Interpretation of geophysical well-log measurements in drill hole UE25a-1, Nevada Test Site, Radioactive Waste Program

Technical Report · Wed Dec 31 04:00:00 EST 1980

OSTI ID:59618

Hagstrum, J T; Daniels, J J; Scott, J H

An exploratory hole (UE25a-1) was drilled at Nevada Test Site (NTS) to determine the suitability of pyroclastic deposits as storage sites for radioactive waste. Studies have been conducted to investigate the stratigraphy, structure, mineralogy, petrology, and physical properties of the tuff units encountered in the drill hole. This report deals with the interpretation of physical properties for the tuff units from geophysical well-log measurements. The ash-flow and bedded tuff sequences at NTS comprise complex lithologies of variously welded tuffs with superimposed crystallization and altered zones. To characterize these units, resistivity, density, neutron, gamma-ray, induced polarization, and magnetic susceptibility geophysical well-log measurements were made. Although inherently subjective, a consistent interpretation of the well-log measurements was facilitated by a computer program designed to interpret well logs either individually or simultaneously. The broad features of the welded tuff units are readily distinguished by the geophysical well-log measurements. However, many details revealed by the logs indicate that more work is necessary to clarify the casual elements of well-log response in welded tuffs.

• Research Organization: Geological Survey, Las Vegas, NV (United States)
• DOE Contract Number: AI08-78ET44802
• OSTI ID: 59618
• Report Number(s): USGS-OFR--80-941
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
58 GEOSCIENCES
DRILL CORES
GEOPHYSICAL SURVEYS
LITHOLOGY
NEVADA TEST SITE
RADIOACTIVE WASTE STORAGE
SITE SELECTION
TUFF
WELL LOGGING
Yucca Mountain Project