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Sedimentology, petrology and x-ray mineralogy of Coniacian-Santonian Niobrara shale, northeastern San Juan basin, New Mexico

Conference · · AAPG Bulletin (American Association of Petroleum Geologists); (USA)
OSTI ID:5699481

This study involves 12 Niobrara cores taken from two wells in Rio Arriba County, New Mexico. Analytical techniques included core logging (312 ft; 95 m) x-ray diffraction (199 analyses), petrography (124 analyses), and electron microprobe (six analyses). Cores are dominated by calcareous silty claystone with subordinant amounts of very fine-grained calcareous sandstone, bentonite, wackestone, and sparite. Sedimentary structures include horizontal lamination and lenticular, wavy, and ripple lamination in sandy core intervals. Burrowing is rare. Framework grains (0-45%) range in size from 40 to 100 {mu} and are composed of quartz, feldspar, chert, and allochemical grains with traces of muscovite, heavy minerals, phosphate, and glauconite. Cement components (2-91%) include calcite, ferroan calcite, dolomite, ferroan dolomite/ankerite, and rare quartz, kaolinite, and pyrite. Matrix components (7-98%) include siliciclastic clay, micrite, and diffuse mixtures of mud and organic matter. Clay minerals include illite-smectite and illite, with subordinant amounts of chlorite and kaolinite. Porosity (plug analyses) rarely exceeds 1%, and permeability averages less than 0.01 md. Fractures in core range in width from 0.1 to 1.5 mm and are cemented by ferroan calcite.

OSTI ID:
5699481
Report Number(s):
CONF-8910195--
Journal Information:
AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 73:9; ISSN AABUD; ISSN 0149-1423
Country of Publication:
United States
Language:
English