Descriptions - Ernest Fossum No. 1-24, sec. 24, T130N, R104W, Bowman Co, ND, Medicine Pole Hills Field, Red River A, B, C and D Zones
Reported Core Interval 9583-9653 ft
Adjusted Core Interval 9591-9661 ft
9583-9593.8 -Brown dolomitic lime mudstone with dolomitization of burrow structures. Very poor spotty oil staining within dolomitized burrows. Thin black shale parting ("karogenite") from 9593.5-9593.8.
9593.8-9596.5 -Gray skeletal lime wackestone. Skeletal fragments are dominantly crinoids and brachiopods. Minor burrow structures. No visible porosity or oil shows.
9596.5-9634 -Brown to gray, dolomite lime mudstone, dolomudstone, and dolowackestone. Burrow structures are common and dominantly large branching Thalassinoides and small circular Planolites. Oil staining is fair to good in the upper portion of the unit. Dolomitization is common both within burrow structures and the surrounding mud “matrix”. Skeletal fragments, mostly crinoids are present but scattered. Bioclastic bed at 9608 and a thin layer of small crinoid grains are present at 9312ft.
9634-9639 -Medium to dark gray skeletal lime wackestone. Skeletal fragments are dominantly crinoids and sparse brachiopods.
9639-9642 -Gray to brown, slightly dolomitic lime mudstone. Small Planolites burrow structures in the upper portion of the unit. Sparse visible porosity within dolomitized burrow structures.
9642-9644 -Gray, skeletal lime mudstone to wackestone. Skeletal fragments are dominantly small crinoids. No visible porosity.
9644-9653 -Brown to gray, burrowed and bioturbated lime mudstone and dolomudstone to dolowackestone. A thin porous interval is present near the base of the unit where dolomitization of “matrix” and burrow structures was more complete. A thin shale bed
9650.5-9650.8 (“karogenite”) rests at the base of the porous interval.