—CO2 fracturing in recent years. From the view of experimental studies about crack propagation mechanism, experimental studies about lithologic change with the interaction of SC—CO2, the development of SC—CO2 fracturing fluid and mathematical model studies about the flowing rules of sand carrying SC—CO2, temperature of wellbore, crack initiation and propagation mechanism, the research progress and deficiency of SC—CO2 fracturing technology were discussed and suggestions were put forward about the design of tackifier, effective evaluation of fracture and enhancement of oil shale reservoir heat transfer and seepage capacity caused by packed fracture, providing a reference for its development.

Key words:fracturing technology; supercritical carbon dioxide; waterless fracturing; oil shale