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Preliminary implementation / results, Task 7A1

Andrew Frampton

Vladimir Cvetkovic

KTH, Sweden

David Holton

Serco Assurance, UK

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Task 7: Long-term pumping tests at Olkiluoto island, Finland

• Main objectiveUnderstand significance/usefulness of PFL measurements

• FeaturesExtensive site-characterisation data prior to the excavation of the ONKALO facility

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Strategy — overview

Model Construction

ConceptualFramework

Boundary Conditions

Top surface

Side boundaries

Bottom boundary

Borehole abstraction

Disturbances

‘Deterministic’ structures

Geometry

Properties

Conditioning

‘Background’ structures

Assessment of uncertainty

Calibration and results

DFN model EPM model

Questions

Tools

Forward modelling

Geostatistics (inverse)

Answers

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Model setup: Features

• Lateral boundariesTrimming (x,y) coords of domain to hydraulic conductors in contact with the Baltic Sea with head = 0

• Top boundaryApplying head = surface elevation

• Fracture zone geometryUsing smallFaces.txt files (”3Dfaces”) so in principle an exact copy of given data

• Using HZ20B_ALT and not HZ20B • Fracture zone transmissivity

Constant (geometric mean) transmissivity

• Additionally: Near-surface DFNProperties such that effective hydraulic conductivity = 1e-8 m/s Sides:

head = 0

Top:head = elevation

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Model setup: Features

• Lateral boundariesTrimming (x,y) coords of domain to hydraulic conductors in contact with the Baltic Sea with head = 0

• Top boundaryApplying head = surface elevation

• Fracture zone geometryUsing smallFaces.txt files (”3Dfaces”) so in principle an exact copy of given data

• Using HZ20B_ALT and not HZ20B • Fracture zone transmissivity

Constant (geometric mean) transmissivity

• Additionally: Near-surface DFNProperties such that effective hydraulic conductivity = 1e-8 m/s

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Model setup: Features

• Lateral boundariesTrimming (x,y) coords of domain to hydraulic conductors in contact with the Baltic Sea with head = 0

• Top boundaryApplying head = surface elevation

• Fracture zone geometryUsing smallFaces.txt files (”3Dfaces”) so in principle an exact copy of given data

• Using HZ20B_ALT and not HZ20B • Fracture zone transmissivity

Constant (geometric mean) transmissivity

• Additionally: Near-surface DFNProperties such that effective hydraulic conductivity = 1e-8 m/s

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Model setup: Features

• Lateral boundariesTrimming (x,y) coords of domain to hydraulic conductors in contact with the Baltic Sea with head = 0

• Top boundaryApplying head = surface elevation

• Fracture zone geometryUsing smallFaces.txt files (”3Dfaces”) so in principle an exact copy of given data

• Using HZ20B_ALT and not HZ20B • Fracture zone transmissivity

Constant (geometric mean) transmissivity

• Additionally: Near-surface DFNProperties such that effective hydraulic conductivity = 1e-8 m/s

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Model setup: Boreholes

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Here is KR24 !

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Model setup: Boreholes

• 1-D features• We use a well model to relate the

borehole residual pressure to the finite-element residual pressure

• depends on fracture transmissivity and on ‘skin’

Q

PP PEw

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Preliminary simulation results

• Simulation SS02a• Natural conditions (ie no pumping)• All required boreholes are included (as conductive features)

• Simulation SS04a• Pumping KR24:

Flux top part Q1 = 12 l/minFlux bottom part Q2 = 5.5 l/min

• All required boreholes are included (as conductive features)

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Heads in open BHsSS02a

0

1

2

3

4

5

6

7

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KR04 KR07 KR08 KR10 KR14 KR22 KR27 KR28

Borehole

He

ad

(m

)

Data

Sim

SS04a

0

1

2

3

4

5

6

7

8

KR04 KR07 KR08 KR10 KR14 KR22 KR27 KR28

Borehole

He

ad

(m

)

Data

Sim

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Heads in packed-off BHsSS02a

0123456789

Borehole

He

ad

(m

)

Data

Sim

SS04a

0

1

2

3

4

5

6

7

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Borehole

He

ad

(m

)

Data

Sim

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KR04: Flow magnitude along BH depth

SS02a (natural) SS04a (pumping)

Simulation:Flow up/down BH

Simulation:Flow to/from fracture

Data:Flow up/down BH (?)

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KR14: Flow magnitude along BH depth

SS02a (natural) SS04a (pumping)

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KR22: Flow magnitude along BH depth

SS02a (natural) SS04a (pumping)

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KR27: Flow magnitude along BH depth

SS02a (natural) SS04a (pumping)

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KR28: Flow magnitude along BH depth

SS02a (natural) SS04a (pumping)

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SummaryHave shown • First implementation of model• Preliminary results for SS02a

(natural flow conditions with all boreholes as conductive features)

• Preliminary results for SS04a (pumping KR24 with all boreholes as conductive features)

Improvements / todo list:• Representation of near surface and BC• Representation of zones (variability)• Background DFN to represent details of

flows• Representation of pumping test

(in particular the details of the test)• Refinement of fractures near intersections• Conditioning of fracture T’s at intersections• Transport simulations• Transient simulations

Model Construction

ConceptualFramework

Properties

Conditioning

DFN model

EPM model

Boundary Conditions

Backgroundstructures

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end