Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer...
Transcript of Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer...
Motivation Geology Geophysics Geostatistics Flow Simulation
Multiple-Point Modeling of Clay Lenses & theImpact on Aquifer Vulnerability
Whitney Trainor and Jef Caers
22nd SCRF Meeting
May 1, 2009
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Goal: Develop a methodology that quantifies the Value ofInformation (VOI) of geophysical data for groundwatermanagement
• Decision-based
• Flow simulation models
• Geostatistics: methods for integrating geophysical data
• Demonstrate importance of data for groundwater modeling
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Arhus Dataset
modified from Jorgensen, et al, 2003
I Geology:Glacial Buried Valleys
I Geophysics:Time-Domain Electromagnetic(TEM)
I Flow Simulation:Aquifer Vulnerability toSurface-born Contaminants
I Decision:Move farms or restrict urbandevelopment at zones of recharge
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Glacial Erosion and Deposition
Network of Buried Valleys
(Jorgensen & Sanderson, 2006)
I “Waxing and wanning ofPleistocene ice sheets”BurVal Working Group, 2006
I Multi-generational glacialvalleys
I Cross-cut oldergenerations
I Can abruptly end
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Glacial Erosion and Deposition
Network of Buried Valleys
(Jorgensen & Sanderson, 2006)
Cross Sectional View
modified from (Thomsen, Sondergaard, & Sorensen 2004)
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Glacial Erosion and Deposition
Network of Buried Valleys
(Jorgensen & Sanderson, 2006)
Cross Sectional ViewSand: ρ > 60 ohm-mClay: ρ < 40 ohm-m
modified from (Thomsen, Sondergaard, & Sorensen 2004)
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
NC Division of Water Resources
Tx - Transmitter loop (40m×40m)
Rx - Receiver loop (10m×10m)
σ - conductivity of layered earth
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
Tx - Transmitter loop (40m×40m)
Rx - Receiver loop (10m×10m)
σ - conductivity of layered earth
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
I Constant current Iwire
produces primary magneticfield Hp
∇× Hp = Iwire
I Current turned-off; changingmagnetic field inducessecondary electric field Es inthe earth∇× Es =
−∂(µHp)∂t
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
I Constant current Iwire
produces primary magneticfield Hp
∇× Hp = Iwire
I Current turned-off; changingmagnetic field inducessecondary electric field Es inthe earth∇× Es =
−∂(µHp)∂t
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
Es produces the image current It
It = σEs
It diffuses outward and downwardover time (t). Diffusion rate:
I is proportional to 1/sqrt(t)
I depends on earthconductivity (σ)
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
Es produces the image current It
It = σEs
It diffuses outward and downwardover time (t). Diffusion rate:
I is proportional to 1/sqrt(t)
I depends on earthconductivity (σ)
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
The diffusing, time varyingcurrent It produces time varyingsecondary magnetic Hs field.
∂(∇× Hs)
∂t=∂Itdt
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
The diffusing, time varyingcurrent It produces time varyingsecondary magnetic Hs field.
∂(∇× Hs)
∂t=∂Itdt
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
The diffusing, time varyingcurrent It produces time varyingsecondary magnetic Hs field.
∂(∇× Hs)
∂t=∂Itdt
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
This decaying magnetic field Hs
produces time-varying voltage∇V in receiver coil Rx
∇V = −∫∂(µHs)
∂t· nds
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Time-Domain Electromagnetics (TEM)
TEM Inversions:
* 1D resistivity (ρ) model, unique toTx-Rx location
* Computationally demanding
* Assume homogeneous half-space
* Only partially account for changingvolume of support
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
How has TEM been used?
X-Section View
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
How has TEM been used?
X-Section View
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
How has TEM been used?
Map View
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
How has TEM been used?
Map View
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
How has TEM been used?
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
How has TEM been used?
Hydraulic Conductivity
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Geostatistical modeling with snesim
Deterministic Modeling of BuriedValleys
Buried ValleyNon-Valley
P(A|B , C )
where:A = “clay lens occurring”B = TEM models (ρ)C = geologic knowledge(training image)
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Calibration
Calibration to Driller’s Log
> 3, 000 TEM
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Calibration
Calibration to Driller’s Log
> 3, 000 TEM
⇒property of
consequence:permeability
⇒
> 700 Driller’s Logs
* subjective observations oflithology
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Calibration
Likelihood
I 7 Collocated TEM &Driller’s Logs (within 25m)
I Likelihoodp(ρ|lithology)
I Changing TEMVolume support
I Error in Driller’s LogInterpretation
Original Likelihood
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Calibration
Likelihood
I 7 Collocated TEM &Driller’s Logs (within 25m)
I Likelihoodp(ρ|lithology)
I Changing TEMVolume support
I Error in Driller’s LogInterpretation
Alternative Likelihood
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Calibration
Likelihood to Probability
I Likelihoodp(ρ|lithology)
⇓I Posterior
p(lithology |ρ)
Original Soft Probability
Alternate Soft Probability
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Calibration
Simulation of Clay Lenses with snesim
Training Images
P(A|B , C )
where:A = “clay lens occurring”B = TEM models (ρ)C = geologic knowledge(training image)
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Calibration
Simulation of Clay Lenses with snesim
Training ImagesP(A|B , C )
where:A = “clay lens occurring”B = TEM models (ρ)C = geologic knowledge(training image)
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Flow Response
Example Permeability Realization
Sand 1000mDClay 0.1 mDVertical Exaggeration x25
Simulation Time: 20 years
Grid Size: 143x91x50
Boundary Conditions:
I 61 Extraction Wells
I Rainfall
I Boundary Recharge
Tracer: Mass Conservation
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Aquifer Vulnerability
Hydraulic connections from surface to aquifer
Surface Tracer- Log Concentration
Geobody Concept
Renard & Caers, 2008
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Aquifer Vulnerability
Hydraulic connections from surface to aquifer
Surface Tracer- Log ConcentrationGeobody Concept
Renard & Caers, 2008
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Aquifer Vulnerability
Hydraulic connections from surface to aquifer
Surface Tracer- Log ConcentrationGeobody Concept
Renard & Caers, 2008
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Aquifer Vulnerability
Hydraulic connections from surface to aquifer
Surface Tracer- Log ConcentrationGeobody Concept
Renard & Caers, 2008
Vulnerability= # of concentration bodies intersecting wells
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Aquifer Vulnerability
Hydraulic connections from surface to aquifer
Surface Tracer- Log ConcentrationGeobody Concept
Renard & Caers, 2008
Vulnerability= # of concentration bodies intersecting wells
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Vulnerability- Cross Section Results
TI 1
permeability
TI 5
permeability
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Vulnerability- Cross Section Results
TI 1
permeability
TI 5
permeability
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Vulnerability- Cross Section Results
TI 1 TI 5
I Fingering vs. Uniform Front
I Tracer within top 10 grid cells (40m)
I Information on near surface more consequential
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Vulnerability vs Clay Lens Size
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Vulnerability vs Clay Lens Size
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Towards VOI
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability
Motivation Geology Geophysics Geostatistics Flow Simulation
Aquifer Vulnerability
Conclusions & Future Work
I Strong trend of clay lens size & aquifer vulnerability
I TEM possibly more informative for clay lenses <25 grid cell2
I Near-surface information: Pulled Array Continuous ElectricalSounding (PACES); top 30m
I Address the TEM support
I Streamline simulation to speed up tracer simulation
I Stochastic simulation of the buried valley locations
Whitney Trainor and Jef Caers: 22nd SCRF Meeting
Multiple-Point Modeling of Clay Lenses & the Impact on Aquifer Vulnerability