28 Fundamental Measurements of Shale Properties and Identifying Data Gaps

Monday, 20 March 2017
8:00 AM - 10:00 AM
Monongahela, 17th Floor

CHARACTERIZATION OF THE CO2-FLUID-SHALE INTERFACE VIA FEATURE RELOCATION USING FIELD-EMISSION SCANNING ELECTRON MICROSCOPY AND IN SITU INFRARED SPECTROSCOPY

Paper number: 28-5
Program: Theme Sessions
Time: 9:20 AM – 9:40 AM

Authors

Abstract

Shale is unique in that it can serve as either a CO2 sealing or a CO2 storage formation. Low permeability, unfractured, shale intervals can act as sealing layers, ensuring vertical containment of geologic storage of CO2. Fractured, organic rich shales, have been shown to be both the source rock and a trap of unconventional gas and oil. Research is underway evaluating the role that shale intervals may play as targets for the storage of anthropogenic CO2.

Hydraulic fracturing fluids and CO2 interactions with shales can influence the properties of the rock by such mechanisms as chemical alteration, matrix swelling/shrinkage, and related geomechanical effects. As such, it is important to understand the influence that hydraulic fracturing fluid-CO2-shale interactions may have on shale mechanical and hydrodynamic properties, and how these interactions vary in different shales.

Experiments include in situ fracturing fluid-rock and SCCO2-rock interaction studies. Shale samples were examined before and after in situ exposure using surface relocation techniques via high-resolution field-emission scanning electron microscopy (FE-SEM) to investigate chemical or physical alterations. This study also targets CO2 storage in shale formations and focuses on characterizing the interface between the injected CO2 and shale with in-situ infrared spectroscopy. Precipitates such as gypsum, barite, strontanite, celestine, and apatite as well as carbonate dissolution and fracture propogation were observed under varying conditions. Results indicate a complex precipitation/dissolution in response to local changes in Eh and pH.

Geological Society of America Abstracts with Programs. Vol. 49, No. 2

doi: 10.1130/abs/2017NE-291244

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