Deep subsurface energy systems rely upon controlled stimulation of host rock using hydraulic fluids to enable optimized exchange of energy, CO2, or hydrocarbons. For production-based systems (enhanced geothermal and unconventional oil/gas), it is desirable to maintain permeability, while in storage systems (CO2 sequestration) minimizing the permeability around the targeted storage zone is paramount. In all scenarios a central goal is to optimize fluid transport within host rock matrix. However, chemical reactions between injected fluids and/or critical CO2, which are at disequilibrium from the reservoir, lead to mineral dissolution and/or precipitation that can influence the efficiency, safety and/or environmental aspects of these technologies. Yet, there is a noticeable lack of studies that investigate quantitative understanding of co-evolving geochemical and transport properties within the rock fabric at scales finer than the centimeter scale.
Direct observation of changes in pore networks, coupled with fluid flow and chemical transformations, requires in-situ methods (e.g., neutron/X-ray imaging and scattering) that can penetrate rock matrices and detect chemical changes at fine spatial (e.g., micrometers) with temporal (e.g., minutes) resolution. While neutron scattering is capable of probing selective changes in porosity and connectivity of the pore network, synchrotron X-ray methods provide unparalleled sensitivity to chemical and mineralogical changes of reactive mineral-forming elements unparalleled by laboratory-based techniques. Together, synchrotron and neutron investigations could be the key for reconstructing and modeling geochemical reactions and changes to fine scale pore/fracture networks. Through this workshop, we will discuss technical and research needs and develop a vision for deepening our understanding of permeability controls in deep reservoir energy systems. The workshop will further define new research opportunities in combining and coordinating neutron and synchrotron techniques to enhance our knowledge of physical and chemical changes in subsurface geological systems.
Organizers:
Vincent Noel (SLAC/SSRL)
John Bargar (SLAC/SSRL)
Adam Jew (SLAC/SSRL)
Yun Liu (SLAC/SSRL)
Eleanor Spielman-Sun (SLAC/SSRL)
Speakers:
Tony Kovscek (Stanford University)
Xin Gu (Portland State University)
Larry Anovitz (ORNL)
Dan Hussey (NIST)
Rex Hjelm (LANL)
Christina Lopano (NETL)
Anthony Chappaz (Central Michigan University)
Yijin Liu (SLAC/SSRL)
Jennifer Druhan (University of Illinois)
Agenda:
1:00 -1:05 pm Welcome and introduction
Neutron investigations
1:05 -1:25 pm Dan Hussey – NIST – Current and future prospects of neutron imaging investigations of deep subsurface energy systems
1:25 -1:45 pm Xin Gu – Pennsylvania State University – Investigating shale weathering using neutron and X-ray scattering
1:45 -2:05 pm Rex Hjelm – LANL – Enhanced Oil Recovery from Tight Shale Probed by Small-angle Neutron Scattering Techniques Emulating Field Conditions
2:05 -2:25 pm Larry Anovitz – ORNL - (U)SANS Analysis of Frustrated Coulombic and Cation Size Effects on Nanoscale Boehmite Aggregation: Implications for Waste Processing at the Hanford and Savannah River Sites
2:25 -2:40 pm 15 minute break
Synchrotron X-ray investigations
2:40 -3:00 pm Yijin Liu – SLAC – Multi-scale and multi-modal x-ray microscopy techniques using both synchrotron and laboratory x-ray sources
3:00 -3:20 pm Christina Lopano – NETL – Chemical imaging of redox reactions at shale-fluid interfaces in fractured shale systems
3:20 -3:40 pm Jennifer Druhan – University of Illinois – Development of reactive transport simulations based on spatiotemporal synchrotron X-ray analysis of reactive fluid imbibition through shale matrices
3:40 -4:00 pm Anthony Chappaz – Central Michigan University – Critical metal resources: The importance of adding speciation analysis to the geochemist's tool box
4:00 - 4:10 pm 10 minute break
4:10 -5:00 pm Round table
- How combining neutrons and synchrotrons could improve our understanding of subsurface geological systems?
- How to develop better collaboration between neutrons and synchrotrons? What are the research opportunities where combining neutrons and synchrotrons is the key to improve our understanding?