Structurally Aligned, Sediment-Starved Fluvial Valleys Encased in Marine DepositsSequence Boundaries Between the Carlile Shale and Niobrara Formation, Central Powder River Basin, U.S.A.

1995 ◽  
Author(s):  
D. K. Larue
Keyword(s):  
River Basin ◽  
Powder River Basin ◽  
Niobrara Formation ◽  
Marine Deposits ◽  
Sequence Boundaries

Sequence stratigraphy of the lower Pierre Shale of the southern Powder River Basin: A ramp margin sequence that terminates Niobrara Formation carbonate deposition

2018 ◽  
Vol 6 (1) ◽  
pp. SA7-SA13
Author(s):  
Armagan Kaykun
Keyword(s):  
River Basin ◽  
Rocky Mountain ◽  
Source Rocks ◽  
Powder River Basin ◽  
Bighorn Basin ◽  
Niobrara Formation ◽  
Sequence Stratigraphic ◽  
Pierre Shale ◽  
Rocky Mountain Region ◽  
Forced Regression

The Upper Cretaceous section of the southern Powder River Basin of the Rocky Mountain region includes the Niobrara Formation, which is one of the most significant source rocks of the Western Interior Cretaceous Seaway, and it is overlain by the lower Pierre Shale interval. The lower Pierre Shale is divided into eight members, which are the progradational highstand deposits of the Gammon Ferruginous Member; lowstand prograding wedge deposits of the Shannon Sandstone, the Unnamed Member, and the Sussex Sandstone; transgressional Ardmore Pedro Bentonite Beds and Sharon Springs members; and highstand deposits of the Mitten Black Shale and Red Bird Silty members. The Shannon and Sussex Sandstone members are known targets for oil production. Based on integrated research of 1490 well logs with two cores, this study demonstrates that the lower Pierre Shale interval is a Type 1 Ramp Margin Sequence. Although previous studies primarily focused on individual sandstone members or parts of the lower Pierre Shale section in relatively limited areas, this study provides an in-depth sequence stratigraphic analysis of the lower Pierre Shale interval. A depositional model was created, which demonstrates that the Shannon Sandstone, Unnamed, and Sussex Sandstone Members were deposited as an encased lowstand prograding wedge between the progradational Gammon Ferruginous Member and the transgressional Ardmore Pedro Bentonite Beds and Sharon Springs members hundreds of miles basinward from the stratigraphically equal Mesaverde lowstand sandstones of the Bighorn Basin. The shift of facies across long distances is explained with a forced regression that has taken place during the deposition of the uppermost Gammon Ferruginous Member and the following deposition of the Shannon and Sussex sandstone members. Rapid eastward progradation of the clastic sediments of the lower Pierre Shale and the following rapid forced regression effectively terminate the deposition of the Niobrara Formation carbonates in the Western Interior Seaway.

Split Estate and Wyoming’s Orphaned Well Crisis: The Case of Coalbed Methane Reclamation in the Powder River Basin, Wyoming

2017 ◽  
Vol 1 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Kathryn Bills Walsh
Keyword(s):  
Natural Gas ◽  
River Basin ◽  
Technological Innovation ◽  
Coalbed Methane ◽  
Powder River Basin ◽  
Gas Wells ◽  
Mineral Rights ◽  
Split Estate ◽  
Legal Condition

This case presents the stakeholder conflicts that emerge during the development and subsequent reclamation of abandoned natural gas wells in Wyoming where split estate, or the separation of surface land and mineral rights from one another, occurs. From 1998 to 2008, the Powder River Basin of northeastern Wyoming experienced an energy boom as a result of technological innovation that enabled the extraction of coalbed methane (CBM). The boom resulted in over 16,000 wells being drilled in this 20,000 square-mile region in a single decade. As of May 2017, 4,149 natural gas wells now sit orphaned in Wyoming as a result of industry bankruptcy and abandonment. The current orphaned wells crisis was partially enabled by the patchwork of surface and mineral ownership in Wyoming that is a result of a legal condition referred to as split estate. As the CBM boom unfolded in this landscape and then began to wane, challenges emerged most notably surrounding stalled reclamation activities. This case illuminates these challenges highlighting two instances when split estate contributed to issues between landowners and industry operators which escalated to litigation.

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