Origin of CO2 gas from the north depression of the middle fault zone in the Hailar-Tamtsag Basin and

Chin J Geochem. 2012)31: 095-102DOI:10.1007/sll631-012-0554-6Origin of Co2 gas from the north depression of themiddle fault zone in the hailar- Tamtsag Basin andnatural gas in nearby depressionsZHANG Tonglei, CHEN Jianfa, ZHU Defeng", and ZHANG ChenState Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, ChinaExploration and Development Research Institute, PetroChina Daqing Oilfield Company Limited, Daging 163712, China*CorrespondingauthorE-mail:327876823@qq.comReceived August 20, 2010; accepted September 25, 2010C Science Press and Institute of Geochemistry, CAS and Springer-Verlag Berlin Heidelberg 2012Abstract Natural gas pools with the high contents of CO2 were discovered during exploring the middle fault zoneof the Hailar-Tamtsag Basin. So far this kind of gas reservoir with COz with characteristics of carbon isotope is special. The stable carbon isotope of CO2 in the study area is relatively light with 8Cco, values ranging from -13.1%0to.2%. The Ar/Ar values of associated argon gas range from 916 to 996, with R/Ra of 1.20-1.26. Based oncomprehensive analysis, it is believed that the Co2 gas in this study area is of crust mantle sourceKey words Hailar-Tamtsag Basin; middle fault zone; CO2 gas; origin1 Introductionterritory of China), is located in Hulun Buir, InnerMongolia Autonomous Region (latitudes 4600n 1982, the fundamental work of petroleum ex-49040 north and longitude 11530 east). Inploration in the Hailar-Tamtsag Basin of the Daqing north-south direction, the northern end of the basin isOilfield started, since then a series of reservoirs have north of the Hailar River, and the southern margin isbeen found in the middle fault zone. In the process of beier Lake extending to the Tamtsag Basin in the Peoexploration, a lot of hydrocarbon reservoirs have been ple's Republic of Mongoliadiscovered with several non-hydrocarbon reservoirsThe Hailar-Tamtsag Basin which pobrought into focus. Figures due later 2006 showed that Inner Mongolia-Da Hinggan Ling Palaeozoic basefour CO2 reservoirs whose predicted OGIP was over ment, is a Mesozoic-Cenozoic basin with the charac-10 billion cubic meters(Wang Jiang et al., 2002)ex- teristics of multi-cyclicity, superimposition as wellisted in the middle fault zone of the Surennoer tecintersexuality of depression and rift basin The hailartonic zone in the Wuerxun Depression, coupled with Basin within the territory of China can be divided into11 CO2 gas wellsfive first-ordered tectonic units called the "three deNot only will gas reservoirs with the high con- pressions and two upheavals". More specifically, itof Co2 augment the risk and cost of exploration, has 20 second-ordered tectonic units including 16 de-also will it be of pivotal application importance. pressions covering an area of 25260 km and 4 heavesTherefore, the origin and accumulation characteristics Two pivotal depressions (Bayinbode-Sangbuer De-of CO2 in natural gas attract considerable attention. pression and Tamtsag Depression)in the Tamtsag Ba-This paper discusses the origin and chemical charac- sin actually refer to the extension of the Huhe Laketeristics of CO2 in the Hailar-Tamtsag Basin of the Depression and Chagannuoer Depression of the Hailarmiddle fault zone in order to provide scientific evi- Basin towards Mongolia. Therefore, accumulationdence for further exploration in this study areafactors such as cause of formation, tectonic pattern,evolutionary history, stratum growth and sedimentary2 Geological backgroundlithology are totally identical (Fig. 1)The Hailar-Tamtsag Basin overlies the basementThe Hailar-Tamtsag Basin which covers an area of Lower-Pa中国煤化工 ozoic triassic(Yimin river, to its western edge (the west coast of cap consistingntaryCN MHGaphic sequenceHulun Lake and Bayanhushu)(40550 km within the upward are the Hinggan Ling Group in the Lowerwww.gyig.accnwww.springerlink.comSpringerChin JGeochem. (2012)31: 095-102Cretaceous, the Tongbomiao, Nantun, Damoguaihe ceous lacustrine mudstone with dark gray and blackand Yimin formations of the Zhalainuoer Group, the colors in the Chagan Formation, the other is theQingyuangang Formation of the Beier Group in the Lower-Cretaceous gray and taupe shale with the faciespper Cretaceous, Paleogene as well as Neogene. The of shallow lake in the Xiazongba FormationHailar Basin is filled by at least 6000 m of sedimentThe Hailar-Tamtsag Basin is a Meso-Cenozoicand the total sedimental thickness of the Tamtsag Ba- extensional basin developed on the Paleozoic foldsin varies between 4000 and 5000 m(Fig. 2)basement. In the lower Mesozoic, the materials fromhe Nantun and Damoguaihe formations are the upper mantle were broken as a result of the highsupposed to be primary source rocks, and the Tong- palaeogeothermal field aroused by the Variscianbomiao and Budate formations are likely to be partial movement; in the Early-Middle Jurassic, faulting insource rocks. Studies on the parent material type of the study area exacerbated owing to the Yanshanianthe Hailar Basin show that kerogens are mainly of movement; during the time from Lower Jurassic totype ll, then type Ill. Especially the proportion of Lower Cretaceous, by the action of tensile stress, thetypes Il+ll in the Nantun Formation is up to 70%. bottom sedimentary cover of the Hailar Basin wasReservoir whose lithology is chiefly sandstone mainlyformed on the basement of paleostructure. Strongdevelops in the Nantun and Damoguaihe formations, volcanic activity and invasion of rock-magma hap.others with the lithologic characteristics of glutenite pened all through the period of depression develop-and mudstone develop in the Tongbomiao Formation. ment and the early phrase of tension On one hand,Similarly, the Tamtsag Basin possesses two primary these magmatic and faulting movements suppliedsource rocks(one is the Upper Jurassic-Lower Creta-channels for CO2 migration; on the other hand, the115°30117°00118°30120°00ussIa020406080100m1Mongoliaasao圆口m画回□ Middle fault zorKide wellD National boundary115°3011700118°30120°00F ig leelee sketch of the I hailar. lamis中国煤化工o Structural characteristic and hydrocarbon actCNMHGoTamtsag Basin. Mongolia: Exploration significance and economic evaluation. Exploration Company. Daqing OilChinJ Geochem. (2012)31: 095-102Stratigraphic unitLithology descriptionErathem System Group(m)ectionHumus, sandy mudstonePaleogeneSandstone, mudstone1000Packsand, argillaceous sandstone, mudstonecoal conMudstone argillaceous siltstone2000Mudstone, siltstone, packsandArgillite, siltstone, packsand3000Mudstone, sandstoneMudstone, oil shale, thick-bedded sandstoneGlutenite. mudstoneIntermediate-acid volcanics, glutenite,Tuffaceous glutenite, sand shale, pyroclastic rock5000Sandstone, volcanic rock, slateSericite slate, silty slate, tuffaceous rockFig. 2. Synthetic histogram of the formations of the HailarYH中国煤化工CNMHGChin JGeochem. (2012)31: 095-102magma with the high contents of COz upwelled along fault zone in the Hailar-Tamtsag Basin have the samethe discordogenic fault and released Co2 because of distribution characteristics that a small number ofdecreasing pressure. At last, these gases arrived at the samples with the contents over 70% account forshallow favorable traps to form gas reservoirs. The 41. 25%, hydrocarbon gas with the contents rangingleft-hand compressor-shearing, under which were lo- contents of CO2 over 85% account for sales with thecated the channels of co2 migration. These discodogenic faults with the characteristics of extension inthe earlier phrase and extrusion in the later phrase alsoplayed a pivotal role for the accumulation of co2 res-ervoir (Wang Pingzai et al., 2003).a Beier Depressiona Wuerxun Depression3 The composition of natural gas and thes Tanan Depressidistribution characteristics of CO, reservoir3.1 The composition of natural gas67070-7575.8080-85859090.9595The composition of gas, with the characteristicsydrocarbon volume (v/\ %of high adaptability, was discovered from the middleFig. 4. The distribution of hydrocarbon gas contents in the middlefault zone in the Hailar-Tamtsag Basin containing bothfault zone of the Hailar-Tamtsag Basin,hydrocarbon and non-hydrocarbon gases. The hydro-arbon gas is dominated by CH4 with the variablecontents of.96%, then heavy-hydrocarbon gas is 3.2 CO2 reservoir and the distribution of wells withfound to be within the range of 0-69.54% the the high contents of COnon-hydrocarbon gas includes CO2(as the main composition), N2 and He, with a wide range of composiSo far three CO2-rich regions(Surennuoer faulttional variations(the distribution of CO2 is 0-99.96%, structure zone, Wunan Trough, Bayantala fault structhe distribution of N2 is 0-76.72%, and the distribu- ture zone) have been discovered in the middle faulttion of He is 0-0. 1%).zone of the Hailar-Tamtsag Basin. Seven wells fromAccording to the component analysis of gas in the first region has been found with all their contentsthe case of 80 wells, the contents of CO2 coming from of CO2 over 90%, such as Su2, Su3, representing thethe middle part of the fault zone in the Hailar- richest CO2 resource. Only one COz-rich gas wellTamtsag Basin were shown to be within a wide range named Wu208-54 has been found in the Wunanof 0 to 99% and with the shape being small at both Trough. And the Bayantala fault structure zone hasends and big in the middle. To illustrate, the samples obtained two COz-rich wells, Sulo and Sul3, bothwith the contents of COz below 5% account for having the contents of CO2 higher than 85%(Fig. 5)66.25%, whereas those with moderate contents arefrequently seen. The samples whose CO2 contents 4 Isotopic compositions of cO2 gas and re-are over 60% account for 27.50%(Fig. 3)lated origin4.1 Isotopic composition of CO2 gasa Beter Depressions wuerxun DepressionCarbon and hydrogen isotopic compositions ofvarious components in the co, reservoir discovered inthe middle fault zone of the Hailar-Tamtsag Basin arepresented in Table 1. The isotopic composition of noble gas(helium, argon)is presented in Table 2As seen in Tablel, a great number of samples5-2020-6060have 8Ccon values less than -10%, nearly all theCarbon dioxide volume (v/v "samples have 8C and 8c values less than -30%oFig 3. The distribution of CO2 contents in the middle fault zone ofand these samples exist in the middle fault zone of thethe Hailar-Tamtsag BasinHailar-Ta中国煤化工 e data in Table2 show thatium in the coSimilarly, but at a lower level, the contents of reservoir isCNMHhydrocarbon gas coming from the middle part of the heliumof atmospheriChin J Geochem. 2012)31: 095-140 kmBeier Depression- Section line of first-class tectonic unitSection line of second-class tectonic unitOver-lap line _/National boundaryStructural upliftCarbon dioxideCarbon dioxide well CFig 5 Sketch map of the blocks with the high contents of Co in the middle fault zone of the Hailar-Tamtsag Basin.4. 2 Origin of CO2voirs generally vary from +7% to-39%o and thesummarized indices of 8 Cc0,, organic CO2 present4.2.1 Characteristics of stable carbon isotope8 Ccon values between-10% and-39. 14%o(mostly inthe range of- 12%o to-%), whereas inorganic COAnalyzing carbon isotope in CO2 is one of the ef- shows 8Cco2 values between+7% and%6, mainlyficient methods to constrain the origin of Co. Based within the range of% to-8%. Shen Ping et al8Cco, in natural gas generally (1991) pointed out that thevalues of inorganhas a wide range of variations from-40%o to 20%0, CO2 were over -7%o while the 8Ccoz values of or-and the majority of the statistic results focus on the ganic COz varied between-10% and -20%. Althoughinterval between-15% and% Volyayev et althe criteria to identify the origin of co2 vary from one1985)researcher to another, a principle that the 8 cco2As a result of researchers' different fields of value of organic Co2 is higher than that of inorganicstudy and stances, various standards were argued to CO2 is stilldiscriminate organic origin or inorganic origin of COzBy tak中国煤化工 ooints from DaiDai Jinxing(Wang Pingzai et al., 2003)proposed that Jinxing(20CN MHG91), Shangguanthe 8, values of Chinese large-scale CO 2 reser- Zhiguan and Zhang Peiren(1990), Moore(1977),Chin J Geochem. (2012)31: 095-102Jenden et al. (1993), and Gould et al. (1981), it is con- Based on the domestic and overseas data of co2 con-cluded that organic 8>, values are below%tents and carbon isotope, Song Yan(1991)carried outmainly within the range of-% to-10%o while inor- detailed studies and drew a dual-factor diagram whichganic8Ccon values are more than -8%, mainly can efficiently discriminate CO2 origin. Additionallywithin the range of -8% to +3%0. Besides that, inor- considering CO2 contents of 212 CO2 reservoirs, cou-ganic CO2 derived from thermal metamorphism of pled with the combination of CO2 contents andvalues of volcanic, magmatogenic and mantled cco2 813Cco, values of more than 100 CO2 reservoirs lo-carbonate has similar 8C values, and therived cated in Australia, New Zealand, Philippines, Thailand,CO2 range from% to4%o(Dai Jinxing, 1995)Japan, Canada, and the former Soviet Union. DaiJinxing established an genetic identification chartTable 1 Carbon isotopie characteristics of CO andGenerally speaking, the typical characteristics of or-hydrocarbon gas in the Co, reservoir ofganic origin are: the contents of co, are below 15%Hailar-Tamtsag Basinand 8 Cco, values are lower than-10%. Whereas, allof the COz reservoirs with 8Cco value equal to orligher than% are of inorganic origin. In addition,the contents of inorganic CO2 are higher than 60%10.24479n922513.1(Dai Jinxing, 1995)-11,4Projecting the data of carbon isotope and cOWul33:2446439.845.3contents into the genetic identification chart(Fig. 7)9132(Song Yan, 1991), we can see that the co, derivedNote: deno datafrom the middle fault zone of the Hailar-Tamtsag Ba-sin possesses special characteristics compared withTable 2 Isotoic composition of noble gas(helium, argon)co, discovered in other areas. However, although thein the CO2 reservoir of the Hailar-Tamtsag Basincontents of COz derived from the Hailar-Tamtsag Ba-FmR/Ra Arsin are over 60%, so it can be classified as inorganicCOz. The fact that the carbon isotopic value of COSul276t0.05)reservoir is pervasively lower than -10% confirmsSulk6558101.2 0.1900 916(5) hat such CO2 can be regarded as organic CO,when it comes to the abSuf 2010.0- Nt 2.08x10 1.49 0.183 289.6(5) which one is correct still needs to beove-mentioned results20240methodsProjecting the isotope data of CO2 in Table 1 intoFig 6 (Dai Jinxing, 1989), we have reasons to believethat CO2 discovered from the middle fault zone of the100K Hailar-Tamisag inorganic CoHailar-Tamtsag Basin is the mixture of organic andA Wanjina tectonic inorganic cO.an tectonic biogas CO,inorganic CO2. Nevertheless, that result was judgedo Lishu area coal-gas coonly by using the carbon isotope data, and furtherxinbei oilfield ol- type gas Coanalysis is still neededo Organic cO in ChinaInorganic co in China50中t4bC . oona20art of cOz fromzoneFig. 6. The distribution of CO2 carbon isotope in the Hailar-Tamtsagof the Hailar-Tamtsag Basin.4.2.2 CO2 contents and a series of indices related to4.2.3 Characteristics ofassociated helium isotopecarbon isotopeAs for hnhml gas, there arethree kindsCO2 of different origins has apparent disparity in As mantle nu中国煤化工 ust and mantlecontent and combinational characteristics of carbonC MH G original statesotope that can be used to constrain the origin of co2He mainly Comes from the a-decay of uranium andthorium while" Ar is the product of potassium decayChinJGeochem. (2012)31: 095-10210lHence,compared with crust-derived noble gas, man- minute quantity of coal-related gas at the stage of hightle-derived noble gas possesses such typical characmaturity and post maturity, most methane with 8C1teristics as high He and 36Ar, high He/He ratio and value higher than -30%o is inorganic. As shown in Figlow4Ar/6Ar ratio. On the contrary, low He/He ratio 8, the fact that the Ci value of hydrocarbon gas inand high Ar/Ar ratio are the typical characteristic the middle fault zone of the Hailar- Tamtsag Basin isof crust-derived material. So obviously, we can use below -30%o illustrates that methane in these gas resSHe/He and4Ar/Ar ratios to distinguish their dif- ervoirs seems to be organic, then these hydrocarbonferent sourcesgases in the study area are identified as the product ofHe/He ratio(Ra)of atmospheric helium isorganIc sources1.40x106(Lupton, 1983). He/'He ratio of mantle-derived helium varies between 1.1x10 and2.0x10. Usually 1. 1x10(Ra) is taken as a repre-sentative value. The mean value of He/He from crustn Wuerxun DepressionA Tanan Depressionis(2-3)x10(Poreda et al., 1986)The Ar/Ar value of atmospheric argon is295.5. The Ar/Ar values from the uppervary over a wide range from 295.5 to 10, nevertheless,the values from the lower mantle are far belowanalytical results of the characteristics of heliumand argon isotopes in two wells(Sul2, Sul6) with thehigh contents of CO2 are listed in Table 2. As can beMethane volume(v/v%)seen from table 2.He//He values of wells Sul2 and Fig. 8. Correlation between CH content and 8Ci from theSul6are1.76×10°and168×106, respectively.AcHailar-Tamtsag Basin,cordingly, R/Ra values are 1. 26 and 1. 2, respectively,and are both higher than those of atmospheric helium,8 C2is also an effective index to distinguish theand between the limits of the mantle-derived and the genetic type of natural gas. Taking carbon isotope ofcrust-derived heliumheavy hydrocarbon into consideration, Dai JinxingThe Ar/Ar values of natural gas from the (1987) believed that the natural gas with 8,higherabove-mentioned two wells are 996 and 916, respethan -25. 1%o and 8C3 higher than -23.2%wastively(Table 2 ), indicating that the argon was man- coal-type gas, whereas the natural gas with 8C2be-Furthermore, we can conclude that argon gas in natu- Zhang Shiya et al. (1988) held that the 8 C2 values ofral gas from the middle fault zone ofcoal-type gas were within the range of -28%0 to-23%Hailar-Tamtsag Basin is derived mainly from thewhile those of oil-type gas varied from%0 to-29%0per mantleBy analyzing ethane carbon isotope of both oil-typeAnalysis of natural gas-associated noble gas(heand coal-type gas in major oil/gas-bearing basins oflium, argon) isotopes indirectly verifies that the Co2 China, Chen Jianfa et al. (1995)argued that 8Creservoir in the middle fault zone of the Hailar-Tamtsag value of coal-type gas varied from-31%o to-22 %,Basin is inorganic and buried deeply inside the Earthmainly in the range from-%0 to -24%0 while 8C2In combination with the above-mentioned convalue of oil-type gas varied from -43%0 to-25%0mainreasonable to believe that the co, reservoir derived Wenzhe et al. ( 1997)thought that 8 c2 value offrom the middle fault zone of the Hailar-Tamtsag Ba- humus type was over-29% while the counterpart ofsin is inorganic. That means the CO2 gas discovered in sapropel-type gas was below -29%o. Although thesethe study area is the only discovery of inorganic CO 2 scholars could not reach a consensus on whether usingwith characteristics of relatively light carbon isotope ethane carbon isotope can distinguish gas type, they(8Cc02 <-10%0)and high contents of CO2(perva- could make it sure that ethane carbon isotope equal tosively over 80%)in the world29%0 or-28%(this paper takes-28% as the limit)could be the boundary of the gas type. The 8C2 val5 Isotopic characteristics of hydrocarbon gas ues of natural gas in the study area are all below -28%and originonly except the sample from Tal2l which has 8C2value overmost of hyd5.1 Origin of hydrocarbon gas in the reservoirarbon gas中国煤化工 -iddle part of theDai Jinxing (1992)pointed out that except a gas, only a part of coal-type gas(Fig. y e of oil-typefault zone oCNMHG102Chin J, Geochem. (2012)31: 095-102n Beier DepressionDai Jinxing(2000)Collected Paper about Natural Gas Geology and Geo◆ Wuerxun Depressionchemistry (roll one)[C]. 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Proceeding of the Australian institute ofThe CO2 reservoir is mainly distributed in thegion of Wuerxun where methane isotopes of gas sam- Jenden P.D. Hilton D.R. Kaplan I.R. et al. (1993)A biogenie hydrocarbonples are all below -30%0(Table 1). Additionallyand mantle helium in oil and gas Fields ] The Future of Energysequence of carbon isotope of hydrocarbon compotion does not show any reversal, suggesting the hy- Lupton 1.E(1983)Terrestrial inert gases: Isotope studies and clues to pridrocarbon components came from organic sourcesmondial components in the mantle [] Ann. Rev. earth Planet Sci. 116 ConclusionsMoore J G(1977)CO -filled vesicles in mid-ocean basin [J]. J. volcanoGeotherm Res (2), 309-327As a special case in the world, data of 8 Ccoz Poreda R., Jenden P. D, and Kaplan LR (1986)Mantle helium in sacra-from inorganic CO2 reservoir in the study area aremento basin natural gas wells []. Geochim. et Cosmochim. Acta. 50,pervasively below -10%02847-2853The natural gas discovered in the Hailar- Tamtsag Shangguan Zhiguan and Zhang Peiren(1990)Active Fault in NorthwestBasin can be divided into two types, CO2 reservoirArea of oi[M]. Seismological Press, Beijingand hydrocarbon reservoir. They have apparently dif- Shen Ping, Xu Yongchang, and Wang Xianbing(1991) Geochemical Charferent distribution characteristics. CO reservoir isteristic of Source Rocks and Gas and Origin of Gas Reservoir [M)mainly distributed in the Wuerxun Depression whilepp 120-121. Gansu Science and Technology Press, Lanzhouhydrocarbon gas is mostly discovered in the region of Song Yan(1991)Genesis of natural gas in the Wanjinta Gas Reservoir,Beier and Tanan at presentSongliao Basin []. Natural Gas Industry. 11, 17-20Based on the data of carbon isotope and related Volyayey B.M. Grin, and Henko Y.(1985) The origin of isotopicallygeochemical parameters such as associated noble gasaItra heavy carbon dioxide [ J]. Internal-Geol. Rev. 27, 1315-1324isotope (helium, argon), coupled with the geological Wang Jiang, Zhang Hong, and Lin Dongcheng(2002) Petroleum geologybackground of the Hailar-Tamtsag Basin, it is reason-and exploration potential of Wuerxun helium-bearing CO2 gas reser-able to believe that in the study area, co2 reservoiroir in Hailar Basin [] Natural Gas Industry. 22, 109-111lines to be inorganic whereas the origin of hydro- Wang Pingzai, Li Mingsheng, and Wang Jiang(2003)Petroleum geologycarbon gases in the CO2 reservoir with mostly oil-typeand exploration potential of Wuerxun helium-bearing Coz gas resergas is organIc.voir in Hailar Basin [ Special Oil Gas Reservoirs. 10(6), 9-12.Zhang Changjun and Long Yong(1995) Sedimentary facies Feature andHydrocarbon Occurrence in Hailar Basin[M]. Petroleum IndustryReferencesZhang Shiye, Bu Jianjun, and Jiang Tairan(1988)A new method to identifyorigin of natural gas using carbon isotope of methane and ethane InJianfa, Li Chunyuan, Shen Ping et al. 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