Hydrologic challenges to heating Cornell using Earth Source Heat (ESH) and a strategy for meeting them

Cathles, Lawrence

Hydrologic challenges to heating Cornell using Earth Source Heat (ESH) and a strategy for meeting them

Abstract

To reduce carbon emissions Cornell proposes to heat its campus by producing >60°C brine from 2 to 3 km depth. Twenty percent of its heating needs can be met by producing at 364 gpm. Demonstrating production and reinjection at this rate constitutes Cornell’s ESH pilot project. The standard hydrologic analysis reported here shows that a transmissivity of >0.26 D m is required. Only in specific locations in specific strata is the transmissibility under Cornell likely to be this high. Production and injection over 20 years will draw fluids and change pressures to distances of 4 to 33 km from the wells. This raises concerns that injected fluids might short-circuit to the production well and cool its produced fluids, and that increased fluid formation pressures could trigger earthquakes. The short-circuiting risk can be eliminated and the earthquake risk reduced by taking advantage of the stratigraphically layered nature of the Cornell subsurface and producing below while injecting above an interval of impermeable strata. A strategy of first finding the most permeable targets with 3D seismic and Fracture Seismic surveys, and then drilling to determine if these locations have sufficient permeability for production and injection to be separated stratigraphically in this fashion is suggested.

Sponsorship

N/A

Date Issued

2020-05-28

Keywords

Earth Source Heat; Hydrology; Seismic events

Types

technical report