Transcript No Slide Title

IODP Expedition 301: The Hydrogeologic
Architecture of Basaltic Oceanic Crust:
Compartmentalization, Anisotropy, Microbiology,
and Crustal-scale Properties on the Eastern
Flank of Juan de Fuca Ridge
IODP Town Hall Meeting
2004 Fall AGU Meeting
San Francisco, CA
14 December 2004
A. T. Fisher1 and Tetsuro Urabe2
and the IODP Expedition 301 Scientific Party
1
University of California, Santa Cruz
2 University of Tokyo
Expedition 301 Science Party:
A. Fisher, T. Urabe, A. Klaus, A. Bartetzko, K. Becker, R.
Coggon, M. Dumont, B. Engelen, S. Goto, V. Heuer, S. Hulme, M.
Hutnak, F. Inagaki, G. Iturrino, S. Kiyokawa, M. Lever, S.
Nakagawa, M. Nielsen, T. Noguchi, W. Sager, M. Sakaguchi, B.
Steinsbu, T. Tsuji, C. G. Wheat
Additional proponents and collaborators:
J. Alt, W. Bach, J. Baross, J. Cowen, S. D’Hondt, E. E. Davis, D.
Kadko, M. McCarthy, J. S. McClain, M. J. Mottl, M. Sinha, G.
Spinelli, V. Spiess, R. Stephen, D. Teagle, H. Villinger, L.
Zühlsdorff
Fundamental questions addressed by IODP
Expedition 301 and related experiments
• What are the magnitude and nature (distribution, extent of
channeling) of permeability in crustal fluid-rock systems, variations,
scaling (temporal, spatial)?
• What are the magnitudes and directions of driving forces, fluid
fluxes, and associated solute and heat transport?
• What are the magnitude and nature of storage properties, variations
with fluid pressure, scaling (temporal, spatial)?
• What are relations between fluid flow, vertical and horizontal
compartmentalization, microbiological communities, seismic
properties, alteration, structure, and primary crustal lithology?
• How large are distinct fluid reservoirs, what are fluid residence
times and fluid velocities, and how do these respond to transient
processes (tides, seismic events)?
Permeability is at the center of
many of these questions…
Things we
measure
Permeability links
observation and process
Things we want
to understand
…and so is the subseafloor
biosphere!
• What is the diversity, distribution,
and size of ecosystems?
• What happens when we move from
oceanic sediments to basement?
• How does microbiology relate to
other aspects of water/rock?
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modified from Parkes et al. (1994), D’Hondt et al. (2003)
Why work on the eastern flank of
Juan de Fuca Ridge?
• The geology is typical in many ways.
• Young crust, thick sediments, create extreme conditions
we can measure and sample.
• Existing boreholes/CORKs help us understand the
system, save time in creating a network of observatories.
• Link with future cabled observatory system: NEPTUNE.
Eventually, we will need to test several areas,
but this is the best place to start.
Expedition 301 and follow-up expeditions will
provide many new opportunities and results…
• First controlled, cross-hole seafloor experiment;
• First multi-directional hydrogeologic experiment (both
vertical and multi-azimuth);
• First active large-scale assessment of storage properties
and effective porosity;
• First combined (simultaneous, co-located) hydrogeologic,
microbiological, tracer, seismic experiment;
• First long-term active experiment (hours to multi-year);
• First attempt to measure multiple scales (temporal,
spatial) with the same techniques, link to primary lithology,
alteration, etc.
Summary of IODP 301 Operational Plans
• Create/modify a network of boreholes (two existing, two new),
penetrating up to ~300-400 m of permeable basement;
• Conduct wireline logging, VSP, short-term packer tests;
• Install long-term observatories (CORKs) to monitor pressure,
temperature, collect fluid samples, colonize microbes; and
• Collect sediment and rock samples and evaluate lithology,
alteration, microbiology, fluid chemistry.
• Prepare for installation of additional holes to conduct crosshole hydrogeologic, microbiological, geochemical, and seismic
experiments at a range of spatial and temporal scales (meters to
kilometers, minutes to years) in the same holes.
IODP 301 site locations…
Second
Ridge area
Second Ridge (SR): Primary Sites
First Ridge (FR), Deep Ridge (DR): Secondary Sites
Planned SR operations
• Replace CORKs at 1026B (higher priority), 1027C (lower priority)
• Drill holes at Site 1301, ≤400 m into basement, core, log, BHTV, VSP, packer,
CORK multiple intervals, additional sediment coring
• Drill Hole SR-2A, ≤200 m into basement, core, sample, log, BHTV, VSP (offset),
packer, CORK multiple intervals
• Long-term testing (1-3 years) within and between holes
Simultaneous and Co-located Hydrogeologic,
Microbiological, Seismic, Tracer Experiments
(1) Hydrogeologic Experiments:
• Single-hole tests
• Use CORK’ed wells as observation points, pump
across wells
• Pump for 24 hours, let equilibrate for 6-12 months,
open valve(s) to overpressured interval(s), allow to
flow for 12-24 months = "artesian well" test
• Test multiple scales, directional properties,
differences in properties and relations
Simultaneous and Co-located Hydrogeologic,
Microbiological, Seismic, Tracer Experiments
(2) Microbiological Experiments:
• Which microbes live where, how?
• Three main stages of analysis:
(a) Sediment coring, sampling
(b) Basement coring, sampling
(c) Long-term fluid sampling, incubation
• Long-term samplers and colonization substrate
deployed within sealed boreholes
• Vent overpressured system at seafloor, time-series
sampling, additional seafloor experiments
Simultaneous and Co-located Hydrogeologic,
Microbiological, Seismic, Tracer Experiments
(3) Seismic Experiments:
• Collect wireline logs in deep basement holes
• Single-hole VSP in Holes 1301B and SR-2A
• Offset VSP, shoot from another ship to the hole
• Determine directional basement seismic properties,
relations to hydrogeologic and other properties
Simultaneous and Co-located Hydrogeologic,
Microbiological, Seismic, Tracer Experiments
(4) Tracer Experiments:
• Thermal, modeling, and geochemical studies suggest
fluid velocities on the order of kilometers per year
• Pump multiple tracers in multiple holes and depths
during hydrogeologic tests
• Monitor individual holes and depths for tracer return
patterns (single-hole tests)
• Monitor for across-hole tracer appearance, also
monitor natural discharge on Baby Bare outcrop
Expedition 301
CORK system features
• In new holes: four nested casing strings
(three to hold open hole, one for CORK)
• Multiple sealing systems: cement, packer(s),
CORK body, CORK casing (top and bottom)
• Tubing extends to depth for fluid and
microbio sampling, pressure monitoring,
several kinds of umbilicals used
• Autonomous temperature loggers,
OsmoSamplers, microbio cells within/below
CORK, hung on Spectra cable
• Pressure logger attached to CORK head by
ROV/sub after CORK deployment
• System allows monitoring of formation and
cased intervals, to evaluate CORK
performance
Expedition 301 CORKs,
casing hangers
Hoisting CORK onto rig floor
Sampling/
monitoring
bay
Top seal
Attaching CORK running tool
Raising CORK
in the rig in
preparation for
deployment
through the
moon pool
Running tubing, protective centralizers
Attaching umbilicals Hero
to pass-throughs on
main CORK seal
Hero
Hero
Hero
Autonomous
temperature
loggers,
attached to
downhole
instrumentation
and cables
Preparing OsmoSamplers and
microbiological substrate cells
Downhole microbiological instrumentation
Three bays on CORK head
for uphole instrumentation
and access to samples
Three CORKs deployed
during IODP Expedition 301
IODP 301 collected and tested many
basement and sediment samples
Extensive
microbiological
sampling and analysis
(9% of basement rock,
much of the sediment)
Summary of IODP 301 basement results
Post-IODP 301 operations
• E. Davis (PGC) and R. Dixon (US-IO) returned to
Exp. 301 CORKs on R/V Thomas G. Thompson in
September 2004
• Installed pressure loggers, closed valves
• Recovered some OsmoSamplers from CORK heads
• Inspected CORK installations
ROPOS operations: September 2004
Expedition 301
achieved critical
objectives
• Successes are
remarkable considering
limited time available to
prepare…
• Now poised to finish
drilling and related work,
conduct long-term, active
tests in the crust…
• Appropriate for the first
expedition of IODP - a
new kind of experiment