摘要
塔里木盆地寒武系盐下白云岩勘探潜力巨大,但是存在白云岩成因机理不清的问题,制约着油气勘探开发。文中综合盆地西北部露头和盆地内重点钻井资料,在岩石学分析的基础上,结合碳氧锶同位素等地球化学分析,对肖尔布拉克组白云岩的成因进行了研究,建立其成因模式。研究结果表明:1)塔里木盆地肖尔布拉克组白云岩总体可归纳为微生物白云岩、晶粒—(残余)颗粒白云岩、含陆源碎屑白云岩等3种类型;2)肖尔布拉克组白云岩主要的3种成因模式为微生物白云石化作用、蒸发泵—渗透回流白云石化作用和埋藏-热液白云石化作用,其中前2种是主体,第3种表现为对前2种的叠加改造;3)肖下段和肖上段白云岩形成模式存在较大差异,肖下段沉积期,由于水体中有机产率较高,有机碳埋藏速率高,有利于厌氧菌群发育,微生物白云石化作用占主导;肖上段沉积期,由于水体变浅,整体变为蒸发环境,剧烈的蒸发作用形成了肖上段的大套蒸发泵—渗透回流白云岩。研究成果可为后续塔里木肖尔布拉克组的白云岩分布规律研究提供理论支撑。
The subsalt dolomites of Cambrian of Tarim Basin has huge potential of hydrocarbon exploration,but its exploration and development were constrained by the unclear genetic mechanism of dolomite.In this paper,by integrating outcrops of the northwestern basin with key well drilling data of the basin,on the basis of petrological analysis,and in combination with geochemistry analysis such as C,O,Sr isotopes,research on the genesis of the dolomite of Xiaoerbulake Formation was conducted and its genetic model was established.The results show that:(1)The dolomites of Xiaoerbulake Formation of Tarim Basin can be concluded into three types,namely microbial dolomites,crystalline-(residual)granular dolomites,and dolomites with continental clastics.(2)The dolomite of Xiaoerbulake Formation was mainly formed by three types of genetic models,namely microbial dolomitization,evaporative pumping-seepage reflux dolomitization,and burial-hydrothermal dolomitization.The former two were the main models and were superimposed and modified by the third one.(3)There are great differences between dolomite genetic models of Lower and Upper Xiaoerbulake Formation.During the sedimentary period of Lower Xiaoerbulake Formation,the high organic yield and the high rate of organic carbon burial in the water body were conducive to the development of anaerobic bacteria,which made microbial dolomitization dominate.During the sedimentary period of Upper Xiaoerbulake Formation,due to the shallowing of the water body,the whole environment became evaporative,and the intense evaporation resulted in the formation of a large set of evaporation pump-seepage reflux dolomite in Upper Xiaoerbulake Formation.The research results can provide theoretical support for the subsequent study on the distribution pattern of dolomites of Xiaoerbulake Formation in Tarim Basin.
作者
冯琳
杨欢
李乐
彭丽
杨果
王晓雪
FENG Lin;YANG Huan;LI Le;PENG Li;YANG Guo;WANG Xiaoxue(Tarim Oilfield Company,PetroChina,Korla 841000,China;Hubei Selenium Industrial Research Institute,Wuhan 430034,China)
出处
《断块油气田》
CAS
CSCD
北大核心
2024年第5期827-835,共9页
Fault-Block Oil & Gas Field
