Seismic constraints on fault angles in Railroad Valley, NV

Conference · Thu Apr 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5021109

Grow, J A; Potter, C J; Miller, J J ^[1]

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1. Geological Survey, Denver, CO (United States)

The USGS has obtained 7 seismic reflection lines in eastern Railroad Valley to delineate fault geometries near the Grant Canyon (GC), Kate Springs (KS), and Eagle Springs (ES) oil fields. A NW-trending 120-channel profile over KS reveals a 2-km-wide bench of Paleozoic carbonates (PzC) at about 1.4 sec depth ([approximately]1.4 km of Miocene valley fill) offset by a large, NW-dipping, high-angle normal fault (> 40[degree]) on the east and by two smaller, high-angle normal faults on the west. This profile is consistent with previously published profiles over ES (2 km N of KS), which have been interpreted as indicating a large high-angle fault E of ES. Interpretations of this eastern high-angle fault are based on shallow reflections and diffractions ([approximately]0.1--0.2 sec) and the absence of fault-plane reflections (too steep for reflection returns). An alternative interpretation attributes the shallow reflections to highly cemented conglomerates or megabreccias in the valley fill rather than the top of a Paleozoic block. Recently proposed exploration holes E of KS and ES may resolve this ambiguity. Two NW-trending 120-channel profiles 2--4 km N of GC (11 km S of KS) reveal a quasiplanar reflecting at surface between 1 and 2 sec (1--2 km) depth dipping [approximately]20[degree]NW. The surface is also seen dipping [approximately]10[degree]N on N-trending lines (with minor undulations of [approximately]0.1 sec). A WNW-trending 1,024-channel seismic profile directly over the GC field delineates this low-angle surface E of the field and shows that the PzC reservoirs at GC are 0.2 sec above the westward projection of the reflecting surface. The authors interpret the low-angle surface to be a normal fault that partially decapitates the pluton and underlies the GC field, as proposed by Karen Lund and others.

• OSTI ID: 5021109
• Report Number(s): CONF-9305259--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:5
• Country of Publication: United States
• Language: English

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02 PETROLEUM
020200 -- Petroleum-- Reserves
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58 GEOSCIENCES
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DEVELOPED COUNTRIES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
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GEOPHYSICAL SURVEYS
MATHEMATICS
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NORTH AMERICA
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PETROLEUM DEPOSITS
RESERVOIR ROCK
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SEISMIC SURVEYS
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USA