SEISMIC CHARACTERIZATION OF FINE-GRAINED UPPER CRETACEOUS RESERVOIRS WITHIN THE GREAT PLAINS POLYGONAL FAULT SYSTEM

2017 ◽  
Author(s):  
Andy Stonge ◽  
Keyword(s):  
Great Plains ◽  
Upper Cretaceous ◽  
Fault System ◽  
Fine Grained ◽  
Seismic Characterization ◽  
Polygonal Fault

Geotechnical engineering significance of Great Plains polygonal fault system

2017 ◽  
Vol 54 (8) ◽  
pp. 1089-1103
Author(s):  
Andy St-Onge
Keyword(s):  
Great Plains ◽  
Upper Cretaceous ◽  
Geotechnical Engineering ◽  
Three Dimensional ◽  
Fault System ◽  
Niobrara Formation ◽  
Well Control ◽  
Fine Grained ◽  
Engineering Significance ◽  
Polygonal Fault

An extensive polygonal fault system (PFS) within fine-grained Upper Cretaceous sediments beneath the Great Plains of North America has implications for geotechnical engineering. Geological well control, outcrop, and three-dimensional seismic data from southeast Saskatchewan exemplify the fault characteristics typically observed within the PFS. The deepest faults are sparse, offset a seismic reflection identified from the Niobrara Formation Govenlock member, and have vertical offsets <2 m. The deformation increases in fault density and vertical offset at shallower depths, reaching 6 faults/km2 with up to 30 m of vertical offset. Upper Cretaceous strata throughout the Great Plains area are at or near outcrop, and the extensive PFS faulting and weathering have weakened the rock. This faulting and weakness have been observed and attributed to other factors such as glacial erosion, overconsolidation, swelling bentonite beds, or landslides from toe erosion at topographic slopes. The PFS faulting should be recognized as an extensive process to be considered when undertaking geotechnical analysis on the Great Plains where underlying Upper Cretaceous rocks exist. Engineering implications include road cuts, dam impoundments, building foundations, and natural slumping.

Great Plains polygonal fault system as expressed in Saskatchewan: Late Cretaceous fault initiation and graben formation

2017 ◽  
Vol 54 (5) ◽  
pp. 477-493
Author(s):  
Andy St-Onge
Keyword(s):  
Great Plains ◽  
Late Cretaceous ◽  
Three Dimensional ◽  
Fault System ◽  
Western Interior Seaway ◽  
Niobrara Formation ◽  
Near Surface ◽  
M Current ◽  
Time Extension ◽  
Polygonal Fault

An extensive polygonal fault system (PFS) has been recognized in fine-grained Late Cretaceous sediments of the Western Interior Seaway of North America. Polygonal fault systems are pervasive organizations of nontectonic faults with fault traces that coalesce to form distinctive polygonal fault patterns. Interpretation of a three-dimensional seismic dataset from southeast Saskatchewan provides insight into fault initiation, timing, and geometry for the Great Plains PFS (GPPFS). Faulting initiates in the Niobrara Formation, with the largest fault throws occurring over Early Cretaceous Viking Formation sandstone accumulations, suggesting that drape compaction over the channel sand initiated some of the faulting. Above this, faulting increases in vertical offset, and the predominant fault strike angles change in the Lea Park, Belly River, and Bearpaw formations (all homotaxial to the Pierre Shale) throughout Campanian time. By late Bearpaw time, the initially almost random fault strike orientations change to well-defined northwest–southeast- and west–east-striking grabens. These grabens have up to 20 m of throw and can be 125 m wide and 900 m long at ∼400 m current depth. Predominant graben faults are the continuation of some of the deeper PFS faults. Moreover, the grabens are present over a Campanian clinoform bed and may be interpreted to indicate Bearpaw time extension tectonics that is local or regional in scale. The PFS helps to explain near-surface faulting observed in Late Cretaceous sediments in the Western Interior Seaway and could be used as a model to help explain Late Cretaceous geology, subsurface groundwater flow, and shallow natural gas reservoir continuity.

Novel 3D seismic characterization of upper Cretaceous formations along the Arabian plate: A case study

2019 ◽  
Author(s):  
Manayer Al-Abdullah ◽  
Anand Prakash ◽  
Muneera Al-Awadhi ◽  
Mafizar Rahaman ◽  
Salem Al-Ali ◽  
...  
Keyword(s):  
Upper Cretaceous ◽  
Arabian Plate ◽  
3D Seismic ◽  
Seismic Characterization

Recognition of an early Holocene polygonal fault system in Lake Superior: Implications for the compaction of fine-grained sediments

Geology ◽  
2004 ◽  
Vol 32 (3) ◽  
pp. 253 ◽  
Author(s):  
Joseph Cartwright ◽  
Nigel Wattrus ◽  
Deborah Rausch ◽  
Alastair Bolton
Keyword(s):  
Lake Superior ◽  
Early Holocene ◽  
Fault System ◽  
Fine Grained ◽  
Polygonal Fault

Development of a major polygonal fault system in Upper Cretaceous chalk and Cenozoic mudrocks of the Sable Subbasin, Canadian Atlantic margin

2004 ◽  
Vol 21 (9) ◽  
pp. 1205-1219 ◽  
Author(s):  
Dorthe Møller Hansen ◽  
John W. Shimeld ◽  
Mark A. Williamson ◽  
Holger Lykke-Andersen
Keyword(s):  
Upper Cretaceous ◽  
Fault System ◽  
Atlantic Margin ◽  
Polygonal Fault

Mechanical stratigraphy and layer-bound normal faulting in the Upper Cretaceous Niobrara Formation, Wattenberg Field, Colorado

2020 ◽  
Vol 57 (2) ◽  
pp. 67-93
Author(s):  
Kyle Bracken
Keyword(s):  
Upper Cretaceous ◽  
Fault System ◽  
Normal Faults ◽  
Valuable Insight ◽  
Niobrara Formation ◽  
Borehole Data ◽  
Fine Grained ◽  
Mechanical Stratigraphy ◽  
Pass Through ◽  
Dip Angle

Layer-bound normal faults are pervasive within the very fine-grained rocks of the Upper Cretaceous Niobrara and Carlile formations in the Denver Basin. 3-D seismic and well log interpretation reveal a complex, segmented fault system that is divided into two discrete tiers: an upper tier located in the Pierre Shale, and a lower tier located in the Niobrara Formation. 3-D fault throw analysis shows maximum throw near the top of the Niobrara Formation with steep, asymmetrical throw gradient down section in the lower Niobrara and Carlile formations. Faults are laterally well-connected in the upper Niobrara Formation and commonly form linear arrays of linked graben systems. In contrast, faults deeper in the stratigraphic section that offset the Carlile and Greenhorn formations are more segmented and commonly form half grabens (as opposed to full, fault-bound grabens). In cross-section, fault planes measured from seismic have a general dip of 45°. However, close inspection reveals that faults consistently change dip angle as they pass through the lower Niobrara Formation, refracting from ~55° to ~35° through the Niobrara C Marl, then back up to ~50° in the Carlile and Greenhorn formations. The fault dip refraction produces a contractional step or bend in the fault plane associated with the lower dip segments. This geometry is investigated further with horizontal image logs and other borehole data to reveal a kinematic relationship between fault dip angle and mechanical stratigraphy. Field examples of normal faults that cut mechanically layered rock help better understand these complex fault geometries and provide reasonable inferences to their development and propagation history. In summary, it is argued that the mechanically layered nature of the Niobrara and Carlile formations is responsible for many of the fault characteristics described and provides valuable insight into understanding the fault system

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