Ann: NZO: RIG SIGNED UP DRILL. BOOTH WELL IN L7 PERM. PERTH BAS, page-38

The shallowest commercial penetration of the Kingia Fm is the 'K' sand in the Cliff Head oilfield at a depth of ~1300m, but that doesn't really answer the true question. The real question that you are asking is what is the shallowest that 'anomalous' porosity preservation has been noted in.

The anomalous porosity preservation starts to be observable from depths greater than 2000m - it is likely still present in shallower depths, but the effect of the additional porosity preservation isn't able to be recognised from the standard porosity-depth trends until about this point. Offset wells around the L7 permit where Booth is to be drilled have recorded both well penetrations where porosity has exceeded 18% at depths slightly greater than 2000m and also penetrations where the Kingia Formation was effectively tight at depths slightly shallower than 2000m. To be honest this is to be expected in a play such as the Kingia Fm where there is a degree of lateral variability in the porosity distribution.

So the short, simplified answer to your question would be that in the area around Booth there are a number of wells at similar depths to the Booth prospect where the porosity preservation in the Kingia Fm does work, and also a couple of examples where the Kingia Fm is tight. Overall, there is more positive data than negative data.