Petrography and characterization of microbial carbonates and associated facies from modern Great Salt Lake and Uinta Basin's Eocene Green River Formation in Utah, USA

2015 ◽  
Vol 418 (1) ◽  
pp. 261-286 ◽  
Author(s):  
Thomas C. Chidsey ◽  
Michael D. Vanden Berg ◽  
David E. Eby
Keyword(s):  
Salt Lake ◽  
Great Salt Lake ◽  
Green River Formation ◽  
Green River ◽  
Microbial Carbonates

Microbial Carbonate Reservoirs and Analogs from Utah

2021 ◽  
Author(s):  
Thomas C. Chidsey ◽  
David E. Eby ◽  
Michael D. Vanden Berg ◽  
Douglas A. Sprinkel
Keyword(s):  
Salt Lake ◽  
Great Salt Lake ◽  
Global Scale ◽  
Oil Field ◽  
Green River Formation ◽  
Williston Basin ◽  
Green River ◽  
Microbial Carbonate ◽  
Temperature Ranges ◽  
Bounding Surfaces

Multiple oil discoveries reveal the global scale and economic importance of a distinctive reservoir type composed of possible microbial lacustrine carbonates like the Lower Cretaceous pre-salt reservoirs in deepwater offshore Brazil and Angola. Marine microbialite reservoirs are also important in the Neoproterozoic to lowest Cambrian starta of the South Oman Salt Basin as well as large Paleozoic deposits including those in the Caspian Basin of Kazakhstan (e.g., Tengiz field), and the Cedar Creek Anticline fields and Ordovician Red River “B” horizontal play of the Williston Basin in Montana and North Dakota, respectively. Evaluation of the various microbial fabrics and facies, associated petrophysical properties, diagenesis, and bounding surfaces are critical to understanding these reservoirs. Utah contains unique analogs of microbial hydrocarbon reservoirs in the modern Great Salt Lake and the lacustrine Tertiary (Eocene) Green River Formation (cores and outcrop) within the Uinta Basin of northeastern Utah. Comparable characteristics of both lake environments include shallowwater ramp margins that are susceptible to rapid widespread shoreline changes, as well as compatible water chemistry and temperature ranges that were ideal for microbial growth and formation/deposition of associated carbonate grains. Thus, microbialites in Great Salt Lake and from the Green River Formation exhibit similarities in terms of the variety of microbial textures and fabrics. In addition, Utah has numerous examples of marine microbial carbonates and associated facies that are present in subsurface analog oil field cores.

scholarly journals Reservoir Characterization of the Lower Green River Formation, Southwest Uinta Basin, Utah

2002 ◽  
Author(s):  
Craig D. Morgan ◽  
Jr., Thomas C. Chidsey ◽  
Kevin P. McClure ◽  
S. Robert Bereskin ◽  
Milind D. Deo
Keyword(s):  
Reservoir Characterization ◽  
Green River Formation ◽  
Uinta Basin ◽  
Green River

Depositional system and lake-stage control on microbialite morphology, Green River Formation, eastern Uinta Basin, Colorado and Utah, U.S.A.

2021 ◽  
Vol 91 (6) ◽  
pp. 636-661
Author(s):  
Abdulah Eljalafi ◽  
J. Frederick Sarg
Keyword(s):  
Structural Diversity ◽  
Green River Formation ◽  
Facies Association ◽  
Uinta Basin ◽  
Green River ◽  
Microbial Carbonates ◽  
Lake Stage ◽  
Lake Margin ◽  
Structure Diversity ◽  
Δ18o And Δ13c

ABSTRACT Lake-margin lacustrine carbonates of the Green River Formation, in the eastern Uinta basin of Colorado and Utah, occur interbedded with fluvial and shoreline-parallel sandstone and shale. Microbial bindstones were deposited in a saline-alkaline lake during and after the Early Eocene Climate Optimum (EECO) (52–50 million years ago) that is characterized by global hot-house conditions, elevated atmospheric CO2, and highly fluctuating climate conditions. The stratigraphic architecture, chemostratigraphy, and morphology of the microbialites and other associated carbonate beds can be related to these climatic conditions. Three facies associations are recognized in the carbonate units across the lake margin from upper littoral to lower sublittoral environments: facies association 1, delta proximal non-microbial carbonates, characterized by quartzose bioclastic, peloidal, intraclastic packstones and grainstones–rudstones, quartose peloid wackestones and sandy oil shale; facies association 2, microbialite associated non-microbial carbonates, composed of ostracod, ooilitic, peloidal packstones–grainstones and intraclastic packstones, grainstones and rudstones; and facies association 3, microbial carbonates, consisting of diverse forms of stromatolitic and thrombolitic lithofacies. Multiple scales of carbonate cyclicity are suggested by shifts of δ18O and δ13C stable isotopes and deepening-upward microbialite facies. High-frequency cycles, on the order of 1 to 5 m thickness, are characterized by positive shifts in stable isotopes and interpreted deepening trends from littoral to lower sublittoral conditions. Large-scale trends, on the order of tens to hundreds of meters thickness record long-term lake changes, including: 1) sparse microbialite deposition during initial fresh conditions in lake stage 1, with low macro-structure diversity and light δ18O and δ13C isotope values; 2) transitional lake stage 2 corresponding to moderate macro-structural diversity, large meter-scale biostromal and biohermal buildups, and a positive shift in δ18O and δ13C isotope values that suggest increasing saline and alkaline conditions; 3) a highly fluctuating lake stage 3 that contains the highest microbialite macro-structural diversity and marks the interval of heaviest δ18O and δ13C isotope values, suggesting the greatest lake restriction, and the highest salinity and alkalinity conditions; and 4) a rising lake stage 4 that marks the lowest microbialite macro-structure diversity and a reversal in trend of δ18O and δ13C isotope values, that indicate deepening and freshening conditions.

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