A Sequence-stratigraphic Study of Mudstone Heterogeneity: A Combined Petrographic/Wireline Log Investigation of Upper Jurassic Mudstones from the North Sea (U.K.)
Published:January 01, 2002
Joe H. S. Macquaker, Clive R. Jones, 2002. "A Sequence-stratigraphic Study of Mudstone Heterogeneity: A Combined Petrographic/Wireline Log Investigation of Upper Jurassic Mudstones from the North Sea (U.K.)", Geological Applications of Well Logs, Mike Lovell, Neil Parkinson
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Subtle lithofacies variations in a mudstone-dominated succession are described using combined optical, electron-optical (backscattered electron imagery), and electrofacies methods. In this study, 110 samples were collected from Upper Jurassic strata from the North Sea. Within this interval, seven lithofacies are described: clay-rich mudstones, silt-rich mudstones, sand-rich mudstones, laminated mud-stones, nannoplankton-rich mudstones, concretionary carbonate rocks, and muddy sandstones. These are composed of clay minerals, organic matter, pyrite, quartz, feldspars, and carbonate cements and have characteristic wireline-log signatures (gamma-ray, neutron-porosity, and density logs). The data demon-strate that in these relatively monotonous, mudstone-dominated successions: (1) mudstone lithofacies vary greatly, particularly with respect...
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Geological Applications of Well Logs
This book provides examples of the use of well logs across a broad range of applications. The “Technology and Techniques” section includes papers on logging in high-angle wells and on logging and imaging while drilling. The “Sedimentology and Stratigraphy” section, introduced by John Doveton (University of Kansas), includes studies from the North West Shelf of Australia, Kalimantan, and Iberia as well as from the North Sea, where important new contributions have been made on the wireline signature of mud rocks. The section on “Fractures and the Stress Field,” with a review paper by Colleen Barton (GMI), includes imaging examples from the North Sea and papers on the characterization of fractures for nuclear-waste disposal. Case histories in the volume come from a wide range of petroleum-related applications and from geotechnical and groundwater studies. Most of the papers were presented originally at the “Geological Applications of Wireline Logs” conference convened by the Geological Society (London) in 1999. The objective of the conference was cross-fertilization of approaches among a range of specialists who use well logs in their work. All users of log data should find inspiration in this volume.