还原性流体-泥岩盖层相互作用的岩石学和地球化学记录——以松辽盆地南部王府凹陷青山口组泥岩为例

发布时间：2018-04-16 04:37

本文选题：泥岩盖层 + 还原性流体　；参考：《石油与天然气地质》2017年05期

【摘要】：天然气田(藏)中渗漏的还原性流体将导致泥岩盖层的成分(尤其是常量和微量元素)变化。这种变化记录了还原性流体—岩石相互作用事件,并具有指示油气藏位置的意义。利用天然类比方法,并以松辽盆地南部王府凹陷青山口组泥岩为对象,对天然气田(藏)中还原性流体引起的泥岩成分变化和流体在盖层中的运移方式进行了研究。结果表明:研究区渗漏流体的主要还原性成分为CH_4,其次为H2S;在流体-岩石相互作用过程中,泥岩中红色的Fe~(3+)被还原为无色的Fe~(2+),从而导致了漂白现象的出现。Fe~(2+)以胶体的形式随流体运移至别处或以铁结核的形式重新沉淀;漂白过程中U含量的升高、Ga和Sc含量的降低,与U、Mo、V和Ni含量在纵向上的规律性变化均和流体的还原性有关;在泥岩盖层中,还原性流体主要在浮力的驱动下发生纵向运移,且地层抬升可导致其水位降低;天然气田(藏)泥岩盖层中微量元素的规律性变化具有指示还原性流体流动路径和方向的意义。
[Abstract]:The leakage of reductive fluid in natural gas field will lead to the change of the composition of mudstone caprock, especially the constant and trace elements.This change records the reductive fluid-rock interaction events and has the significance of indicating the location of oil and gas reservoirs.Using natural analogy method and taking Qingshankou formation mudstone in Wangfu sag of southern Songliao Basin as an object, the changes of mudstone composition caused by reductive fluid in natural gas field (reservoir) and the migration mode of fluid in caprock are studied.The results show that the main reducing component of leakage fluid in the study area is CH4, followed by H _ 2S, and in the process of fluid-rock interaction,The red Fe~(3 in mudstone is reduced to colorless Fe~(2, which leads to the occurrence of bleaching phenomenon. Feb2) moves with the fluid to another place with the form of colloid or reprecipitates in the form of iron nodules.The increase of U content and the decrease of SC content in bleaching process are related to the regular changes of U _ (Mo) V and Ni contents in the longitudinal direction, and the longitudinal migration of reducing fluids in mudstone caprocks is mainly driven by buoyancy.The regular change of trace elements in mudstone caprock of natural gas field (reservoir) has the significance of indicating the path and direction of reducing fluid flow.
【作者单位】：吉林大学地球科学学院;华北理工大学矿业工程学院;中国石油吉林油田分公司勘探开发研究院;
【基金】：国家自然科学基金面上项目(41172091,41572082,41372133) 河北省矿业开发与安全技术重点实验室开放基金项目(2016kykf02)
【分类号】：P618.13

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