Michael D. Vanden Berg

Sediment mineralogy based on visible and near-infrared reflectance spectroscopy

Abstract Visible and near-infrared spectroscopy (VNIS) can be used to measure reflectance spectra (wavelength 350–2500 nm) for sediment cores and samples. A local ground-truth calibration of spectral features to mineral percentages is calculated by measuring reflectance spectra for a suite of samples of known mineralogy. This approach has been tested on powders, core plugs and split cores, and we conclude that it works well on all three, unless pore water is present. Initial VNIS studies have concentrated on determination of relative proportions of carbonate, opal, smectite and illite in equatorial Pacific sediments. Shipboard VNIS-based determination of these four components was demonstrated on Ocean Drilling Program Leg 199.

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

Abstract Utah contains unique analogues of microbial hydrocarbon reservoirs in the modern Great Salt Lake and the lacustrine Eocene Green River Formation within the Uinta Basin. Characteristics of both lake environments include shallow-water, ramp margins that are susceptible to rapid widespread shoreline changes, as well as comparable water chemistry and temperature that were ideal for microbial growth and formation/deposition of associated carbonate grains. Thus, microbialites in Great Salt Lake and cores from the Green River Formation exhibit similarities in terms of microbial textures and fabrics. A detailed petrographic analysis provides unique insights into these modern and ancient deposits that can be used to determine reservoir characteristics in other microbial carbonate petroleum plays. Great Salt Lake is a hypersaline lake and carbonate ‘factory’, containing actively forming microbial mats, stromatolites, thrombolites and associated carbonate grains. Open constructional pores are common within a spectrum of microbial structures. Green River Formation cores display excellent examples of stromatolites and thrombolites that contain primary megascopic pore and microporosity, as well as carbonate grainstones composed of ooids, peloids and skeletal material with abundant interparticle and intraparticle porosity. West Willow Creek oil field produces from a Green River microbial buildup/mound, a feature not currently recognized in Great Salt Lake.

Unconventional energy resources: 2015 review. Shale gas and liquids

This paper includes 10 summaries for energy resource commodities including coal and unconventional resources, and an analysis of energy economics and technology prepared by committees of the Energy Minerals Division of the American Association of Petroleum Geologists. Unconventional energy resources, as used in this report, are those energy resources that do not occur in discrete oil or gas reservoirs held in structural or stratigraphic traps in sedimentary basins. Such resources include coalbed methane, oil shale, U and Th deposits and associated rare earth elements of industrial interest, geothermal, gas shale and liquids, tight gas sands, gas hydrates, and bitumen and heavy oil. Current U.S. and global research and development activities are summarized for each unconventional energy resource commodity in the topical sections of this report, followed by analysis of unconventional energy economics and technology.This paper includes 10 summaries for energy resource commodities including coal and unconventional resources, and an analysis of energy economics and technology prepared by committees of the Energy Minerals Division of the American Association of Petroleum Geologists. Unconventional energy resources, as used in this report, are those energy resources that do not occur in discrete oil or gas reservoirs held in structural or stratigraphic traps in sedimentary basins. Such resources include coalbed methane, oil shale, U and Th deposits and associated rare earth elements of industrial interest, geothermal, gas shale and liquids, tight gas sands, gas hydrates, and bitumen and heavy oil. Current U.S. and global research and development activities are summarized for each unconventional energy resource commodity in the topical sections of this report, followed by analysis of unconventional energy economics and technology.

An examination of the hypersaline phases of Eocene Lake Uinta, upper Green River Formation, Uinta Basin, Utah

AbstractThe early evolution of ancient Lake Uinta has been the focus of significant study due to the enormous hydrocarbon reserves in the Uinta Basin’s lower to middle Green River Formation. In contrast, the upper Green River Formation, which includes strata recording the lake’s highest level (Mahogany zone), as well as three previously poorly delineated hypersaline phases, is less understood but still important for developing a complete lacustrine system evolutionary model. Detailed descriptions and mineralogy from several cores, as well as examination of geophysical logs from hundreds of oil and gas wells, were used to help delineate these three hypersaline lake phases and better define the events related to the infilling of Lake Uinta. Lake Uinta’s first hypersaline phase, recorded in the Uinta Basin, occurred synchronously with the upper R-6 and Mahogany zone deposition. Evaporite minerals, mostly nahcolite nodules and small shortite crystals, were deposited in the basin’s paleo-depocenter in central Uintah County. The second hypersaline phase is represented by a nearly basin-wide small-evaporite-crystal facies (both nahcolite and shortite), as well as a large-evaporite-nodule facies (nahcolite), also centered on the basin’s eastern paleo-depocenter in central Uintah County. Near the end of the second hypersaline phase, sediments originating from the southeast and north began to infill the lake, pushing the paleo-depocenter to the west. The third hypersaline phase is represented by a thick sequence of lacustrine sediments with disseminated evaporite minerals (nahcolite, shortite, and other more exotic sodium evaporite minerals) and bedded salts (halite and trona) centered in north-central Duchesne County.