الملف ١٤٥٠\١٩١٩ "بلاد الرافدين وكردستان: تقارير جيولوجية عنها" [و‎‎١‎٨‎٤] (٥٢٢/٣٩٠)

Some three miles N.W. of the Kurah Chai, in the uppermost horizons of the N.E. limb of the
•p is the sulphur spring of Gharrah. This is an emanation of sulphuretted hydrogen accom-
a ied as usual by bituminous earth. In the plain ab'the foot of the hills immediately opposite
this spot, a long trench and a round pit have been dug, evidently on natural seepages, since they
both contain tarry oil floating on water. There are a few unimportant bituminous beds outcrop
ping between this spot and Gharrah.
(ii) Prospects of Boring .—The prospects of obtaining oil by boring cannot be called attractive, j
but the steady yield from the pits at Palkanah, though very small, arouses the question whether
omething more could not be made of this and possibly other spots along the fold. The anticline is
not only strongly overfolded and fold-faulted, but is a tightly compressed, considerably contorted
isocline Possibly other reversed strike faults—which are never easy to recognize—are more
f eauent than a survey would indicate : that they do exist is shewn in the Kifri and Aq Su
sections We may at once disabuse our minds of any hope that this could ever prove a rich held.
What I have said regarding the Kirkuk area applies still more disadvantageously to this anticline.
The most that could be expected is a very narrow held w r ith capricious oil pools tapped by rapidly
declining wells. A remunerative well struck in such an area is sometimes more a curse than a
blessingras it raises false hope and leads to further expensive experiments.
In the absence of any undisturbed spot with favourable structure, one would be unwilling to
locate any test boring far from the natural occurrences. In making a location for a deep bore I
should be inclined to assume that the axial plane of the main anticline is a little S.W. of the sum
mit of the range, and select a spot, therefore, N.E. of the summit, so as to allow for a considerable
hade of the axis locus. If it were necessary to prove one way or the other whether the area
contained remunerative supplies of deep-lying oil, I should bore in the above position, hrst, in the
Palkanah area, secondly at Gharrah, and perhaps, thirdly, between the two sulphuretted hydrogen
occurrences E. of Tuz Khurmatu. The result, as I have said, must be looked upon as entirely
speculative.
A proposition less hazardous is the exploitation with shallow boring, especially of the minor
anticline in the N.E. flank at Palkanah. That the natural indications in this area occur on the
overfolded side of the axis and not on the other side, is perhaps an adverse point, as this restriction
is rather in favour of the seepages occurring along a strike fault. The undertaking would be
speculative, but less expensive and therefore less hazardous. Borings should be located on the
N.E. side of the double limestone ridge, beginning at the highest point.
Lastly, there is the question of hand-dug wells or pits. I would suggest one or two experimental
pits between some of the present pits, along the same line, to ascertain whether an actual surface
seepage is necessary as an indication of oil below ; there is room for such pits. I should also be
inclined to suggest, provided that a shallow boring is not to be faced, that an experimental pit be
sunk on the N.E. side of the limestone to a depth of say 200—300 feet, piercing the steeply dipping
limestone on the way. The Burmans reach depths of 400 feet in this way by using a diving
apparatus, through which a supply of air is pumped down to the digger. Light is thrown down by
a mirror at the surface, and the diggings are hauled to the surface in the usual way. Their wells
are four feet square, shafts timbered most of the way down. Ihe difficulty would be getting through
the limestone, but this might be engineered by judicious use of blasting powder. The Burmans
get through hard bands by dropping a heavy weight from the mouth of the well ; this, however, is a
cumbrous, though sufficiently effective method, and might fail in the case of a highly-inclined band
of limestone.
Kifri coal.—The Kifri coal mines are situated about 3 miles E.S.E. of Kifri in the upper-half
of zone “ a ” of the Lower Stage of the Red Clay and Sandstone Series, some 1,100 feet above the
top of the Ears gypsum series. The mines are flooded with water and the coal occunences not
properly visible. The occurrences in situ at the surface are very scanty and obscured ; one of these
occupied a locally contorted and faulted spot. From the meagre evidence one gathered that the f .
coal shewed the usual characteristic of Tertiary coal in being extremely pockety ’. It appears \
to be restricted to a length of not more than 800 yards along the strike. In one small stream-cornse
I found a small mass of it, which might well have originated from an isolated tiee-trunk. The
working of such deposits consists usually in taking what can be seen until it is too thin or impure
to pa^. From the use made of it by the Turks and from the number of buildings they erected
round the mines, one would judge the deposits to be of comparative importance, especially in a
country short of fuel. The dip of the strata at the mines is unfortunately high ; the beds twist a
little locally, but the general dip is about 55 in a N.E. direction.
The coal varies much in quality. A carefully averaged sample has been already analysed and
has shewn a low calorific value. It is a true bignite, very light and friable, and I could find no
immediate association with oil or bitumen.
This coal occurrence is of much theoretical interest. In Assam and Burma theie is a ^ery
distinct relationship between the occurrence of oil and of coal. In my memoirs on these two aieas
I have tried to shew that this relationship is a mutually supplantive one. Coal may supplant oil
laterally in the same series, and seems to do so towards the shores of the ancient gulf in which the
petroliferous sediments were laid down, or, more usually, it takes the place of oil as it were, in the
succeeding strata, which belong either to the following fluviatile period, or may be classed as prema
ture fluviatile deposits in the top of the oil-bearing series. In Kifri it occurs in the lowest horizons
of the fluviatile series. It is significant that the first occurrence of coal met with on my present
tour, is in a geographical position which cannot be very far from the margin of the old Fars Gulf.
Along the Tigris, which occupies a more central part of the gulf, no coal was observed.
< 1
i
E. H. PASCOE, Supdt.,
Geol. Sur., India.
Dated 29th March, 1919.