四川盆地二叠系火山碎屑岩气藏勘探重大发现及其启示
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摘要
近期,中国石油天然气股份有限公司风险探井——永探1井测试获得22.5×10~4 m~3/d的高产气流,首次在四川盆地发现了喷溢相火山碎屑岩气藏,实现了火山岩气藏勘探的重大突破。为了评价该盆地二叠系火山岩气藏的勘探前景,系统总结了该区火山岩气藏的勘探历程、永探1井区气藏的特征、天然气成藏的控制因素与模式。研究结果表明:①在经历了长达50余年的火山岩持续探索后,得益于勘探思路的转变和地震预测技术的进步,得出了简阳地区二叠系发育爆发相火山岩异常体、天然气成藏条件好,是该盆地又一个重要的天然气勘探新领域和新对象的认识,指导了风险探井——永探1井的部署及重大勘探发现;②永探1井二叠系发育厚逾100 m的优质火山岩孔隙性储层,其储集岩石类型以喷溢相角砾熔岩、含凝灰角砾熔岩为主,储集空间主要为溶蚀微孔、角砾间溶孔及气孔,孔隙度介于6.68%～13.22%、平均为10.26%,渗透率介于0.01～4.43 mD、平均为2.35 mD;③该气藏埋深介于4 500～6 000 m,产层中部地层压力为125.625 MPa,压力系数达2.22,为异常高压气藏,天然气组成中甲烷含量为99.03%,微含硫化氢;④简阳—三台地区发育爆发相火山岩且紧邻德阳—安岳裂陷寒武系优质烃源岩,早期张性深断裂沟通源储,上部发育上二叠统龙潭组泥岩、下三叠统厚层膏岩等多套盖层,具备形成大型构造—岩性复合圈闭气藏的有利条件,有利勘探面积达6 000 km~2。结论认为,永探1井火山岩气藏的发现,证明了该盆地二叠系火山岩具有较大的油气勘探潜力,坚定了转变勘探思路、加快进军新区新领域、寻找更多更大勘探发现的信心。
Recently, a high-yield gas flow of 22.5×10~4 m~3/d was achieved in the wildcat well Yongtan 1, deployed by the PetroChina Southwest Oil and Gasfield Company, and an extrusive facies vocaniclastic gas reservoir was first discovered in the Sichuan Basin, which is a major breakthrough in the exploration of volcanic rock gas reservoirs. In order to further evaluate the exploration potential in Permian volcanic rock gas reservoirs in this basin, we systematically reviewed and summarized the exploration process of volcanic rocks in this study area, as well as the characteristics of gas reservoirs of well Yongtan 1, the controlling factors and modes of hydrocarbon accumulation. The following findings were obtained.(1) Over the past five decades of gas exploration of volcanic rocks, the change of exploration thought and progress in seismic prediction contribute to a major discovery in this study area, i.e., the well location deployment of Yongtan 1 was determined in the Jianyan area,where the volcanic anomalies of the Permian developed outbursts are well developed and the gas reservoir conditions are favorable. This also proves that another new gas exploration area in this basin was found.(2) From the data of Yongtan 1, we found high-quality volcanic porous reservoirs with a thickness of over 100 m developed in the Permian strata, the effusive volcanic rock types dominated by breccia and tuffaceous breccia, reservoir space composed of dissolution pores, interbreccia dissolution pores, and other pores, the porosity of which is between 6.68%and 13.22% and 10.26% on average, the permeability between 0.01 and 4.43 mD and 2.35 mD on average.(3) This abnormally high pressure gas reservoir was buried 4 500–6 000 m deep underground with the middle formation pressure being 125.625 MPa and the pressure coefficient being up to 2.22. Methane content in the minor H_2S-bearing produced gas flow reached up to 99.03%.(4) Volcanic rocks in the Jianyang–Zhongjiang–Santai area are developed, and they are adjacent to the Cambrian high-quality source rocks in the Deyang–Anyue rifting. The early extensional deep faults play a role in connecting source and storage. There are many sets of caprocks, such as the Upper Permian Longtan Formation and Lower Triassic layered thick paste rocks, providing conditions for forming large-scale tectonic–lithologic composite trap gas reservoirs, and the favorable exploration area reaches up to 6 000 km~2. In conclusion, this major discovery not only proves that Permian volcanic rocks in the Sichuan Basin has large potential for oil and gas exploration, but reaffirms the confidence in changing our exploration thought,speeding up new exploration zones and areas, and discovering more and bigger gas fields.
Recently, a high-yield gas flow of 22.5×10~4 m~3/d was achieved in the wildcat well Yongtan 1, deployed by the PetroChina Southwest Oil and Gasfield Company, and an extrusive facies vocaniclastic gas reservoir was first discovered in the Sichuan Basin, which is a major breakthrough in the exploration of volcanic rock gas reservoirs. In order to further evaluate the exploration potential in Permian volcanic rock gas reservoirs in this basin, we systematically reviewed and summarized the exploration process of volcanic rocks in this study area, as well as the characteristics of gas reservoirs of well Yongtan 1, the controlling factors and modes of hydrocarbon accumulation. The following findings were obtained.(1) Over the past five decades of gas exploration of volcanic rocks, the change of exploration thought and progress in seismic prediction contribute to a major discovery in this study area, i.e., the well location deployment of Yongtan 1 was determined in the Jianyan area,where the volcanic anomalies of the Permian developed outbursts are well developed and the gas reservoir conditions are favorable. This also proves that another new gas exploration area in this basin was found.(2) From the data of Yongtan 1, we found high-quality volcanic porous reservoirs with a thickness of over 100 m developed in the Permian strata, the effusive volcanic rock types dominated by breccia and tuffaceous breccia, reservoir space composed of dissolution pores, interbreccia dissolution pores, and other pores, the porosity of which is between 6.68%and 13.22% and 10.26% on average, the permeability between 0.01 and 4.43 mD and 2.35 mD on average.(3) This abnormally high pressure gas reservoir was buried 4 500–6 000 m deep underground with the middle formation pressure being 125.625 MPa and the pressure coefficient being up to 2.22. Methane content in the minor H_2S-bearing produced gas flow reached up to 99.03%.(4) Volcanic rocks in the Jianyang–Zhongjiang–Santai area are developed, and they are adjacent to the Cambrian high-quality source rocks in the Deyang–Anyue rifting. The early extensional deep faults play a role in connecting source and storage. There are many sets of caprocks, such as the Upper Permian Longtan Formation and Lower Triassic layered thick paste rocks, providing conditions for forming large-scale tectonic–lithologic composite trap gas reservoirs, and the favorable exploration area reaches up to 6 000 km~2. In conclusion, this major discovery not only proves that Permian volcanic rocks in the Sichuan Basin has large potential for oil and gas exploration, but reaffirms the confidence in changing our exploration thought,speeding up new exploration zones and areas, and discovering more and bigger gas fields.
引文
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[2]四川省地质矿产勘探开发局.四川省区域地质志[M].北京:地质出版社,1991.Sichuan Bureau of Geology and Mineral Resources.Regional geology in Sichuan Basin[M].Beijing:Geology Publishing House,1991.
[3]何斌,徐义刚,肖龙,王雅玫,王康明,沙绍礼.峨眉山地幔柱上升的沉积响应及其地质意义[J].地质论评,2006,52(1):30-37.He Bin,Xu Yigang,Xiao Long,Wang Yamei,Wang Kangming&Sha Shaoli.Sedimentary responses to uplift of Emeishan mantle plume and its implications[J].Geological Review,2006,52(1):30-37.
[4]Chung S L&Jahn B M.Plume-lithosphere interaction in generation of the Emeishan flood basalts at the Permian-Triassic boundary[J].Geology,1995,23(10):889-892.
[5]Mahoney J J&Coffin M F.Large igneous provinces:Continental,oceanic,and planetary flood volcanism[M].Washington DC:American Geophysical Union,1997.
[6]Xu Y G,Chung S L,Jahn B M&Wu G Y.Petrologic and geochemical constraints on the petrogenesis of Permian-Triassic Emeishan flood basalts in Southwestern China[J].Lithos,2001,58(3):145-168.
[7]张招崇.关于峨眉山大火成岩省一些重要问题的讨论[J].中国地质,2009,36(3):634-646.Zhang Zhaochong.A discussion on some important problems concerning the Emeishan large igneous province[J].Geology in China,2009,36(3):634-646.
[8]Thompson G M,Ali J R,Song X&Jolley D W.Emeishan Basalts,SW China:Reappraisal of the formation's type area stratigraphy and a discussion of its significance as a large igneous province[J].Journal of the Geological Society,2001,158(4):593-599.
[9]Wignall PB.Large igneous provinces and mass extinctions[J].Earth-Science Reviews,2001,53(1):1-33.
[10]何鲤,罗潇,刘莉萍,黎平,周贵祥.试论四川盆地晚二叠世沉积环境与礁滩分布[J].天然气工业,2008,28(1):28-32.He Li,Luo Xiao,Liu Liping,Li Ping&Zhou Guixiang.A discussion on depositional environment in late Permian and distribution of reef-bank in Sichuan Basin[J].Natural Gas Industry,2008,28(1):28-32.
[11]张若祥.川西南“峨眉山玄武”气藏特征研究[D].成都:西南石油大学,2006.Zhang Ruoxiang.Study on the characteristics of the"Emeishan Xuanwu"gas reservoir in Southwestern Sichuan[D].Chengdu:-Southwest Petroleum University,2006.
[12]邓敏,侯明才,张本健,李秀华.川西南部周公山地区峨眉山玄武岩有利储层分析[J].中国地质,2014,41(2):378-386.Deng Min,Hou Mingcai,Zhang Benjian&Li Xiuhua.Favorable reservoir analysis of Emeishan basalt in Zhougongshan area of Southwest Sichuan Province[J].Geology in China,2014,41(2):378-386.
[13]梅庆华,何登发,文竹,李英强,李皎.四川盆地乐山-龙女寺古隆起地质结构及构造演化[J].石油学报,2014,35(1):11-25.Mei Qinghua,He Dengfa,Wen Zhu,Li Yingqiang&Li Jiao.Geologic structure and tectonic evolution of Leshan-Longnüsi paleo-uplift in Sichuan Basin,China[J].Acta Petrolei Sinica,2014,35(1):11-25.
[14]李伟,易海永,胡望水,杨庚,熊璇.四川盆地加里东古隆起构造演化与油气聚集关系[J].天然气工业,2014,34(3):8-15.Li Wei,Yi Haiyong,Hu Wangshui,Yang Geng&Xiong Xuan.Tectonic evolution of Caledonian paleohigh in the Sichuan Basin and its relationship with hydrocarbon accumulation[J].Natural Gas Industry,2014,34(3):8-15.
[15]刘宝珺,许效松.中国南方岩相古地理图集(震旦系-三叠系)[M].北京:科学出版社,1994.Liu Baojun&Xu Xiaosong.Atlas of lithofacies and paleogeography in South China(Sinian-Triassic)[M].Beijing:Science Press,1994.
[16]李伟,张志杰,党录瑞.四川盆地东部上石炭统黄龙组沉积体系及其演化[J].石油勘探与开发,2011,38(4):400-408.Li Wei,Zhang Zhijie&Dang Lurui.Depositional system evolution of Upper Carboniferous Huanglong Formation in eastern Sichuan Basin[J].Petroleum Exploration and Development,2011,38(4):400-408.
[17]杨毅,张本健,蒋德生,裴森奇,周子琰.四川盆地西南部上二叠统峨眉山玄武岩成藏模式初探[J].天然气工业,2010,30(5):46-49.Yang Yi,Zhang Benjian,Jiang Desheng,Pei Senqi&Zhou Ziyan.A preliminary study on hydrocarbon pooling patterns of the Upper Permian Emeishan basalts in southwestern Sichuan Basin[J].Natural Gas Industry,2010,30(5):46-49.
[18]邹才能,杜金虎,徐春春,汪泽成,张宝民,魏国齐等.四川盆地震旦系-寒武系特大型气田形成分布、资源潜力及勘探发现[J].石油勘探与开发,2014,41(3):278-293.Zou Caineng,Du Jinhu,Xu Chunchun,Wang Zecheng,Zhang Baomin,Wei Guoqi,et al.Formation,distribution,resource potential and discovery of the Sinian-Cambrian giant gas field,Sichuan Basin,SW China[J].Petroleum Exploration and Development,2014,41(3):278-293.
[19]周进高,沈安江,张建勇,郝毅,谷明峰,李文正.四川盆地德阳-安岳台内裂陷与震旦系勘探方向[J].海相油气地质,2018,23(2):1-9.Zhou Jingao,Shen Anjiang,Zhang Jianyong,Hao Yi,Gu Mingfeng&Li Wenzheng.Deyang-Anyue interplatform rift in Sichuan Basin and its direction of exploration in Sinian[J].Marine Origin Petroleum Geology,2018,23(2):1-9.
[20]张璐,谢增业,王志宏,展铭望,国建英,李亚红.四川盆地高石梯-磨溪地区震旦系-寒武系气藏盖层特征及封闭能力评价[J].天然气地球科学,2015,26(5):796-804.Zhang Lu,Xie Zengye,Wang Zhihong,Zhan Mingwang,Guo Jianying&Li Yahong.Caprock characteristics and sealing ability evaluation of Sinian-Cambrian gas reservoirs in Gaoshiti-Moxi area,Sichuan Basin[J].Natural Gas Geoscience,2015,26(5):796-804.
[21]唐德海,段金宝.四川盆地嘉陵江组嘉四段-嘉五段膏盐岩分布及油气意义[J].特种油气藏,2017,24(2):80-85.Tang Dehai&Duan Jinbao.Distribution and reservoir significance of gypsum salt rocks in Jia 4-Jia 5 interval of Jialingjiang Formation in the Sichuan Basin[J].Special Oil&Gas Reservoirs,2017,24(2):80-85.
[22]林良彪,郝强,余瑜,淡永,彭勇民.四川盆地下寒武统膏盐岩发育特征与封盖有效性分析[J].岩石学报,2014,30(3):718-726.Lin Liangbiao,Hao Qiang,Yu Yu,Dan Yong&Peng Yongmin.Development characteristics and sealing effectiveness of Lower Cambrian gypsum rock in Sichuan Basin[J].Acta Petrologica Sinica,2014,30(3):718-726.
[23]李双建,孙东胜,郑孟林,孟宪武.四川盆地寒武系盐相关构造及其控油气作用[J].石油与天然气地质,2014,35(5):622-638.Li Shuangjian,Sun Dongsheng,Zheng Menglin&Meng Xianwu.Salt related structure and its control on hydrocarbon of the Cambrian in Sichuan Basin[J].Oil&Gas Geology,2014,35(5):622-638.
[2]四川省地质矿产勘探开发局.四川省区域地质志[M].北京:地质出版社,1991.Sichuan Bureau of Geology and Mineral Resources.Regional geology in Sichuan Basin[M].Beijing:Geology Publishing House,1991.
[3]何斌,徐义刚,肖龙,王雅玫,王康明,沙绍礼.峨眉山地幔柱上升的沉积响应及其地质意义[J].地质论评,2006,52(1):30-37.He Bin,Xu Yigang,Xiao Long,Wang Yamei,Wang Kangming&Sha Shaoli.Sedimentary responses to uplift of Emeishan mantle plume and its implications[J].Geological Review,2006,52(1):30-37.
[4]Chung S L&Jahn B M.Plume-lithosphere interaction in generation of the Emeishan flood basalts at the Permian-Triassic boundary[J].Geology,1995,23(10):889-892.
[5]Mahoney J J&Coffin M F.Large igneous provinces:Continental,oceanic,and planetary flood volcanism[M].Washington DC:American Geophysical Union,1997.
[6]Xu Y G,Chung S L,Jahn B M&Wu G Y.Petrologic and geochemical constraints on the petrogenesis of Permian-Triassic Emeishan flood basalts in Southwestern China[J].Lithos,2001,58(3):145-168.
[7]张招崇.关于峨眉山大火成岩省一些重要问题的讨论[J].中国地质,2009,36(3):634-646.Zhang Zhaochong.A discussion on some important problems concerning the Emeishan large igneous province[J].Geology in China,2009,36(3):634-646.
[8]Thompson G M,Ali J R,Song X&Jolley D W.Emeishan Basalts,SW China:Reappraisal of the formation's type area stratigraphy and a discussion of its significance as a large igneous province[J].Journal of the Geological Society,2001,158(4):593-599.
[9]Wignall PB.Large igneous provinces and mass extinctions[J].Earth-Science Reviews,2001,53(1):1-33.
[10]何鲤,罗潇,刘莉萍,黎平,周贵祥.试论四川盆地晚二叠世沉积环境与礁滩分布[J].天然气工业,2008,28(1):28-32.He Li,Luo Xiao,Liu Liping,Li Ping&Zhou Guixiang.A discussion on depositional environment in late Permian and distribution of reef-bank in Sichuan Basin[J].Natural Gas Industry,2008,28(1):28-32.
[11]张若祥.川西南“峨眉山玄武”气藏特征研究[D].成都:西南石油大学,2006.Zhang Ruoxiang.Study on the characteristics of the"Emeishan Xuanwu"gas reservoir in Southwestern Sichuan[D].Chengdu:-Southwest Petroleum University,2006.
[12]邓敏,侯明才,张本健,李秀华.川西南部周公山地区峨眉山玄武岩有利储层分析[J].中国地质,2014,41(2):378-386.Deng Min,Hou Mingcai,Zhang Benjian&Li Xiuhua.Favorable reservoir analysis of Emeishan basalt in Zhougongshan area of Southwest Sichuan Province[J].Geology in China,2014,41(2):378-386.
[13]梅庆华,何登发,文竹,李英强,李皎.四川盆地乐山-龙女寺古隆起地质结构及构造演化[J].石油学报,2014,35(1):11-25.Mei Qinghua,He Dengfa,Wen Zhu,Li Yingqiang&Li Jiao.Geologic structure and tectonic evolution of Leshan-Longnüsi paleo-uplift in Sichuan Basin,China[J].Acta Petrolei Sinica,2014,35(1):11-25.
[14]李伟,易海永,胡望水,杨庚,熊璇.四川盆地加里东古隆起构造演化与油气聚集关系[J].天然气工业,2014,34(3):8-15.Li Wei,Yi Haiyong,Hu Wangshui,Yang Geng&Xiong Xuan.Tectonic evolution of Caledonian paleohigh in the Sichuan Basin and its relationship with hydrocarbon accumulation[J].Natural Gas Industry,2014,34(3):8-15.
[15]刘宝珺,许效松.中国南方岩相古地理图集(震旦系-三叠系)[M].北京:科学出版社,1994.Liu Baojun&Xu Xiaosong.Atlas of lithofacies and paleogeography in South China(Sinian-Triassic)[M].Beijing:Science Press,1994.
[16]李伟,张志杰,党录瑞.四川盆地东部上石炭统黄龙组沉积体系及其演化[J].石油勘探与开发,2011,38(4):400-408.Li Wei,Zhang Zhijie&Dang Lurui.Depositional system evolution of Upper Carboniferous Huanglong Formation in eastern Sichuan Basin[J].Petroleum Exploration and Development,2011,38(4):400-408.
[17]杨毅,张本健,蒋德生,裴森奇,周子琰.四川盆地西南部上二叠统峨眉山玄武岩成藏模式初探[J].天然气工业,2010,30(5):46-49.Yang Yi,Zhang Benjian,Jiang Desheng,Pei Senqi&Zhou Ziyan.A preliminary study on hydrocarbon pooling patterns of the Upper Permian Emeishan basalts in southwestern Sichuan Basin[J].Natural Gas Industry,2010,30(5):46-49.
[18]邹才能,杜金虎,徐春春,汪泽成,张宝民,魏国齐等.四川盆地震旦系-寒武系特大型气田形成分布、资源潜力及勘探发现[J].石油勘探与开发,2014,41(3):278-293.Zou Caineng,Du Jinhu,Xu Chunchun,Wang Zecheng,Zhang Baomin,Wei Guoqi,et al.Formation,distribution,resource potential and discovery of the Sinian-Cambrian giant gas field,Sichuan Basin,SW China[J].Petroleum Exploration and Development,2014,41(3):278-293.
[19]周进高,沈安江,张建勇,郝毅,谷明峰,李文正.四川盆地德阳-安岳台内裂陷与震旦系勘探方向[J].海相油气地质,2018,23(2):1-9.Zhou Jingao,Shen Anjiang,Zhang Jianyong,Hao Yi,Gu Mingfeng&Li Wenzheng.Deyang-Anyue interplatform rift in Sichuan Basin and its direction of exploration in Sinian[J].Marine Origin Petroleum Geology,2018,23(2):1-9.
[20]张璐,谢增业,王志宏,展铭望,国建英,李亚红.四川盆地高石梯-磨溪地区震旦系-寒武系气藏盖层特征及封闭能力评价[J].天然气地球科学,2015,26(5):796-804.Zhang Lu,Xie Zengye,Wang Zhihong,Zhan Mingwang,Guo Jianying&Li Yahong.Caprock characteristics and sealing ability evaluation of Sinian-Cambrian gas reservoirs in Gaoshiti-Moxi area,Sichuan Basin[J].Natural Gas Geoscience,2015,26(5):796-804.
[21]唐德海,段金宝.四川盆地嘉陵江组嘉四段-嘉五段膏盐岩分布及油气意义[J].特种油气藏,2017,24(2):80-85.Tang Dehai&Duan Jinbao.Distribution and reservoir significance of gypsum salt rocks in Jia 4-Jia 5 interval of Jialingjiang Formation in the Sichuan Basin[J].Special Oil&Gas Reservoirs,2017,24(2):80-85.
[22]林良彪,郝强,余瑜,淡永,彭勇民.四川盆地下寒武统膏盐岩发育特征与封盖有效性分析[J].岩石学报,2014,30(3):718-726.Lin Liangbiao,Hao Qiang,Yu Yu,Dan Yong&Peng Yongmin.Development characteristics and sealing effectiveness of Lower Cambrian gypsum rock in Sichuan Basin[J].Acta Petrologica Sinica,2014,30(3):718-726.
[23]李双建,孙东胜,郑孟林,孟宪武.四川盆地寒武系盐相关构造及其控油气作用[J].石油与天然气地质,2014,35(5):622-638.Li Shuangjian,Sun Dongsheng,Zheng Menglin&Meng Xianwu.Salt related structure and its control on hydrocarbon of the Cambrian in Sichuan Basin[J].Oil&Gas Geology,2014,35(5):622-638.