ABSTRACT

Six cores from the Mississippian Lodgepole Formation from selected wells in southwestern Manitoba were analyzed for fractures. These cores were not mechanically oriented at the time of cutting, but subsequently oriented using the paleomagnetic signal within those rocks as a "fossil compass needle". This allowed the delineation of in situ orientations for measured fracture populations.

Porosity development on the most significant open fracture populations appears to be a result of dissolution. Some fractures show corroded surfaces. The resulting mismatch between juxtaposed fracture surfaces inhibits their closure during drawdown. Propping by partial mineralization in some fractures also contributes to holding them open. Other evidence of a fluid flow event through these rocks includes the presence of "alteration rims" lining some fractures.

The above information was used to plan horizontal well directions to either maximize intersection with open fractures in order to enhance production, or limit intersection in cases where water production was a problem.