--> Abstract: No Title Available, by D. R. Thorn; #90987 (1993).

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THORN, DAVID R., Schlumberger Well Services, Morrison, CO; and JOHN-MARK COATES, Colorado School of Mines, Golden, CO

ABSTRACT: NO TITLE AVAILABLE:

Interpretation of Formation Microscanner images from horizontal wellbores in a fractured reservoir in the Denver basin were compared with an outcrop study of the reservoir rock to confirm interpretations of structural style, fracture spacing, fracture frequency around faults, and vertical continuity of fractures. Outcrop gamma ray logging was used to identify the reservoir interval exposed in a quarry, 65 miles south of the field. Fracture properties such as orientation, vertical continuity, spacing and aperture were measured in the subsurface using Formation Microscanner logs. Observations in the quarry of listric faulting, fracture density increasing around faults and fracture healing compared well with FMS data. These observations increased confidence in the subsurface interpretati n.

Two transects were also made along the quarry face, one within the "target interval," a clean chalk bench and one outside the target interval, a shalier bed. The transects were similar to the path and length of a 2,000' horizontal wellbore to compare fracture frequency and spacing. These transects quantify the importance of staying in the target interval when drilling a horizontal wellbore.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.