Fracture tracer injection response to pressure perturbations at an injection well

Collab Team

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

The EGS Collab project constructed an approximately ten-meter scale field site where fracture stimulation and flow/transport models can be validated against controlled, in-situ experiments. The first multi-well experimental site was established at the 4850 level of the Stanford Underground Research Facility (SURF) in the Homestake Mine located in South Dakota. Hydraulic fractures were created at an injection well drilled sub-horizontal from the drift. A flow system was established in one set of fractures by injection water at approximately 400 ml/min between a set of packers 164 feet from the drift wall in the injection well through a hydraulically stimulated fracture. Injected water was recovered from five locations in 4 nearby wells. From the end of October to the middle of November of 2018, a series of fracture characterization tests were conducted using a series of 10 tracer tests (7 which used C-dot and chloride as conservative solute tracers) to assess the flow pathway in the stimulated fracture. The injected tracers were detected in three of the five water production locations where the total water recovery ranged from approximately 50 to 80% of the injected water depending on the day the test was being conducted. Analysis of a series of tracers during this two-week period suggest a large change in the flow fracture field occurred during this testing period. A comparison of the tracer breakthrough curves at the production well showed a marked decrease in the initial and peak concentration over time, whereas the OB well exhibited an increase in the initial and peak concentration arrival during this fracture characterization testing period. These changes are believed to be in response to a number of higher-pressure short-term injections at the injection well in early November (2ndto the 6th). Results of this testing suggest that the fracture flow pathways can be altered as a result of the pressure perturbations in the injection well on the integrity of adjacent monitoring wells. Results from the EGS Collab project will support the DOE Geothermal Technology Office FORGE and other EGS development efforts.

Original languageEnglish (US)
Title of host publicationGeothermal
Subtitle of host publicationGreen Energy for the Long Run - Geothermal Resources Council 2019 Annual Meeting, GRC 2019
PublisherGeothermal Resources Council
Pages371-379
Number of pages9
ISBN (Electronic)0934412243, 9781713806141
StatePublished - 2019
EventGeothermal Resources Council 2019 Annual Meeting - Geothermal: Green Energy for the Long Run, GRC 2019 - Palm Springs, United States
Duration: Sep 15 2019Sep 18 2019

Publication series

NameTransactions - Geothermal Resources Council
Volume43
ISSN (Print)0193-5933

Conference

ConferenceGeothermal Resources Council 2019 Annual Meeting - Geothermal: Green Energy for the Long Run, GRC 2019
Country/TerritoryUnited States
CityPalm Springs
Period9/15/199/18/19

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Geophysics

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