Norwest Energy downgrades Xanadu potential after 3D program

The Norwest Energy Ltd.-operated joint venture has revised its structural model of the Xanadu oil discovery in permit TP/15 in the inshore sector of the Perth basin, Western Australia following receipt of the final processed 3D seismic data from the 40 sq km Xanadu Transition Zone survey run in July this year.

Norwest said that the fault geometry that defines the up-dip structure has changed such that the up-dip area to the north of the Xanadu-1 discovery well intersection is reduced. Consequently commerciality of the up-dip resource is likely to be marginal. Three reservoirs in this zone have been shown to be of limited thickness and each likely to require horizontal well completion.

The company said further engineering and commercial studies are required before contingent resources can be determined and a decision made on whether future appraisal can be justified.

On a more positive note, Norwest said the area down-dip of the discovery well offers greater resource potential, but only in the ‘A’ sand and this too is regarded as relatively high risk.

The JV will now undertake further analysis to integrate the revised structural model with down-dip data acquired from Xanadu-1 to determine whether the chance of success for a down-dip appraisal well might be increased.

Norwest said there is still untapped prospective potential within and adjacent to the 3D seismic coverage to the north of the Xanadu horst and in a structural culmination to the west of the down-dip area. The JV will consider a 2D survey in this area to mature a drilling prospect.

Additional prospective resource potential is seen within the deeper Kingia/High Cliff Formations, but further work is required to quantify these prospective resources.

The original Xanadu-1 well, drilled in 2017, intersected three sandstone reservoir units with the upper ‘A’ sand interpreted as having 4.6m of net oil pay. Oil was recovered with wireline techniques.

At that time, it was conjectured that two deeper sands (‘B’ and ‘C’) may host oil pay in an up-dip location. The 3D seismic survey was programed to test that potential, but found instead there is no evidence of a thickening of the reservoir sequence in that direction.

Norwest is operator of the Xanadu project with 25% interest. Triangle Energy has 45% and the 3C Group 30%.