哈拉哈塘油田哈6—新垦区块奥陶系碳酸盐岩成岩环境

Diagenetic environment for Ordovician carbonate rocks in Ha 6-Xinken block of Halahatang oilfield in Tarim Basin,China

通过孔洞充填物的碳、氧同位素和包裹体分析,探讨塔里木盆地哈拉哈塘油田哈6—新垦区块奥陶系储层碳酸盐岩的形成环境。除加里东期的淡水喀斯特充填外,还存在海西期埋藏充填、印支—燕山期埋藏充填及喜马拉雅期的埋藏充填。研究表明奥陶系沉积后,经历了同生成岩期、早成岩期和近地表成岩期,后逐步埋藏进入中成岩期,加里东期构造运动使该区经历了抬升、剥蚀以及大气水溶蚀成岩环境,随中生界再次埋藏,构成了中期开启型成岩演化系统。

This paper discusses the digenetic environment of the Ordovician carbonate rocks in Ha 6-Xinken block of the Halahatang oilfield through analyzing the carbon and oxygen isotopes and fluid inclusions of the fillings in the holes and pores.The result indicates that there are four large-scale filling periods of calcite to form the carbonate rock reservoirs,including the karst filling of fresh water in the Caledonian period,and three periods of buried filling occurred in the Hercynian,IndosinianYanshanian and Himalayan periods.The researches demonstrate that the digenetic process is complicated in this area and can be roughly divided into two stages.After Ordovician sedimentation,this area went through the processes of the syndiagenesis,the early diagenesis and the near-surfacediagenesis and then,gradually approached to the middle stage diagenesis one by one.The late stage diagenesis environment in the Caledonian period went through the uplifting,denudation and atmospheric water dissolution due to the tectonic movement.This set of formations was covered and buried by the late deposit formations in the Mesozoic,which together composed the open type digenetic revolution system in the middle stage.