BY J. B. HENDERSON. 59 



The oil in these cases only came up intermittently 

 and ceased coming when boring was finished. In the case 

 of the gas, in some wells it behaved in exactly the same way. 



In the exposition which followed, Mr. Henderson 

 demonstrated by means of a simple apparatus that if, in 

 boring with a big head of water in the bore, a stratum is 

 struck containing oil or gas at less pressure than the pressure 

 of the column of water in the bore, the water in the bore 

 will flow into the stratum^not the oil or gas into the bore. 

 When the tools or bailer are lifted, thereby momentarily 

 decreasing the bore water pressure, some oil or gas will 

 follow the tools or bailer ; but, as they ascend, the 

 pressure again increases and stops the flow. For obvious 

 reasons greater volumes of gas would be liberated than of 

 oil. 



If the volume of gas liberated was sufficient to e4ib- 

 lish an '" air lift " then the gas would continue flowing so 

 long as the air Lift worked. This was shown by the appar- 

 atus, and reference made to how this worked at the Roma 

 Bore. 



If the air lift is once blocked and the excess pressure 

 from the bore water gets at the gas bearing stratum, then 

 the gas flow will cease. This was also demonstrated by 

 the apparatus, and a parallel drawn with the loss of gas in 

 the Roma Bores. 



The lecturer then pointed out that the conditions 

 demonstrated undoubtedh' occurred in several of the 

 Queensland bores in which small quantities of oil were 

 found while boring. It is therefor? certain that oil bLaring 

 strata were pierced in several bores, most of them in the 

 Central District, and it is also certain that, had the bores 

 been pumped out to lower the pressure, a supply of oil 

 would have been obtained. What the supply would have 

 ^mounted to per da}', and what is the quality of the oil, 

 is, of course, not known. It is also impossible to foretell 

 the result of the great water pressure on these strata for 

 the long time which has elapsed since boring. It may 

 have driven the oil away and may not. The lecturer 

 demonstrated with the apparatus conditions under which 

 it would be driven awa}', and some in which it would not. 



