"Is it usually the same for every drilling horizon and drilling location? ie, will MK-2 have the same por. per. of MK-1 and does implicitly pebbly arkose formation have the same por, per, of lower/upper angwa?"
Permeability and porosity can vary widely between basins, between different formations/reservoirs and even vertically and laterally within a single reservoir.
One problem with trying to characterize reservoir properties is you're trying to gain a picture of the entire reservoir based on a very limited data set. You're relying largely on indirect measurements of porosity and permeability (eg via wireline logs) rather than measurements made on actual samples of the reservoir rock. Even when you have rock samples wot work on....you're working on rock at surface conditions not reservoir conditions (eg confining pressure).
I would expect The Pebbly Arkose to have different poro/perm properties to the Upper Angwa....mainly due to grain size (PA is coarser) and age/burial history. Finer grained formations generally have more clay/silt sized matrix in between the sand clasts which will affect permeability. Younger rock units will generally have a shorter less complex burial history which translates to less compaction. Compaction generally leads to a reduction on porosity and permeability.
Re Upper and Lower Angwa.....the Upper Angwa is dominated by interbedded sands and finer grained units while the Lower Angwa has thicker sands units...Ive seen it often described as a massive sand unit. Massive sand units are usually cleaner (less clay matrix) than the thinner sands within an interbedded sand/clay sequence like the U Angwa.
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