24 
Presence of Oil. 
Paragraph 6. — Apart from the petrol absorbed from the gas no liquid oil has yet been noticed in any material 
yielded from this bore. 
Probable Conditions of Gas Field. 
Paragraph 7. — From the data observed in this No. 4 bore, the records from Nos. 2 and 3 Roma bores, and from 
other facts, the Committee are of opinion that the gas yield is likely to prove of permanent value, that is that the yield 
of gas is likely to be enormous and to last for years. It exists in the strata at a static pressure which is very great and 
will probably prove to be in the region of 1,400 lbs. per square inch, which implies that the capacity of the sands for 
carrying gas is correspondingly great. 
Possible Proximity of Oil. 
Paragraph 8. — While natural gas fields result from petroleum deposits, some gas fields are known which do not 
yield any oil. Other natural gas fields yield oil only in small quantities and over small areas of the gas field. The finding 
of a natural gas containing petrol of the composition found at Roma is looked on as a very strong indication of the close 
proximity of oil. It is not, however, proof of such proximity, and is certainly no proof of the presence of oil in 
commercially payable quantities. The most that can be said is that the fact that the gas contains petrol materially 
increases the prospects of success in boring for oil. 
An analysis of the gas at Roma is given by Mr. Cameron : — * 
Paraffin series (including ethane 9.8 per cent.) 
Benzine series 
Olefin series 
Carbon monoxide 
Carbon dioxide 
Nitrogen and residual gas 
Oxygen and hydrogen 
82 . 4 per cent. 
5.0 „ 
1.5 
5.8 
1.5 
3.4 
0.00 
77 
7 7 
77 
77 
It is a wet gas which is very suggestive of the presence of oil in the strata. No evidence of a 
structure can be found at Roma unless the rounded hill on which the bores are situated represents 
a local dome-shaped fold, but I am of opinion that some favourable structure exists since I think 
the presence of such large bodies of gas under such pressures in this locality connote the existence 
of favourable structural conditions. It may be that the gas is sealed in by the lenticularity of 
the beds, but such conditions are favourable to the accumulation of oil also. In such a case, 
however, the presence of the lens at depth cannot be ascertained by geological work at the surface, 
which is very unfortunate, for the only means of locating such a structure is the drilling of wild-cat 
wells, which is a very expensive and often a very disappointing business. The only other recorded 
instance of the existence of a wet natural gas in a bore in Queensland is one found by Mr. Ball 
at Ruthven, a few miles south of Longreach. Small quantities of gas are coming from an old bore 
which was drilled to 4,070 feet. The Government Analyst found a sample collected by Mr. Ball 
to contain — 
Carbon dioxide 
Air 
Methane 
Higher paraffins (as ethane) 
Inert gases 
32 . 2 per cent. 
2.0 
32.5 
2.8 
30.5 
7 7 
77 
77 
7i 
100.0 
Instances of the occurrence of methane in boreholes are fairly frequent, but since this is commonly 
connected with the presence of coal seams and carbonaceous beds such occurrences are of no 
importance in the quest for petroleum. 
G. Occurrences of Petroleum. 
Small showings of petroleum have been noted during the drilling of many wells in 
Queensland, but such showings have no serious significance as a rule. During our visit to the 
bore now being drilled at Orallo, Mr. Ball took a sample of the mud fluid being used in connexion 
with the work. The plant in use is a modern rotary, and the mud-laden fluid is circulated from 
the surface inside the drill pipe to the bottom of the hole and back again to the surface, bringing 
with it the debris produced by the rotation of the drilling bit, and also forming a coating on the 
walls of the borehole. The depth of the bore was 1,312 feet at the time, and no claim was made 
that the strata was oil-bearing. The sample taken by Mr. Ball was analyzed by the Government 
Analyst with the following results : — 
Specific gravity at 26° C. .. .. .. ..1.21 
Weight of sample . . . . . . . . . . 700 grams 
Weight of free oil in sample .. .. .. .. 0.44 grams 
Percentage of free oil in sample, 0.063. 
The extracted oil had the consistency of mineral grease at 20° C. 
* Loc. cit. p. 33. 
