Identification of regions enriched or depleted in radioelements through nondistributional analysis of aerial radiometric data

Throughout the aerial radiometric reconnaissance survey portion of the U.S. Department of Energy's National Uranium Resource Evaluation (NURE) program, the identification of outliers (anomalies) was an important approach to locating regions with radio-element concentrations that are either higher or lower than expected. The method introduced herein to locate such regions involves three steps: selection of a high (or low) threshold for the variate of interest; use of the sample percentile to identify all points of interest; and movement of a window over the selected data to locate significant clusters of observations. These steps, applied to aerial radiometric ²¹⁴Bi (equivalent uranium) data collected over the Copper Mountain area in Wyoming, resulted in the identification of areas enriched in that variate.     

Compaction of granular soils by uniform vibration equivalent to vibrodriving of piles

Summary A programme of laboratory tests was undertaken to identify the volume reduction of a range of granular soils in response to uniform vibration. The purpose of the tests was to quantify the potential compaction settlement of granular soils due to vibrations typical of those experienced when sheet or bearing piles are installed or extracted by vibrodriver. The vibrations in soils within 2–20 m of a vibrodriven pile are well defined as sinusoidal, at the frequency of the vibrodriver, and typically in the range of 1.0g down to 0.02g (whereg=gravitational acceleration). Thein-situ conditions were replicated in the laboratory by vibration of a Rowe cell containing a soil sample. This allowed control of stresses before and during vibration. Tests were conducted on nine granular soils, ranging from uniform Leighton Buzzard sands to a sandy fine-to-medium gravel. Soil samples were prepared at minimum relative density, generally in the saturated state, but also dry and partly saturated. Each sample was consolidated at a selected effective stress of between 10 and 100 kPa. It was then vibrated vertically at increments of controlled acceleration, under conditions of free drainage and maintained confining stress. Reduction in sample thickness was measured continuously. Results showed that even in a small, drained, sample the full volume reduction was reached only after many minutes, although the early response was more rapid. The trends of results showed that: increased surcharge pressure reduced the subsequent vibratory compaction; well-graded soils showed greater compaction than more uniform sands; compaction increased markedly when acceleration exceeded 1 g; saturated soils showed larger compaction than dry and partially saturated soils; compaction was influenced little by frequency, although rate of compaction reduced with frequency increase.     

Locating maximum variance segments in sequential data

An automated method is presented for the identification of peaks in sets of sequential data. The method is based upon the location of those segments with maximum variance and has the advantage of guarding against the masking of small-scale effects by large-scale effects. The procedure is illustrated with data taken as part of the National Uranium Resource Evaluation project.This work was performed under the auspices of the U.S. Energy Research and Development Administration, Grand Junction Office.     

Predicting oil quality from sidewall cores using PFID, TEC, and NIR analytical techniques in sandstone reservoirs, Rio Del Rey Basin, Cameroon

The expense and uncertainty of obtaining fluid samples from MDT tools provide a strong incentive for an alternative method for assessing oil character. Sidewall cores, which are inexpensive and easy to obtain, contain sufficient oil for microanalyses that can provide indications of oil quality (degree of degradation), API gravity, and numerous additional characteristics, including sulfur content, acid number, and viscosity.The present study is concerned with the application of the micro-techniques PFID (pyrolysis-flame ionization detection), TEC (thermal extraction chromatography), and NIR (near infra-red spectroscopy) for the characterization of oil from sidewall cores taken from two exploration wells in the Rio Del Rey Basin of Cameroon in 1993.