--> Abstract: Estimating Reservoir Scale Fracture Networks in the Tensleep Formation Using FMI Logs and 3D Seismic, Teapot Dome, Wyoming, by Valerie L. Smith, Bryan C. Schwartz, Thomas H. Wilson, and Alan L. Brown; #90078 (2008)

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Estimating Reservoir Scale Fracture Networks in the Tensleep Formation Using FMI Logs and 3D Seismic, Teapot Dome, Wyoming

Valerie L. Smith1, Bryan C. Schwartz3, Thomas H. Wilson1, and Alan L. Brown2
1Geology and Geography, West Virginia University, Morgantown, WV
2SIS, Schlumberger, Houston, TX
3ExxonMobil, Houston, TX

Analysis of FMI log observations prepared by Schlumberger were used to evaluate the characteristics of fracture systems in the Tensleep Formation along the length of Teapot Dome in Wyoming. FMI logs and 3D seismic data over the field were provided by the Rocky Mountain Oil Testing Center. Oil production from the Tensleep at Teapot Dome is restricted to a mile-square area of structural closure in the southern end of the dome. Open fractures in the Tensleep Formation penetrated by the FMI wells in the producing area consist predominantly of three sets: two hinge-oblique sets and one hinge-parallel. The local structural hinge trends about N30W. Fractures with the NW hinge-oblique orientation are more numerous than the hinge-parallel and NE-hinge-oblique sets. They strike on average N71W and closely parallel the drilling induced fractures in the Tensleep which have average strike of N74W.

Production from the field occurs in the upper A and B Sandstone members which coincides with oil staining seen in cores. No open fractures were observed in the A Sandstone in the well from the producing area. Fractures in the B Sandstone consist primarily of the hinge-parallel set (average strike N23W). A smaller number of open fractures in the B Sandstone have the hinge-oblique (~N70W) strike. Open fractures in the intervening B Dolomite are more numerous than in the A and B sandstones and consist primarily of the hinge-oblique set (~N75W). The overlying dolomites, although fractured, are generally assumed to represent permeability barriers.

Spacing, length, and aperture distributions are estimated for the fracture sets comprising the fracture network controlling production from these tight eolian dune sand deposits. Network properties inferred from the FMI data are combined with 3D seismic analysis to develop a layered fracture model suitable for field-scale flow simulation.

 

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas