库车坳陷大北地区古近纪沉积特征及盐湖演化  

Paleogene Sedimentary Properties and Salt Lake Evolution in Dabei of Kuqa Depression

作　　者：许丽[1,2] 李江海[1,2] 王洪浩[1,2] 黄少英[3] 能源[3] 

机构地区：[1]造山带与地壳演化教育部重点实验室,北京100871 [2]北京大学,北京100871 [3]中国石油塔里木油田分公司,新疆库尔勒841000

出　　处：《特种油气藏》2016年第5期56-61,共6页Special Oil & Gas Reservoirs

基　　金：国家重点基础研究发展计划"973"项目"中国西部古亚洲洋构造域火山岩油气藏形成的地质背景"(2009CB219302)

摘　　要：依据岩性组合及测井曲线变化,对大北地区古近系膏盐岩进行分段研究,结合元素地球化学分析,研究其沉积环境,建立古盐湖演化模式。研究认为:该区古近系膏盐岩可分为3段,即下部膏泥岩段、中部膏盐岩段和上部泥岩段。古气候主要为干热气候,湖泊可分为微咸水湖、半咸水湖、咸水湖和盐湖,为常年性较深水湖泊下的缺氧还原环境。研究区盐湖演化存在多期补给和咸化事件,初始阶段(膏泥岩段)对应于3次海侵事件及3次强烈蒸发阶段;中—高级阶段(膏盐岩段)在强烈蒸发时期发生2次盐湖淡化事件;消亡阶段(泥岩段)盐湖快速淡化。该研究为研究区盐下油气勘探提供了地质基础,对古气候、古环境指示具有重要意义。Based on lithological associations and logging,the Paleogene gypsum-salt rock in Dabei is researches by subsection. Geochemical element analysis is used to investigate its sedimentary environment and establish the evolution model of palesalt lake. Research shows that the Paleogene gypsum-salt rock in this area can be divided into three subsections,namely gypsum mudstone subsection in the power part,gypsum-salt rock in the middle part and mudstone subsection in the upper part. The paleoclimate is mainly characterized by dry-hot climate and the lakes can be classified into light saltwater lake,brackish lake,salt water lake and salt lake,which are considered as perennial anoxic reducing environment under deep water lake. The salt lake evolution in this area includes multi-stage supplies and salty events and there are 3 transgressions and 3 intensive evaporations in the initial stage( gypsum mudstone subsection). There are 2 salt lake desalt events in the intensive evaporation period in medium-senior stage( gypsum-salt subsection). The salt lakes desalt rapidly in the dying stage( mudstone subsection). This research could lay a geological foundation for the pre-salt hydrocarbon exploration in this area and also provide significant guidance for the indications of paleoclimate and palaeoenvironment.

关 键 词：膏盐岩 沉积特征 古盐湖演化 大北地区 库车坳陷 

分 类 号：TE122.1[石油与天然气工程—油气勘探]