石油实验地质2017，Vol.39Issue(1)：94-98,5.DOI:10.11781/sysydz201701094
四川盆地川西坳陷雷口坡组四段稀土元素地球化学特征及意义
Geochemical characteristics of rare earth elements and their geological significance in the fourth member of the Middle Triassic Leikoupo Formation in western Sichuan Basin
摘要
Abstract
The composition and characteristic parameters of rare earth elements in sediments provided sedimentary en⁃vironment as well as fluid and source information, which can be used to judge the sedimentary environment of source rocks and reservoirs and the sources of oil and gas. The tests of rare earth elements in carbonate rocks from the fourth member of the Middle Triassic Leikoupo Formation in the western Sichuan Basin indicated that the total REE content was low. The LREE and HREE differentiation were obvious. Obvious negative δCe and positive δEu anomalies were observed. The low total REE content and negativeδCe anomaly reflected a relatively open and weakly oxidizing low⁃energy environment when the fourth member of the Middle Triassic Leikoupo Formation was deposited. This environ⁃ment was favorable for the breeding and growth of hydrocarbon generation organisms, hence providing a material basis for the formation of hydrocarbon source rocks in the Middle Triassic Leikoupo Formation. The positive δEu anomaly suggested a strongly reducing environment for fluid activity during the late period, which was favorable for organic matter preservation. Enriched LREE, poor HREE, positive δEu anomaly and a REE distribution pattern similar to hydrothermal fluid indicated that the fourth member of Leikoupo Formation experienced late hydrothermal alteration. Hydrothermal migration channels also provided good permeability for deep oil and gas migration.关键词
稀土元素/地球化学特征/碳酸盐岩/雷口坡组四段/川西坳陷/四川盆地Key words
rare earth elements/geochemical characteristics/carbonate/fourth member of Leikoupo Formation/western Sichuan Basin/Sichuan Basin分类
天文与地球科学引用本文复制引用
梁世友,陈迎宾,赵国伟,王彦青,胡烨..四川盆地川西坳陷雷口坡组四段稀土元素地球化学特征及意义[J].石油实验地质,2017,39(1):94-98,5.基金项目
国家科技重大专项“大型油气田及煤层气开发”（2016ZX05005－001－005）资助。 （）
