INVESTIGATION OF CHEMICAL AND MORPHOLOGICAL CHANGES IN SHALE- SUPERCRITICAL CO2-WATER SYSTEMS FOR SUSTAINABLE UNCONVENTIONAL HYDROCARBON EXTRACTION

摘要

Unconventional hydrocarbon reserves in shale and other tight formations continue to provide an increasing level of energy security particularly for the United States. Despite significant advancements in horizontal drilling and hydraulic fracture technologies, the extraction of these unconventional hydrocarbons is still challenged by limited extraction efficiency as well as environmental concerns. Particularly the use of a large quantity of water for hydraulic fracturing or fracking and their post-treatment has emerged as one of the main challenges for the shale gas extraction. Studies have also reported that the fracturing operations can lead to the leaching of heavy and radioactive metals into the fracking fluid. As a result, there is an increasing concern of the potential contamination of ground water systems and a need for more rigorous treatment for post-fracking fluid..