HEUUM, THE NEW BALLOON GAS 



451 



come liquid. The liquid, after being sepa- 

 rated from the helium gas, is allowed to 

 warm up until it returns to its normal 

 gaseous condition, when it is put back into 

 the mains and used as ordinary natural 

 gas. 



This process does not in the least in- 

 jury the quality of the natural gas for 

 heating purposes — in fact, it improves it, 

 for the helium, the only substance re- 

 moved, is incombustible. 



THE SEARCH FOR HEEIUM-BEARING GASES 



While the experimental work on ex- 

 tracting helium was under way, members 

 of the Geological Survey, of whom I was 

 ' one, were engaged in a search for further 

 supplies of the helium-bearing gas, for 

 it was very evident that the Petrolia, 

 Texas, field, in which operations were 

 started, would supply only a fraction of 

 the quantity desired by the United States 

 alone. Furthermore, a gas field is an 

 ephemeral thing, some fields lasting ten 

 years and others only a year or so ; so 

 that it was necessary not only to keep the 

 supply ahead of the demand, but to esti- 

 mate as closely as possible how long each 

 field would last, and in this way avoid the 

 mistake of installing expensive machinery 

 in a practically exhausted field. 



This work was begun in June, 1918, 

 and in September the Geological Survev 

 was able to advise the military authori- 

 ties that sufficient supplies of the gas had 

 been located to furnish over five million 

 cubic feet of helium per week, or enough 

 to meet the demands of the United States 

 and of Great Britain and France as well. 



The search for helium was simplified 

 by the fact that all the helium-rich gases 

 are apparently poor in heating value, and 

 information as to the heating quality of 

 a gas is usually not cfifficult to obtain. 



The richest gas is the "wind gas" of 

 southern Kansas and northern Oklahoma, 

 which for so many years had consistently 

 been allowed to go to waste. A sample of 

 this gas which I collected in the Augusta 

 field, Kans., contained over 2 per cent of 

 helium and is the richest variety known. 



WHERE AND HOW THE GAS OCCURS 



We soon found, moreover, that in the 

 Kansas, Oklahoma, and Texas fields the 

 helium gas occurs only in a certain group 



of geologic formations, and that in the 

 strata above and below this group the 

 helium content is very low. Another 

 characteristic of the rich gas is its com- 

 mon occurrence at shallow depths — the 

 best gas usually occurs above 600 or 800 

 feet, and gas in sands deeper than 1,600 

 feet is very poor in helium. 



These three principles, once established, 

 narrowed down the promising areas con- 

 siderably and permitted intensive studies 

 of the richest supplies. In some of the 

 best fields practically every gas well was 

 sampled, the samples being taken in small 

 steel tubes, especially designed for the 

 purpose, and sent immediately to the Bu- 

 reau of Mines laboratory for analysis. 



Possible sources outside of the Kansas- 

 Oklahoma-Texas area were not neglected, 

 however ; many samples were collected in 

 Ohio, Wyoming, Louisiana, Montana, 

 California, and elsewhere, but only in 

 Ohio were valuable supplies discovered. 



OUR LARGEST HEUUM ElEED 



The largest of the helium gas fields is 

 Petrolia, which is located on the flat prai- 

 ries of northern Texas, about 100 miles 

 north of Fort Worth. The gas here is 

 found in sands from 1,400 to 1,600 feet 

 deep and carries practically 1 per cent 

 of helium, which is regarded as a good 

 working proposition. 



It is the Petrolia gas that is now being 

 treated by the small experimental plants, 

 and the Government has taken a ten- 

 year lease on the helium output 'of the 

 field and is now erecting plants capable 

 of turning out at least 50,000 cubic feet 

 a day. 



At present there are about fifty gas 

 wells in Petrolia, some of which origi- 

 nally produced as much as 30 or 40 mil- 

 lion cubic feet of raw gas a day. When 

 the field was first opened, about 1910, 

 the gas issued under a pressure of 700 

 pounds per square inch, but the field has 

 now seen its best days and the pressure 

 has declined to less than 100 pounds. 



Had the demand for helium come three 

 years earlier, Petrolia alone could prob- 

 ably have furnished enough to satisfy the 

 military program of the United States, 

 but the production of the field has now 

 fallen to a point where the helium con- 

 tent totals less than a million cubic feet 



