四川盆地前震旦纪沉积岩新认识与油气勘探的意义
|
摘要
四川盆地前震旦纪地层至今未被钻井揭示,前人对该盆地的基底特征进行过很多有益的探索性研究,认为四川盆地的基底具有双重性。通过对近年来该盆地新采集的二、三维地震资料解释成果的分析研究,得出以下新认识:四川盆地震旦系之下仍发育厚度介于3 000～5 000m含古生物化石的巨厚沉积岩,地层层位属于新元古界南华系澄江组;按地震反射时间推算,盆地基底埋深(沉积岩厚度)介于8 000～15 000m;前震旦纪沉积岩地震反射连续性较好、能量较强,推测其岩性主要为碎屑岩,在盆地内可能未变质或仅轻微变质,有可能成为有价值的、新的勘探领域。鉴于四川盆地震旦系之下的沉积岩是天然气勘探值得探索的新领域,目前处于尚待认识的阶段,建议钻探超深井以揭示深部地层的奥秘,井位宜选择在埋深相对小、无火山岩刺穿的区域。
No satisfactory discovery has ever been found by the previous drilling data in the Pre-Sinian formations in the Sichuan Basin,although it was considered that the bottom basin is of double-layer structure from its characteristic by the precedent researchers in their exploratory studies.Through interpretation and analysis of the newly collected 2D and 3D seismic data from this basin in recent years,new understandings are obtained as follows.First,the sedimentary rocks with huge thickness of 3000-5000 m are well developed beneath the Sinian in this basin,and the formation is classified as the Chengjiang Formation of Nanhua system in the Neoproterozoic.Second,according to the calculation by the seismic reflection time,the burial depth of the bottom basin,i.e.,the thickness of the sedimentary rocks,is between 8000 and 15000 m.Third,due to the good continuity and reflection energy from the seismic inversion,it is presumed that there mainly exist the clastic rocks,and the possible non-metamorphism or low-grade metamorphism does exist within this basin.In that sense,it is concluded that there is great gas exploration potential in the deeper formation of this basin.Based on the above understandings,it is suggested that ultra deep wells be drilled to explore the deeper formations in this basin,and the well sites be better selected at such areas with rather shallow depth and without being pieced by the volcanic rocks.
No satisfactory discovery has ever been found by the previous drilling data in the Pre-Sinian formations in the Sichuan Basin,although it was considered that the bottom basin is of double-layer structure from its characteristic by the precedent researchers in their exploratory studies.Through interpretation and analysis of the newly collected 2D and 3D seismic data from this basin in recent years,new understandings are obtained as follows.First,the sedimentary rocks with huge thickness of 3000-5000 m are well developed beneath the Sinian in this basin,and the formation is classified as the Chengjiang Formation of Nanhua system in the Neoproterozoic.Second,according to the calculation by the seismic reflection time,the burial depth of the bottom basin,i.e.,the thickness of the sedimentary rocks,is between 8000 and 15000 m.Third,due to the good continuity and reflection energy from the seismic inversion,it is presumed that there mainly exist the clastic rocks,and the possible non-metamorphism or low-grade metamorphism does exist within this basin.In that sense,it is concluded that there is great gas exploration potential in the deeper formation of this basin.Based on the above understandings,it is suggested that ultra deep wells be drilled to explore the deeper formations in this basin,and the well sites be better selected at such areas with rather shallow depth and without being pieced by the volcanic rocks.
引文
[1]翟光明.中国石油地质志:卷十四川油气区[M].北京:石油工业出版社,1993.
[2]冉隆辉.论四川盆地天然气勘探前景[J].天然气工业,2006,26(12):42-44.
[3]韩永辉,康忠林.上扬子地台基底演化探讨[J].石油与天然气地质,1983,4(4):371-382.
[4]冉隆辉,谢姚祥,王兰生.从四川盆地解读中国南方海相碳酸盐岩油气勘探[J].石油与天然气地质,2006,27(3):289-294.
[5]郭正吾.四川盆地形成与演化[M].北京:地质出版社,1994.
[6]赵友年,陈斌.四川省主要构造单元及其特征[J].四川地质学报,2009,29(增刊1):88-94.
[7]赵友年,陈斌.四川省地质构造演化简述[J].四川地质学报,2009,29(增刊1):95-98.
[8]康义昌.四川盆地的基岩结构及其与上覆层的关系[J].石油实验地质,1986,8(3):235-241.
[9]罗志立.四川盆地基底结构的新认识[J].成都理工学院学报,1998,25(2):191-200.
[10]宋鸿彪,罗志立.四川盆地基底及深部地质结构研究的进展[J].地学前缘,1995,2(3/4):231-237.
[11]罗志立.川中是一个古陆核吗[J].成都理工学院学报,1986,13(3):65-73.
[12]罗志立,孙玮,代寒松,等.四川盆地基准井勘探历程回顾及地质效果分析[J].天然气工业,2012,32(4):9-12.
[13]谢琪,张宗命.“川中微型大陆”与四川盆地形成[J].四川地质学报.1982,3(增刊1).
[14]贵州地质局.黔东板溪群的划分与邻省几个主要剖面的对比及对板溪群时代的初步认识[R].贵阳:贵州地质局,1964.
[15]袁海华.川西及其邻区震旦系的划分及其界线年龄的初步研究[C]∥纪念中国地质学会成立六十周年论文集.成都:成都地质学院,1982.
[2]冉隆辉.论四川盆地天然气勘探前景[J].天然气工业,2006,26(12):42-44.
[3]韩永辉,康忠林.上扬子地台基底演化探讨[J].石油与天然气地质,1983,4(4):371-382.
[4]冉隆辉,谢姚祥,王兰生.从四川盆地解读中国南方海相碳酸盐岩油气勘探[J].石油与天然气地质,2006,27(3):289-294.
[5]郭正吾.四川盆地形成与演化[M].北京:地质出版社,1994.
[6]赵友年,陈斌.四川省主要构造单元及其特征[J].四川地质学报,2009,29(增刊1):88-94.
[7]赵友年,陈斌.四川省地质构造演化简述[J].四川地质学报,2009,29(增刊1):95-98.
[8]康义昌.四川盆地的基岩结构及其与上覆层的关系[J].石油实验地质,1986,8(3):235-241.
[9]罗志立.四川盆地基底结构的新认识[J].成都理工学院学报,1998,25(2):191-200.
[10]宋鸿彪,罗志立.四川盆地基底及深部地质结构研究的进展[J].地学前缘,1995,2(3/4):231-237.
[11]罗志立.川中是一个古陆核吗[J].成都理工学院学报,1986,13(3):65-73.
[12]罗志立,孙玮,代寒松,等.四川盆地基准井勘探历程回顾及地质效果分析[J].天然气工业,2012,32(4):9-12.
[13]谢琪,张宗命.“川中微型大陆”与四川盆地形成[J].四川地质学报.1982,3(增刊1).
[14]贵州地质局.黔东板溪群的划分与邻省几个主要剖面的对比及对板溪群时代的初步认识[R].贵阳:贵州地质局,1964.
[15]袁海华.川西及其邻区震旦系的划分及其界线年龄的初步研究[C]∥纪念中国地质学会成立六十周年论文集.成都:成都地质学院,1982.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心