Advancing Geothermal Energy Exploration

Abstract

Abstract Geothermal energy is a renewable energy source that is coming into more widespread use. Given the recent advancements in geothermal energy, it is an energy source that should be given serious consideration as new policies and regulations are set in place to reduce greenhouse gas emissions. While there are long-standing projects around the world utilizing geothermal resources, many places are still investigating geothermal resource potential, including several states within the United States. One state that has had limited geothermal exploration in recent years is Oklahoma. This paper compounds research efforts for Oklahoma geothermal resource evaluation and potential use and additionally provides information and background for potential sedimentary reservoirs that can be further evaluated for carbon sequestration pore space use. Three regions of Oklahoma were analyzed for geothermal resource potential: the Anadarko Basin, Arkoma Basin, and Osage County. Well logs from 105 wells were identified to analyze geothermal potential and subsurface temperature variations based on bottom hole temperatures (BHT). Results indicate that the Anadarko Basin has low potential for geothermal energy production, as temperatures >100°C (212°F) are not reached until a depth of ~4,000 m (~13,000 ft). The Arkoma Basin wells reached temperatures of 100°C (212°F) at a depth of ~2,000 m (~6,500 ft), indicating potentially higher temperature resources at relatively shallower depths. The areas of higher temperatures appear to be dispersed, so more localized studies should be conducted in this region. The Osage County wells were only drilled to depths of <~1,000 m (~3,300 ft), but some had BHT of >40°C (~100°F) at these depths, indicating possible higher potential at depth. These results indicate that direct use of low-to-medium geothermal resources in Oklahoma can be exploitable further and that this preliminary investigation of geothermal resources in Oklahomashould be used as a basis for further exploration to target geothermal energy sources in the state.