Operator Norwest Energy NL 27.945%
JV Partners AWE Limited 44.252% (via subsidiaries)
Bharat PetroResources 27.803%
Total Area 508.3km²
During Q2 CY2015, Norwest successfully completed the EP413 Arrowsmith 3D seismic acquisition survey on behalf of the EP413 Joint Venture. The survey was designed to assess the extent of the resource surrounding Arrowsmith-2. During Q4 CY2015, the processing of the 3D dataset was completed, including pre-stack depth migration and fracture analysis. Final results indicate a substantial improvement in structural definition, providing a greatly improved understanding of the geology within the permit boundaries, and with confirmation that the geology supports ongoing development plans for the permit.
The main formations of interest from the Arrowsmith-2 testing are present throughout the survey area, with the fracture analysis indicating an increased presence of natural fractures to the southern end of the block (Carynginia Formation), meaning increased natural gas flow is likely from this area. An unexpected outcome from the 3D seismic survey was the discovery of additional prospectivity in the southern end of the permit, named the Brand Prospect. This area is approximately 7.5km south of Arrowsmith-2 on the north-plunging Permian anticline, located on the Arrowsmith-Woodada Permian Terrace. This prospect targets tight gas in the Kockatea, Beekeeper, Carynginia, Irwin River Coal Measures and High Cliff Sandstone, with conventional gas possible from the naturally fractured Carynginia. On the basis of similarities in structural form and seismic character with that seen further south over the Woodada Gas Field, there is also the potential for stratigraphically trapped conventional gas.
EP413 Brand Prospect
This new prospectivity in no way detracts from the reported shale gas potential of the permit, particularly as the shale formations are continuous throughout the block, however it presents itself as an additional opportunity to evaluate, particularly with reference to planning the optimal surface location for a well. As this is a new discovery within the permit, the Joint Venture is carefully evaluating this information, and will complete a detailed review and interpretation of the entire 3D seismic survey area to determine the best location for the upcoming well. Due to this new geological knowledge, in mid-December 2015, Norwest and the EP413 JV partners made a request to the Department of Mines and Petroleum for a variation to the work program, to allow for additional time to evaluate this area. Due to the evidence of this new geological knowledge, approval was granted in early January 2016, such that Year 3 and Year 4 of the approved work program are now swapped, with the drilling of a well not required until Year 4 (commencing February 2017).
EP413 Hydrocarbon Plays – Summary
|Carynginia (Beekeeper) Formation
Irwin River Coal Measures
High Cliff Sandstone
|Conventional Gas||Porous / fractured Permian formations
Fractured Carynginia / Beekeeper
Dolarenitic sands within the Beekeeper
|Tight Gas / Conventional Gas||Fractured lower Kockatea Shale|
Further work this year will fully assess the options for this highly prospective permit. A detailed in-house interpretation is now underway, and an EP413 Joint Venture meeting is planned for early February to finalise the work program for the year.
Norwest completed the EP413 3D seismic survey in May 2015. The approvals were granted following the completion of the following surveys:
- Level 1 flora and fauna habitat assessment (2012)
- Level 2 botanical and weed survey (2014)
- Aboriginal heritage survey (2013)
- Dieback survey (2013)
To complete the acquisition it was necessary to mulch vegetation to form vehicle access lanes, in a grid pattern with lanes approximately 400 metres apart. Vegetation was cut close to the ground surface, with the greenstock mulched – this method provides the best opportunity for rapid rehabilitation of vegetation. The botanical surveys completed previously were used to deviate the mulching lanes around significant environmental features including rare flora, waterways, rock outcrops, slow-recovering species and fauna habitat.
As part of the rehabilitation commitment under the EPBC Act, the EP413 Joint Venture is required to provide funding to the Department of Parks and Wildlife (DPaW) to purchase suitable land to offset the clearing of the black cockatoo foraging habitat, and to compensate for residual impact of the survey. Norwest is pleased to announce that DPaW has now identified a suitable 290 hectare privately-owned parcel of land containing abundant black cockatoo nesting sites and foraging habitat, which the EP413 Joint Venture will now fund the purchase of. The cost of the land acquisition will be less than had been previously estimated and approved by the Joint Venture in its work program and budget.
The first annual rehabilitation monitoring survey was undertaken in November 2015 by botanists.