Science Centres: Coasts

A better picture for oil exploration

Oblique view of the Matakaoa Avalanche, north of East Cape, produced with multi-beam swath bathymetry.

Geological processes operating on the seafloor are like a window into the past. With modern marine geoscience technologies, this window can be used to guide exploration for oil reservoirs buried far below.

New Zealand’s oil industry relies on seismic reflection data to find geological structures, such as folds and faults, that can form traps for oil and gas deep beneath the seafloor. However, seismic reflection alone may not provide a detailed and unambiguous interpretation of these structures and strata. NIWA scientists are combining the technique with multi-beam swath bathymetry and sediment cores to examine the seafloor in detail. From this, we can get a better picture of what’s gone on in the past, deeper down where the oil reservoirs may be.

We’re finding that the picture is often more complex than it may appear from seismic reflection data alone. For instance, we’ve found huge ‘bites’ taken out of the seafloor by submarine avalanches in eastern Bay of Plenty. Using seismic reflection alone, the boundaries of the ‘bitemarks’ would often be mistaken for faults.

"This research helps the oil industry to better interpret their seismic data," says collaborator Dr Mac Beggs of GeoSphere Ltd., who presented the work to the New Zealand Petroleum Conference earlier this month.