Stochastic Modelling of Fluvial Sandstone Bodies

Author(s):  
J. P. P. Hirst ◽  
C. R. Blackstock ◽  
S. Tyson
2019 ◽  
Vol 56 (3) ◽  
pp. 247-266
Author(s):  
Ian Anderson ◽  
David H. Malone ◽  
John Craddock

The lower Eocene Wasatch Formation is more than 1500 m thick in the Powder River Basin of Wyoming. The Wasatch is a Laramide synorgenic deposit that consists of paludal and lacustrine mudstone, fluvial sandstone, and coal. U-Pb geochronologic data on detrital zircons were gathered for a sandstone unit in the middle part of the succession. The Wasatch was collected along Interstate 90 just west of the Powder River, which is about 50 km east of the Bighorn Mountain front. The sandstone is lenticular in geometry and consists of arkosic arenite and wacke. The detrital zircon age spectrum ranged (n=99) from 1433-2957 Ma in age, and consisted of more than 95% Archean age grains, with an age peak of about 2900 Ma. Three populations of Archean ages are evident: 2886.6±10 Ma (24%), 2906.6±8.4 Ma (56%) and 2934.1±6.6 Ma (20%; all results 2 sigma). These ages are consistent with the age of Archean rocks exposed in the northern part of the range. The sparse Proterozoic grains were likely derived from the recycling of Cambrian and Carboniferous strata. These sands were transported to the Powder River Basin through the alluvial fans adjacent to the Piney Creek thrust. Drainage continued to the north through the basin and eventually into the Ancestral Missouri River and Gulf of Mexico. The provenance of the Wasatch is distinct from coeval Tatman and Willwood strata in the Bighorn and Absaroka basins, which were derived from distal source (>500 km) areas in the Sevier Highlands of Idaho and the Laramide Beartooth and Tobacco Root uplifts. Why the Bighorn Mountains shed abundant Eocene strata only to the east and not to the west remains enigmatic, and merits further study.


2017 ◽  
Vol 54 (4) ◽  
pp. 265-293 ◽  
Author(s):  
Roger Matson ◽  
Jack Magathan

The Hanna Basin is one of the world’s deeper intracratonic depressions. It contains exceptionally thick sequences of mature, hydrocarbon-rich Paleozoic through Eocene rocks and has the requisite structural and depositional history to be a significant petroleum province. The Tertiary Hanna and Ferris formations consist of up to 20,000 ft of organic-rich lacustrine shale, shaly mudstone, coal, and fluvial sandstone. The Upper Cretaceous Medicine Bow, Lewis, and Mesaverde formations consist of up to 10,000 ft of marine and nonmarine organic-rich shale enclosing multiple stacked beds of hydrocarbon-bearing sandstone. Significant shows of oil and gas in Upper Cretaceous and Paleocene rocks occur in the basin. Structural prospecting should be most fruitful around the edges where Laramide flank structures were created by out-of-the-basin thrust faults resulting from deformation of the basin’s unique 50-mile wide by 9-mile deep sediment package. Strata along the northern margin of the basin were compressed into conventional anticlinal folds by southward forces emanating from Emigrant Trail-Granite Mountains overthrusting. Oil and gas from Pennsylvanian to Upper Cretaceous aged rocks have been found in such structures near the Hanna Basin. Only seven wells have successfully probed the deeper part of the Hanna Basin (not including Anadarko’s #172 Durante lost hole, Sec. 17, T22N, R82W, lost in 2004, hopelessly stuck at 19,700 ft, unlogged and untested). Two of these wells tested gas at commercial rates from Upper Cretaceous rocks at depths of 10,000 to 12,000 ft. Sparse drilling along the Hanna Basin’s flanks has also revealed structures from 3,000 to 7,000 feet deep which yielded significant shows of oil and gas.


1998 ◽  
Vol 37 (1) ◽  
pp. 179-185
Author(s):  
Morten Grum

On evaluating the present or future state of integrated urban water systems, sewer drainage models, with rainfall as primary input, are often used to calculate the expected return periods of given detrimental acute pollution events and the uncertainty thereof. The model studied in the present paper incorporates notions of physical theory in a stochastic model of water level and particulate chemical oxygen demand (COD) at the overflow point of a Dutch combined sewer system. A stochastic model based on physical mechanisms has been formulated in continuous time. The extended Kalman filter has been used in conjunction with a maximum likelihood criteria and a non-linear state space formulation to decompose the error term into system noise terms and measurement errors. The bias generally obtained in deterministic modelling, by invariably and often inappropriately assuming all error to result from measurement inaccuracies, is thus avoided. Continuous time stochastic modelling incorporating physical, chemical and biological theory presents a possible modelling alternative. These preliminary results suggest that further work is needed in order to fully appreciate the method's potential and limitations in the field of urban runoff pollution modelling.


1992 ◽  
Vol 57 (10) ◽  
pp. 2100-2112 ◽  
Author(s):  
Vladimír Kudrna ◽  
Pavel Hasal ◽  
Andrzej Rochowiecki

A process of segregation of two distinct fractions of solid particles in a rotating horizontal drum mixer was described by stochastic model assuming the segregation to be a diffusion process with varying diffusion coefficient. The model is based on description of motion of particles inside the mixer by means of a stochastic differential equation. Results of stochastic modelling were compared to the solution of the corresponding Kolmogorov equation and to results of earlier carried out experiments.


PLoS ONE ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. e29406 ◽  
Author(s):  
Melanie I. Stefan ◽  
David P. Marshall ◽  
Nicolas Le Novère

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