An approach to noble-gas isotopic compositions in natural gases and gas-source tracing in the Ordos

NOTESAcknowledgements This work was supponed by the National NaturaScience Foundation ot China(GrantFund for the Doctoral Program of Higher Education of China I Grant NoAn approach to noble-gas1. Toder. R. Wiener. 1. oulair. L. et al. Shared DNA se. isotopic compositioons intaby-evidence for independent aditions to eutherian and maru. natural gases and gas-sourceReimer,IKIechle.M.Senger,Get al.An easy and reliable tracing in the ordos basinprocedure of microdissection technique for the analysis of chro-osumal breakponts and marker chromosomes, ChromosomeChinaearch.1999.7:3553. Boni.R. Xin, H. Hohl. D, et al. Syringocystadenoma papill.Terum: A study of potential tumor suppressor genes, Am 3. LIU Wenhui, SUN Mingliang XU YongchangDermmatopathol, 2001. 23(2):874. Akiyama. M. Kwame, H. Ohashi, H. et al. functional disomy Stute Key LaboratGas GeochemIstry 1.an]hou institute of geol.for Xq26. 3-qter in a boy with an unbalanced t (X: 21)(g26.3: ogy. Chinese Academy of Sciences. Lanzhou 7.30 00. China (e-mailp!1. 21 translocation, Am J. Med. Genet, 2001. 99(2):11Xia, J.H. Yang. Y. Dai. H. P. et al. Construction of 14 DNAprobe for specific chromosomal bands. Acta Genetica Sine. 1994. Abstract Isotopic compositions of noble gases, i.e. He Ar214x253Kr and Xe, are measured in natural gases from the Zhongbu6 Song. W.Q. Cui. XQ Xu w.S. et al. Microdissection and P(r gasfield in the Ordos Basin. And heavy noble-gas isotopesof the terminal part of big M chromosome long arm from horsebean, (Kr. Xe)are here first used in geochemically studying naturalChinese Science Bulletin (in Chinese), 1996, 41(4: 361Darg. B. Y. Hu Z M, Zhou. Y H et al. Construction of singlgases and gas-source correlation, Isotopic compositions ofhromosome DNA library from lilium regale Wilson. Chinese heavy noble gases in natural gases, especially Xe, showScience Bulletin. 1998fwo-source mixing in the Zhongbu gasfield. Gas sourees ares Cheng, Z. K. Yan. HH. Dang. B. Y et aL.. MicRodissection and somewhat different in the northeast and the southwest of theamplification of the chromosome arm 5s in a rice telotetrasomic. gasfield. Generally, the gas source of the Lower PaleozoicChinese science bulletin, 1998, 4.3(7): 590Tian. C. Lu. Y. F. Deng. J. F. el al. The cloning ofmakes a greater contribution in the southwest than in thenortheast in the field. two kinds ofHMW-GSIDx5 gene fragment using chromosome microdissec- ated from isotopic compositions of heavy noble gases and10. LIu.B.Rong I.K. Dong, Y. S. ct al. Microd ssection of chro from their relation with the Ar isotopic composition. There-mosome 7B of common wheat and cloning of low-copy specific fore, the comprehensive study on isotopic compositions ofDNA Sequences. Chinese Science Bulletin. 1999. 44light and heavy noble gases can supply more useful informaYu QX.Fan. L.C. Cui J.X.et al., High resoiution G-banding tion on gas-source correlation and tracingidiogram on pachytene bivalents of rice field eels (Monoptrusalbus Zuiew ) Science in China. ser. R. 1994. 3709): 109Keywords: noble gas. Kr. Xe isotope, natural gas, gassource corre-Telenius. H. Carter. N. P, Bebb. C. E. et al. Degerate oligosingle degerale primer Genomics, 1992. 144: 737Cherian A T, Garcia Hh.ee Tucker, J. PCR int it follow ed bs isotopic compositions has develuped rapidly. especially onmade from single microdissected chromosomes. Mammalian Ge. light noble gases, He. Ar, and Ne". Comparatively. thenome.19y,10:628study of heavy noble gases in gaseous matter is less. but14 LiK Yu Q.X. Mao Y et al 1.ocalization uf rDNA genes of the study of Xe. which was first found to be a higher3q12-424 and 7q1426 by digoxigenin labeled in situ hybridi73- 196051. In hydrocarbon gases. because of analytic tech15.Yang Y.P. Womack. I.E. Human chromosome 17 comparative nique difficulties, studies on heavy noble gases are nearlyanchor loti are conserved on bovine chromosome 19. GenomIcsnot conducted Only Xu et al. studied Xe and its isotope in995,27:293some hydrocarbon natural gases from the Songliao Basin16. Amores. A Force. A Yan, Y. L et al. lcbratish Hox clusters in Tokyo University" 1. He found abnormal phenomena of17. Macrae. AD. Brenner. S, Analysis of the dopamine receptorin natural gases and preliminarilyfamily in the compact genome of the puffer fish Fugu rubripes. thought that these phenomena are related to radioactivityfission of continental areas. But in China. the analytic dataI8. Mason, P. I Stevens. D. J.Luzzatto, L ct al. Genome structure of heavy noble gases are not obtained up to now. In factand sequence of the Fugu rubripes glucose. 6-phosphate dehydro- because there is the character of relative steadiness in19. Elgar. G, Rattray. F. Greystrong Jctcomic structure and heavy noble gas Xe etc, their migration and diffusion arenucleotide sequence of the p55 gene of the puffer fish Fugu ru- much weaker than light noble gases, especially than Hebripes. Genomics, 1995, 27(3): 442And compared with Ar. there are great potentialities in theCC. Baxendale. s.Abdulla, S, Elgar. Gi. el al. Comparative sequencenalysis ot the human and pufferfish Huntington's disease genes,of Xe because the air pollution influences moreNat Genet. 1995. 101): 67.weaklYH中国煤化工es. We svstcmati( Received September 14.200!, callyCNMHGChinese Science Bulletin Vol 47 No 6 March 2002NOTESbon natural gases that come from the Zhongbu gasfield of some extent by noble gas isotope compothe Ordos Basin. Combining the gas compositions anddata of the corresponding gni noble gases, we provided I Sample analysis and resultsThe Ordos Basin is the second largest gas-bearing positions of heavy noble gases is similar to that of isotebasin in China. Our samples were collected from a large compositions of light noble gases Since the abunnarural gas field of this basin- the Zhongbu gasfield. In dances of heavy noble gases in natural gases are lowerthis area, natural gases are mainly stored in different lay- than those in air, we have rebuilt a set of the high-vacuumers of the weathering crust that belongs to the Upper Ornd low-leakage analysis system. After repeated experidovician system. There are two suits of hydrocarbon ments, the non-noble gases in natural gases (includingsource rocks mainly: Permo-Carboniferous coal-related hydrocarbons, N, O H;. etc. those are active gases)weregas source rocks and Ordovician carbonate oil-type gas absorbed by spongy titanium, which can meet the demandsource rocks. Their corresponding source-reservoir-cap of completely measuring noble-gas isotopes in naturalassemblage is a Permo-Carboniferous Ordovician assem. gases. In the noble gases from which the active gases hacblage. Generally, the natural gas source of this area is a been removed, the light ones(He and Ne)were separatemixture of Permain- Carboniferous coal-related gases and by absorbing the ones(Ar. Kr, and Xe) with activatedrdovician oil-type gases. Moreover, the ratio of the mix- charcoal and liquid N; then. the finger was heated graduture and the main gas source are key problems of exploraally, discharging Ar, Kr and Xe from the frozen activatetion and development. We try hard to use gas geochemis- charcoal to be detected on line on a VG5-400MStry means. especially the newly built heavy noble-gasBecause the abundances of Kr and Xe are very lowisOtopic method. to provide useful clues for the explana- in the samples of natural gases. we used the electronmul-n of gas source in this gasfieldtiplier with ion counter or the Daly-photomultiplier duringThe present research shows that the distribution of isotopic detection. As for the analytical precision of the Krthe two-suit gas-source rocks basically overlap with the and Xe isotopes, table I lists the data of Kr and Xe iso-gas-generating center in the studied area. and this is con- topes of an air standard sample which is surveyed threeAodBurinOrdoviciantherewereseveralerodedto0.2.comparEdwithacknowledgedisotopicratios,theby relatively stable sedimentary features of this times. The +(3o)x of isotopic ratios ranges from 0.02alleys on the weathering crust, where Carboniferous and errors of the measured isotopic ratios are all less than 5%Permian were deposited. so the possibility of the gas mix- expect Xe/ Xe andXe/ Xe labout 10%).Weof systematically analyzed noble gas isotopes. He, ar, Kr andthe gas pools from the gas source rocks and the difference Xc. of nine natural gas samples from the Zhongbu gas-in migration passages of natural gases, which is shown to field of the Ordos Basin, and the result is listed in table ITable 1 He, Ar Kr, Xe isotope data in the air and gase of the Zhongbu ga-ticldSampleKri "KJ"KrKr“Krxe“" Ar Ho/HeMa0.2134们)2181)0.28274915172:15Rv0.20220.201403052002340218047156.4%652136.6022563-1769h.51400st“kr^"kr“Krkr"kr"Kr次x" Xe/ Xe" Xe/ Xe/. Xe/Xe"Xe“AtI xe xexexe 15xe xe xexeShan57O,m02015020180.296400605490547195.1656.70024102m019114shan84o,m、20060.19900287000261002790.520970615.37251-11248500Shan450,mx34020380.2080.297200220103131.516866665.15562832416194.20Shan70.m3s0.8380.1920.29290027804080.5206680952136531)5认6Shan 55 Om02350029545126.7895.1536425234-1958Shan620.m0.19730.1955028700022003710.5106.60521363724420274.10Shan gs0.19200.19400.29062581)512769865.06.7481.4121931154.90.19830.19940.295.003080.50826.8385.1996.5192.47820531212:80Shn1810.m*0.17690.18920.28700208000.502064255.17363312323194159-7Ma Measured average: Rv recognize value: Wn. well number: St: strataoH中国煤化工6 March 2002CNMHGNOTES2 Gas-source correlation of light noble gas isotopesously. This indicates that the gases are typical of the crustLight noble gases are mainly applied in the researchderived and do not have an obvious mixture withof natural gases, namely the isotopic compositions of He deep-source gases. Therefore. the gas, source age of thisand Ar. Isotopic compositions of light noble gases in kind of natural gases can be estimated by the chronolognatural gases can indicate the main source of natural gases. cal accumulation effect of Ar isotopesi.e. crust source or mantle source, by using the relation- 3 Gas-source correlation of heavy noble gas isotopesship between He and Ar isotopes. with regard to theAnalytic data of the Ke ann in table l and theirsitions are plotted in fig. I, in which the values ofthan 10: and those ofar/Ar vary obvimpositions are shown in fig. 2Fig. 2 shows that the Ke isotopic ratios andXe/ xe, 2Xe/ xe in all samples are similar to thosein air in the range of analytical error. which reveals thatKr in the gases was dissolved in the water where sourcerocks were deposited. balanced with Kr in the air and entered the gases during digenesis. Since the Kr isotopicsource has not an obvious relation with organic matter andinorganic minerals of gas source rocks, Kr and its isotopiccompositions play little role in gas-source Correlationwhile Xe isotopic compositions may provide some usefulinformation on the source of natural gasesFig. 2 also shows that all Xe isotopic compositionsin CHa-rich gases have no obvious difference with that inair. It indicates that the Xe of natural gases mainly comesfrom air. But the value of Xe/Xe demonstrates sysfrom the Zhongbu gasfield of the Ordos Basisome variations in some samplesFig. 2. isotopic compositions distribution of heavy noble gases Ke and Xe in natural gases from the Zhongbu g: lele:"hinese Science Bulletin Vol 47 No. 6 March 2002中国煤化工CNMHGNOTESt i,The relation of .Xe/UXe and Xe/creases along with decreasing ofXe/Xe. This varianatural gases. In studied samples of natural gasetion likely relates to the chronological accumuiation effectis comparatively enriched in the samples of ShanThis feature is clear in the values of xc/ Xe andand Shan84 well andE is relatively depleted in the Ar/Ar (fig. 5). From this figure. it can be seen that thesample of Shanl81 well. The data of other samples are values ofAr/"Ar and Xe/xe have a ccrtain relationlar to those in air within the range of the analytical in general. It means that the"Ar/Ar rano ncreascs witherror Concerning geological settings of the three samples. the decrease of 6xe/0Xe. This distribution can behe former two samples lie in the northeast of the studied clearly divided into two groups. each relating to geologicarea and the latter one lies in the southwest, which reflects settings. Therefore it should be of geologic significancethat two kinds of gases have different gas sources and this coincided with the geological settingFi 3 shows the relation of Xe/ Xe andXe/Xe. from which we can find two features. firstsecond 136xe/ Xe ratios and 2Xe/l Xe ratios have a tXe/ Xe ratios of all samples are lower than that in airpositive correlation. It means that the value of Xe in-a h 8creases with increasing ofXe. Whether or not their re-lation is a coincidence is unclear because Xe and 2Xeome Irom different parent source systems. But Xei Xe ratios of all samples are lower than that in air. indiating relativeXe excess in natural gasesFig 4. Relation of"Ar/Ar and/"Xe in natural gaves fron theZhongbu gasfield or the Ordos BasinSouthwestNortheastof Xe/ Xe andE/ Xe in natural gases from theZhongbuof the Ordos basinii) Features and relation of Xe and Ar isotopiccompositions. Xe and Ar, respectively, belong to twoFig. 5. Relation ot Xe/Xe and"Ar/ At in natural gauses lr-amr thedifferent radioactive decay senes, especiallyXe and (nongbu gasfield of the Ordos BasinAr. Although they show an obvious chronological acIn Group A, the wells are Shan84. Shan62, Shan57cumulation effect, respectively. their mutual relations have Shan58 and Shan4.5. respectively. These natural-gas wellsan obvious indicating significance because their parent are mainly distributed in the east and northeast of theelements are different in different rock associations. The studied area. In Group B, the wells are Shan 84. Shan18Ihronological study on"Ar/Ar has been mentioned and Shan98. respectively, which are mainly distributed inabove. and many factors can affect the estimation of the west and southwest of the studied area. This distribusource-rock ages. The age estimation by the isotopic com- tion relates to geologic settings of the arei as mentionedpositions of the heavy noble gas Xe is comparatively above. This means that natural gases that form in carboneffective, especially for the gas-source estimation of natu. ate source-rocks of the Lower Paleozoic contributc moreral gases that form in difTerent source rocks. This work in the southwest than in the northeast. Since the lithologineeds a large number of data accumulation and special associations of source rocks are different. the relations ofstudies. here the preliminary analysis is madc onlythe values of*Ar/Ar and Xe/Xe arc different asIn fig 4.Ar/ Ar and2Xe/"Xe have a negative well. In sedimentary organic matter. the distributions ofcorrclation in general. It means the value of Ar/Ar in- parent elements. C. Th and K that relate to noble gas iso-H中国煤化工6 March 2002CNMHGNOTESlopes are not the same(table 2)Tabe. Abundance distributions of elements, U. Th and K in carbonate Ar isotopic compositions. Therefore. the comprehensiverocks and coal-bearing senes source rocks from thCarbonate Coal measureonate/coalstudy of isotopic compositions of light and heavy noblesource rucks measure rocksgases can supply more useful information on gas-sourceg·gK(IL.17≈1.0ence and Technology Program I Grant No. 99. 110-01-1231ReferencesTable 2 shows that both in carbonate rocks and clayXu Yongchang, Applacation ot noble Eases and it, I\otope in gerocks the abundances of K are similar in the studied areaology of petroleum, Translation Collected Works in Geology ufbut the abundances of U and Th in both rocks are greatlyPetroleum 13)(in Chinese ). Belying: Science Pre-. 1976. 249different. It means that the radiogenic Xe and"Ar in thecarbonate rocks and clay parent rocks that formed in dif. 2. Lu Wenhiu. Xu Yngchang. The relatinship between argon inlerent ages should be obviously different. Therefore, whennatural gases and potassium and argun in hydrocarbon sourdthee/ Xe ratios are similar. the 0 Ar/ Ar ratios inocks and reservoir rocks. Annual research report. BrugeuchemIs-clay source rocks are obviously lower than that in carbon-try and gasgeochemistry laboratory Lanzhou Institute uf Geologyate rocks. Then the sample of studied area can be clearlyChinese Academy of Science< lin Chinese, Lanzhou: Gansu puhlishing House of Science and Technology. 1987. 191 200divided into two groups. Referring to the above analysis, 3. Xu Yongchang. Liu Wenhui Shen Ping et al. Geochemistry otGroup A relates to coal-bearing series or clay source rocksNoble Gases in Natural Gases. Reijing: Science Pre\. 1996.Iand group b relates to carbonate rocks in which the abun-dances of U and Th are relatively low. The position of 4. Lu Wenhui, Xu Yongchang Signifie ance of the tsintopne composiShan74 well between twhas mixedtions of He and Ar in natural gases. 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Ian]hou InPaleozoic gasesstitute ot Geology, Chinese Academy.): Sciences in (hinese).ons of heavy noble gases KrLanzhou Gansu Publishing House of Science and Technology1987.246250and Xe in natural gases, especially Xe, shows some mixed 12. Sun Mingliang. The analysis technology of nuble gas isotope infeatures. The gas sources are different in the northeast andnarural gases. Acta Sedimentologica Sinica Iin Chinese). 2IX01thwest of the gasfield. Generally, the gas source of theLower Paleozoic makes a greater contribution to the gases 13. Sun Shaohua, Liu Shunsheng. Wang Jiyang. The heal now field inin thc southwest than in the northeast in the field withthe Ordos Basin. Nw China. (eolectcni a et Met allogcnIaome mixture from the Upper Paleozoic. Two kinds ofChinese,1996.20(1:-9can be classified according to therEceived AugUst 22. 2IMJ1Chinese Science Bulletin Vol 47 No 6 March 2002中国煤化工CNMHG