海相油气地质2023，Vol.28Issue(4)：360-370,11.DOI:10.3969/j.issn.1672-9854.2023.04.003
塔里木盆地柯坪地区下寒武统吾松格尔组白云岩地球化学特征及其成因演化
Geochemical characteristics,genesis and evolution of dolomite of the Lower Cambrian Wusonggeer Formation in Keping area,Tarim Basin
摘要
Abstract
The discovery in the Wusonggeer Formation as a potential new layer for risk exploration in the Cambrian subsalt dolomite field is a significant breakthrough in Tarim Basin.Understanding the genesis and evolution of dolomite is crucial for the formation,preservation,and evaluation of high-quality carbonate reservoirs.This study focus on the outcrops of Wusonggeer Formation in the Keping area.By analyzing the geochemical characteristics including trace element content,rare earth element content,and carbon and oxygen isotopes composition of the Wusonggeer Formation's dolomite,origin of dolomitization and source of dolomitized fluids in the study area were discussed,and possible dolomite patterns were explored.It is shown that the dolomites in the study area have formed in a sedimentary environment characterized by arid and hot climates,saline seawater,and oxidation.The relatively low ∑REE value(5.51-89.10 μg/g,with an average value of 27.32 μg/g)and obvious low negative value of δ13C(from-3.14‰to-0.73‰),and the high negative value of δ18O(from-10.45‰ to-6.19‰)indicates that the diagenesis process was significantly affected by the leaching of atmospheric fresh water.The 87Sr/86Sr value and REE distribution patterns of the dolomite are similar to those of dolomite originating from seawater,and the salinity index(Z)of the dolomite is higher than that of normal seawater.Therefore,it is inferred that the dolomite fluid mainly comes from high salinity seawater.This study provides important insights into the formation mechanism of dolomite reservoirs and the prediction of high-quality reservoirs in the study area.关键词
白云岩/地球化学特征/成因模式/吾松格尔组/柯坪地区/塔里木盆地Key words
dolomite/geochemical characteristics/genetic pattern/Wusonggeer Formation/Keping area/Tarim Basin分类
能源科技引用本文复制引用
南航宇,张天付,谢淑云,周玥,况志伟,马佳怡..塔里木盆地柯坪地区下寒武统吾松格尔组白云岩地球化学特征及其成因演化[J].海相油气地质,2023,28(4):360-370,11.基金项目
本文受中国石油天然气股份公司重大科技专项"海相碳酸盐岩有效储层形成与保持机理及分布预测研究"(编号:2021DJ0503)和"碳酸盐岩油气藏提高采收率关键技术研究"(编号:2021DJ1501)联合资助 （编号:2021DJ0503）
