A Ductile and Brittle Geomechanical Study and Stable Isotope Geochemical Analysis of the Mississippian Boone Formation

Karen Mason Buckland
University of Arkansas, Department of Geosciences Fayetteville, Arkansas, USA
[email protected]

The Mississippian Boone formation exposed in northwest Arkansas is a chert and limestone sequence that is correlative with the Mississippi Lime, a reservoir in the subsurface of northern Oklahoma and southern Kansas that has low permeability, and is producing with the aid of stimulation by hydraulic fracturing. Occurrences of chert nodules and laterally extensive chert layers in the sequence are variable. Locally, chert bedding is continuous and comprises up to 50% of the outcrop. Elsewhere, the chert is nodular and intermittent. The response to fracturing is dependent on the quantity of chert. Fossils interbedded in chert nodules, erratic olistoliths, and variable quantities and morphologies of chert indicate a dynamic diagenetic setting that is not fully understood. Samples collected from representative outcrops are being targeted to establish a geomechanical and diagenetic framework for this reservoir. Compressive strength testing and fracture analysis of core plugs from each sample will be used to characterize fracture development and enhancement of permeability in the reservoir. Thin section petrography will help constrain aspects of the diagenetic record regarding the natural porosity, permeability, and replacement of carbonate by silica and calcite. δ¹⁸O stable isotope data will be taken and used to constrain the paleotemperatures during diagenesis. This work will illustrate whether different kinds of chert and limestone exist in different areas of the Boone Formation, and will describe the record of diagenesis at those intervals. Results from geomechanical testing will help determine the optimal horizons for horizontal drilling and hydraulic fracturing in the Mississippi Lime unconventional reservoir.

AAPG Search and Discovery Article #90157©2012 AAPG Foundation 2012 Grants-in-Aid Projects