Violet Grove time-lapse data revisited: a surface-consistent matching filters application

Mahdi H. Al Mutlaq, Gary F. Margrave

We apply the surface-consistent matching filters to a real data set from the Violet Grove area in central Alberta. Detecting time-lapse difference on this data has proved to be difficult due the small impedance contrast at the Cardium reservoir where CO₂ is injected. However, we decided to examine the matching filters algorithm on this data for two main reasons: 1) to test the algorithm on a real data set and 2) to compare our results with previous processing on the same data. For this purpose, we evaluate two zones: a shallow one above the reservoir centered on the Ardley Coal Zone, and a deeper one below the reservoir.

After applying the surface-consistent matching filters to the monitor survey, we reduce most of the mismatch caused by acquisition differences and near surface variations. Dif- ferences caused by nonrepeatable noise in the data are difficult to remove since they are nonstationary. The shallow window above the reservoir is dominated by the near-surface noise compared to the deeper window of analysis. Despite this issue, we notice an im- provement in the pre-stack and the post-stack image after applying the surface-consistent matching filters.