Deep-Water Clastic Sediments: A Core Workshop

This core workshop on deep-water clastic sediments was organized to provide participants with an opportunity to view cores from a variety of deep water depositional settings and to demonstrate the application of process sedimentology in the interpretation of depositional environments from the study of cores and associated subsurface data. The studies assembled for presentation in the workshop have dealt with sedimentary sequences which have been interpreted as having formed by deposition of non-calcareous, clastic sediment in relatively deep water and also have been concerned principally with coarser deep-water sediments of such stratigraphic sequences because of their potential as hydrocarbon reservoirs. The notes were organized to provide written discussions of the studies in which the cores were used. In addition it was a principal objective of the organizers that each contribution contain subsurface wireline logs and extensive photographic coverage of the whole-diameter core sequences.
Deep-Water Facies of the Spraberry Formation (Permian), Reagan County, Texas Available to Purchase
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Published:January 01, 1981
Abstract
The Spraberry Formation forms the heart of a multibillion-barrel oil field in the Midland Basin, west Texas. Production is from very fine sandstones and siltstones that form low-permeability and low-pressure reservoirs across eight counties in west Texas. The Sun Oil Co., Lottie Jalonick #1 core is continuous through the upper 222 feet (68 m) of the Spraberry Formation and is ideal for facies analysis.
Four lithofacies comprise the terrigenous clastics of the Spraberry and Dean Formations: (1) cross-laminated, massive, and parallel-laminated sandstone, (2) laminated siltstone, (3) bioturbated siltstone, and (4) black, organic-rich shale. Silty dolomite mudstone is a very minor carbonate component. Though not common in other cores, numerous fining-upward sequences of sandstone overlain by shale and laminated siltstone are common in the Jalonick core. These are interpreted to be deposits from saline density currents, generated in shelf lagoons and salt pans, as they were dispersed beyond channel mouths in the distal fringe of an upper Spraberry submarine fan. Laminated siltstones were deposited out of suspension from saline density interflows.