File 1450/1919 ‘Mesopotamia & Kurdistan: Geological Reports on’ [‎195r] (412/522)

of 1,800 feet. It should not be carried much below this depth as it would then
get too near the underground crest.
No. 3 location for 3,000 feet depth will test all horizons down to that depth
if they contain a lot of oil, but if there is a narrow pool of oil occupying only
the apex of any porous band and not extending down the flank, it will test the
deeper horizons only. Or to consider actual figures, suppose a long narrow pool
of oil existed at 1,200 feet depth below surface, a well on No. 2 location would
strike this. A well on No. 3 location would enter this same horizon down the
flank at a distance of 1,300 feet from the underground axis, and 300 feet in a
vertical direction below the crest of this particular band. If therefore th e oil
did not extend for a distance of 1,350 feet down the gently dipping flank of this
band it would be missed at No. 3 location.
From the ^ above it is evident that for a complete test of the anticline it
would be necessary to drill two wells such as Nos. 2 and 3 locations, but which
ever were drilled first, if it proved a failure, would be an exceedingly un
favourable sign for the other. If they both failed to get oil the anticline should
at once be finally abandoned, c
A successful field at Naft KLhana would raise the question of the possibility
of oil in the Qasr-i-Shirin, Chah Surkh and any other intermediate anticlines,
though in most of this country it would be buried too deeply beneath Upper
Ears and Bakhtiari strata to be within reach of the drill.
Mr. Brown of the Anglo-Persian Oil Co., who went to examine the coal
deposits of Kifri and neighbouring oil shows, reports seepages of oil coming
from the Middle Ears beds near Tuz Khurmatli, but owing to the obscuring
of the evidence by deposits of Alluvium the structure was not entirely resolved,
and he does not on this account recommend the locality for immediate test.
It is situated about 30 miles further from Baghdad than Naft Khana,
(34) Sit and Abu Jir .—The prospects of obtaining oil at Hit must remain
to some extent speculative without drilling. As a general rule the Asmari
Limestone is not a suitable reservoir rock, but at Hit there is a porous variety
which could store oil. As only a thickness of 50 feet of this limestone is
exposed it is impossible to say what may lie underneath, and there is no
inherent improbability of finding some of it dolomitised by which action a
considerable reduction in volume is effected leaving an excellent oil reservoir
rock. On lithological grounds it is not impossible that the Asmari Limestone
may contain suitable reservoir rocks for oil.
As regards a cap rock it is difficult to conceive that oil could migrate far
through the compact homogeneous Asmari Limestone in its typical form,
especially heavy asphaltic oil. The existence of porous strata or zones in the
limestone has already been presupposed, and the hard compact variety with
which these are interbedded would serve to detain any oil contained. Then
too the associated shales would form an excellent cap rock, but we do not know
whether these occur above or below the petroliferous horizon, or whether they
themselves are the source of the oil. In any case from what the author has
seen of the series, he finds it easier to regard it as successfully fulfilling the
r61e of cap rock than of reservoir rock.
The partial dome structure of Hit has dips of such slight inclination that
it might easily be thought they would be insufficient for the concentration
of a heavy asphaltic oil. However, the seepages of bitumen and gas are there
in such quantity that a considerable concentration must have taken place.
The same remarks apply in their entirety to the Abu Jir anticline, which has
given rise to the seepages of Abu Jir, Jebhah and Ain-al-Awasil.
In spite of the scarcity of the evidence, in the main the necessary condi
tions for the occurrence of oil in quantity exist at Hit and Abu Jir, the point
on which it is most difficult to judge being the nature and extent of the
possible oil reservoir rock. Eavourable evidence on this is two-fold, the
existence of porous or cavernous limestone at Hit, and the occurrence of
bituminous seepages of such large extent. However, the only satisfactory
solution there can ever be here is the drilling of a well both at Hit and Abu Jir.
These two wells would finally condemn the district should they get nothing.

File 1450/1919 ‘Mesopotamia & Kurdistan: Geological Reports on’ [‎195r] (412/522)

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File 1450/1919 ‘Mesopotamia & Kurdistan: Geological Reports on’ [‎195r] (412/522)

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