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Geochemical and thermal evidence of high temperature geothermal activity from the MH-2B slimhole, Western Snake River Plain, Idaho

snake river plain geothermal drilling
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Slim Hole Reservoir Characterization for Risk Reduction

PROCEEDINGS, 41st Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, February 22-24, 2016 SGP-TR-209 1

Presented by DOSECC President Dennis Nielson, Ph.D., PG and DOSECC Associate Sabodh K. Garg, Ph.D.


High initial capital requirements and subsurface risk are commonly cited as significant impediments to more widespread development of hydrothermal resources. However, expensive production wells are often drilled at the early stages of development when risk is high. By drilling and testing slim holes at early stages, a developer can realize a significant reduction in risk at reasonable cost. In this paper, we will review different drilling approaches, their costs and impact on risk reduction. Slim holes have been promoted for reservoir characterization because of lower cost. However, they are also conducive to enhanced data collection that is critical for establishing conceptual models. Properly conducted injection tests provide reservoir engineering information that is equivalent to data collected from large well tests. When utilized in the reservoir testing phase, slim holes can provide greater volumetric sampling of a prospect than production-size wells at an equivalent cost. Therefore, significant risk reduction can be realized before the initiation of high-cost field development. Exploration is a knowledge-based activity and data collection and application to conceptual reservoir models is a requirement. We briefly discuss the data framework of the Play Fairway approach to demonstrate risk reduction.

slim hole drilling considerations

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Geothermal Play Fairway Analysis of the Snake River Plain, Idaho

Geothermal Play Fairway Analysis


Presented by Dennis L. Nielson, DOSECC President, at the Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, January 26-28, 2015


Play Fairway Analysis is a systematic approach to exploration that integrates data at the regional or basin scale in order to define exploration targets (plays), and then interrogates these data to highlight plays that have the highest likelihood of success. Play Fairway Analysis provides greater technical rigor than traditional geothermal exploration approaches, and facilitates quantification of play risks even when data are sparse or incomplete. It is a mature practice in petroleum, but represents a new approach for geothermal that we believe will aid in the discovery of buried or blind systems. A key challenge will be adapting fairway analysis to geothermal exploration in a way that provides both meaningful results and measurable return on investment. In this project, we focus on the Snake River Plain where, during Project HOTSPOT, our team discovered a blind hydrothermal system at Mountain Home Air Force Base in Idaho. From that discovery we are able to define key parameters that characterize the elements necessary for a geothermal reservoir based on basaltic (plume-related) magmatism, fracturing that defines a reservoir volume, seals that are provided by lake beds, hyaloclastics, and highly altered clay-rich basalts, and fluid recharge that is controlled by faulting and the primary permeability of basalt flows. Project Hotspot identified three different play types in the SRP (a) high thermal gradients along the volcanic axis beneath the SRP aquifer, (b) extremely large low temperature systems, and (c) blind high-temperature systems like that discovered at Mountain Home. Phase 1 of this project will assess the distribution and viability of these plays throughout the SRP region; Phase 2 will focus on detailed analyses of specific plays as we move from a Regional/Basin focus to a Play/Prospect focus. Our approach is to analyze direct and indirect methodologies for identifying critical reservoir parameters: heat source, reservoir permeability, seal and recharge.

Read full publication here.


Best Practices in the Development of Scientific Drilling Projects, Cohen & Nielson, 2007

Nielson: scientfic drilling company best practices


Continental Scientific Drilling has an established record in advancing the earth sciences. The Continental Scientific Drilling Program was carried out in the U.S. between 1985 and 1994 and has been succeeded by the International Continental Scientific Drilling Program. Currently, projects of national and international interest are underway, and scientific drilling on continents and oceans is not as clearly separated as it once was. The process of developing a scientific drilling project, particularly one of international scope, is complex and both scientists and funding agencies need to understand the practical requirements that lead to success. In an effort to provide input to funding agencies concerning the scientist’s perspective of the proposal process and to provide a road map for scientists contemplating a scientific drilling proposal, DOSECC convened a workshop in May 2003 to address Best Practices in the Development of Scientific Drilling Projects. This report defines the stages from initial concept through the post-drilling activities, and presents recommendations that will be of interest for proponents of scientific drilling projects, particularly those that will have international participation.





Lake and Marine Drilling Planning and Operations Manual, Nielson, 2003

Offshore Geotechnical Drilling Company, Bonneville Basin Drilling Company


This manual will aid scientific investigators and operations managers in planning and budgeting off shore operations using DOSECC’s drilling systems. Each drilling project has unique scientific objectives and logistical issues, and it is difficult to consider all variables in a general presentation. However, this manual provides information that we hope will be useful in the planning and budgeting process. A successful drilling project will require close coordination between the scientific and drilling teams, and that cooperation should start during the initial planning process.

The planning process focuses on the preparation of drilling proposals. DOSECC will be responsible for preparation of the drilling budget  that includes supply purchases, mobilization of equipment, drilling operations and demobilization. The scientific team is responsible for budgeting for the science crew (salaries,  transportation and living expenses), handling the core on site (including any on-site science investigations) and shipment of the core back to laboratory or curation facilities. Due to their knowledge of the local environment and government, the Principal Investigators are generally responsible for the acquisition of all required permits and permissions.

DOSECC is committed to the protection of all personnel and the environment in which the drilling operations are taking place. DOSECC has a written Health, Safety and Environment (HSE) policy and will conduct drilling operations in accordance with its provisions. As participants in scientific drilling projects, science team members will be expected to follow the DOSECC HSE policy.