--> Wyodak Coal, Tongue River Member of the Fort Union Formation, Powder River Basin, Wyoming: "No-Coal Zones" and Their Effects on Coalbed Methane Production, by Mark Ashley, #10094 (2005)
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Wyodak Previous HitCoalNext Hit, Tongue River Member of the Fort Union Formation, Powder River Basin, Wyoming: "No-Previous HitCoalNext Hit Zones" and Their Effects on Coalbed Methane Production*

By

Mark Ashley1

 

Search and Discovery Article #10094 (2005)

Posted November 27, 2005

 

*Oral Presentation at Rocky Mountain Section AAPG Annual Meeting, Jackson, Wyoming, September 24-26, 2005. Appreciation is expressed to Lyn George, Technical Program Chair, and Don French, for encouraging the author to submit this presentation.

 

Click to view presentation in PDF format.

 

1Yates Petroleum Corporation, 105 S. 4th, Artesia, NM 88210, phone: 505 748 4310 ([email protected])

 

Abstract 

The Powder River Basin contains more than 80 percent of the state's Previous HitcoalNext Hit resources within the Tongue River Member of the Fort Union Formation (upper Paleocene). The Fort Union Formation is divided from older to younger into the Tullock, Lebo Shale, and Tongue River Members. The coals of the Tongue River Member consist of approximately 32 Previous HitcoalNext Hit seams with a combined thickness in excess of 300 ft. One of the major Previous HitcoalNext Hit seams within the Tongue River Member is the Wyodak Previous HitcoalNext Hit.  

The Tongue River Member of the Fort Union Formation was deposited by a fluvial-deltaic system filling Lake Lebo. Extensive peat deposits accumulated within poorly drained interdeltaic and deltaic swamps. There are “no-Previous HitcoalNext Hit zones” within the Wyodak Previous HitcoalNext Hit seam where the Previous HitcoalNext Hit has been replaced by sandstones and shales. The “no-Previous HitcoalNext Hit zones” are distributary fluvial channels that meandered throughout the swamps. Several methods have been developed to predict the locations of the fluvial channels and avoid drilling “no-Previous HitcoalNext Hit zones.” Additionally, the relationship between adjacent Previous HitcoalNext Hit seams may imply a pattern of production.

 

 

Geologic map of Powder River Basin (after Flores and Bader, 1999), with study area

 

Isopach map of Wyodak Previous HitcoalNext Hit

 

 

Depositional environment of Wyodak Previous HitcoalNext Hit

 

Click to view sequence of six maps depicting or suggesting Wyodak Previous HitcoalNext Hit attributes (structure, isopach, structure of overlying Big George Previous HitcoalNext Hit (BGC), BGC structure with “no-Previous HitcoalNext Hit zones,” interval isopach, and interval isopach with “no-Previous HitcoalNext Hit zones”).

 

Reference 

R.M. Flores and L.R. Bader, 1999, Fort Union Previous HitCoalNext Hit in the Powder River Basin, Wyoming and Montana: A synthesis, in 1999 Resource Assessment of Selected Tertiary Previous HitCoalTop Beds and Zones in the Northern Rocky Mountains and Great Plains region: U.S. Geological Survey Professional Paper 1625-A, Chapter PS, p. i-iv, 1-71.