Leads E, F and G and (Figure 2.1.7) represent thrust sheets of the Humber Arm Allochthon (the Cow Head Group), stacked over the depressed and faulted Carbonate Platform. In places, these thrust sheets have a seismic signature similar to that of the carbonate platform and thus could involve platform and/or near slope-break platform rocks with likely porosity development.
This is a large, thick and unbroken thrust sheet. The three strong reflectors within the anticlinal feature resemble the seismic signature of the carbonate platform (Figures 2.18 and 2.19). Current structural models do not involve the platform in thrusts of the Taconic orogeny, but these models are entirely based on outcrops much further to the east of this location. A thrusted carbonate platform section could be well karstified and would likely have significant fractured porosity. The thrust sheet may have been eroded at the top prior to the deposition of the Lourdes Limestone over it. There is considerable structural relief on this feature. The area of closure is approximately 40 square km. The thrust sheet would both overlie and be juxtaposed with potential source rocks in the Triangle Zone.
Leads F and G
This leads represent two distinct thrust sheets identified on several seismic lines. They are much smaller than Lead E and have a structural closure between 10 and 20 square km. Vertical relief is also much smaller. Similar reservoir and source rocks, as discussed for the Lead E, are expected. The two leads need more seismic coverage to firm up.
New seismic data acquisition and modern stratigraphic processing are necessary to consolidate these prospects and leads in order to select the less risky drilling location. Future analysis will study the platform seismic character at the potential reservoir horizons to model the anticipated seismic response for porosity and reservoir fluids.