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Joseph MooreMay 7, 2019

An Historical Perspective: EGS and the Utah Frontier Observatory for Research

in Geothermal Energy (FORGE)

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Benefits of Geothermal Energy

Electric Generation

Space Heating

Spas

• Low emission• Base load power• Peaking• Renewable• Vast resource• Low costs once

established• Small geographic

footprint

Photo: B. Ayling

Photo: NREL

Photo: CYRQ Energy

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Moore and Simmons, 2013

(FORGE)

Geothermal Applications

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Productive Fracture

7 cm

Conventional Geothermal Power

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• Large in situ fluid volumes• Convective heat transfer• Extensive natural fracture systems• Production from a few high

permeability fractures • Flow rates >~ 40 L/sec; • Energy densities of 10-20 MWe/km2

• Production from a few to ~800 MWe• Microseismicity common but

generally at low levelsAverage = 6 MWe;Biggest = 50 MWeAt 200oC flow rate of 23 L/s = 1MWe750-1000 US homes

Cyr

q En

ergy

Characteristics of Conventional Systems

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Temperatures at 3 km

Temperatures at 6 km

Enhanced Geothermal

SystemsResource Base

T = 150C

T = 150C

Data from SMU

Tester and others, 2006

USGS EstimatedPotential in Western

States = 518,000 MWe

www.UtahFORGE.com Tester and others, 2006

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Compiled from Tester and others, 2006 and Breed and others, 2013

40 Years of EGS Stimulations

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4 deep wells beneath 4 km sedimentary rockProspect area 2000 km2

Temperatures >240oC Flat fractures connect wells (compressive envir.) ~1 MW produced

Seismic Cloud

The Cooper Basin Experience

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• No EGS systems greater than a few MWe developed

• Low flow rates (<40 L/s)/heat recoveries

• Single reactivated fracture zones dominate EGS reservoirs

• Fractures reactivated by hydroshearing/thermal effects

Hydroshearing

Current Status of Enhanced Geothermal System Development

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• Several projects have generated seismic events exceeding M 3 (max M 5.5)

• Continuous monitoring of seismicity• Seismic activity minimized by:

− Avoiding injection into large through going faults

− Long term, low pressure, low rate stimulation rather than short term high pressure injection

− Hydroshearing of critically stressed fractures

− Bleed off pressures− Stimulate in stages

• Net zero injection• Other stimulation techniques

(thermal stimulation)

Basel, 2009 - Meir et al., 2015

Basel, 1356 - Karl Jauslin

Induced Seismicity

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Must Understand:

• Rock Type: isotropic or anisotropic • Temperature Distributions• Structural History: distribution of existing faults• In-situ Permeability• Potential for Inducing Seismicity• Temperature Distributions• Stress Field: determines drilling direction• Infrastructure • Environmental Impacts

Lessons Learned

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• Temperature >175oC and <225oC

• Depths >1.5 km• Low permeability

crystalline rocks (granite)

• Low risk from induced seismicity

• Low environmental risks

• No connection to hydrothermal system

FORGE Criteria

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DOE Roadmap

Three critical research areas of the FORGE Roadmap with their associated core R&D actions

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FORGE will provide opportunities to develop: • High-temperature drilling tools and

zonal isolation technologies for horizontal drilling in hot crystalline rocks

• Techniques to modify/manage existing stress fields to take advantage of existing fractures

• Methods to manage and forecast induced seismicity

• Best management practices for EGS development

• Predictive numerical models• Education and research opportunities

at all levels

Worn Drill Bit

Advancing EGS Development

Damaged Packer

New Packer

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DOE EGS Supporting Activities

• EGS demonstration projects nearfield and far field: Newberry, Desert Peak, The Geysers, Desert Peak, Raft River

• EGS Collab project: small scale field site in the Sanford Underground Research Facility at the Homestake Mine, SD

• Drilling research (improved bits, directional drilling orientation sensors, downhole motors)

• Lost circulation material• Diverters• $65 M for FORGE research

activities in next 5 yearsCollab Project

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Milford Utah FORGE Site

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TPC12

9-1

52-21

82-33NM Wash

• More than 100 gradient and deep wells

• Legacy gravity, MT, thermal, groundwater, structural, seismic (monitoring since 1981), geochemical, petrologic data

• Seismic monitoring since 1981

• Water levels and pump tests conducted

Site Is Data Rich

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• 2 Geothermal fields• Windfarm• Solar field• Biogas facility

Utah Renewable Energy Corridor

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Geologic Setting

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• Completed three wells; 58-32 (7536 ft), 68-32 (1000 ft), 78-32 (3280)

• Completed extensive geological, geophysical and geochemical surveys

• Conducted stimulation tests in 58-32 and monitored seismicity

• Completed cultural and biological surveys

2014-2019 Activities

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• Establish baseline conditions for reservoir creation

• Demonstrate ability to stimulate fractures behind casing

• Perform three stimulations Stimulation 1: Open hole Stimulation 2: Cased hole

- Stimulate critically stressed fractures Stimulation 3: Cased hole

- Stimulate non-critically stressed fractures

Optimally oriented fractures

Fracture network

Proof of Concept-Testing 58-32

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• 5 seismometers• Nodal array• DAS cable • 12 level geophones string • 2 geophones in a 330 m well

Nodal Array

DAS Cable

Seismic Monitoring

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Vision for the FORGE Laboratory

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THANK YOU

Funding provided by the US Department of Energy with additional support from Utah School and Institutional Trust Lands Administration, Beaver County, the Governor’s Office of Energy

Development. Additional support provided by and Smithfield Foods and Seequent Limited.