摘要
四川盆地下寒武统筇竹寺组页岩气勘探研究目前主要集中在川南、川西南地区,对于川北米仓山前缘的研究特别是页岩层系中裂缝脉体的研究较少,制约了该地区筇竹寺组的勘探进程。通过岩心-薄片观察、流体包裹体测温、流体地球化学分析等方法研究了川北米仓山前缘筇竹寺组成脉流体特征及流体活动对页岩气保存的意义。结果表明:研究区筇竹寺组有2期方解石和1期石英充填,第1期方解石脉形成于早奥陶世,成脉流体为层内地层水、海水、大气淡水的混合流体;第2期方解石脉形成于早白垩世,成脉流体为层内地层水和深部热液的混合流体,与液烃、气相甲烷一起充注;第3期石英脉形成于晚白垩世,成脉流体为层内的硅质流体,与气相甲烷一起充注。筇竹寺组2期方解石成脉时受到了深部热液和大气淡水的影响,页岩气保存条件遭受一定程度的破坏,而第3期硅质流体来源于页岩层内,表明筇竹寺组的后期改造作用不强,页岩保留了一定的自封闭性。研究成果为米仓山前缘筇竹寺组页岩气勘探提供了理论依据。
Exploration research on Lower Cambrian Qiongzhusi Formation in Sichuan Basin is mainly concentrated in southern and southwestern Sichuan.Less research on Micangshan front in northern Sichuan especially on the frac-ture veins in shale strata series restricts exploration progress of Qiongzhusi Formation in this area.Vein-forming flu-id characteristics and implications of fluid activity for shale gas preservation of Qiongzhusi Formation at Micangshan front of northern Sichuan is studied by means of core-slice observation,fluid inclusion temperature measurement and fluid geochemistry analysis.The results show 2 stages of calcite and 1 stage of quartz filling in Qiongzhusi For-mation of studied area.Calcite veins of the first stage formed in Early Ordovician with vein-forming fluid being mixed fluid of innerlayer formation water,seawater and atmospheric fresh water.Calcite veins of the second stage formed in Early Cretaceous with vein-forming fluid being mixed fluid of innerlayer formation water and deep hydro-thermal fluid,filling together with liquid hydrocarbon and gaseous methane.Quartz veins of the third stage formed in Late Cretaceous with vein-forming fluid of innerlayer siliceous fluid,filling together with gaseous methane.Qion-gzhusi Formation was affected by deep hydrothermal solution and atmospheric fresh water during the second stage of calcite veins formation,and shale gas preservation conditions were damaged to a certain extent,while siliceous flu-id of the third stage originated from shale layer,indicating that transformation effect of Qiongzhusi Formation was not strong in later stage with a certain degree of shale self-sealing preservation.The research provides theoretical ba-sis for shale gas exploration at Micangshan front of Qiongzhusi Formation.
作者
李小佳
李峰
邓双林
吴娟
邓宾
刘树根
LI Xiaojia;LI Feng;DENG Shuanglin;WU Juan;DENG Bin;LIU Shugen(No.3 Gas Production Plant of Sinopec Southwest Oil&Gas Company,Deyang 618000,China;College of Energy,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu 610059,China;Xihua University,Chengdu 610039,China)
出处
《大庆石油地质与开发》
CAS
北大核心
2023年第5期27-35,共9页
Petroleum Geology & Oilfield Development in Daqing
基金
中国石油化工股份有限公司重点科技项目“四川盆地及周缘油气富集规律与分布预测”(P20059)
四川省科技计划项目“四川盆地深层海相页岩储层特征”(2018JY0437)。
关键词
米仓山前缘
筇竹寺组
脉体
流体包裹体
流体地球化学
流体活动
页岩气保存
Micangshan front
Qiongzhusi Formation
vein
fluid inclusion
fluid geochemistry
fluid activity
shale gas preservation
