塔里木盆地巴楚—麦盖提地区古生界油气藏成藏期次

Research on Hydrocarbon Accumulation Periods of Palaeozoic Reservoirs in Bachu-Maigaiti Area of Tarim Basin

本文利用塔里木盆地巴楚—麦盖提地区8口井53块样品开展了流体包裹体的荧光观察和显微测温、测盐系统分析,并结合埋藏史、热演化史确定了研究区古生界油气藏的主要成藏期次及成藏时间。研究结果表明,研究区古生界油气藏曾发生过2期4个幕次的油气运聚事件,即:海西晚期的早成藏阶段,其可进一步划分为晚石炭世—早二叠世(距今309.40~289.20 Ma)和晚二叠世—早三叠世(距今262.90~241.20 Ma)2个幕次;喜马拉雅晚期的晚成藏阶段,主要以高成熟油充注及天然气成藏为主,其可划分为新近纪晚期(距今6.31~4.17 Ma)和第四纪早期(距今2.31~1.62 Ma)2个幕次。结合盆地构造演化史认为,2期油气运聚事件分别受海西晚期和喜马拉雅晚期构造运动控制,印支—燕山期构造抬升中止了烃源岩演化,形成了海西晚期和喜马拉雅晚期2个重要的油气成藏时期。

Fluid inclusion analysis is an effective method in the research of oil and gas migration,accumulation,and charging.In this study,the accumulation-forming stage and time of the petroleum reservoir in the Bachu-Maigaiti area locating in Tarim basin were determined on the basis of fluorescence microscope observation and measurement of salinity and temperature regarding the fifty-three samplesfrom eight wells by fluid inclusion analysis,in combination with the burial and thermal histories.The results indicate that 4 acts of 2 hydrocarbon migration and accumulation periods occurred in Paleozoic.The first period is the early accumulation stage during the Late Hercynian period,and can be further divided into two episodes,i.e.,Late Carboniferous-Early Permian of（309.4-289.2）Ma and Late Permian-Early Triassic of（262.9-241.2）Ma;The second period is the Late Himalayan period that can be divided into Late Neogene of（6.3-4.2）Ma and Early Quaternary of（2.3-1.6）Ma,and during which the high maturity hydrocarbon and natural gas primarily filled.According to the history of tectonic evolution of the basin,the two hydrocarbon migration and accumulation events were originally triggered by the late Hercynian and Late Himalaya tectonic movements,and then the evolution of the hydrocarbon source rocks was ended by the Indosinian-Yanshanian tectonic uplift,all of which jointly constituted the two hydrocarbon accumulation periods.