Harriet Field – A Two Dimensional Modelling Study

A series of two dimensional interpolation models was constructed using wells from the Harriet Field. These models were designed to assess the effects of: (a) shale interbeds within the Flag Sand and (b) the fluid content (i.e. gas vs. oil vs. water) on the seismic response. The model responses closely resemble the seismic data.

The results indicate that both of these factors have an impact on the seismic expression of the top Flag Sand interface and the associated amplitude anomaly which occurs immediately below it. In addition, apparent velocity variations which have been observed over the field are probably related, at least in part, to tuning effects resulting from shale and fluid content variations.

In the models constructed, the presence of hydrocarbons correlates with low frequency zones in the seismic data which occur in association with high amplitude in the trough beneath the top Flag Sand reflector.