UW Researchers Release New Thermal Maturity Assessment Publication on Mowry Shale

Researchers at the University of Wyoming have published a new study conducting a thermal maturity assessment to better understand the Mowry Shale.

The article, “Raman spectroscopy of electrostatically isolated organic matter for thermal maturity assessment: A case study on the Mowry Shale,” was published in the International Journal of Coal Geology and was written by Tarek Ismail, a UW Ph.D. candidate in energy and petroleum engineering, and Soheil Saraji, an associate professor of energy and petroleum engineering.

The study was funded through the UW School of Energy Resources’ (SER) competitive proposal opportunity to study and optimize the recovery of oil and gas from the Mowry Shale in the Powder River Basin.

The study evaluates the thermal maturity of the Mowry Shale using pyrolysis, vitrinite reflectance and Raman spectroscopy, with emphasis on the impact of sample preparation.

“Thermal maturity assessment is a geochemical process used by geologists and petroleum engineers to determine how much heat and pressure a ‘source rock’ has been exposed to over millions of years,” Saraji says. “The goal of a maturity assessment is to find the specific temperature range where the rock is actively generating hydrocarbons, a helpful indicator of locating the sweet spots for oil and gas recovery.”

Saraji, who also directs SER’s Center of Excellence in Subsurface Energy and Digital Innovation, says the publication is the first to use research conducted in UW’s Multidisciplinary Advanced Stimulation Laboratory.

The laboratory, a collaborative research space between SER and the College of Engineering and Physical Sciences, is equipped to advance the understanding of subsurface processes through integrated geomechanics, fluid dynamics and advanced reservoir characterization.

“This high-impact publication is one of the first major outcomes from the newly opened Multidisciplinary Advanced Stimulation Lab,” Saraji says. “This study showcases exactly why the lab was established -- to provide researchers with advanced, state-of-the-art tools necessary to tackle complex subsurface challenges and drive innovation in energy science.”

The publication introduces a novel and effective sample preparation technique based on electrostatic isolation, establishing a robust foundation for characterizing organic matter maturity with Raman spectroscopy. The new method offers a reliable and significantly more time-efficient and cost-effective approach for evaluating the thermal maturity of the Mowry Shale.

“The success of this methodology not only advances our ability to analyze this critical Wyoming geologic formation but also demonstrates a high potential for applicability to other shale formations, paving the way for future research,” says Tim Fischer, the oil and gas program manager in SER’s Center for Economic Geology Research. “The high-quality data generated is a testament to the powerful research being conducted at UW and, as we move into subsequent phases of this work, we are eager to leverage these foundations for applied research in collaboration with our industry partners to benefit Wyoming.”

The full study can be accessed at https://doi.org/10.1016/j.coal.2025.104910.