Borehole Image Interpretation Techniques and Examples: Mississippian of Northeast Oklahoma.

Greg Flournoy
Schlumberger, Oklahoma City, OK

The subsurface Mississippian section within northeast Oklahoma (east of the Nemaha Ridge) has become an area of increasing interest to the petroleum industry. Historically, this area has been characterized as more oil prone compared to the Mississippian producing formations west of the Nemaha Ridge. Recent exploration efforts within the Mississippian (Osagean) carbonates and cherts have yielded some interesting revelations. This Mississippian section is currently being evaluated both in vertical well bores using conventional logging programs and in horizontal well bores using conventional logs and formation micro-imaging. This technique allows for detailed analysis as to textures, bedding within the section, faults and most importantly, fractures. The fractures seen are classified as to resistive (healed, natural), conductive (open, natural) and drilling induced (horizontal stress). One of the most interesting revelations has been the natural fracture density observed in vertical well bores as compared to the natural fracture density in horizontal well bores. This presentation deals with logging tool parameters and techniques for interpretation of borehole images in horizontal wells with numerous comparisons of surface outcrop photos and subsurface borehole images.

AAPG Search and Discovery Article #90152©2012 AAPG Southwest Section Meeting, Fort Worth, Texas, 19-22 May 2012