Temperature Impact on Adsorption Contribution to Sequestration of CO2 in Immature Shale Formations
The environmental concerns to reduce carbon dioxide emissions have led to huge advancements in carbon capture and sequestration in different geological formations in the past two decades. Due to the high abundance of shale basins around the world, in recent years, CO2 sequestration potential in these formations has become an attractive option. However most of the shale formations are considered immature to become shale oil or shale gas. These types of shale usually contain high organic matter (kerogen) generally expressed as total organic carbon (TOC) compared to mature shale reservoirs. The poor petrophysical properties of shale rocks in terms of porosity and permeability the adsorption capacity became very significant factor that controls the amount of CO2 these formations can store. Previous experimental studies showed that high TOC indicate high adsorption capacity.
In this study, adsorption of CO2 at high pressure and on intact shale rocks from shale will be investigated. Also, the temperature impact on adsorption will be investigated using gravimetric adsorption system combined with full geochemical characterization on shale samples. Furthermore, accurate adsorption isotherms will be developed about the adsorption behaviors of shale rocks with temperature.
Most of the studies conducted on adsorption of CO2 in shale used crushed shale samples which alters the intact rock inherited petrophysical properties and thus will give misleading information about the actual adsorption and storage potential of the formation.
In this study an investigation of temperature effect on adsorption capacity of intact shale is investigated at high pressure and temperature to give an accurate storage potential and correct adsorption isotherms.
The results showed that the equilibrium temperature has a great effect on the adsorption behavior of CO2 on the tested samples. The organic matter behavior and clay mineral presence also affected the adsorption of CO2.