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

Mahdi H Almutlaq and Gary F. Margrave

ABSTRACT

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.

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