Supercritical CO2-water-shale Interactions under Supercritical CO2 Stimulation Conditions

As one of the main unconventional gas reservoirs, the exploration and exploitation of shale gas reservoirs has been a hot spot of global resources development. The traditional water-based fracturing fluid with the disadvantages of large water consumption and serious formation damage does not apply to shale gas reservoirs stimulation. Supercritical CO2 fracturing technology, using harmlessness CO2 for sand-carrying fluid, was brought forward to apply to development of shale gas reservoirs, with the advantages of no water consumption, no damage to formation, contributing to CH4 desorption, etc. When applying supercritical CO2 as the fracturing fluid, in fractures supercritical CO2 interacts with shale in the presence of water. The study on the interactions of shales and supercritical CO2 in the presence of water is a basic issues in stimulation of supercritical carbon dioxide within shale reservoirs. The objective of this study is to solve the key problems which the interactions of shale, supercritical CO2 and water involves, such as mineral elements migration, microscopic pore structure and so on. Copyright (C) 2018 The Authors. Published by Elsevier Ltd.