- The final interpretation of the gravity gradiometry/magnetic survey confirms Oilex’s structural mode of the Wallal Graben, which is clearly imaged by 2D seismic data in the company’s adjacent permits (STP_EPA_0106 & STP_EPA_0107).
- The graben is present in Oilex’s three, 100% owned, exploration areas encompassing approximately 11,739 km² (~2.9 million acres).
- The Wallal Graben appears to have significant conventional and unconventional play types consistent with those identified elsewhere in the Canning Basin. Amongst these play types Oilex has identified large areas of what is thought to be prospective Bongabinni and Goldwyer Formations, which are proven source rocks in the Canning Basin.
- Application for formal exploration permit has commenced on an exclusive basis.
STP-EPA-0131 IN DEPTH
Wallal Graben Geology
Only low resolution gravity and magnetic data and sparse vintage 2D seismic data of variable quality have been previously acquired over the south-west Canning Basin and no wells drilled to date have penetrated the graben-fill.
This low resolution gravity/magnetics data appears inconsistent with seismic data in relation to the size and extent of the Wallal Graben in the Canning Basin. Interpretation of the 2D seismic data and subsequent depth conversion identified an extensive half graben up to 5.5km deep – something that Oilex identified as particularly promising for the generation of hydrocarbons.
The nearby Samphire Graben is well imaged on both gravity and magnetic and 2D seismic data, resulting in it being clearly defined on published structural maps of this area. A regional 2D seismic line acquired in 1985 ties both the Wallal and Samphire Grabens. This line clearly shows the lateral extent of the two depocenters with the Wallal Graben being narrower but deeper than the Samphire Graben.
The Goldwyer Formation, a well acknowledged unconventional play (See EIA Report
), is also interpreted to exist. The Wallal Graben may be a relative sweet spot for these organic-rich source rocks due to the geological history of this area of the Canning Basin. Numerous conventional plays may also exist within the Wallal Graben, enhancing the attractiveness of the acreage.
Due to the confined nature of the depositional environment, it is considered that the source rocks within the Wallal Graben may be richer than those deposited in the other areas of the Canning Basin and where increased oceanic circulation and less anoxic conditions prevailed.