摘要
近期在四川盆地震旦系—寒武系获得了天然气勘探的新突破,而对于震旦纪末—寒武纪早期构造运动的认识还存在较大争论。通过岩石学特征、地震剖面特征、沉积环境等方面的研究,认识到震旦纪末的构造运动与寒武纪早期的构造运动存在明显差异。研究认为桐湾运动是以整体隆升与沉降为特征,并发育三幕构造运动,即灯影组二段富藻层沉积末期的桐湾Ⅰ幕、灯影组二段沉积末期的桐湾Ⅱ幕与灯影组三段—灯影组四段沉积末期的桐湾Ⅲ幕,桐湾期的灯影组镶边碳酸盐台地还存在轻微裂化作用下的热液沉积。寒武纪早期的兴凯运动以裂陷为主,发育两幕构造运动,即麦地坪组沉积期的兴凯Ⅰ幕与筇竹寺组沉积期的兴凯Ⅱ幕,兴凯期的上扬子碳酸盐台地遭遇较强的裂解,热液作用普遍较强,但至兴凯Ⅱ期时,裂陷活动主要发生在川南—黔北地区,川中—川北较弱。桐湾期的隆升剥蚀不仅控制了三大岩溶风化壳的发育,且其形成的绵阳—宜宾—会东巨大侵蚀沟谷控制了下寒武统麦地坪组的泥岩与页岩为主的碎屑岩沉积;兴凯运动不仅控制了有利烃源岩的发育,且与桐湾运动一起控制了有利源-储配置区的分布。因此,四川盆地震旦纪末—早寒武世发育两类不同性质的构造运动,前者主要促进了储层的发育,后者主要促进了烃源岩的发育,二者共生组合形成了震旦系与寒武系的良好油气成藏组合。
Recently,a new breakthrough has been made in natural gas exploration of Sinian-Cambrian Sichuan Basin,but there is also a big debate on the understanding of Late Sinian-Early Cambrian tectonic movement.Through the research on petrologic characteristics,seismic profile characteristics,sedimentary environment and other aspects,it is recognized that a great difference exists between the Late Sinian tectonic movement and Early Cambrian tectonic movement.It is considered that Tongwan tectonic movement is characterized by overall uplift and subsidence with three episodes of tectonic movement,i.e.,Tongwan Episode I,II and III refers to the late sedimentary period of algae-rich layer in Member 2 of Dengying Formation,the late sedimentary period in Member 2 of Dengying Formation,and the late sedimentary period in Member 3 and Member 4 of Dengying Formation respectively.It is also considered that hydrothermal sedimentation exists in the rimmed carbonate platform of Dengying Formation in Tongwan period under the action of slight cracking.Moreover,the Early Cambrian Xingkai tectonic movement is dominated by riftogenesis in two episodes of tectonic movement,i.e.,Xingkai Episode I and II refers to the sedimentary periods of Maidiping Formation and Qiongzhusi Formation respectively.The Upper Yangtze carbonate platform underwent intense cracking in Xingkai period,and hydrothermal process was generally strong.However,till Xingkai Episode II,rift activities mainly occurred in the south of Sichuan Basin and north of Guizhou,while weaker in Central and Northern Sichuan Basin.It is believed that the uplift and denudation not only controlled the development of three major karst weathering crusts in Tongwan period,and the huge Mianyang-Yibin-Huidong erosion gully was formed to control the clastic sediments dominated by mud and shale in Lower Cambrian Maidiping Formation.Xingkai movement controlled not only the development of favorable source rocks,but also the distribution of favorable source-reservoir configuration zones in combination with Tongwan movement.Therefore,two different tectonic movements were developed in Late Sinian-Early Cambrian Sichuan Basin and its adjacent areas.These two tectonic movements promoted the development of reservoirs and source rocks respectively,of which the paragenetic association led to a favorable hydrocarbon accumulation assemblage in Sinian and Cambrian.
出处
《石油学报》
EI
CAS
CSCD
北大核心
2015年第5期546-556,563,共12页
Acta Petrolei Sinica
基金
中国石油天然气集团公司勘探与生产专项"四川盆地灯影组
龙王庙组地层及岩相古地理研究"(2012ZD01-02-03)资助
关键词
四川盆地
震旦纪
寒武纪
桐湾运动
兴凯运动
灯影组
麦地坪组
筇竹寺组
岩溶
储层
烃源岩
热液作用
Sichuan Basin
Sinian
Cambrian
Tongwan tectonic movement
Xingkai tectonic movement
Dengying Formation
Maidiping Formation
Qiongzhusi Formation
karst
reservoir
source rock
hydrothermal process
