, ~ ( j ? j f GeoehelDieaI Studies of Natural Gas I PART m. INERT GASES IN WESTERN CANADIAN NATURAL GASES* ~ By BRIAN HITCHONt -j (This is the last of a Series of three Parts presented by the author tor publication in the Journal. Parts I I, and II appeared, in the Summer and Fall issues respectively.)
ABSTRAGr 1 INTRODUcrION GEOCHEMISTRY AND ORIGIN OF In natural gases, the stratigra NITROGEN l phic and geographic variations in J T HIS paper is the third aud final Downloaded from http://onepetro.org/JCPT/article-pdf/2/04/165/2165406/petsoc-63-04-03.pdf by guest on 30 September 2021 1 the contents of both nitrogen and part of a series concerned with Before considering this subject heIiwn are of geochemical interest, further it is very important to con although only helium is of com the geochemistry of natural gas in 1 mercial importance. Nitrogen may Western Canada. It is a discussion sider the units in which the analy l originate from a great variety of of the inert gases nitrogen and he tical data are reported. Ideally, sources, including air, either orig lium. The first paper (1) dealt knowledge of the mass of the in J inally trapped in the sediments or '~ introduced dissolved in percolating with the hydrocarbons and the sec dividual components of natural groWldwaters, the denitrification of ond (2) with the acid gases. Due gases in the sedimentary basin is nitrogenous compounds or the de to their generally unreactive na desirable. From the reports of cay of certain radioactive minerals. ture, chemically, compared to hy Buckley and his co-workers (5) it In contrast, there exist radioac drocarbons or the acid gases, both may be surmised that the bulk of tive sources for all natural helium, nitrogen and helium are common the material is methane, with much and thus the problem of the migra lesser amounts .of other components. tion and accumulation of helium ly classed as inert gases. It is con in rocks differs from that of the venient to discuss them together in The concentrations reported in this other components of natural gases. this series of papers. series of papers are in volume per Helium owes .its origin mainly to cent. Consideration of regional the radioactive decay of uranium variations of the partial pressure and thorium, and its accumulation Although they differ in their to the differential rates of upward modes of origin, migration and ac of some components in various stratigraphic units indicates that diffusion through the sedimentary cumulation, both nitrogen and he strata from the basement rocks. the isoconcentration patterns for The geochemical evidence gives lium are of interest geochemically. partial pressure are essentially sim credence to a mathematical model With respect to both inert gases, ilar to those for volume per cent in of the diffusion process, with spe the discussion will follow the se cial reference to helium. the same respective units and for quence established in the first paper the same components. lContents of nitrogen ranging of this series. from about 8 per cent to 85 per In view of the origin of the hy cent characterize natural gases in southern Alberta from strata rang Nitrogen is the chief component drocarbons cited in a previous'pa _:',0 .. ing in age from Upper Devonian to of the Earth's atmosphere, com per (ll, it is important to realize Lower Cretaceous. In strata of the prising 78 per cent by volwne. It that high concentrations of nitro ~< Middle Devonian Elk Point Group, gen (and also of acid gases and ;':, , the amount of nitrogen in natural is most probably mainly a product '. :..- gases increases to a maximum of of the early degassing of the crust, helium) in some natural gases may nearly 20 per cent as the deposi although some may be a remnant result more from the lack of gen tional edge in the Peace River re from an early primordial atmos eration of hydrocarbons than from gion is approached. ElseWhere, in the generation of large' quantities other stratigraphic units, concen phere (3, p. 441). Its extraction trations are generally less than 10 from natural gas is therefore of of nitrogen. In part, a lack of per cent. Concentrations of helium little commercial importance. He generation of hydrocarbons may ac generally over 0.1 per cent are lium is of great economic value, count for the difficulty experienced found predominantly in natural in detennining the'cause or region gases from the Peace River arch, and the demand in North America the Sweetgrass arch and the hinge is expected to increase from the al variations in the content of nit belt of the Alberta basin. Contents present rate of 600 million cubic rogen in natural gases in Western in the range of 1.0 to 1.9 per cent feet per year to over 2 billion cubic Canada. helium have been found in the conunercial gas occurrences in Up feet per year by 1980 (4). At tWs Nitrogen in natural gases may per Cambrian strata in southern time (1963), the United States Gov be generated in a variety of ways. Saskatchewan. "'.' ernment controls virtually all pro The high content of nitrogen in the duction and distribution of helium atmosphere and its inert character ! and consumes over 75 per cent of have been noted by many writers, 1 the heIiwn produced in the free *Oontribution No. 242, Research who have attributed its presence in Council of Alberta: world. The heliwn-rich natural natural gases to air originally trap gases discovered recently in Saskat ped in the sediments. The absence chewan are therefore of consider of oxygen in natural gas is believed .. ;: able importance, and the technical tResearch Geologist, Research to be due to its removal during de Council of Alberta, Edmonton, Al and economic aspects of helium composition of the associated or berta, Canada. production from these gases have ganic matter and its affinity for been evaluated (4). metals, especially iron. Technology, Winter, 1963, Calgary 165 -.', . Nitrogen may originate from the Hoering and Moore (15) showed hypothesis merits further stUdy, denitrification of nitrates and nit that wide variations exist between and provides yet another possible rites by bacteria, and Rybakova the Nl5/N14 ratio of natural gases source for nitrogen in natural gases. (6) has found denitrifying bacteria and the associated crude oils, and in crude oil. Kaveev (7) concluded that the natural gas was relatively that the nitrogen in natural gases enriched in the lighter isotope. GEOCHEMISTRY AND ORIGIN OF at Tatar, U.S.S.R., appeared to be They attributed this difference HELIUM a product of the decomposition of to an origin of the nitrogen There exist radioactive sources organic sediments. A relationship through decomposition of the nitro for all natural helium (8), and thus Inight be expected, therefore, be genous compounds in crude oil or the problem of the migration and tween the content of nitrogen in sedimentary material. As the ra accumulation of helium in rocks natural gas and the total nitrogen tio of nitrogen to argon in natural differs from that for the other com in the associated crude oil. Nitro gas is much higher than in the ponents of natural gases. gen and other inert gases are pres atmosphere, they thought it un The fact that helium is a prod ent dissolved in sea water, and a likely that the nitrogen represented uct of the decay of such natural portion of the nitrogen in natural the remains of air trapped in the radioactive elements as uranium gas may originate by its release sedimentary material that fonned and thorium led early workers to from trapped sea water. A rela the source of the natural gas. At Downloaded from http://onepetro.org/JCPT/article-pdf/2/04/165/2165406/petsoc-63-04-03.pdf by guest on 30 September 2021 postulate that its origin in natural Lwnship between the nitrogen con the same time they observed sys gases is due to the presence of such [(:n t of natural gas and the degree 1 tematic variations in the N 5/N14 elements in either the sedimentary th(~ of wave turbulence to which ratio across a natural gas field, and rocks or the associated fonnation sediments have been subjected may attributed these variations to frac fluids (11, 16, 17, 18, 19, 20), In therefore be anticipated. tionation of the nitrogen isotopes deed, FaIT and Rogers (21) and 'Moderate quantities of nitrogen during migration. As neither the Rogers (22) even went so far as are present in certain radioactive ratio of the argon isotopes in these to suggest that petroleum originat minerals (8). This nitrogen could natural gases, the ratio of nitrogen ed by the action of helium on me reach the pore spaces of serlimen to argon, the absolute content of thane. Attempts to demonstrate tary rocks by diffusion from radio nitrogen, nor the present direction a correlation between the content of active minerals contained therein of fluid movement were determ helium in natural gas and the ra or from minerals in the Precam ined, the possibility that these iso dioactivity of the associated forma brian basement. Many authors, in topic variations are due to differ tion fluids have been unsuccessful. cluding Levorsen (9) and Landes ences in the source of the nitrogen, This led Lepape (23) to suggest (10), have noted a general relation as well as to the mode and direc that helium originated from fran ship between the contents of helium tion of migration, cannot be ruled cium, Which he presumed was a and nitrogen in natural gases. out. radioactive element with a half Lind (11) even suggested that the In several stratigraphic units life so short that it has since prac radioactive decomposition, caused (Beaverhill Lake Group, Woodbend tically completely decayed to its by alpha-particles, of a nitrogen Group, Mannville Group, and Bow daughter products. No direct cor compound simultaneously generates Island Formation), there is a def relation has been observed betwecn both helium and nitrogen. Goslin's inite tendency for higher concentra the contents of helium and radon (12) investigation of the rapid lib tions of nitrogen to be found in in natural gases (24, 25, 26, 27). eration of nitrogen from animal natural gases from southern Al Hyden (28) was unable to find a and plant proteins in flasks to berta and southwestern Saskatche relationship between the uranium which radium is added is similar wan. In some instances, these nit content of crude oils and the age in this respect, as is Evdokimov's rogen-rich gases are closely asso of the reservoir rock, although Lind (3) suggestion that part of the ciated with gases rich in carbon (11l, Lepape (29), Grechnii (30) hydrogen used in the biochemical dioxide (2), the origin of which may and Pierce et al. (27) have notcd synthesis of methane may be de be linked to the possible metamor that there is a relationship betwecn rived from the decomposition of phism of bituminous carbonates in the helium content of natural gas water by natural radioactivity. northern Montana by Tertiary (?) and eithcr the age of the rocks or intrusives. The generation of even The idea of multiple sources for the distance of the gas-bearing moderately large quantities of nit nitrogen in natural gas seems rea strata from the Precambrian base rogen from nitrogenous organic ment. Such relationships suggest sonable. Relationships should exist matter in these same rocks by the between the nitrogen and methane that the major source of helium igneous intrusives seems unlikely. lies within the Precambrian base contents and the presence of heavy However, it is important to note oil between nitrogen and helium, ment rocks. that many of these stratigraphic and between the content of nitro units, or their correlatives, crop out It is pertinent -at this point to gen and the degree of wave turbu or are present beneath a thin cover consider the helium isotopes now lence to Which the sediments have of Cretaceous rocks. Movement of known. There are two stable iso been subjected. It will be demon formation waters in all units is topes of helium-He3 and He·l-and strated later that all these relation northward, and the influx of two very short-lived artificially ships do exist. To date, however, groundwater takes place near the prepared radioactive isotopes-He5 there do not appear to be methods outcrop. Dissolved gases in this and HeG• The isotope He3 is the of analysis sufficiently specific to northward-flowing water may well stable end product of the decay of distinguish the relative importance have initial compositions similar to H3, and He3 originating in this man of the contributions of each of the atmosphere; depletion of oxy ner is found only in regions sub these processes to the total nitro gen in the underground environ ject to cosmic ray bombardment. gen in natural gas. ment may be anticipated, resulting Hill (31) has suggested a reaction The work of Hoering (14) and in nitrogen-rich natural gases. This of the type Li6 (n, "') H'*Ir->-He',
166 Journal of Canadian Petroleum whicn 'Morrison and .Pine (32) con that the ratio of He3 to He-! is theory of Mayne (38) and posfulat sider responsible for most of the about ten times as high in atmos 00 continuous crustal degassing 6 He" in the lithosphere. It is inter pheric helium (He3/He' 1.3x10- ) throughout geologic time. What ".- esting to note that Lepape (33) ob as in heliwn from natural gases ever the true situation, both theor served a relationship between the (He"jHe' 1.6 x 10-7 ) (8). ies imply the entry· of large content of heliwn in natural gases amounts of He4 and much smaller and the content of lithium in the The low terrestrial abundance of amounts of He3 into the sediment associated formation waters. helium, compared to its cosmic ary rocks from the Precambrian abundance, and the relative abun 4 basement. NUClei of He result from the dances of He3 in natural gases and radioactive decay of several mem in the atmosphere have been the The mode of migration of-helium bers of the three natural radioac subject of considerable study in the is of considerable importance. The tive families, and from the decay of past few years. Brown (35, p. 260 radioactive nuclides that decay to Sm147. The terrestrial abundance 268) has demonstrated that the yield helium may be present in of samarium is very small (0.18 inert gases were preferentially lost either the crystal structure of the p.p.m. in granites), and so it may during the formation of the Earth minerals in the rocks or as aque be concluded that the majority of due to their inability to fann com ous solutions in the pore spaees. the He' originates from any of the pounds (liquids or solids) except at Diffusion is the only mechanism by Downloaded from http://onepetro.org/JCPT/article-pdf/2/04/165/2165406/petsoc-63-04-03.pdf by guest on 30 September 2021 following reactions: very low temperatures, and this led which the helium produced in a Th232~>-6He'+!Pb208 him to postuiate the theory of cru crystal may be transferred to the stal degassing. Damon and Kulp surrounding pore space. It is clear. U235~>-7He' +!Pb20' (36) assumed a major crustal de therefore, that the presence of frac U238~>-8He'+!P])206 gassing at an early stage in the tures, cleavages, parting planes and history of the Earth and concluded similar lattice discontinuities are -Both He" and He' are found in that helium is accumulating in the important In facilitating the egress the atmosphere and in natural gas crust of the Earth at the present of helium by presenting larger sur es. All available evidence indicates time. Turekian (37) used the face areas of escape than would 0.7,----,---,--,----.-.--,----,----,--,--,
10 I 0.6 \ \
::E \ :J 0.5 \ -' 1 w , :r: \ i I \ ) Z W 0.4 o \ o U '.,- 0: \ • • , W ~ a. o \ , . w 0.3 • • '{ ::E \ •• • • \: ',' :J \ ... • •• -' o • o • o o • > 0.2 • .' o • • • o o •• •••• o 0.1 o o • o o o
o 00 ro o'---L --'--e-L..e--"6---"e-..t:..i>--'-"9-!./...L--=~-'---' o 2000 4000 6000 8000 10000 0 o.r 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 ~~ DISTANCE FROM PRECAMBRIAN (FEET) "NOR MALlZED" DISTANCE FROM PRECAMBRIAN_ ..'. Figure 1.-Left: Concentration of helium in natural Right: Concentration of helium in natural gases from gases from Alberta, plotted against distance of the Alberta, plotted as a proportion of the total thickness helium-bearing strata above the Precambrian base of sedimentary rocks at those points. The curVe is the ment. The general relationship is indicated by the same as that in the 9-rawing to the left. hand-drawn curve. ,-, Solid circles represent natural gases from the Sweetgrass arch, the hinge belt of the Alberta basin and the margins of the Peace River arch that are characterized by concentrations of heliwn higher than those for natural gases elsewhere at the same adjusted level. Analytical data from Shaw (44). Technology, Winter, 1963, Calgary 167 otherwise be present in an unfrac rocks will be insignificant. This basement, as the crust has been tured mineral. Once the heliwn accounts for the lack of correlation shown to be the main source of has reached the pore space, it may between the heliwn content of nat helium. migrate as bubbles in the forma ural gases and the radioactivity of tion waters, together with natural the surrounding rocks, as found by An attempt was made to evaluate gas, or it may move in solution in several workers. this concept using published analy formation water or crude oil, or it tical data for natural gases from may continue its migration by dif The above arguments suggest Alberta (44). The relationship fusion. The tortuous nature of pore that the major portion of the he· between the volume per cent of he space, the virtual lack of perme lium in nautral gas probably orig lium in the natural gas and the ability, even for gas, across the inated from the decay of radio distance of the gas·bearing strata bedding of most shales (39) and active minerals in the Precambrian above the Precambrian basement the low solubility of heliwn in oil basement. Vertical diffusion has may be illustrated in two ways and in saline water (40, 41) mean been suggested as the main mode (Figure 1), The concentration of that diffusion is the most likely of migration, with differential hold helium may be plotted directly mode of migration, except where up within the sedimentary rocks ac against the distance of the helium the rate of movement of the fonna counting for the accumulation of bearing strata above the Precam significant amounts of helium in brian rocks CFigw'e 1, left) show tion waters is greater than the rate Downloaded from http://onepetro.org/JCPT/article-pdf/2/04/165/2165406/petsoc-63-04-03.pdf by guest on 30 September 2021 of diffusion of the helium. natural gas. It may be expected ing that, in general, the highest therefore that, in general, the con concentrations of helium are near The accumulation of significant centration of helium in natural gas est the Precambrian rocks. In amounts of helium in natural gas will vary in relation to the distance problems concerning diffusion it is may be accounted for by the dif of the gas-bearing strata above the important to consider the boundary ferential hOld-up of diffusing hel ium within the sedimentary rocks. The hold-up factors include varying retentivities of the rocks, which are related to variations in porosity, permeability and tortuosity, to dif fering water saturations, and to fluid movements in the strata. Faris et al. (42) have discussed the relationship of tortuosity to gas permeability. Horizontal move ment of water will seriously dis rupt the vertical diffusion of heliwn if the rate of water flow is greater than the rate of diffusion. !Both uranium and thorium are found in sedimentary rocks, and a contribution of He4 may be expect ed from this source. The uranium plus-thoriwn contents of the aver age metamorphic, igneous, argilla ceous' carbonate and arenaceous rocks are 15.7. 15.6, 15.1. 5.4 and 2.2 p.p.m., respectively (43). However, it is known that the rate of radio active decay is functionally expon ential. This means that the uran ium and thoriwn in the old Pre cambrian basement rocks have been decaying to helium and lead for a considerably longer time than the uranium and thorium in the com paratively recent sedimentary rocks, and also at a greater rate of decay. Much of the helium pro duced by the decay of uranium and thorium now present as detrital • Over 0.1 minerals in sedimentary rocks will have been in the pore spaces of the x Less than 0.1 source rocks and 'Will have been lost in the atmosphere during wea $CAL( ." ""eeS 6~ thering. Thus, except in rare in 3Z'60=::r"L.....,.--=-<}Z = __ 96 stances in which the sedimentary rocks contain syngenetic uranium or thorium deposits, the contribu Figure 2.-Regional variations in the concentration of helium in natural gases from Alberta, in relation to the Sweetgrass arch, the hinge belt tion of heliwn from radioactive of the Alberta basin and the Peace River arch. Analytical data from elements within the sedimentary Shaw (44), Axis of Sweetgrass arch from de Mille (45), 168 Journal of Canodian Petroleum ~., 1 '__"' , .:.. .- , , .'. < 'I .... 50 belt of the Alberta basin contain Z helium in concentrations greater '"U", 40 than 0.1 per cent. As it has ,been U ",Za: assumed that the production rate "-w 0: 30 of helium at the basement ,- sedi >0: U:> mentary rock int~rface is unifonn ZU 20 everywhere, then, in order to ac WU :>0 count for this difference, the rate a 10 W of release of helium from the base 0: ment at the Sweetgrass arch, at ... 0 ZERO 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 the hinge belt of the Alberta basin • VOLUME PER CENT HELIUM and at the margins of the Peace River arch must be greater than Figure 3.-Frequency histogram of the variations in the content of helium in natural gases from Alberta. elsewhere. It was suggested by Hitchon (46) that tension in the basement in these regions may be conditions. The concentration of ner (Figure 1, right), gases from sufficient to cause fracturing and
helium in the atmosphere is 3 x 10-7 the Sweetgrass arch region, from rupture of the crystal lattice of the Downloaded from http://onepetro.org/JCPT/article-pdf/2/04/165/2165406/petsoc-63-04-03.pdf by guest on 30 September 2021 per cent. This may be approximat near the hinge belt of the Alberta minerals in the basement rocks, ed to zero concentration as compar basin and from the margins of the thus increasing the pore space of ed with the concentration in natur Peace 'River arch fall into a sep the rocks and so facilitating the al gases. A reasonable assumption arate group characterized by con release of helium into the pore is that, regionally, there is a uni centrations of helium higher than space, with a consequent more ra form production of helium at the those of gases elsewhere at the pid diffusion upward. Figure 2 il basement - sedimentary rock inter same adjusted level above the base lustrates the greater concentration face, and that a steady state has ment. I!'igure 2 is a map of Alber of helium in natural gases from been reached, with zero concentra ta shOWing the basement regions regions of tension, such as the tion at the sedimentary rdck - at referred to above, and showing the Peace River arch, the Sweetgrass mosphere interface. variation of helium concentration arch and the hinge belt of the Al in natural gases with respect to berta basin. By assuming these two bOWldary these regions. In general, natural , conditions it becomes necessary to gases from the Peace River arch, Ne"'"lon and Round (47) have j express the distance of the helium the Sweetgrass arch, and the hinge discussed and mathematically eval- bearing strata above the basement as a proportion of the total thick ness of sedimentary rocks at that point This is because the concen tration over different thicknesses varies from a unifonn amOWlt at the basement - sedimentary rock in terface to zero at the sedimentary rock - atmosphere interface. When the data are plotted in this man-
.,'r---,--,---,---,----,
r-0.47
.. " / .~. ~'." ~ ~ ~ ~ " '<. 54°'-c--"<."'---L~1.-'- .,-':-;;- ~ 540 LEGEND 1200 1180 1160 1140 ."... Direcllon of flUid mlgrohon o Original in-place all 118 " 110° The very varied sources postu lated for nitrogen render it difficult ~155° 55°r-f-",,'-rr---~. ____ to deduce, in anyone instance, the I origin of this gas. In some strati i~ graphic units, a relationship be tween the nitrogen content of the "'Iw natural gas and a shore-line envir !-·I'" a:i u onment appears probable. In other W.tro'''' units, no such relationship is evi --,I" dent. Concentrations of nitrogen «:l!l '< \~ in natural gases from southern Al c...... berta and southwestern Saskatche S r '< 1 c...... wan may possibly be related to the 53° I '" '< __---'153° influx of aerated groundwater, but ~/':; I only further investigation will clue· ,I '< ./2.5 ' 1--1/ idate this concept. ) ).. /;- 1"C.." ." / I/ Y so} 0...... "'( /./ '. ~ '< '< / /'. CI Natnral gases in Lower Palaeozoic '\ 0/" 'l: \. _ Cit strata -...... s,.,.',: \ F. Go"?1: 2.5 '. \ The helium-rich natural gases in ..\ 6'<,,~ the Upper Cambrian rocks of south 0, l<> : ern Saskatchewan consist predom \ ~\ inantly of nit1'Ogen <94.40 to 96.56 L EGENO \_. s'-, ~/ -1151' per cent), with concentrations of 51°', , helium in the range of 1.08 to 1.90 I:·:· :l Subcrop per cent (4). Other inert gases pre .",.,. Dlrec!lon of flUid m'grohon sent include argon (0.23 to 0.29 per • Ong,nol in-ploce o,I>IOmm.bbls.. cent) and neon (0.01 per cent re o Origmol,n-plcce o,I Natural gases in, Upper Devonian Woodbend Group strata The isolated nature of the reef o Onginalln-place orl <10 mm.bbls. masses of the Leduc Formation has resulted in separate natural gas .... Onginol in-place g05>60 b.c.f. isoconcentration trends within each /::, Orlgrnol In-place go!'> <60 b.c.f. reef mass. Concentrations of nitro _5'-- Volume per cent isoconcentrofion contour!'> gen generally over 5 per cent and SCALE IN MILES up to 12.8 per cent are found in 3~_~?~_~6 natural gases from the carbonates Figure 7.-Regional variations in the content of nitrogen in natural gases surrounding the Peace River arch from Wabamun Group strata in Alberta and British Columbia. The and in the Sturgeon Lake reef com- stippled area refers to the subcrop beneath the Cretaceous strata. Technology, Winter, 1963, Calgary 171 isoconcentration pattern and the the majority of values are less than cent. Amounts over 3 per cent are fluid flow pattern is Wlcertain. 1 per cent. For natural gases from found chiefly in gases associated the 'Daiber Group and Halfway with the heavy crude oils in a Natural gases in Permian strata Formation there is a closer rela series of fields on the flanks of the tionship of nitrogen isoconcentra Williston ·Basin in southeastern Although the range in concentra tion trends and fluid-flow pattern Saskatchewan. In this region, con~ tion of nitrogen in natural gases (Figure 9) than for nitrogen in tents of up to 14.8 per cent nitro from Pennian strata is small (up gases from either the Charlie Lake gen have been found. This asso to 6.5 per cent), the pattern of or Baldonnel Formations, or for ciation of heavy crUde oils and regional variations (Figure 8) is acid gases in the same stratigraphic natural gases relatively rich in nit similar to that for the other non unit. rogen in a "shelf" environment hydrocarbon components. (54) suggests control of the genera Natural gases in Jurassic strata tion of both the crude oil and the Natu..ral gases in Triassic strata natural gas by the environment of The concentration of nitrogen in deposition of the sediments. No gases have been analysed in natural gases from Jurassic strata which the concentration of nitrogen in Western Canada is variable, al Natnral. gases in Lowe1· Cretaceous was greater than 7 per cent, and though commonly less than 3 per Downloaded from http://onepetro.org/JCPT/article-pdf/2/04/165/2165406/petsoc-63-04-03.pdf by guest on 30 September 2021 M anmJiHe Group strata. In northeastern British Columbia, THWEST TERRITORIES northern Alberta and in the region 122" 120" Iisg 116" ~'7" adjacent to the HDisturbed Belt," r------1------;----'-'-T-"-'- \ the content of nitrogen in natural ; gases from Mannville Group strata seldom exceeds 2 per cent and is , I commonly less than 1 per cent. __+ \59" Elsewhere in Alberta and south western Saskatchewan, amounts up I , to 19.6 per cent have been record I : ed. although generally they are in I\ the range of 5 to 8 per cent. There is no clear relationship between I : fluid-flow pattern and nitrogen 1so concentration contours. I Nat1t?'al gases in Lower Cretaceous " ___L 7 i~ Viking Formanon strata In general, the level of nitrogen I concentration in natural gases from ! rocks of the Viking Formation is higher than in gases from the strata immediately beneath. Few natural gases contain less than 1 per cent nitrogen and many con tain over 4 per cent. The largest concentrations are found in strata from the correlative Bow Island Formation in southern Alberta, the maximum amount being 8.84 per cent. Natu,ral gases in Upper Gretaceous~ Oardium Formation strata With the exception of the minor LEGEND non-associated natural gas OCCUl' renc(~ at Holbourne (4.80 per cent DIrection of flUId migrahon nitrogen). all natural gases from Original in-place oil <10 mm. bbls. Cardium Fonnation strata contain ed less than 2.5 per cent nitrogen, .... Original in-place gas>60 b.c.f. and generally less than 1,5 per cent. ~ Origmal in-place gas <60 b.c.f. Natnral gases in Upper Cretaceous .---5 -- Volume per cent isoconcentration contours Belly River Fonnation. strata The nitrogen content of natural SC ALi:: IN MILES gases from arenaceous roel,s near 3.0' 16 (\ _'< 6.: 96 ~"-=_:'==:--:-==-lW~"'" the base of the Belly River Forma tion is consistently over 1 per cent Figure S.-Regional variations in the COntent of nitrogen in natural gases from Permian strata in Alberta and British Columbia. and generally in the range of 1.5 to 172 Journal af Canadian Petroleum --,.------(-'.~'~ .; 4.0 per cent, although a content of ne?rly 10.9 per cent has been rec orded. No systematic regional I~ trends are apparent t;;·~,.. ", Natural gases in Tertiary strata The nitrogen content of the two {~~~~~ .,'. '.' samples analysed is approximately ::l"::11~'- ,;' ~. 2.5 per cent. ,.. SUMMARY AND CONCLUSIONS This study of the geochemistry of nitrogen in natural gases from . Western Canada has indicated that "multiple origins are probable, al though in a number of instances it has been possible to infer a Downloaded from http://onepetro.org/JCPT/article-pdf/2/04/165/2165406/petsoc-63-04-03.pdf by guest on 30 September 2021 single source. Such instances in clude the association of relatively nitrogen-rich gases with near-shore ,"~ .' environments in the Middle Devo nian strata of northern Alberta, and the prevalence of natural gases with very high contents of nitro gen in strata of the Beaverhill Lake Group and Woodbend Group, and "I, in Lower Cretaceous rocks of south "I ,ern Alberta and southwestern Sas , katchewan. 'Here, an origin from air dissolved in percolating north ward-moving groundwaters at the outcrop or shallow subcrop in northern 'Montana cannot be ruled out. Helium has originated only from the radioactive decay of .' ".': certain elements, chiefly uranium and thoriwn, and has a vertical e and regional distribution pattern -- Original in-place oil>IOmm. bbls. that .reflects a major source in the 0 Original in-place oil <10 mm. bbls. ," " Precambrian basement and an ac cumulation due to variations in 4. Original m-place 9as>60 b.c.f. rates of predominantly vertical dif- 6 Original in-place gas <60 b.c.f. fusion within the sedimentary rocks. __5'-- Volume per cent isoconcentration contours ACKNOWLEDGMENTS SCALE IN MILES The Vil'riter expresses his thanks 32 16 0 32 64 96 to the many organizations that supplied data used in this study. Figure 9.-Regional variations in the content of nitrogen in natural gases, from strata of the Daiber Group and Halfway Formation in Alberta .and These are listed individually in the 'British Columbia. Acknowledgments to Part r of this .\ series of papers. The sources for 3. Goldschmidt, V. M., "Geochem- Nauk S.S.S.R., 115, 813-815, istry," Olarendon Press, Oxford, 1957. the· remainder of the analytical 1954. data are given in a previous paper 7. Kaveev, M. S., "Problem of the (11. 4. Lee, H., "The Technical and Origin of Nitrogen Adapted to Economic Aspects of Helium the Series of Lower Pennian Production in Saskatchewan," and Carboniferous Deposits of REFERENCES Jou,r. Oanadian Petrol. ,Tech., 2, Tatar, A.S.S.R.," Doklady Akad. ,;: No. I, 16-27, 1963. Nauk S.S.S.R., 91, 335-337, 1953. Ritchon.. B., llGeochemical Studies of Natural Gas, Part 1. 5. Buckley, S. E., Hocott, O. E., 8. Eankama, K., j'Isotope Geol Hydrocarbons in Western Can and Taggart, M. S., "Distribu ogy," McGraw-Hill Book 00., adian Natural Gases." Jour. tion of Dissolved Hydrocar Inc., New York, 1954. Oanadian Petrol. Tech., 2, No. bons in Subsurface Waters," in 2, 60-76, 1963. Habitat of Oil, 850-882, 1958, 9. Levorsen, A. I., "Geology of Amer. Assoc. Petrol. Geol., Petroleum," Freeman and Oom Hitchon, B., "Geochemical Tulsa, Oklahoma. pany, San Francisco, califor Studies of Natural Gas, Part nia, 1954. II. Acid Gases in Western Ca 6. Rybakova, S. G., ''Microflora in nadian Natural Gases," JOU7·. Crude Oil from Deep Tertiary 10. Landes, K. K., "Petroleum Oanadian Petrol. Tech., 2, No. Formations on the Apsheron Geology," John Wiley and Sons, 3, 100-116, 1963. "Peninsula," Doklady Akad. Inc., New York, 1959. Tecf:.1nology, Winter, 1963, Calgary 173 .r .:-" 11. Lind, S. C., "Origin of Terres Congres Geologique Interna 41. Rakestraw, N. W., Herriclc, C. trial Helium and its Associa tional, 9, 339-348, 1952. __ E., and Urry, W. D., "The He tion with other Gases," Proc. lium-Neon Content of Sea Wa Nat. Acad. Sd., 11, 772-779, 27. Pierce, A. P., Mytton, J. W., ter and its Relation to Oxygen 1925. and Gatt, G. E., "Radioactive Content," Jour. Amer. Ghem. Elements and their Daughter Soc., 61, 2806-2807, 1939. 12. Goslin, E., "The Argon-Nitro Products in the Texas Pan gen Ratio of Natural Gas," handle and other Gas and Oil 42. Fa,ris, S. R., Gounwy, L. S., Compt. Rend. Acad. Sci., Paris, Fields in the United States," Lipson, L. E., and Webb, T. S., 200, 1137-1139, 1935. U.S. Geol. Sw"Vey, Prof. Paper "Verification of Tortuosity 300, 527-532, 1956. Equations," Bull. Amer. Assoc. 13. Evdokimov, V. A., "Experimen Petrol. Geol., 38, 2226-2232, tal Biochemical Production of 28. Hyden, H. J., "Uranium and 1954. Methane," Mikrobi07ngiya, 28, Other Trace Elements in Crude 594-597, 1959. Oils of Western United States," 43. Green, J., "Geochemical Table U.S. Geol. Survey, Prof. Paper of the Elements for 1959," Bull. 14. Hoering, T., "Variations of Nit 300, 511-519, 1956. Geol. Soc. Amer., 70, 1127-1184, rogen-15 Abundance in Natur 1959. ally Occurring Substances," 29. Lepape, A., "Origin of Helium Science, 122, 1233-1234, 1955. in Natural Gases. Occurrence 44. Shaw, D. R., "Helium and Hy of Gases Richest in Helium in drogen Survey," Albel'ta Oil 15. Haering, T., and Moore, E. H., Ancient Lacustrine Deposits," and Gas Conservation Board, "The Isotopic Composition of Com,pt. Rend. Acad. Sci., Paris, Calgary, Alberta, 1962. Downloaded from http://onepetro.org/JCPT/article-pdf/2/04/165/2165406/petsoc-63-04-03.pdf by guest on 30 September 2021 the Nitrogen in Natural Gases 199, 1643-1645, 1934. and Associated Crude Oils," 45. DE: Mille, G., "Regional Habi Geochim. et Cosmochim. Acta, 30. Grechnii, Ya., V., "Regularities tat of Oil-Bearing Formations 13, 225-232, 1958. in the Chemical Composition of in Alberta," in Oil Fields in Gas Accumulations in the Ter Alberta, 12-25, 1960, Alberta 16. Kauenhowen, W., "Geology and restrial Crust," Ukrain. Khim. Soc. Petrol. Geol., Calgary, Al Technic of the North American Zh"r., 12, 42-52, 1937. berta. Helium Occurrences," Petro leum Zeit., 20, 3-6, 1924. 31. Hill, R. D., "Production of 46. Hitclwn, E., "The Significance HeS," Pity•. Rev., 59, 103, 1941. of the Geochemistry of Natural 17. Wells, R. C., "Origin of Helium Gas in Exploration," Preprint, Rich Natural Gas," Jour. 32. Morrison, P., and Pine, J., "Ra Amer. Assoc. Petrol. Geol., Washington Acad. Sci., 19, 321 diogenic Origin of Helium Iso Alberta Soc. Petrol. Geol. Re· 327, 1929. topes in Rocks," Ann. New gional Meeting, Banff, Alberta, 18. Kh70pin, V. G., "Geochemistry YO1-k Acad. Sci., 62, 69-92, 1955. May 25-28, 1960. of Noble Gases and Radioactiv 33. Lepape, A., "Origin of Helium 47. Newton, R., and Round, G. P., ity," P'rirodnwie Gazui, 2, 61-82, in Natural Gases: Relation be "The 'Diffusion of Helium 1931. tween Contents of Helium and Through Sedimentary Roclts," 19. Kreici-Graf, K., "Radium and Lithium in some Sodium Chlor Geoc7dm,. et Cosmoch'im. Acta, Helium in Petroleum Strata." ide-containing Mineral Waters," 22, 106-132, 1961. Petroleum Zeit., 14, 12-14, 1932. Compt. Rend. Acad. Sci., Paris, 200, 163-165, 1935. 48. Kana, Y., and Yamagnti, B., 20. Mm/er-Gii,rr, A., "Helium - its "The Contents of Helium and Origin and Occurrence," Zeit. 34. Rankama, K., and Sahama, T. Other Constituents in the Nat Ver. Dent. [ng., 84, 245-247, G., "Geochemistry," The Uni ural Gases of Japan," Rept. 1940. versity of Chicago Press, Chi Aeronau.tical Reseamh Inst., cago, Illinois, 1950. Tokyo Imperial Univ., 1, 347 21. Farr. C. C., and Rogers, M. N .. 358, 1926. "Helium and the Genesis of 35. Brown, H., "Atmospheres of Petroleum," Nature, 121, 938, the Earth and Planets," Unti 49. Wager, R., "Gases Accompany '1928. versity of Chicago Press, Chi ing Helium," Kali, 26, 240-244, cago, Illinois, 1949. 1932. 22. Rogers. M. N., "Helium and the Genesis of Petroleum," 36. Damon, P. E., and Ku,lp, J. L., 50. Nognti, IC, "The Helium Con New Zealand JO'lw. Sci. Tech., "Inert Gases and the Evolu tained in Japanese Natural 11, 389-393, 1930. tion of the Atmosphere," Geo Gases," Jour. Chern. Soc. Jap an, 62, 298-299, 1941. 23. Lepave, A., "Origin of Helium cMm. et Oosmochim,. Acta, 13, 280-292, 1958. in Natural Gas. Helium and 51. Gurevich, M. S., "Paragenesis Ekacesium (element 87)," 37. Turekian, K. K., 'The Terres of UndergroWld Waters and Compt. Rend. Acad. Sci., Paris, trial Economy of Helium and Natural Gases," Trudy Lab. 200, 163-165, 1935. Argon," Geochim. et Gosmo Gidrogeo7. Problem im. F. P. 24. Satterly, J., and McLennan, J. chim. Acta, 17, 37-43, 1959. Savarenskogo, Akad. Nau1c a., "The Radioactivity of the S.S.S.R., 3, 35-47, 1948. 38. Mayne, K. I., "Terrestrial He Natural Gases of Canada." 52. Foote, P. D., "Nitrogen and Trans. Roy. Soc. Canada, 12, lium," Geochim. et Cosmochim. Acta, 9, 174-182, 1956. Uranium " Nature, 114, 789, Ser. 3, 153-160, 1918. 1924. ' 25. Levi, M. G., Nasini, A. G., and 39. Weeks, L. G., "Habitat of Oil Oori, de P., "Rare Gases and and Some Factors that Con 53. ~'hite, W. C., and Yagoda, H., Radioactivity in Natural Hy trol It," in Habitat of Oil, 1-61, "Abundance of N15 in the Nit drocarbon Gases in Italy," 1958, Amer. Assoc. Petrol. rogen Occluded in Radioactive Gazz. Chirn. Ital., 62, 799-821, Geol., Tulsa, Oklahoma. Minerals," Science, 111, 307, 1932. 1950. 40. Urry, W. D., "Further Studies 26. Faul, H., Gott, G. B., Manger, of Rare Gases. III. The He 54. Hitchon, E., Paper prepared for G. E., Mytton, J. W., and Saka~ lium-Neon Content of Ocean the Geology of Natural Gas, kura, A. Y., "Radon and He Waters," Jour. Amer. Chent. 2nd Edition, Amer. Assoc. Pet· lium in Natural Gas," 19th Soc., 57, 657-659, 1935. 'I·ol. Geol., Tulsa, Oklahoma. 174 Technology, Winter, 1963, Calgary