Multicomponent seismic survey at Spring Coulee: a data repeatability study

Donald C. Lawton, Pietro (Peter) Giuseppe Gagliardi, Malcolm B. Bertram, Han-xing Lu, Kevin W. Hall, Joanna Kathleen Cooper, Eric V. Gallant, Kevin L. Bertram

A 3 km long 3-component seismic line was recorded at Spring Coulee, Alberta, using an Envirovibe source, with a nominal shot and receiver spacing of 10 m and a maximum useable source-receiver offset of about 1500 m. Offsets greater than 1500 m were limited primarily by wind noise overwhelming signal. The line was recorded twice over a time period of 10 days. The vertical and radial component data from the two surveys were processed using the same flows, but with independent static solutions and velocity analyses. Spring Coulee is a `good' data area, with only a thin weathering layer, and P-P and P-S reflections from PreCambrian basement evident on processed sections. An nrms metric was used to assess the repeatability of shot gathers and processed P-P and P-S sections between the two surveys. For shot gathers, nrms values ranged from 0.3 to 0.9 for raw vertical component data, and 0.4 to 1.2 for radial component data (Figure 1). After an 8-12-50-60 Hz bandpass filter was applied, nrms values reduced by 0.2 for both vertical and radial component data, respectively. For migrated sections, nrms values for P-P data were about 0.4 in the high-fold, central part of the seismic line, but greater than 1.1 for P-S data. The poorer repeatability of the P-S data with respect to the P-P data is due to unresolved receiver static corrections and differences in ambient wind noise between the two surveys.