首页|川东北地区五峰组-龙马溪组页岩地球化学特征及有机质富集模式

川东北地区五峰组-龙马溪组页岩地球化学特征及有机质富集模式

扫码查看
四川盆地是我国页岩气开发的主力产区,川东北地区作为四川盆地的页岩气开发的接替区,备受关注.为了探究川东北地区上奥陶统五峰组-下志留统龙马溪组富有机质页岩的控制因素及富集模式.采用电感耦合等离子体质谱(ICP-MS)方法对川东北地区五峰组-龙马溪组 14件页岩进行元素分析,并结合测井曲线特征,探讨五峰组-龙马溪组沉积体系、氧化还原条件、陆源碎屑输入、初级生产力和古气候关系.识别出了 3个三级层序(SSQ1,SSQ2和SSQ3),海平面经历了由高—低—高—低的过程,结合页岩元素的w(V)/w(Cr),w(V)/w(V+Ni),w(Ni)/w(Co),w(Sr)/w(Cu),w(Sr)/w(Ba),T(℃)等参数,指示了五峰组-龙马溪组,经历了氧化—贫氧—缺氧还原—贫氧—氧化的淡水环境;气候经历了温暖湿润—干旱寒冷—温润湿润—干旱寒冷—温暖湿润演化过程,温度经历了降低—升高—降低—升高的过程.川东北地区五峰组-龙马溪组有机质富集模式可划分为Ⅲ阶段模式,第Ⅰ阶段,五峰组到龙马溪组底部沉积时期,有机碳逐渐增高阶段;第Ⅱ阶段,龙马溪组中部,有机碳富集阶段(甜点段);第Ⅲ阶段,龙马溪组上部,有机碳逐渐降低阶段.期望为川东北地区页岩气的勘探提供依据,下一步,将开展研究区重大地质事件对有机质富集的资源响应研究,深化页岩气富集模式.
Geochemical characteristics and organic matter enrichment model of Wufeng-Long-maxi formations shale in northeast Sichuan China
The Sichuan Basin,located in southwestern China,is considered the primary producing area for shale gas development in the country.Its rich shale gas reserves have made it a significant contributor to China's energy production.Within the Sichuan Basin,north-east Sichuan has emerged as a region of particular interest for shale gas development.In order to investigate the controlling factors and en-richment patterns of organic matter-rich shales from the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in northeast Sichuan,inductively coupled plasma mass spectrometry(ICP-MS)was used to analyze 14 shale samples from the Wufeng Formation-Longmaxi Formation in northeast Sichuan.Combined with the characteristics of logging curves,the sedimentary system,redox conditions,terrestrial debris input,primary productivity,and paleoclimate relationship of the Wufeng Formation to the Longmaxi Forma-tion were explored.As a result,three third-order sequences(SSQ1,SSQ2,and SSQ3)were identified,and the sea level experienced a pro-cess from high-low-high-low,which,in combination with the shale elemental parameters of w(V)/w(Cr),w(V)/w(V+Ni),w(Ni)/w(Co),w(Sr)/w(Cu),w(Sr)/w(Ba),and T(℃),indicated that the Wufeng Formation-Longmaxi Formation underwent an oxidized-poorly oxygen-ated-anoxic reduced-poorly oxygenated-oxidized freshwater environment;the climate has undergone a warm-humid,dry-cold,warm-hu-mid,dry-cold,warm-humid evolution,and the temperature has gone through the process of decreasing-increasing-decreasing-increas-ing.The organic matter enrichment pattern of the Wufeng Formation-Longmaxi Formation in northeast Sichuan can be divided into a Ⅲ stage pattern.Stage Ⅰ,the depositional period from the Wufeng Formation to the bottom of the Longmaxi Formation,is a stage of gradu-al increase in organic carbon;stage Ⅱ,the depositional period of the middle part of the Longmaxi Formation,is a stage of enrichment of organic carbon(sweet-spot member);and stage Ⅲ,the depositional period of the upper part of the Longmaxi Formation,is a stage of gradual decrease in organic carbon.It is expected to provide a basis for the exploration of shale gas in northeast Sichuan,and the next step will be to carry out research on the resource response of major geological events to organic matter enrichment in the study area and deepen the shale gas enrichment model.

shalesedimentary systemgeochemistrydepositional environmentpaleoclimatewufeng-longmaxi formationsNorth-east Sichuan

张治波、郭英海、郑伟清、曾春林、李岩、赵迪斐、张家明

展开 >

中国矿业大学资源与地球科学学院,江苏徐州 221116

中国冶金地质局一局环境科技有限公司,河北雄安 071703

自然资源部页岩气勘探重点实验室(重庆市地质矿产研究院),重庆 401120

页岩气勘探开发国家地方联合工程研究中心(重庆地质矿产研究院),重庆 401120

中国地质调查局花岗岩成岩成矿地质研究中心,湖北武汉 430205

展开 >

页岩 沉积体系 地球化学 沉积环境 古气候 五峰组-龙马溪组 川东北

江苏省研究生科研实践创新计划资助项目中国地质调查局花岗岩成岩成矿地质研究中心开放基金国家自然科学基金资助项目

KYCX22_2600PMGR20210241772130

2024

煤炭科学技术
煤炭科学研究总院

煤炭科学技术

CSTPCD北大核心
影响因子:2.095
ISSN:0253-2336
年,卷(期):2024.52(8)
  • 25