Geology and Geological EngineeringDaniel J. Soeder
Energy Resources Initiative
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Daniel J. SoederB.S. (1976) Cleveland State University (Ohio)
M.S. (1978) Bowling Green State University (Ohio)
Director, Energy Resources Initiative
South Dakota School of Mines & Technology
Rapid City, SD 57701
It took 30 years for my 1980s research on shale gas and other unconventional resources to become relevant. I spent the interim working on groundwater hydrology and environmental research, but once the technology caught up with shale gas, I got back into it. Now I'm looking at environmental risks of unconventional oil and gas development, and investigating the interesting movement of fluids through shale.
Energy research is becoming increasing multi-disciplinary. Although focused on geological sources of energy, such as petroleum, natural gas, and geothermal, the Energy Resources Initiative at SD Mines seeks to coordinate ongoing energy-related research with different departments across campus and improve collaboration with other institutions. One of the main goals is to develop research projects relevant to industry to engage students in addressing real-world issues. Our vision is a world-class energy research program that will solve important problems while providing students with practical experience.Some projects under development are described below:
The South Dakota School of Mines & Technology seeks to establish a high-precision core analysis laboratory for ultra-low permeability or tight rocks. These so-called impervious rocks are becoming increasingly important as oil and gas reservoirs, geothermal heat sources, and lithologies to contain and trap greenhouse gases, toxic chemical waste, and nuclear waste. Such rocks are not usually completely impervious like a steel slab, but typically possess permeabilities that are three to six orders of magnitude lower than a conventional porous rock. As such, specialized and sensitive equipment is required for meaningful measurements of petrophysical properties such as grain density, pore volumes, single and multi-phase permeability, pore size distribution, capillary entry pressures, flowpath aperture and tortuosity, pore volume compressibility, the response of flowpaths to increased net stress, permeability hysteresis from high stress excursions, and the affinity of various minerals and macerals for the adsorption of different gases. Instruments proposed for this lab include a custom-designed and constructed steady-state permeameter, complimented by ancillary commercial instruments for rock characterization such as a mercury porosimeter, helium pycnometer, and an adsorbed gas analyzer. A commercial pulse permeameter will also be obtained to compare gas expansion measurements with steady-state data.
The Pierre Shale is an Upper Cretaceous, organic-rich shale present at the surface and in the shallow subsurface across a substantial portion of South Dakota. Some layers within the Pierre are known to contain significant amounts of organic material, and much of this is Type 2 kerogen that is prone to oil generation. Oil shows are, in fact, commonly reported by drillers penetrating the Pierre Shale on their way to deeper targets. This formation has been largely ignored in favor of other highly-productive shales in the region such as the Bakken in North Dakota, and also bypassed because most of it is too shallow for effective hydraulic fracturing, the main recovery technique used for shale gas and tight oil. The fracking process requires at least 2,500 feet of overburden to create the efficient vertical fractures sought by producers. At shallower depths, the fractures break horizontally and are inefficient flowpaths. Recent developments in drilling engineering may allow for the economic recovery of shallow tight oil from the Pierre. SD Mines will be evaluating the organic content, thermal maturity, and stratigraphic framework of the Pierre Shale for possible development.
Although western South Dakota currently has little shale gas or tight oil development within the state, it is surrounded by large shale gas plays in the Powder River basin of eastern Wyoming, significant condensate and shale gas production in the Denver-Julesburg basin in eastern Colorado, and the huge Bakken Shale tight oil play in North Dakota and Montana. Large quantities of chemical additives used in hydraulic fracturing (fracking), such as friction reducers, corrosion inhibitors, and biocides transit South Dakota on their way to these various production sites. Little is known about the degradation rates and breakdown paths of these chemicals in groundwater. In the event of a spill, the approaches for mitigation and remediation would be largely unknown, resulting in potentially significant and long-lasting groundwater contamination. The goals of the proposed work are to determine the degradation pathways, daughter products, and breakdown rates for up to a dozen water-soluble, organic chemicals commonly used as frack fluid additives. The objectives include obtaining laboratory data from microcosm and sand-column experiments, and then using these data to run reactive transport models to assess the mobility of these chemicals in aquifers.
Sources of methane gas in groundwater tend to be either biological, from the action of methanogenic bacteria, or geological. Geological sources may include organic-rich rocks in the stratigraphic column adjacent to the aquifers, such as coal seams or black shales, natural gas accumulating with water in conventional traps, or gas escaping into aquifers from a loss of wellbore integrity. Methane in groundwater itself is not a hazard, but if it escapes into the air, it becomes explosive at concentrations between 5% and 15%. Monitoring methane in the headspace of groundwater wells can help to assess this risk. A commercial, laser-based, laboratory methane sensor has been modified for field use to monitor methane in air in the headspace of groundwater wells. The unit is currently undergoing field tests at the Flaming Fountain well near the SD State Capitol building. This well, drilled in 1910, had enough methane in the groundwater to sustain a flame for many years, giving it the name. Although there is still some methane in the water, the Flaming Fountain no longer flames, and monitoring the methane concentrations is expected to help the State Engineer determine some ways to restore the flame.
Anthropogenic earthquakes caused by the injection of wastewater from oil and gas wells is a significant problem in some parts of the country, Oklahoma in particular. We believe that poroelastic deformation caused by excessive rates of residual waste injection may be responsible for triggering these earthquakes. This research seeks to model downhole stresses and determine the threshold at which too much injection will trigger seismicity. Earthquake hazard assessment from ground motions caused by these stress adjustments will also be modeled.
Pierre Shale outcrop at Redbird, Wyoming 2018.
Methane sensor deployed for field tests at Flaming Fountain, Pierre SD 2019.
USGS time series of seismicity in the south central U.S.
SDSM&T, Dept. of Geology and Geological Engineering, 501 E. Saint Joseph St., Rapid City, SD 57701
phone: (605)394-2802 / fax: (605)394-6703 / email: email@example.com