Australia's Norwest Energy Updates on Operations at its Upstream Assets

Structurally, the Xanadu Prospect is a prominent horst block lying parallel to the coastline in very shallow water. Xanadu-1 will target Permian sands from a depth of approximately 2,625 feet (800 meters). Near-shore sands of the Dongara Sandstone represent the primary target, with secondary targets in the fluvio-deltaic Irwin River Coal Measures and the regressive marine sands of the High Cliff Sandstone.

Retrieval and mapping of additional 2D marine seismic data has provided a comprehensive regional interpretation of the structural setting and charge history for the Xanadu oil prospect.

The structural mapping, which is based on good quality 2D seismic data, as well as high resolution gravity data resulting from a 2009 airborne 3D Full Tensor Gradiometry Survey, indicates the Xanadu Prospect is geologically similar to both the Cliff Head and Hovea structures. On the basis of reliable seismic correlations, the stratigraphic section at Xanadu is expected to be very similar to that encountered at Vindara 1, 4.3 miles (7 kilometers) to the north-northwest.

In estimating potential Xanadu hydrocarbon volumes, the reservoir parameter values observed in Vindara 1 have been the primary reference. Vindara 1, testing a rotated fault block, had only minor hydrocarbon shows. The failure of this well, and similar structural tests further north, is considered to be due to insufficient charge and/or breach of seal resulting from fault re-activation.

The Xanadu structure is considered to be more favorably located for hydrocarbon charge. Additionally, leakage on fault planes is considered less likely because of the interlocking nature of the fault network which gives rise to the Xanadu horst.

In estimating the recoverable oil volumes summarised in Table 1 below, a 50 percent recovery factor has been assumed.

Table 1


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