Joshua Arneson Chosen to be UIUC Capitol Scholar
The Office of Undergraduate Research at the University of Illinois at Urbana-Champaign (UIUC) chose Joshua Arneson to be one of its 2016 Capitol Scholars. Arneson is a senior in the UIUC Department of Geology who has been working on his senior thesis as part of an Illinois State Geological Survey project titled “A nonconventional CO2 EOR target in the Illinois Basin: Oil reservoirs of the thick Cypress Sandstone,” which is sponsored by the United States Department of Energy. As one of UIUC’s Capitol Scholars, Arneson presented his poster “Using petrophysics to determine the presence of residual oil zones for the thick Cypress Sandstone at Noble Field” to members of the Illinois State Legislature, their staff, and the general public at the State Capitol on May 5.
Joshua Arneson, a senior in the UIUC Department of Geology, worked on his senior thesis as part of the Nonconventional CO2 EOR project. He graduated in May of 2016. Image courtesy of Joshua Arneson.
Arneson has been developing a petrophysical method to identify residual oil zones (ROZs) on geophysical logs in collaboration with project members Scott Frailey, Nathan Grigsby, and Nathan Webb. Residual oil zones are reservoirs of low oil saturation that may be present below the oil-water contact of a conventional reservoir. The high water saturation of ROZs makes them uneconomic for primary or waterflood development. However, such reservoirs have been the target of successful carbon dioxide (CO2) enhanced oil recovery projects in places like the Permian Basin of West Texas. The tendency for underlying brine aquifers to “steal” CO2 during injection makes them nonconventional, because a portion of the CO2 is stored in the aquifer and is unable to interact with oil and enhance production.
Arneson has been applying Archie’s Equation and the Ratio Method to geophysical data acquired from wells in Noble Field, Illinois. Archie’s Equation and the Ratio Method are two approaches to calculating a water saturation profile of a reservoir, which can be used to identify the presence of an ROZ. By determining a petrophysical method that accurately calculates the water saturation profile of an oil reservoir, and comparing that water saturation profile with the “ideal” profile of an ROZ-bearing reservoir, the project can provide geologists and oil field operators with a method to screen for ROZ-bearing reservoirs. “It’s like an indicator; it’s a visual way” to identify ROZs, according to Arneson.
Example of an ideal water saturation profile. Image courtesy of Joshua Arneson.
Once the petrophysical method is validated, it will be used to evaluate the potential ROZ resource of other oil fields within the thick Cypress Sandstone fairway in the Illinois Basin—an area of the Basin where oil reservoirs in the Cypress Sandstone tend to be under produced and have low primary oil recovery because of excessive water coning. This, in turn, will provide a better understanding of the spatial distribution of ROZs across the Basin. A reliable method to identify the presence of such zones and their oil-saturation assists in assessing the economic viability of CO2 storage and enhanced oil recovery projects and thus the possibility of implementing those projects in the Illinois Basin.
For Arneson, the opportunity to present this research at the State Capitol is “a great capstone to [his] whole college experience. Being able to do three years of work here at the Survey, it’s a nice finale."
by Dan Klen
Contact: Nathan Webb