NSLS-II   |   Brookhaven National Laboratory

Synchrotron Techniques in Support of Sustainable Subsurface Energy Technologies

Catherine Peters, Princeton University

Catherine A. Peters and Jeffrey P. Fitts
Department of Civil & Environmental Engineering, Princeton University

Numerous synchrotron techniques provide valuable information about rock structure, spatial distributions of minerals, and composition of mineral precipitates. Such information is critical to understanding thermodynamic and kinetic processes relevant to geochemical processes of the subsurface.  Geochemical processes play an important role in the context of subsurface energy technologies including geologic carbon sequestration, geothermal energy production, deep borehole nuclear waste disposal, subsurface energy storage, etc. For example, acid-driven dissolution of carbonate minerals can increase fracture permeability, and in the context of geologic carbon sequestration this could jeopardize storage security. Geochemical processes are also important in sustainable management of flowback and produced waters in oil & gas operations. For example, addition of sodium sulfate can be added to induce precipitation of the sparingly soluble mineral barite (barium sulfate), which fortuitously co-precipitates toxic trace elements like Radium and Arsenic.

This presentation includes an overview of synchrotron techniques that have been used in Dr. Peters’ research to elucidate mineral spatial patterns and void space in fractured and porous media. The following examples will be presented. (1) X-ray computed tomography for 3D characterization of rock fracture geometry and its evolution in reactive flows. (2) X-ray attenuation to measure fracture surface geometry changes in 2D. (3) X-ray computed tomography to reveal microscopic pore structure evolution caused by calcite depletion. (4) X-ray computed tomography to generate 3D maps of mineral distributions in shales. (5) Micro XRF and micro XRD imaging to generate 2D maps of reactive minerals on fracture surfaces. (6) X-ray nanoprobe imaging of co-precipitated substances in barite nanoparticles.