métodos de caracterización de sitios

1. High Resolution Head Profiles for
Flow System Characterization in
Fractured Sedimentary Rocks
Jessica Meyer, Beth Parker, and John Cherry
Centre for Applied Groundwater Research
University of Guelph
MGWA Spring 2012 Conference
Conduits, Karst, and Contamination
Address Groundwater Challenges
April 19, 2012

2. Contact Information
Jessica Meyer
Email: meyerj@uoguelph.ca
Phone: 519-824-4120 x56142
Beth Parker
Email: bparker@uoguelph.ca
Phone: 519-824-4120 x53642

3. References
Black, W.H., H.R. Smith, and F.D. Patton. 1986. Multiple-level ground water monitoring with the MP system. In Proceedings of the
Surface and Borehole Geophysical Methods and Ground Water Instrumentation Conference and Exposition, October 15-17,
1986, Denver, Colorado, 41-61, Dublin, Ohio: NWWA.
Cherry, J.A. and P.E. Johnson. 1982. A multilevel device for monitoring in fractured rock. Ground Water Monitoring Review 2, no.3:
41-44.
Cherry, J.A., B.L. Parker, and C. Keller. 2007. A new depth-discrete multilevel monitoring approach for fractured rock. Ground
Water Monitoring & Remediation 27, no.2: 57-70.
Einarson, M.D. 2006. Multilevel ground-water monitoring. 11 In Practical Handbook of Environmental Site Characterization and
Ground-Water Monitoring, ed. D.M. Nielsen, 808-845. Boca Raton, Florida: CRC Press.
Einarson, M.D. and J.A. Cherry. 2002. A new multilevel ground water monitoring system using multichannel tubing. Ground Water
Monitoring and Remediation 22, no.4: 52-65.
Freeze, R.A. and P.A. Witherspoon. 1967. Theoretical analysis of regional groundwater flow: 2. Effect of water-table configuration
and subsurface permeability variation. Water Resources Research 3, no.2: 623-634.
Gross, M.R. 1993. The origin and spacing of cross joints: examples from the Monterey Formation, Santa Barbara coastline,
California. Journal of Structural Geology 15, no.6: 737-751.

4. References (cont.)
Meyer, J.R., B.L. Parker, and J.A. Cherry. 2008. Detailed hydraulic head profiles as essential data for defining hydrogeologic units in
layered fractured sedimentary rock. Environmental Geology 56, no.1: 27-44.
Ostrom, M.E. 1978. Lithostratigraphy, petrology, and sedimentology of late Cambrian-early Ordovician rocks near Madison,
Wisconsin. In Lithostratigraphy, Petrology, and Sedimentology of Late Cambrian - Early Ordovican Rocks Near Madison,
Wisconsin: Prepared for the Eighth Annual Meeting Great Lakes Section Society of Economic Paleontologists and Mineralogists,
September 30-October 1, 1978, Madison, Wisconsin, ed. M.E. Ostrom, Madison, Wisconsin: University of Wisconsin - Extension
Geological and Natural History Survey.
Parker, B.L., J.A. Cherry, and B.J. Swanson. 2006. A multilevel system for high-resolution monitoring in rotasonic boreholes. Ground
Water Monitoring and Remediation 26, no.4: 57-73.
Sudicky, E.A. and R.G. McLaren. 1992. The Laplace transform Galerkin technique for large-scale simulation of mass transport in
discretely fractured porous formations. Water Resources Research 28, no.2: 499-514.
Toth, J.A. 1995. Hydraulic continuity in large sedimentary basin. Hydrogeology Journal 3, no.4: 4-16.
Underwood, C.A., M.L. Cooke, J.A. Simo, and M.A. Muldoon. 2003. Stratigraphic controls on vertical fracture patterns in Silurian
dolomite, northeastern Wisconsin. AAPG Bulletin 87, no.1: 121-142.
Young, H.L. 1992. Summary of ground-water hydrology of the cambrian-ordovician aquifer system in the northern midwest,
United States, USGS Professional Paper 1405-A. United States Government Printing Office: Washington D.C.
Young, H.L. and D.I. Siegel. 1992. Hydrogeology of the Cambrian-Ordovician aquifer system in the northern midwest, United
States, USGS Professional Paper 1405-B. United States Government Printing Office: Washington, D.C.

5. Wisconsin Fractured
Rock Research Site
• Dense Non Aqueous
Phase Liquid (DNAPL)
source zone
• Dissolved phase plume
impacted a 4.2 km2 area
Flow model domain
DNAPL source zone
Max extent dissolved phase plume
8 km
N

6. Regional Scale
Hydrogeology
Modified from Figure 1
Young, 1992, USGS Professional Paper 1405-A
Approximate Extent of
Cambrian/Ordovician
Aquifer System

7. Site Stratigraphy
Stratigraphy after Ostrom 1978

8. Well Monitored Plume
• ~154 monitoring
locations
• Flow generally
toward east to
southeast
• Maximum plume
length in 2003
~ 2.8 km

9. Plume Overlies
Regional Aquifer
Most Laterally Extensive Plume
DNAPL
Source
Regional Aquifer
Regional Aquitard
Stratigraphy after Ostrom 1978

10. Wisconsin Fractured
Rock Research Site
• Dense Non Aqueous
Phase Liquid (DNAPL)
source zone
• Dissolved phase plume
impacted a 4.2 km2 area
Flow model domain
DNAPL source zone
Max extent dissolved phase plume
8 km
N

11. Step One:
Defining Hydrogeologic Units
• In groundwater flow models all parts of the
system are assigned to a hydrogeologic unit
• Therefore, this assignment is a critical task

12. Hydrogeologic Units
(HGUs)
• Represent partitions of the groundwater flow
domain that are hydraulically consistent at a
specified scale
• Used as a framework for conceptual and
numerical models of groundwater flow and
contaminant transport

13. Aquifer and Aquitard HGUs
Adapted from Tóth, 1995, Hydrogeology Journal, v.3, no.4
Aquifer
Aquifer
Aquifer
Aquitard
Aquitard

14. How Many HGUs???
HGU1?
HGU2?
HGU3?
Stratigraphy after Ostrom 1978

15. Data Sets Commonly Used
to Delineate HGUs

16. HGU Delineation
Not Clear from K Data

17. Head Profiles and HGUs
“ . . . It is the permeability ratio that
controls the nature of the potential
field.”
Freeze and Witherspoon, 1967, WRR, v.3, no. 2
Head
Depth
Figure 3B (Freeze and Witherspoon, 1967)

18. Hypothesis
High resolution hydraulic head
profiles are essential evidence for
defining hydrogeologic units in
fractured sedimentary rock

19. High Resolution
1. Depth discrete
AND
2. Detailed

20. Multilevel System (MLS)
Generic Multilevel System
Definition:
A single device assembled
on surface and then
installed in a borehole or
a multi-screened casing
to divide the hole into
many separated intervals
for data acquisition from
many depth-discrete
segments of the hole
Monitoring
Interval
Sealed
Interval

21. Three Companies Produce
Four Different MLSs
CMT
Waterloo
Water FLUTe
Westbay
Cherry and Johnson 1982
Cherry et al. 2007
Black et al. 1986
Parker et al. 2006
Einarson 2006
Einarson and Cherry 2002

22. Maximum Number of Ports:
FLUTe, Waterloo, CMT Systems
Number of tubes that will fit
in the borehole diameter
FLUTe
Solinst Waterloo
Number of tubes that will fit
in the 2 inch casing
Solinst CMT
Maximum of 7
ports

23. Westbay System Components
Packer
• independent hydraulic
inflation
Pumping Port
• hydraulic conductivity
testing and purging
Casing
• variable lengths
Measurement Port
• in-situ measurement, low-K
testing, and fluid sampling
Courtesy of Schlumberger Water Services, Westbay Inc.

24. Westbay Systems Use
Valved Ports and Wireline Tools
Pressure Profiling
Figure courtesy of
Schlumberger Canada Ltd.
Valve
Sample
bottle

25. Why the Westbay System?
• Provides the maximum number of monitoring
zones
• QA/QC procedures provide confidence in
packer/casing seals
• Uncertainty in calculated heads between
closely spaced monitoring zones is ~ ± 1 cm
High resolution head profiles

26. Approach
• Detailed geologic logs
– Lithology and fractures
• Geophysical logs
– Standard suite, ATV, etc.
• Hydrophysical/hydraulic logs
– Active line source temperature
– High resolution packer testing
– FLUTe K profiling
• Design and install a high resolution MLS

27. MLS Design Goals
• Avoid cross-connecting (blending) HGUs
– Short monitoring zones
– Seal un-monitored sections of the borehole
• Maximize the number of monitoring zones
– High resolution profiles of hydraulic head and
groundwater chemistry

28. DFN
Data Set

29. Key Point
• Geologic and geophysical data are crucial in
the design process
However
• Geologic and geophysical data alone cannot
locate hydraulic interfaces/changes

30. 9 High Resolution
Westbay MLSs
MP-6
MP-16
MP-17
MP-18
MP-19S/D
MP-21S/D
MP-15

31. High Resolution Design
Packer
Monitoring Interval
Multilevel System
monitors 129.5 m of
bedrock
46 monitoring zones
1.8 zones per 10 m
83% of monitoring
zones are < 2.5 m long

32. Schematic Head Profile

33. Inflections:
Sharp Changes in Head

34. Vertical Component
of Hydraulic Gradient
h1
h2
L
h1 - h2
L
Maximum Vertical
Gradient
=

35. Schematic Vertical
Gradient Profile
Upward
Gradient
Downward
Gradient

36. 9 High Resolution
Westbay MLSs
MP-6
MP-16
MP-17
MP-18
MP-19S/D
MP-21S/D
MP-15

37. Head Profiles
are Geometric
• Thick sections of no
measurable vertical gradient
– Horizontal flow
– Interconnected fracture
network
• Thin sections of large vertical
gradient (inflections)
– Resistance to vertical flow
Dh=3.45 m
-1.2
Meyer et al 2008

38. Stratigraphy Does
Not Predict Inflections
The inflections do not always
correlate with lithostratigraphic
units or contacts
Dh=3.45 m
Meyer et al 2008

39. Head Profiles
are Repeatable
December 2003
August 2011
Meyer et al 2008

40. Key Points
Head profiles are geometric
Stratigraphy does not predict position of
inflections
Head profiles are repeatable
Thin sections of large (some >1 ) vertical
gradients

41. What Do the
Inflections Represent?
Resistance to vertical flow occurring across:
1. Low bulk vertical K unit/bed (aquitard)
2. Contact/Interface that restricts vertical
flow

42. Eau Claire Aquitard
Modified from Figure 11
Young, 1992, USGS Professional Paper 1405-A

43. Eau Claire Formation
Southern Wisconsin
• Is commonly thought of as a shale
• Has a distinctive gamma signature often used
as an indication of the aquitard unit
• Eau Claire Formation and aquitard unit known
to be discontinuous

44. 9 High Resolution
Westbay MLSs
MP-6
MP-16
MP-17
MP-18
MP-19S/D
MP-21S/D
MP-15

45. Eau Claire Formation
Gamma Signature
Eau Claire Formation
~8m

46. Vertical Gradients
In the Eau Claire Formation
MP-17 Vertical gradent in the Eau Claire Formation = -1.55
Aquitard is much thinner than stratigraphic unit

47. What Do the
Inflections Represent?
Resistance to vertical flow occurring across:
1. Low bulk vertical K unit/bed (aquitard)
2. Contact/Interface that restricts vertical
flow

48. No Clay/Shale Bed
at Inflection
Meyer et al 2008

49. Cause for the Resistance
to Vertical Flow?
Hypothesis:
Some inflections represent a
discontinuity between
fracture networks of
adjacent units
Meyer et al 2008

50. Influence of Fracture Networks
Mechanical Layer
unit of rock that behaves
homogeneously in response to
stress
Mechanical Interface
the contact between two
mechanical layers
Vertical Fractures do not
extend across mechanical
interfaces
(Gross 1993)

51. Discontinuity Restricts
Vertical Flow
Figure from Underwood et al. 2003

52. Discrete Fracture
Network Model
Stylistic modeling of groundwater flow using the
discrete fracture network code FRACTRAN
Sudicky and McLaren, 1992, WRR, 28, no.2

53. FRACTRAN Simulations
Matrix for each unit has the
same properties
• Km = 10-6 cm/s
• n = 15%
Parameters consistent with field
measurements
• Average horizontal gradient ~ 0.01
• Average vertical gradient ~ 0.03
• Bulk Kh ~ 3.0 x 10-3 cm/s
• Bulk Kv ~ 2.1 x 10-5
Mechanical
Layer
Mechanical
Interface
Meyer et al 2008

54. FRACTRAN Simulations
Head Profiles
0
5
10
15
20
25
30
35
40
45
7.0 7.5 8.0 8.5 9.0 9.5 10.0
Hydraulic Head (m)
Z(m)
X=50m
X=100m
X=150m
Unit 1
Unit 2
Unit 3
Unit 4
Meyer et al 2008

55. Key Point
Inflections may occur due to discontinuities
between fracture networks of adjacent units

56. Interpreting
HGUs
Inflections interpreted as
occurring across the:
1. Contact between
HGUs
2. Low bulk vertical K
HGUs (aquitards)
Meyer et al 2008

57. MP-6 HGUs
11 HGUs defined
for MP-6
Meyer et al 2008

58. Moderate to high
horizontal K
throughout the
profile
System of stacked
aquifer units
10-310-5
cm/s
10-4
Meyer et al 2008

59. Vertical Gradients
Correlate Across the Site
MP-6
MP-16
MP-17
MP-18
MP-19S/D
MP-21S/D
MP-15
A A’

60. Thirteen Potential HGUs

61. Schematic Flow System

62. Summary of Key Points
Difficult to predict position of inflections
based on geologic/geophysical data alone
Inflections may occur due to discontinuities
between fracture networks of adjacent units
High resolution head profiles are valuable data
for delineating HGUs in layered sedimentary
rock systems