Exploration

[ Up ] [ Introduction ] [ Seismic Expressions ] [ Results ] [ Bayu-Undan ] [ Tahbilk ] [ Skua ] [ Jabiru ] [ Cornea ] [ Anomaly1 ] [ Anomaly2 ] [ Anomaly3 ] [ North Rankin ] [ Enfield ] [ Macedon ] [ Chinook ] [ Carnarvon ] [ Novara NW ] [ Zeewulf ] [ Jupiter ] [ Scarborough ] [ Otway ] [ Kingfish ] [ Exploration ] [ Skua Detail ] [ Macedon Detail ] [ Implications ] [ Summary ] [ Acknowledgements ] [ References ] [ Authors ] [ Update ]

USING SEISMIC LEAKAGE INDICATORS AS AN EXPLORATION TOOL

Mapping and interpreting leakage-related effects on 3D seismic data

3D seismic can often allow the size and extent of HRDZs, and other leakage-related effects, to be mapped accurately. Understanding the length, extent and distribution and the intensity of these seismic anomalies, can potentially provide important information about the hydrocarbon charge and preservation history of traps located below these HRDZs. The following assumptions can be made about a cluster of HRDZs above a structure or stratigraphic trap:
1. The leakage is from an accumulation, not a migration pathway.
2. The leaked hydrocarbons have moved mostly vertically through the overlying formations with little lateral movement.

If these assumptions are valid, then the extent of anomalies mapped above an accumulation provides an indication of the area of the accumulation as it existed prior to any leakage. This information can be combined with the depth mapping of the structure to estimate the original hydrocarbon volume. The combined volume of the HRDZs can be used to estimate the amount of leakage, thereby allowing the volume of remaining hydrocarbons to be assessed.

In the present study, two areas with seismically-imaged, seepage-related anomalies have been investigated in detail, namely the Skua-Swift region in the southern Vulcan Sub-basin and the Macedon gas field in the Carnarvon Basin.