Credit: Photographic Services, Shell International Limited

3.2.1. Petrophysical Interpretation

North Sydney P-05 - Pertophysical Summary

North Sydney P-05 was drilled to evaluate hydrocarbon prospectivity within the Middle to Lower Mississippian Windsor and Horton groups. The well was drilled to a total depth 1660.8 mMD, terminating in the Upper Mississippian Mabou Group (Point Edward Formation).  The original target units of this well were not penetrated.

The well was logged in two sections with both logging suites acquiring identical log types.  Gamma Ray, Induction, Sonic, Neutron porosity and Bulk density data were collected for the entire well.  Large portions of the well bore were washed out considerably, however a reasonably smooth bore hole enabled the acquisition of useful neutron and bulk density data for most of the well.  However, zones of high borehole rugosity result in overly optimistic porosity values, especially in coaly intervals and highly washed-out shales.

Shale volumes were calculated from the gamma ray curve, using 20 API as a clean sand value and 90 API as a shale value.  Porosity values were calculated from the bulk density curve, using a grain density of 2650 kg/m3.  Potential pay zones were identified using the following cut-offs:

  • VSh < 0.40
  • Phie >0.06
  • Sw <0.70

Pay flags calculated within the Sydney Mines and Waddens Cove Formations can be attributed to elevated porosity values due to coal wash-out.  There is some hydrocarbon prospectivity within the underlying South Bar Formation.  Several thin intervals of minor crossover between the density and neutron curves as well as gas shows on the mudlog indicate the presence of gas within sandstones of the formation.  High porosities associated with pay flags within the Point Edward Formation are elevated due to borehole washout.  The neutron porosity curve in these cases seem to be less affected by the wash-out than the density, suggesting there may be gas keeping the neutron curve subdued, producing some neutron-density cross-over.

There was no formation testing done and the well was subsequently abandoned.

North Sydney P-05 Reservoir Evaluation Summary
Zones (Fm.) Top
Flag Name Net
Vsh Avg
PhiE Avg
Sw Avg
Sydney Mines 548.6 916.8 368.2 PAY 0.0 0.30 0.11 N/A Coal indicating pay
Waddens Cove 916.8 1045.4 128.6 PAY 2.0 0.26 0.11 0.32  
South Bar 1045.4 1392.9 347.5 PAY 32.8 0.28 0.11 0.29  
Point Edward 1392.9 1660.8 267.9 PAY 0.0 0.26 0.14 N/A Borehole breakout elevating porosity