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Title: Potential Experimental Topics for EGS Collab Experiment 3

Abstract

To facilitate the success of FORGE, the DOE GTO has initiated a new research effort, the EGS Collab project, which will utilize readily accessible underground facilities that can refine our understanding of rock mass response to stimulation and provide a test bed at intermediate (~10 m) scale for the validation of thermal-hydrological-mechanical-chemical modeling approaches as well as novel monitoring tools. The first two EGS Experiments 1 and 2 are planned be performed under different stress/fracture conditions, and will evaluate different stimulation processes: Experiment 1 will focus on hydrofracturing of a competent rock mass, while Experiment 2 will concentrate on hydroshearing of a rock mass that contains natural fractures. Experiment 3 is scheduled to begin in 2019 will build off the lessons learned in Experiments 1 and 2 and will investigate alternate stimulation and operation methods to improve heat extraction in an EGS reservoir. This paper evaluates potential experiments that could potentially be conducted in Experiment 3. The two technical parameters defining energy extracted from EGS reservoirs with the highest economic uncertainty and risk are the production well flow rates and the reservoir thermal drawdown rate. A review of historical and currently on-going EGS studies has identified that over 1/2 ofmore » the projects have identified heat extraction challenges during their operation associated with these two parameters as well as some additional secondary issues. At present, no EGS reservoir has continuously produced flow rates on the order of 80 kg/s. Short circuiting (i.e. early thermal breakthrough) has been identified in numerous cases. In addition, working fluid loss (i.e. the difference between the injected fluid mass and the extracted fluid mass as compared to the injected mass) has been as high as 90%. Finally, the engineering aspects of operating a true EGS multi-fracture reservoir such as repairing/modifying fractures and controlling working fluid fluxes within multiple fractures for the effective EGS fracture management has not been sufficiently studied. To examine issues such as these, EGS Collab Experiment 3 may be conducted in the testbeds prepared for Experiments 1 and 2 by improving the previously performed stimulations, or conducted at a new site performing new stimulations with alternate method. Potential experiments may include using different stimulation and working fluids, evaluating different stimulation methods, using proppants to enhance permeability, and other high-risk high-reward methods that can be evaluated at the 10-m scale environment.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [6];  [7]
  1. National Renewable Energy Laboratory (NREL), Golden, CO (United States)
  2. Idaho National Laboratory
  3. Sandia National Laboratories
  4. Los Alamos National Laboratory
  5. Lawrence Livermore National Laboratory
  6. Lawrence Berkeley National Laboratory
  7. Colorado School of Mines
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Geothermal Technologies Office (EE-4G)
OSTI Identifier:
1431419
Report Number(s):
NREL/CP-5G00-71260
DOE Contract Number:
AC36-08GO28308
Resource Type:
Conference
Resource Relation:
Conference: Presented at the 43rd Workshop on Geothermal Reservoir Engineering, 12-14 February 2018, Stanford, California
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; EGS; Collab; FORGE; hydraulic fracturing

Citation Formats

Johnston, Henry, Mattson, Earl, Blankenship, Douglas, Frash, Luke, Morris, Joe, Kneafsey, Timothy, and Miskimins, Jennifer. Potential Experimental Topics for EGS Collab Experiment 3. United States: N. p., 2018. Web.
Johnston, Henry, Mattson, Earl, Blankenship, Douglas, Frash, Luke, Morris, Joe, Kneafsey, Timothy, & Miskimins, Jennifer. Potential Experimental Topics for EGS Collab Experiment 3. United States.
Johnston, Henry, Mattson, Earl, Blankenship, Douglas, Frash, Luke, Morris, Joe, Kneafsey, Timothy, and Miskimins, Jennifer. Wed . "Potential Experimental Topics for EGS Collab Experiment 3". United States. doi:.
@article{osti_1431419,
title = {Potential Experimental Topics for EGS Collab Experiment 3},
author = {Johnston, Henry and Mattson, Earl and Blankenship, Douglas and Frash, Luke and Morris, Joe and Kneafsey, Timothy and Miskimins, Jennifer},
abstractNote = {To facilitate the success of FORGE, the DOE GTO has initiated a new research effort, the EGS Collab project, which will utilize readily accessible underground facilities that can refine our understanding of rock mass response to stimulation and provide a test bed at intermediate (~10 m) scale for the validation of thermal-hydrological-mechanical-chemical modeling approaches as well as novel monitoring tools. The first two EGS Experiments 1 and 2 are planned be performed under different stress/fracture conditions, and will evaluate different stimulation processes: Experiment 1 will focus on hydrofracturing of a competent rock mass, while Experiment 2 will concentrate on hydroshearing of a rock mass that contains natural fractures. Experiment 3 is scheduled to begin in 2019 will build off the lessons learned in Experiments 1 and 2 and will investigate alternate stimulation and operation methods to improve heat extraction in an EGS reservoir. This paper evaluates potential experiments that could potentially be conducted in Experiment 3. The two technical parameters defining energy extracted from EGS reservoirs with the highest economic uncertainty and risk are the production well flow rates and the reservoir thermal drawdown rate. A review of historical and currently on-going EGS studies has identified that over 1/2 of the projects have identified heat extraction challenges during their operation associated with these two parameters as well as some additional secondary issues. At present, no EGS reservoir has continuously produced flow rates on the order of 80 kg/s. Short circuiting (i.e. early thermal breakthrough) has been identified in numerous cases. In addition, working fluid loss (i.e. the difference between the injected fluid mass and the extracted fluid mass as compared to the injected mass) has been as high as 90%. Finally, the engineering aspects of operating a true EGS multi-fracture reservoir such as repairing/modifying fractures and controlling working fluid fluxes within multiple fractures for the effective EGS fracture management has not been sufficiently studied. To examine issues such as these, EGS Collab Experiment 3 may be conducted in the testbeds prepared for Experiments 1 and 2 by improving the previously performed stimulations, or conducted at a new site performing new stimulations with alternate method. Potential experiments may include using different stimulation and working fluids, evaluating different stimulation methods, using proppants to enhance permeability, and other high-risk high-reward methods that can be evaluated at the 10-m scale environment.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 14 00:00:00 EST 2018},
month = {Wed Feb 14 00:00:00 EST 2018}
}

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