Interpretation of PP and PS seismic data from the Mackenzie Delta, N.W.T.

Carlos E. Nieto and Robert R. Stewart

ABSTRACT

The MKD-8 multicomponent seismic line was acquired in the spring of 2000 by the CREWES Project and Devon Canada Ltd. (formerly Anderson Exploration Ltd.). It was a six kilometre long line across a transition zone from floating to ground-fast ice in the Mackenzie Delta, N.W.T. The seismic data was processed to final stacked sections for both PP and PS wave. These sections have been interpreted in this work using logs from a neighbour well, Hansen G-07. The well is around 800 m away (southwest) from the MKD-8 line.

This represents the first known PS section in the Canadian Arctic. A very compelling correlation is found between the PP and PS sections. The Mackenzie Bay, Kugmallit, and Richards Sequences were interpreted in the well logs. Since the P sonic log from G-07 was limited to the depth range from 1200 m to 3200 m, the only sequences that could be interpreted in the seismic sections were the Kugmallit and the Richards. The P-wave synthetic matches the section very well. Some other dominant reflectors (K1 and K2), that correspond to lithological changes inside the Kugmallit Sequence were used to interpret the PS section.

Since the Hansen G-07 does not have a S sonic log, Vp/Vs values are inferred from Mallik 2L-38. These values are between 2.09 and 2.19 for the Iperk and Mackenzie Bay Sequences. Using this value as a reference it was found that the optimal Vp/Vs ratio to correlate PP and PS sections was 1.9, which corresponds to permafrost and ice.

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