Ananke-1With very little information emerging from Woodside...

Ananke-1
With very little information emerging from Woodside regarding the success or otherwise of their Ananke-1 well, I had a look at information submitted by MEO Australia (the adjacent permit holder) to the ASX going back to 2009.

I have attached some pictures from MEO’s presentations that I thought were relevant.

It appears that MEO’s Artemis-1 well encountered a Late Jurassic Dingo-aged sandstone 10-20 m thick above the Main Unconformity but below the gas-water contact of -3127 m seen at Wheatstone and Pluto. The presence of these Dingo sandstones above the unconformity means that sub-cropping Calypso and Legendre sandstone beneath the unconformity are connected to Wheatstone (and probably also to Pluto) where the same sands occur in communication with subcropping Triassic gas-charged reservoir sands below. This is the likely reason why Artemis-1 failed.

An analogy to the Perseus gas field had been invoked by MEO where the trap is formed in a down-thrown Jurassic fault block margining Triassic fault blocks which contain the Rankin and Goodwyn gas fields. The trap relies on fault seal on the margining faults and no reservoir connection above the Main Unconformity. In addition, high seismic amplitudes seen at Artemis in sandstones did not prove not to be related to reservoired gas as anticipated.

But while gas was not discovered at Artemis-1, the geology encountered, particularly the presence of reservoir-quality sands does provide an opportunity. It means that any sandstone reservoirs above the -3127 m GWC at Wheatstone and in communication with the field, will be gas-charged.

But the main questions as to how big this play could be relates to reservoir distribution across the region; reservoir quality; how thick the reservoir is (it appears to be approximately only 10 m thick at Wheatstone but may thicken in relative lows off the high block); and how big is the closure.

Based on the geology documented by MEO and available to us, we do have a very good analogy to Ananke. And that is the giant, multi TCF Io/Jansz gas field to the west. The reservoirs at both are Late Jurassic in age. The reservoirs at both are also connected to older Triassic reservoirs in adjacent fields and share common GWC’s.

However without the wells, it is difficult to gauge reservoir distribution, thickness and quality across the region. But based on MEO’s published depth map at the Main Unconformity and cross-sections also from MEO, I have tried to get an indication of how big an area the Ananke closure might cover above the Wheatstone/Pluto GWC.

While the Dingo sandstone has been encountered in the Wheatstone wells (albeit thin), the sands are not present over all highs such as at Pluto and also at the Guilford-1 well. But note that the structure lies directly below the shelf edge making depth conversion extremely difficult.

Although MEO say that they purchased the Foxhound 3D survey covering Ananke, it appears that MEO’s map is old and may not incorporate this data. In going back over older ASX presentations from MEO, it also appears that this exploration concept was identified and described by MEO earlier.

What my scratchings reveal is that Ananke could be enormous. Perhaps not quite in the same league as Io/Jansz, but big and in the multi TCF range. Possibly big enough to supply a second Pluto LNG train. Maybe Woodside will have more to say about this today (or not!).