Date of Award

December 2022

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

William Gosnold

Abstract

This analysis of the logistics of repurposing plugged and abandoned oil wells for use in district heating indicates that it is economically feasible and provides a guide to inform the development of geothermal direct use in the Williston Basin. This study focused on Williston State College where data on campus infrastructure, heating and cooling loads, oil well status, and geothermal resource potential are available. I selected a PA well and an SWI well that lie within 2 km of the WSC campus for the production and injection wells for the analysis. The alternative to using PA wells, drilling a new production well, is significantly less economical. The WSC campus buildings occupy an area of >250,000 sqft and energy usage is 36 MMBTU per year. The geothermal resource is 80+ °C (176 °F) water in the 177 m (580 ft) thick Inyan Kara formation (Cretaceous) at a depth of 1.5 km (5230 ft.). The geothermal resource lies in a 110 m thick Inyan Kara sandstone unit with a known porosity of 21%, a productivity index of 31.93 bbl/day/psi, Total Thermal energy of 1.12 x1016J, and Heat produced as 2.81 x 109 BTU/day. I used the GEOPHIRES software to input the resource parameters of the selected well. The GEOPHIRES simulation indicates that the LCOH for this analysis is 12.0 $/MMBTU which exceeds the current price of heat by natural gas. However, switching to geothermal from natural gas would eliminate approximately 215million metric tons/year of CO2. Extending this analysis throughout the Williston Basin suggests that the replacement of fossil fuels by geothermal district heating could eliminate CO2 production of hundreds of millions of tons per year.

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