Credit: Photographic Services, Shell International Limited

3.3.1. Petrophysical Interpretation

North Sydney F-24 - Petrophysical Interpretation

Drilled as a follow-up well to the North Sydney P-05 well, F-24 was drilled to test the deliverability of potential reservoir sands within the Morien Group’s South Bar Formation identified in the P-05 well.  Drilled only 5.6 km southeast of P-05, F-24 reached a total depth 1704 m MD.  Gamma Ray, Neutron Porosity, Bulk Density, and Sonic logs were run from TD to surface casing; log quality was very good in this well.

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

Thin pay flags within the Sydney Mines Formation are being triggered by elevated porosity values occurring in coal wash-out sections.  Minor mud-gas shows can also be observed on the mud log through this interval.  There were no pay flags identified within the Waddens Cove Formation; this was mainly due to the increased shaley nature of the formation.  Some thin coal seams do indicate good porosity and have lower water saturation.

The South Bar Formation in this well showed two considerable elevations in background gas on the mud log.  Petrophysical analysis over the interval calculated four thin pay zones near the base of the formation.  These flags are solid indications of the presence of gas, and two intervals were flow tested: 4077 – 4285 ft. (1242 – 1306 m), and 4960 – 4985 ft. (1511 – 1519.5 m).  Both test intervals were acidized and one interval was subsequently hydraulically fractured to stimulate flow.  Neither interval flowed any hydrocarbons.  It is worth noting that porosities in the sands tested at this well were significantly lower than the porosities encountered in the South Bar Formation in North Sydney P-05. Flow testing of these higher quality sands may have resulted in a successful test. The well terminated in the Mabou Group’s Point Edward Formation.

North Sydney F-24 Reservoir Evaluation Summary
Zones (Fm.) Top
Flag Name Net
Vsh Avg
PhiE Avg
Sw Avg
Sydney Mines 521.8 946.4 424.6 PAY 0.0 0.19 0.18 N/A Coal indicating pay
Waddens Cover 946.4 1085.0 138.6 PAY 0.0       Tight / High Shale Volume
South Bar 1085.0 1436.1 351.1 PAY 1.4 0.31 0.06 0.49  
Point Edward 1436.1 1704.0 267.9 PAY 1.1 0.25 0.08 0.49