ICDP Proposal Abstract
© ICDP, the International Continental Scientific Drilling Program, 1996-2023 - www.icdp-online.org
Cornell University Deep Geothermal Test Borehole: Scientific Workshop Proposal
North America, U.S.A., New York, Ithaca, Grenville
New
Workshop-proposal: ICDP-2019/11
For the funding-period starting 2019-01-15
For the funding-period starting 2019-01-15
by
Hiroshi
Asanuma,
David F.
Bruhn,
David F.
Bruhn,
Ernst
Huenges,
Teresa Eileen
Jordan,
Jefferson William
Tester
Abstract
We propose a workshop to outline a science plan for a “hole of opportunity.” Cornell University proposes to drill an exploratory
geothermal energy borehole to a depth in the range of 4 - 5 km, which will penetrate nearly 3 km of Paleozoic sedimentary rocks and
= 1 km of amphibolite-grade Grenville metamorphic rocks, in central New York state, United States. The proponents of this ICDP
workshop proposal envision that this borehole should be a scientific opportunity to gain understanding of how heterogeneous mid- to
high-grade metamorphic rocks and low porosity sedimentary rocks respond to pore pressure manipulation. An ICDP Workshop will
expand the expertise available to identify the best strategy for obtaining from the borehole the vital samples and measurements
required to advance understanding of the mechanical response of heterogeneous, low porosity rocks to stress perturbations.
The proposed project has a direct societal value, through the potential to advance use of geothermal energy in broad continental
regions, as well as its direct scientific value. The production of small magnitude strain in rock through fluid injection is a practical
means for interconnecting porosity to improve fluid flow. However, much attention is currently focused on the growing recognition
that fluid injection as part of several types of energy subsurface activity can sometimes trigger earthquakes of sufficient strength to
cause damage and public concern. Examples are well known for alternative energy (geothermal), fossil fuel (hydraulic fracturing and
wastewater injection), and mitigation technologies (carbon sequestration), yet similar operations operating in many locations have
caused no similarly large earthquakes. The conundrum is to predict which intervals of rocks, in which areas, can be stimulated a)
successfully, and b) safely. Setting aside energy technologies, the scientific need for improved understanding of mechanical
response to pressure perturbations is broader, inclusive of stress perturbations with natural causes. We feel that a Workshop that
focuses on designing borehole experiments is essential to provide the basis for improving and validating general models.
The proposed Workshop will be convened at Cornell University, preferably in the last quarter of 2019. We will invite an international
group of borehole specialists, seismologists, rock mechanics theoreticians and experimentalists, regional geology specialists, and
representatives from the drilling industry and geothermal energy industry. The workshop will focus on design of an integrated set of
experiments for two days, followed on a third day by preparation of a report, and possibly a proposal, by a sub-group.
Scientific Objectives
- 1).
- To improve understanding of fracture-dominated fluid flow and the thermo-poroelastic response within rocks at 2.5-4.5 km depth of varying bulk properties (variations defined by petrology, layering, metamorphic fabric, and cohesive strength) and varying categories of fractures (variations defined by parameters such as fracture spacing, mineral fills, orientations).
- 2).
- To document the mechanical state and poroelastic properties of variable lithologic categories of mid- to high-grade metamorphic rock and low porosity sedimentary rock under the conditions of pressure manipulation needed to produce geothermal heat 3).
- To better understand the properties and conditions that influence technical uncertainties associated with intentionally circulating fluids through fractured basement rocks
Keywords
Cornell,
Geothermal Anomaly,
Grenville,
New York,
North America,
U.s.a.
Location
Latitude:
42.44722
,
Longitude:
-76.48306
© ICDP, the International Continental Scientific Drilling Program, 1996-2023