Extension of in-situ stress test analysis to rapid hole evacuation at Yucca Mountain due to a network of open conduits
Yucca Mountain is underlain by tuffaceous rocks that are highly fractured and jointed. During drilling of bore-holes at Yucca Mountain there were numerous occurrences of lost circulation when whole mud was taken by the formation. This evidence suggests that parts of Yucca Mountain are controlled hydrologicaly by a network of open conduits along the existing joints and fractures. Also at Yucca Mountain, stress tests have been performed in-situ by charging a small section along the boreholes with an excess pressure head of water. For many of these tests, the initial drop in water head was so rapid that within seconds up to hundreds of meters of fall had occurred. The opening of fractures as the excess head increases has previously been proposed as an important factor in explaining the shape of the stress test curves at lower pressures. We propose that such induced hydraulic fractures, under increasing water heads, can grow to a length sufficient to intersect the existing network of open joints and fractures. We extend our previous model to incorporate flow out along these open conduits and examine the initial rapid drop in terms of these extended models. We show that this rapid evacuation model fits the observed data from many slug tests in wells in the vicinity of Yucca Mountain. This result is confirmation of the drilling evidence that a network of open conduits exists at various depths below the water table and over a large geographic region around Yucca Mountain.
- Research Organization:
- Technology and Resource Assessment Corp., Boulder, CO (United States)
- OSTI ID:
- 227035
- Report Number(s):
- DOE/NV/10461-T44; ON: DE96007228; TRN: 96:001836-0003
- Resource Relation:
- Other Information: PBD: Jan 1994; Related Information: Is Part Of Investigations of hydro-tectonic hazards at the proposed Yucca Mountain high-level nuclear waste repository. Annual report - Nevada; Livingston, D.E. [ed.]; PB: 300 p.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
99 MATHEMATICS
COMPUTERS
INFORMATION SCIENCE
MANAGEMENT
LAW
MISCELLANEOUS
YUCCA MOUNTAIN
STRATIGRAPHY
WATER TABLES
HIGH-LEVEL RADIOACTIVE WASTES
UNDERGROUND DISPOSAL
RADIOACTIVE WASTE FACILITIES
SITE CHARACTERIZATION
GEOLOGIC FRACTURES
FLUID FLOW
ZEOLITES
TUFF
HYDROLOGY
STRESSES
BOREHOLES
LOST CIRCULATION
MATHEMATICAL MODELS