黔北地区安页1井下志留统松坎组天然气成因

doi:10.11743/ogg20180301

摘要/Abstract

摘要： 黔北安页1井是四川盆地外围获得重大油气突破的页岩气井，该井下志留统松坎组具有较好的油气资源潜力。为了对该区出气地层（松坎组）天然气的成因进行深入研究，我们将该区下志留统松坎组与下志留统石牛栏组以示区分，并对松坎组展开了地球化学、气体组分和气体同位素等一系列实验。实验结果表明：该区松坎组特殊岩性组合条件下的TOC均值为0.16%，R_o分布在2.75%~2.92%，均值为2.95%，干酪根类型以Ⅱ₁型为主；松坎组气体烃类组分主要以甲烷为主（96%以上），含少量的乙烷、丙烷及其它烃类气体。研究区松坎组天然气干燥系数明显小于五峰-龙马溪组页岩气干燥系数，同时研究区新滩组的CO₂含量明显高于上覆松坎组和下伏五峰-龙马溪组的CO₂含量。松坎组气体同位素δ¹³C₁值在-33.2‰~-33.9‰，均值为-33.5‰；δ¹³C₂值在-36.5‰~-37.0‰，均值为-36.8‰；δD_CH₄值在-145.8‰~-156.6‰，均值为-150.0‰；该组干酪根碳同位素值在-32.9‰~-32.6‰，均值为-32.75‰。结合CO₂示踪天然气运移理论、天然气干燥系数以及气源对比特征，说明安页1井松坎组地层中的天然气主要来源于本层泥页岩热裂解生成的页岩气。

关键词: 天然气干燥系数, CO₂示踪天然气运移, 气源对比, 安页1井, 页岩气, 松坎组, 黔北地区

Abstract: The Well Anye(AY)1 of north Guizhou,in the Sichuan Basin,is a shale gas well of major breakthrough in oil and gas exploration of the basin.The Lower Silurian Songkan Formation of this well has good resources of potential of oil and gas.To better understand the genesis of natural gas in the gas reservoir of the formation,we distinguished the Lower Silurian Songkan and Shiniulan Formation in the area,and made a series of experiments in geochemistry,gas composition,gas isotopes.The experimental results show that(1)under special lithologial combinations,the average content of TOC of the Songkan Formation in this area is 0.16%,the R_o value varies from 2.75% to 2.92% with the average of 2.95%,and the kerogen type is mainly Type Ⅱ;meanwhile its gas accumulation is dominated by methane(over 96%),plus a small amount of ethane,propane,and other hydrocarbon gases;(2)the natural gas drying coefficient of the Songkan Formation in the study area is much smaller than that of the Wufeng-Longmaxi Formation,and the CO₂ content of the Xintan Formation is significantly higher than that of the Songkan and Wufeng-Longmaxi Formation;(3)the δ¹³C₁ value of gas isotopes in the Songkan Formation ranges from -33.2‰ to -33.9‰,with the average of -33.5‰;δ¹³C₂ value is in the range between -36.5‰ and -37.0‰,and the average is -36.8‰,while the δD(CH₄) value is within the range between -145.8‰ and -156.6‰,averaging at -150.0‰,and the kerogen carbon isotope value in the formation is from -32.9‰ to -32.6‰,with the average of -32.75‰.Combining CO₂ tracer gas migration theory,gas drying coefficient and gas source correlation characteristics,we conclude that the natural gas of the Songkan Formation strata from Well AY1 is mainly derived from the formation's mudstone shale gas after heat cracking.

Key words: gas drying coefficient, CO₂ tracer gas migration, gas source correlation, Well AY1, shale gas, Songkan Formation, north Guizhou

中图分类号:

TE122.1

张金川,雷怀玉,张福,等. 黔北地区安页1井下志留统松坎组天然气成因[J]. 石油与天然气地质, 2018, 39(3): 419-428. doi: 10.11743/ogg20180301 Zhang Jinchuan,Lei Huaiyu,Zhang Fu,et al. Origin of on natural gas in the Lower Silurian Songkan Formation from Well Anye 1,north Guizhou area[J]. Oil & Gas Geology, 2018, 39(3): 419-428. doi: 10.11743/ogg20180301

参考文献

[1] Jinxing Dai,Caineng Zou,Shimeng Liao,et al.Geochemistry of the extremely high thermal maturity Longmaxi shale gas,southern Sichuan Basin[J].Organic Geochemistry,2014,74:3-12.
[2] 邹才能,董大忠,王社教,等.中国页岩气形成机理、地质特征及资源潜力[J].石油勘探与开发,2010,37(6):641-653. Zou Caineng,Dong Dazhong,Wang Shejiao,et al.Geological characteristics,formation mechanism and resource potential of shale gas in China[J].Petroleum Exploration and Eevelopment,2010,37(6):641-653.
[3] 聂海宽,张金川.页岩气聚集条件及含气量计算-以四川盆地及其周缘下古生界为例[J].地质学报,2012,86(2):349-361. Nie Haikuan,Zhang Jinchuan.Shale Gas Accumulation Conditions and gas content calculation:a case study of Sichuan Basin and its periphery in the Lower Paleozoic[J].Acta Geologica Sinica,2012,86(2):349-361.
[4] 张金川,汪宗余,聂海宽,等.页岩气及其勘探研究意义[J].现代地质,2008,22(4):640-646. Zhang Jinchuan,Wang Zongyu,Nie Haikuan,et al.Shale gas and its significance for exploration[J].Geoscience,2008,22(4):640-646.
[5] Caineng Zou,Zhi Yang,Jingxing Dai,et al.The characteristics and significance of conventional and unconventional SinianeSilurian gas systems in the Sichuan Basin,central China[J].Marine & Petroleum Geology,2015,64:386-402.
[6] 戴金星,夏新宇,秦胜飞,等.中国有机烷烃气碳同位素系列倒转的成因[J].石油与天然气地质,2003,24(1):1-11. Dai Jinxing,Xia Xinyu,Qin Shengfei,et al.Causation of partly reversed orders of δ¹³C in biogenic alkane gas in China[J].Oil & Gas Geology,2003,24(1):1-11.
[7] Whiticar M J.Carbon and hydrogen isotope systematic of microbial formation and oxidation of methane.Chem[J].Geology,1999,161:291-314.
[8] Yang Liu,Jinchuan Zhang,Jun Ren,et al.Stable isotope geochemi-nstry of the nitrogen-rich gas from lower Cambrian shale in the Yangtze Gorges area,South China[J].Marine and Petroleum Geology,2016,77:693-703.
[9] Yang Liu,Jinchuan Zhang,Xuan Tang.Predicting the proportion of free and adsorbed gas by isotopic geochemical data:A case study from lower Permian shale in the Southern North China basin(SNCB)[J].International Journal of Coal Geology,2016,156:25-35.
[10] 王鹏,沈忠民,刘四兵,等.川西坳陷天然气非烃气地球化学特征及应用[J].天然气地球科学,2014,25(3):394-401. Wang Peng,Shen Zhongmin,Liu Sibing,et al.Geochemical Characteristics of nonhydrocarbon in Natural Gas in West Sichuan Depression and Its Implications[J].Natural Gas Geoscience,2014,25(3):394-401.
[11] 王正和,谭钦银,何利,等.川东南-黔北志留系石牛栏组沉积与层序地层[J].石油与天然气地质,2013,34(4):499-507. Wang Zhenghe,Tan Qinyin,He Li,et al.Deposition and sequence stratigraphy of the Silurian Shiniulan southeastern Sichuan-northern Guizhou province[J].Oil & Gas Geology,2013,34(4):499-507.
[12] 何利,谭钦银,王瑞华,等.川东南早志留世石牛栏期沉积相、沉积模式及其演化[J].矿物岩石,2013,33(4):96-106. He Li,Tan Qinyin,Wang Ruihua.Sedimentary facies,sedimentary model and evolution of the shiniulan formation of early silurian in the southeast sichuan[J].Journal of Mineralogy and Petrology,2013,33(4):96-106.
[13] 钟宁宁,卢双舫,黄志龙,等.烃源岩TOC值变化与其生排烃效率关系的探讨[J].沉积学报,2004a,22(增刊):73-78. Zhong Ningning,Lu Shuangfang,Huang Zhilong,et al.An approach to the evolution of TOC value for source rock and its relation to efficiencies of hydrocarbon generation and expulsion[J].Acta Sedimentologica Sinica,2004a,22(Suppl.):73-78.
[14] 钟宁宁,卢双舫,黄志龙,等.烃源岩生烃演化过程TOC值的演变及控制因素[J].中国科学,2004b,34(增刊Ⅰ):120-126. Zhong Ningning,Lu Shuangfang,Huang Zhilong,et al.The evolution and controlling factors of the TOC value of hydrocarbon generation[J].Science China,2004b,34(Suppl.Ⅰ):120-126.
[15] 周中毅,贾蓉芬.碳酸盐岩生油岩的有机地球化学、岩石学特征[J].地球化学,1974,(4):278-298. Zhou Zhongyi,Jia Rongfen.Organic geochemical and petrological characteristics of carbonate rocks as a source rock for petroleum[J].Geochimica,1974,(4):278-298.
[16] 傅家谟,刘德汉.碳酸盐岩有机质演化特征与油气评价[J].石油学报,1982,(1):1-8. Fu Jiamo,Liu Dehan.Some Characteristics of the evolution of organic matter in carbonate formations[J].Acta Petrolei Sinica,1982,(1):1-8.
[17] 秦建中,刘宝泉,国建英,等.关于碳酸盐烃源岩的评价标准[J].石油地质实验,2004,26(3):281-286. Qin Jianzhong,Liu Baoquan,Guo Jianying,et al.Discussion on the ecaluation standards of carbonate source rocks[J].Petroleum Geology & Experiment,2004,26(3):281-286.
[18] 马永生.中国海相油气勘探[M].北京:地质出版社,2006,1-530. Ma Yongsheng.Marine oil and gas exploration in China[M].Beijing:Geological Publishing House,2006,1-530.
[19] 彭平安,刘大永,秦艳,等.海相碳酸盐岩烃源岩评价的有机碳下限问题[J].地球化学,2008,37(4):415-422. Peng Pingan,Liu Dayong,Qin Yan,et al.Low limits of organic carbon content in carbonate as oil and gas source rocks[J].Geochimica,2008,37(4):415-422.
[20] Robert G.Loucks,Robert M.Reed,Stephen C.Ruppel,et al.Morphology,genesis,and distribution of nanometer-scale pores in siliceous mudstones of the Mississippian Barnett Shale[J].Journal of Sedimentary Research,2009,79:848-861.
[21] 龙鹏宇,张金川,李玉喜,等.重庆及周缘地区下古生界页岩气成藏条件及有利区预测[J].地学前缘,2012,19(2):221-233. Long Pengyu,Zhang Jinchuan,Li Yuxi,et al.Reservoir-forming conditions and strategic select favorable area of shale gas in the Lower Paleozoic of Chongqing and its adjacent areas[J].Earth Science Frontiers,2012,19(2):221-233.
[22] 蒲泊伶,包书景,王毅,等.页岩气成藏条件分析-以美国页岩气盆地为例[J].石油地质与工程,2008,22(3):33-36. Pu Boling,Bao Shujing,Wang Yi,et al.Analysis of shale gas reservoir forming condition-A case study of shale gas basins in the United States[J].Petroleum Geology and Engineering,2008,22(3):33-36.
[23] Martineau D F.History of the Newark East field and the Barnett Shale as a gas reservoir[J].AAPG Bulletin,2007,91(4):399-403.
[24] Richard M Pollastro,Daniel M Jarvie,Ronald J.Hill,et al.Geologic framework of theMississippian BarnettShale,Barnett-Paleozoic total petroleum system,Bendarch-FortWorth Basin,Texas[J].AAPG Bulletin,2007,91(4):405-436.
[25] Milici R C,Swezey C S.Assessment of Appalachian Basin Oil and Gas Resources:devonian shale-middle and upper paleozoic total petroleum System[J].U.S.Geological Survey,Open-File Report Series,2006,2006-1237.
[26] 宋岩,徐永昌.天然气成因类型及其鉴别[J].石油勘探与开发,2005,32(4):24-29. Song Yan,Xu Yongchang.Origin and identification of natural gases[J].Petroleum Exploration and Development,2005,32(4):24-29.
[27] Gang W,Gao G,Hao S,et al.Carbon isotope of ethane applied in the analyses of genetic types of natural gas[J].Petroleum Exploration and Development,1997,19:164-167(in Chinese with English abstract).
[28] Dai Jinxing.Identification and distinction of various alkane gases[J].Science in China(Series B),1992,35(10):1246-1257.
[29] Hao F,Zou H.Cause of shale gas geochemical anomalies and mechanisms for gas enrichment and depletion in high-maturity shales[J].Marine and Petroleum Geology,2013,44:1-12.
[30] 戴金星.天然气中烷烃气碳同位素研究的意义[J].天然气工业,2011,31(12):1-6. Dai Jinxing.Significance of the study on carbon isotopes of alkane gases[J].Natural Gas Industry,2011,31(12):1-6.
[31] Jinxing Dai,Caineng Zou,Dazhong Dong,et al.Geochemical characteristics of marine and terrestrial shale gas in China[J].Marine and Petroleum Geology,2016,76:444-463.
[32] Zhang T,Krooss B M.Experimential investigation on the carbon isotopic fractionation of methane during gas migration by diffusion through sedimentary rocks at elevated temperature and pressure[J].Geochimical et Cosmochimica,2001,65:2723-2742.