Title: Inert and Adsorptive Tracer Tests for Field Measurement of Flow-Wetted Surface Area

Abstract

Abstract Field tests in a discrete rock fracture validated a combined inert/adsorbing tracer test method to estimate the contact area between fluids circulating through a fracture and the bulk rock matrix (i.e., flow‐wetted surface area, A). Tracer tests and heat injections occurred at a mesoscale well field in Altona, NY. A subhorizontal bedding plane fracture ∼7.6 m below ground surface connects two wells separated by 14.1 m. Recovery of the adsorbing tracer cesium was roughly 72% less than the inert tracer iodide. Using an advection‐dispersion‐reaction model in one‐dimension, the adsorbing/inert tracer method identified substantial flow channelization. These results are consistent with Ground Penetrating Radar (GPR) and thermal sensors. All characterization methods suggest circulating fluids were concentrated in a narrow, 1–2 m wide channel directly connecting the injection and production well. The inert/adsorbing tracer method identified two flow channels with areas of 28 and 80 m ² . A one‐dimensional heat transport model predicted production well temperature rises 20.5°C in 6 days, whereas measured temperature rise was 17.6°C. For comparison, two‐dimensional heat transport through a fracture of uniform aperture (i.e., homogeneous permeability) predicted roughly 670 days until production well temperature would rise 17.6°C. This suggests that the use of a fracturemore » of uniform aperture to predict heat transport may drastically overpredict the thermal performance of a geothermal system. In the context of commercial geothermal reservoirs, the results of this study suggest that combined inert/adsorbing tracer tests could predict production well thermal drawdown, leading to improved reservoir monitoring and management.« less

Authors:

Hawkins, Adam J.  ^[1];

• Search DOE PAGES for author "Hawkins, Adam J."
• Search DOE PAGES for ORCID "0000-0003-1853-0010"

Becker, Matthew W.  ^[2];

• Search DOE PAGES for author "Becker, Matthew W."
• Search DOE PAGES for ORCID "0000-0001-8242-0591"

Tester, Jefferson W. ^[3]

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+ Show Author Affiliations

1. Stanford Univ., CA (United States)
2. California State Univ., Long Beach, CA (United States)
3. Cornell Univ., Ithaca, NY (United States)

Publication Date:

Wed May 09 00:00:00 EDT 2018

Research Org.:

California State Univ. (CalState), Long Beach, CA (United States); Cornell Univ., Ithaca, NY (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:

1539737

Alternate Identifier(s):

OSTI ID: 1464869

Grant/Contract Number:  

EE0006763; EE0006764; DE EE0006764; DE EE0006763

Resource Type:

Accepted Manuscript

Journal Name:

Water Resources Research

Additional Journal Information:

Journal Volume: 54; Journal Issue: 8; Journal ID: ISSN 0043-1397

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources