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The Vermillion Basin of SW Wyoming/NW Colorado: Structural Styles and Seismic Pore Pressure Prediction through Over-Pressure

Rigatti, Vincent G.1, Tony LeFevre1, Richard Newhart2, Kimberly Kaiser1, Scott Goodwin1, and Robert Parney3
1Questar Exploration and Production Co, Denver, CO
2Questar Exploration and Production Co, Salt Lake City, UT
3Tricon Geophysics Inc, Denver, CO

     The Vermillion basin is a sub-basin of the Greater Green River basin and includes the Canyon Creek, Trail, Kinney, E & W Hiawatha, & Sugarloaf fields. The basin straddles the Wyoming/ Colorado state lines and includes Sweetwater County, Wyoming and Moffat County, Colorado.
     This sub-basin of the Greater Green River basin lies just to the northeast of the eastern terminus of the Uinta Mountain front and exhibits transpressional tectonics with evidence of recent extension. The area is characterized by SW-NE trending anticlines cored by compressional faults. The folds exhibit steep fore-limbs and gentle back-limbs, and some areas exhibit large back thrusts.
     The first discovery of gas in the Vermillion basin was made by Questar predecessor Mountain Fuel Supply Company in 1927 at Hiawatha Field in NW Colorado. Since that time several prolific fields have been discovered and the area has produced approximately 1 TCFG and 8 MMBO. To date most of the production has come from shallow Mesaverde sandstones, however there is an emerging play targeting the deeper Dakota, Frontier and Baxter formations. There is a regional over-pressure cell in the lower part of the Baxter Formation through the Frontier (3,000-4,000 ft thick) that requires mud weights in the 12-15 ppg range to drill.
     Within the Vermillion basin there is approximately 200 square miles of 3D seismic, composed of 3 separate surveys acquired over the last 12 years. The data has been merged and processed into one continuous volume of good-excellent quality (Nominal 30 fold with 110 * 110 bin spacing). Source is a mix of Vibroseis and Dynamite data and recently reprocessed in 2006. In addition to standard processing (stack, migration, PSTM) of the merged 3D volumes, the data has also been processed to generate a 3D pore pressure volume.


AAPG Search and Discovery Article #90071 © 2007 AAPG Rocky Mountain Meeting, Snowbird, Utah