The MH-2 science drill hole, on Mountain Home Air Force Base, Idaho, was drilled in 2012 to a total depth 1821 m as part of Project Hotspot. It encountered flowing artesian thermal water at 1,745 m below ground surface. This signature of a potential blind high temperature geothermal resource indicates that further analyses are needed to characterize the resource. Whole rock core was recovered to a total depth of 1821 m below ground surface and a suite of wireline logs collected. In this thesis I describe the lithologies represented in the core, correlate these lithologies to outcrop analogs, and identify and characterize petrophysical properties observable within the wireline logs, which represent fine-scale variations in stratigraphy, composition and/or alteration. The lithologies in the core are a series of basalts, brecciated and altered basalt, basaltic sands, carbonate-rich muds, and siliciclastic sediments. Basalt flows with evidence of increasing influence of an aqueous environment with time typify the lower half of core, whereas the upper half represents a period of diminished volcanism, lacustrine depositional environment, and a catastrophic water overflow event. The top of the core represents a resurgence of basaltic volcanism in the area. An overprint of brecciation at depth, fracturing, and secondary mineralization records the history of the geothermal system. All the elements of a relatively shallow and potentially energy generating geothermal resource are present at the MH-2 well location. These new data from the MH-2 borehole contributes to evaluating a parallel geothermal risk assessment of the Snake River Plain. Play fairway analysis was implemented for perhaps the first time in a geothermal regime. The Snake River Plain was divided up into three distinct play types; the area surrounding the Mountain Home Air Force Base was systematically identified as prospective. A region where sedimentary and altered rocks may create a seal, and blind faults create porosity in deep basalts.
| Identifer | oai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-5711 |
| Date | 01 May 2016 |
| Creators | Varriale, Jerome A. |
| Publisher | DigitalCommons@USU |
| Source Sets | Utah State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | All Graduate Theses and Dissertations |
| Rights | Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact Andrew Wesolek (andrew.wesolek@usu.edu). |
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