HELIUM 



287 



moved upward into traps in the sedimentary column. 

 Concentrations of helium found by drilling occur 

 mixed with other kinds of natural gas, particularly 

 the hydrocarbon gases, nitrogen, and carbon dioxide. 

 Helium in concentrations higher than that of the 

 atmosphere has also been found in the firedamp of 

 many coal mines, in gases from mineral springs, in 

 volcanic gases, and in gases from glacial till and 

 other shallow sources. 



Many natural-gas fields have been tested for 

 helium by the U.S. Bureau of Mines (Anderson and 

 Hinson, 1951; Boone, 1958; Munnerlyn and Miller, 

 1963 ; Miller and Norrell, 1964a, 1964b, 1965 ; Moore, 

 Miller, and Shrewsbury, 1966; Moore and Shrews- 

 bury, 1966, 1967, 1968 ; Cardwell and Benton, 1970a, 

 1970b, 1971). The analyses indicate that in general 

 the concentration of helium in gas fields increases 

 with geologic age of the reservoir rocks (Pierce, 

 1960) . Gas with more than 0.3 percent helium occurs 

 mostly in geologically old rocks, generally of Paleo- 

 zoic age, and less extensively in younger rocks. 



Dobbin (1968) briefly described the occurrences 

 of helium and other nonflammable natural gases that 

 have been found in the United States and Canada, 

 and Jodry and Henneman (1968) reported on the 

 occurrence, origin, and other aspects of helium. 



RESOURCES 



IDENTIFIED AND HYPOTHETICAL RESOURCES 



All helium recovered in the United States except 

 that from gas fields in the Shiprock area of north- 

 western New Mexico (discontinued in 1969) and 

 from the Pinta Dome field near Navajo, Ariz., has 

 come from Kansas and the panhandle areas of 

 Oklahoma and Texas. Recovery has been from gases 

 with helium content of 0.3 percent or more, the mini- 

 mum content considered economically feasible to 

 recover with present technology (Lipper, 1970, p. 

 82). 



So long as natural gas continues to be produced 

 in quantity, helium-rich gas fields will continue to 

 be the main source of helium as a byproduct. Ac- 

 cording to U.S. Bureau of Mines estimates (Thomas- 

 son, 1971, p. 4) , at the end of 1970 at least 80 per- 

 cent of proved helium reserves of 154 billion cubic 

 feet in gases containing 0.3 percent or more of 

 helium were in the five fields — Hugoton, Panhandle, 

 Greenwood, Keyes, and Cliff side (table 56) — that 

 now produce most of the helium. The remaining 

 proved reserves are in 83 scattered fields in Arizona, 

 Colorado, Kansas, Montana, New Mexico, Oklahoma, 

 Texas, Utah, Wyoming, and West Virginia. In most 

 of these fields the helium is not recovered as the gas 

 is withdrawn for fuel. 



The reserves of natural gas of the United States 

 and Canada are reported annually by the American 

 Gas Association and the Canadian Petroleum Asso- 

 ciation, respectively. The Potential Gas Agency pub- 

 lishes biennial estimates of the potential gas supply 

 that is as yet undiscovered. Using the 1968 figures 

 of these organizations for average helium content 

 of gases in the various regions, Lipper (1970, p. 

 82) estimated total helium resources of the United 

 States at about 935 billion cubic feet. He divided 

 this figure into 250 billion cubic feet of proved re- 

 serves, 155 billion probable, 220 billion possible, and 

 310 billion speculative. The average helium content 

 on which these figures are based ranges from 0.006 

 percent in the gulf coast of Louisiana and Texas, 

 where gas reserves and potential are large, to 0.278 

 percent in a seven-State area extending from Min- 

 nesota and Michigan southward to Missouri, where 

 natural-gas reserves and potential are small. 



The extent of helium resources outside North 

 America is mostly unknown because the natural gas 

 resources are not well known. Significant discov- 

 eries have been reported in Canada, Africa, the Mid- 

 dle East, and the U.S.S.R.; however, commercial 

 production from these countries is small. On the 

 basis of a geologic comparison of the sedimentary 

 rocks of the world with those of the United States, 

 Hendricks (1965) estimated the possible ultimate 

 discoveries of natural-gas resources of the sedi- 

 mentary basins of land areas and their bordering 

 continental shelves. Assuming that these gas re- 

 sources contain amounts of helium comparable to 

 those of the United States, on a volume-for-volume 

 basis, an estimate of possible ultimate discoveries 

 of helium outside the United States is nearly seven 

 times that of the United States, which is estimated 

 to have more than 1 trillion cubic feet. The esti- 

 mate for the United States, however, includes the 

 Hugoton, Panhandle, and adjacent gas fields with 

 huge gas volume and large helium content. Gas 

 fields of comparable size occur elsewhere, but thus 

 far none have been reported with comparable helium 

 content. Therefore, such an estimate of world helium 

 resources, at this stage, is highly optimistic. 



How much of the discoverable resources of natural 

 gas and helium might be economically recoverable 

 depends on economic, geological, and geographical 

 factors, which, for the present, are mostly unknown. 

 For example, liquefied natural gas (LNG) is now 

 becoming an important export from countries with 

 large gas resources. The liquefaction process leaves 

 a residual gas enriched in helium. This helium can 

 be recovered and sold if there is sufficient market 

 demand. 



