ASSESS, MONITOR, AND HANDLE THE SEISMIC RISKS IN THE BALMATT PROJECT - A Flemish case study - GEOENVI project
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ASSESS, MONITOR, AND HANDLE THE SEISMIC RISKS
IN THE BALMATT PROJECT
A Flemish case study
13/04/2021
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BALMATT GEOTHERMAL PROJECT
▪ Exploration of the deep
geothermal potential in the
Campine area
▪ Lower Carboniferous
Limestone Group
▪ Depth: > 3000 m
▪ Local source of heat and
combined heat and power
▪ Technical and economical
viability
▪ Started in 2010
13/04/2021
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STATUS BALMATT CENTRAL PLANT
▪ 3 wells completed and tested
▪ Reservoir 3200 – 3600 m
▪ Fractured limestone reservoir
▪ Production temperature: 121 – 126°C
▪ Flow rate: 70 – 150 m3/h
▪ Thermal output: 4.500 – 10.000 kW
▪ Connection with existing district heating
▪ Temperature range: 95 – 70°C
▪ Heat demand: 23.000 GWh/y
▪ Electricity production
▪ Prototype flexible ORC for integration with
district heating (AC)
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TIMING BALMATT GEOTHERMAL PLANT
▪ 14/09/2016 – 15/08/2018
▪ Drilling and testing of wells
▪ 26/11/2018 – 14/05/2019 – Test phase
▪ Testing of the installations
▪ Production and injection test
▪ 14/05/2019 – 21/06/2019
▪ Start op of production
▪ 380 h full load
▪ Production temperature: 121°C
▪ Injection temperature: 55 – 65°C
▪ Output: 4500 kW heating
▪ 23/06/2019 – now:
▪ Suspension of operations due to earthquake
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INVESTIGATION OF SOURCE MECHANISM AND POSSIBLE IMPACT
▪ Earthquake of 23 June 2019
▪ Peak ground acceleration: 0,11 m/s²
▪ Ground velocity: 1,01 mm/s op 30 m
▪ Mercalli scale: II – III
▪ Adaptations of installations
▪ To avoid abrupt shutdown
▪ To lower injection pressure
▪ To lower the flow rate
▪ Test program to evaluate the relation
between production and seismicity
▪ Extension of the seismometer network
▪ Adaptation of TLS parameters
▪ Modelling and calibration
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LEGAL BASIS
▪ Flemish decree on the deep subsurface (8 MEI 2009)
▪ Art. 2. 41° Ground movement (“bodembeweging”): any movement of the earth that can be
wholly or partially attributed to activities that are licensed under this decree, or long-term
soil movement such as subsidence or bottom rise, or short-term ground movement such as
seismicity.
▪ Art. 63/10. 2°: The holder or last holder of a license shall take all measures that can
reasonably be expected of him to prevent the activities to which the license refers cause
damage from ground movement.
▪ Art. 63/14: In the permit, the Flemish Government can impose the obligation on its holder to
carry out measurements to estimate the probability of ground movement as a result of the
licensed activities. The Flemish Government can determine further rules for the
measurements stated in the first paragraph.
▪ Art. 63/25: the holder of a license for geothermal energy is legally obliged to compensate any
damage caused by the activity to which the license relates.
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IMPLEMENTATION IN CASE OF BALMATT
▪ Special condition in the environmental permit (“omgevingsvergunning”)
▪ Insurance for possible damage due to induced earthquakes
▪ Seismic monitoring
▪ Stage 1: existing network NIRAS – ROB: detection of seismic events due to injection tests
▪ Stage 2: extended network of 7 seismometers as of November 2018
▪ Stage 3: extended network of 13 seismometers as of March 2021
▪ Continuous measurements linked to TLS
▪ Update of TLS based on evaluation event 23/06/2019
▪ Plan for test production to better characterize the seismic risk related to deep
geothermal from Lower Carboniferous Limestone Group near Mol
▪ Continuous evaluation of seismic response as a function of production parameters
▪ Periodic update of TLS
▪ Adding predictive modelling
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TRAFIC LIGHT SYSTEM
Risk level Parameter evaluation Action
▪ Aim: avoiding sensible earthquakes Magnitude Ml ≤ 1.5;
AND
Seismicity rate (for
Keep operational conditions
events Ml>1) ≤1/hr;
▪ Based on 4 parameters AND
Event locations
▪
prograding in SSE or
Magnitude NNW direction;
AND
▪ Location (epicenter) PGA ≤ 0.02m/s²
▪ Number of earthquakes per time unit Magnitude Ml>1.5;
OR
Reduce flow rate with 30%
(by decreasing frequency of
Seismicity rate (for ESP in steps of 0.1Hz/5min)
▪ Ground movement events Ml>1) >1/hr;
OR
AND
Report events to listed
▪ Velocity Event locations
prograding towards E;
authorities
AND
▪ Acceleration OR
Event locations
Perform further
seismological analysis by
prograding towards W; external company for all
▪ 3 levels OR
PGA > 0.02m/s²
events with Ml>1
▪ Green: continue operations Magnitude Ml>2.5;
OR
Shut down plant (by turning
off ESP) and shut-in
▪ Orange: adapt operations Event locations >
500m1 east of
injection well.
AND
▪ Rood: stop operations
injection zone; Report events to listed
OR authorities
Event locations > 500m AND
west of injection zone; Perform further
seismological analysis by
OR external company for all
PGA > 0.04m/s². events with Ml>1 before
any restart of operations
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©VITO – Not for distribution 9ACCESS TO DATA AND WAY FOREWARD
▪ Quasi real time reporting of seismic
activity through the project website
▪ Monitoring data is transferred
to/shared with ROB and other
parties for research
▪ Welcome the idea to establish a EU
code of best practices for seismicity
monitoring and control
▪ Welcome the idea of harmonized
guidelines of seismic monitoring
and control based on good practice
13/04/2021
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