RESEARCH
Relative Permeability in CO2-Oil-Brine Systems
Lindsey is conducting relative permeability experiments to assess multiphase fluid flow (oil, brine, and CO2) through the Morrow B Sandstone in the Farnsworth Field in Texas. Her experiments are carried out on unique sandstone lithofacies that have undergone various diagenetic processes. Thus, this research will improve our understanding of relative permeability behavior on heterogeneous sandstones with a range of pore types and pore networks, with implications for enhanced oil recovery and and CO2 storage.
Lindsey shown with high-pressure components of her experimental flow system in a heating box, which enables conducting experiments that simulate multiphase fluid flow under reservoir conditions.
Chemomechanical Changes during Geologic Carbon Sequestration
Zhidi’s experiments simulate chemomechanical processes in geologic carbon sequestration environments. She is running flow-through fluid-rock interaction experiments on Morrow B Sandstone cores with unique cement compositions and textures to identify chemical reactions and resultant permeability changes. In addition, she is also employing mechanical tests to identify the extent of mechanical degradation that may arise from the reaction between the sandstones and CO2-rich fluids. Potential compaction can have consequences for CO2 storage and injectivity.
Zhidi conducting a Brazil test, which enables her to measure the apparent stiffness and tensile strength of the sandstone core following reaction with CO2-rich fluid. The experiment was conducted in Bhaskar Majumdar’s lab in the Materials Engineering Department at NM Tech.
Geophysical Signals during Recharge Events in Karst
We conducted recharge experiments to identify geophysical responses generated during recharge events in karst aquifers, using seismometers, a GPS instrument, and a resistivity survey. In addition, the equipment monitored responses during a natural recharge event, and all recharge events generated large amplitude seismic signals. Data analysis is ongoing, but the data will likely be used to delineate the karst conduit network (which controls flow and transport through karst aquifers), to identify flow conditions in the aquifer, and to quantify discharge in subsurface conduits.
The pool was dumped into the dry overflow spring to identify geophysical signals generated during recharge events in karst aquifers. Video by Emily Morton.
Flow and Transport
I am interested in flow and transport through aquifers, and I have focused on water temperature as a tracer in karst aquifers. Water temperature is a useful water quality parameter that is easy and cheap to monitor. Using data collected at many springs and cave streams, we developed a thermal pattern classification scheme using heat transport theory, which provides insight for flow path geometries and recharge modes. We also demonstrated water temperature’s non-conservative behavior in the environment and developed analytical solutions which allow conduit properties such as diameter to be estimated using water temperature data. This research facilitates better characterization of these systems.
Tyson Spring Cave, MN. Photo by Matt Covington.
Calvin Alexander and Scott Alexander ready to empty a pool into a sinkhole during the multitracer study described in Luhmann et al. (2012).
Fluid-Rock Interaction
I am also interested in fluid-rock interaction, and my efforts have focused on running laboratory experiments at elevated temperatures and pressures to simulate carbon sequestration settings and serpentinization systems. These experiments are conducted to explore complex feedbacks between chemical reactions and changes in pore-scale geometries as fluids flow through geological reservoirs. Our experimental flow system as well as analytical equipment such as X-ray computed tomography allows us to identify chemical reactions and rates and determine changes in porosity, permeability, and reactive surface area as a function of reaction progress. Core scale observations improve our understanding of reactive transport processes.
(a) Hydrothermal flow system and (b-d) flow-through reaction cell. Flow system facilitates experiments at elevated temperatures and pressures to simulate different geological systems (Luhmann et al. 2017, Chemical Geology).
X-ray computed tomography reconstruction of dissolution channel that developed in a dolomite core subjected to CO2-charged brine (Luhmann et al. 2014).
