Log Acquisition Research Articles

OPLC and HPTLC methods in physicochemical studies of a new group of antimycotic compounds.

In this study two high-performance methods [overpressured layer chromatography (OPLC) and high-performance thin-layer chromatograpy (HPTLC) under reversed-phase conditions] are used to evaluate the hydrophobicity properties of newly synthesized bioactive compounds. The retention behavior of 24 2-(2,4-dihydroxyphenyl)benzothiazoles are examined for acquisition of log k data. With water-methanol mixtures as the mobile phases, the concentration range in which the correlation between log k and methanol content is linear is established for both methods and used to determine the hydrophobicity parameters of log kw by linear extrapolation. The effect of substituents on retention constants is quantitated by using the group contribution parameters (tauw). The results suggest the use of OPLC methods for quick analysis of physicochemical properties of a large number of organic compounds.

Subsurface Geology of a Prograding Carbonate Platform Margin, Great Bahama Bank: Results of the Bahamas Drilling Project

SEPM Special Publication Series No. 70, Robert N. Ginsburg (Editor), 2001, SEPM (Society for Sedimentary Geology), Tulsa, OK, 271 p. ($65 non-members, $40 members) ISBN: 1-56576-077-8. The present volume summarizes the scientific results of the Bahamas Drilling Project, the fruit of an idea born in Robert Ginsburg's Comparative Sedimentology Laboratory at the University of Miami. Two continuous core holes named Unda and Clino were drilled on the western margin of the famous Bahamas carbonate platform to depths of 454 m and 677 m, respectively, and subsequently analyzed by a large team of geoscientists from different institutions that were brought together to participate in an exemplary project in carbonate geology. The volume contains a preface by the editor and 12 papers grouped into five categories: (1) background, (2) lithostratigraphy and chronostratigraphy, (3) diagenesis and geochemistry, (4) petrophysics, and (5) sequence stratigraphy. The volume includes a total of 163 figures, 35 tables, and a 1.2 m2 fold-out in a pocket in the back cover of the book. The comprehensive index lists 235 topics. Robert Ginsburg provides an introductory overview of the scientific background of the Bahamas Drilling Project, and describes log acquisition and project operations in the first main division of the volume. Fundamental questions of carbonate platform progradation are listed along with previous research in the Bahamas as background to the listed objectives of the project. These objectives include: (1) testing the earlier interpretation of some 30 km of platform progradation based on seismic interpretation (Eberli and Ginsburg, 1987, 1989); (2) evaluating the influence of sea level change on platform facies and architecture; (3) seeking lithologic reasons for seismic sequence boundaries; and (4) characterizing depositional facies, diagenesis, and timing. The drilling was accomplished between April and June 1990, and operations are described briefly and illustrated by photos. Following the …

THE 3-C ACOUSTIC PROCESS—A NEW APPROACH TO PREDICTING ACOUSTIC WAVE PERFORMANCE IN SEDIMENTS

Acoustic wave performance modelling is of considerable interest to seismic interpreters. Conventional interpretative models employ continuous density log data to compute theoretical acoustic data. Their dependence on high quality density log data limits the application of these techniques to areas where good logs have been acquired. Such techniques are therefore commonly used in field studies, but are generally not used in exploration.This paper details a newly developed method of predicting acoustic compression wave performance, based on sequence compaction theory, elastic wave theory and established petrophysical relationships. This allows extension of the existing density log based p-wave velocity prediction methods into areas where log data are minimal and log quality is marginal.Applications of the technique include:improvements to the quality of acquired sonic data;improved velocity control, resulting in better quality synthetic seismograms and more precise control of time-depth conversion; andimproved seismic attribute mapping, offering possibilities of better drilling target selection.With application of the technique, many wells can now be used in which poor log data quality or absence of key logs previously prevented their use as well-to-seismic control points in basin modelling. The technique can be allied to MWD resistivity logging technology to allow continuous computation of acoustic properties and realtime correlation of drilling data to seismic. This results in better location of casing and logging points, and the design of more efficient logging programs, with benefits to both drilling safety and economics.The technique allows improvement in the quality of acquired data and acquisition economics, better utilisation of old data, and better engineering and geologic management practices in current exploration drilling. It has considerable potential for overcoming sonic log acquisition problems associated with poorly compacted rocks, and has application in many areas of sequence and basin studies.

Reversed-Phase Thin-Layer Chromatography with Different Stationary Phases in Studies of Quantitative Structure–Biological Activity Relationship of New Antimycotic Compounds

Reversed-phase thin-layer chromatography with RP-8, RP-18, and RP-18W stationary phases was used in quantitative structure-activity relationship (QSAR) studies of new antimycotic compounds. The retention behavior of 10 dihydroxythiobenzanilides was examined for acquisition of log k' data. With water-acetone mixtures as the mobile phases, the concentration range for which the correlation between log k' and acetone concentration is linear was established for each stationary phase and used to determine hydrophobicity parameters log k'w by linear extrapolation. The effect of substituents on retention constants was quantitated by using the group contribution parameters tau W. On the basis of QSAR equations obtained from these studies, log k'w data can be used to predict antifungal activities of dihydroxythiobenzanilides with satisfactory accuracy.

News Western and Geco-Prakla vie for 4C glory Western Geophysical founder dies Rex Golson Software updated Future mapped for log analysis program Borehole logging acquisition People in the News Document management in Abu Dhabi Reseller for software Uncertainty clouds UK's five year exploration plan Mapping software help for mineral development in Africa Well log database project in Qatar Large 3D

news Western and Geco-Prakla vie for 4C glory Western Geophysical founder dies Rex Golson Software updated Future mapped for log analysis program Borehole logging acquisition People in the News Document management in Abu Dhabi Reseller for software Uncertainty clouds UK's five year exploration plan Mapping software help for mineral development in Africa Well log database project in Qatar Large 3D

Application of inverse filtering to gamma‐ray logs: A case study

The application of digital inverse filter deconvolution techniques to seismic data has been routine for many years. More recently these techniques have been extended to natural gamma‐ray logging in order to improve the spatial resolution of the recorded logs (Czubek, 1971; Conaway and Killeen, 1978a,b). Early work in this field (Scott, 1963) involved an iterative procedure which required repeated processing of an entire log data set. Such a technique does not lend itself to continuous on‐line deconvolution of a log while the logging operation is in progress. The inverse digital filter approach, by contrast, is particularly well suited for implementation in a computer‐based borehole logging data acquisition system. Such a system had been developed at the Geological Survey of Canada (G.S.C.) by 1978 and was described by Bristow and Killeen (1978) and Bristow (1977, 1979).