Stratigraphy and Petrophysics of the Barnett Shale, Newark East Field, Texas

Prerna Singh¹, Roger Slatt¹, Chandra Rai², Carl Sondergeld² and Chris Stamm³.  (1) School of Geology and Geophysics, University of Oklahoma, Norman, OK, (2) Mewbourne School of Petroleum and Geological Engineering, University of Oklahoma, Norman, OK, (3) Devon Energy Corporation, Oklahoma City, OK  [email protected]

Barnett Shale is one of the most prolific shale gas plays in the U.S. However, a thorough geologic knowledge, including its depositional and diagenetic history, stratigraphy, and characteristics as a reservoir rock, is still unknown. Hence, to fill the gap, this work is being undertaken.

Continuous long cores from the field are being studied to document the detailed internal stratigraphy, architecture, and reservoir characteristics of the Barnett Shale. Visual, petrographic, and mineralogic analysis reveals several distinct shale facies arranged in a complex stratigraphic stacking pattern. An initial study suggests that the Barnett Shale in this area, rather than representing a continuous depositional succession, consists of low-energy shale packages bounded by surfaces indicative of higher-energy environments. A careful study indicates the significance of depositional processes, which have constrained the facies successions, geometries, and cyclicity in the study area.

With an understanding of the processes that affect the mechanical and petrophysical properties of the Barnett Shale, it will be possible to interrelate the lithofacies with their rock mechanical properties. It is observed that subtle variation in the organic content, mineral composition, and petrophysical properties of the facies parallel this stratigraphic stacking, and facies exhibit distinctive well log patterns. An ongoing work of the petrophysical and mechanical characterization of each of the facies is being done, which will aid in delineating more fracturable and productive intervals within the Barnett Shale.