Correlation of Mechanical Stratigraphy in the Mississippian
Calleb Jennings and Christopher Liner
The Mississippian formation of Oklahoma and Kansas has recently developed as a world class unconventional reservoir with wells producing up to 800 bbl/day. The Mississippian is composed of multiple distinct lithologic zones including limestone, hard chert, and soft tripolitic chert. These zones are difficult to discern with traditional log correlation, but mechanical stratigraphy has the potential to improve previous correlations of the Mississippian. This study uses full wave sonic logs from Osage County, OK to analyze the elastic properties of the Mississippian. Our work computes all possible isotropic elastic parameters in an effort to partition the Mississippian section into units that may be correlated between wells. Raw material for this study consists of P-sonic, S-sonic, and density logs in two wells. From sonic log data we compute metric P- and S-wave velocities, then calculate the two independent isotropic elastic parameters (Lame's constant and shear modulus) at every log depth through the Miss and a short section above and below. Young's modulus, a key parameter related to brittleness and fracability, is shown to vary vertically and laterally in the Mississippian. Through our work to separate the Mississippian into multiple distinguishable units, we may be able to better correlate logs in this area as a guide for oil exploration mapping and completion.
AAPG Search and Discovery Article #90176©AAPG Mid-Continent Meeting, Wichita, Kansas, October 12-15, 2013