准噶尔盆地中部1区块三工河组流体包裹体特征及对油气多期充注—调整过程的指示

A Sign to the Multi-phases Hydrocarbon Charge and Adjustment:Fluid Inclusion Study from the Sangonghe Formation in the No.1 Block,the Middle Junggar Basin

油气充注过程中形成的流体包裹体为研究成藏过程提供了依据。利用准噶尔盆地中部1区块56块三工河组含油储层样品,通过系统的流体包裹体显微鉴定、微束荧光光谱和均一温度测试等包裹体分析测试手段,结合盆地构造—热演化和烃源岩生排烃史模拟结果,研究了主要含油区块三工河组油气充注的期次和年代,探讨了油气充注—调整的过程。结果表明：有机包裹体主要以发黄色、蓝色、白色荧光的油包裹体为主,荧光光谱主峰波长分别对应于535-545μm、475-485μm和505-515μm等3个波长段,在成岩宿主矿物内被捕获的时序关系总体上依次变新;研究区在中晚侏罗世曾发生最早期的油气聚集,但随着晚侏罗世末的构造抬升和剥蚀,古油藏遭受破坏而形成炭质沥青;现今油气藏主要经历了2期有效油气充注,成藏时间晚于二叠系烃源岩的生烃高峰期;第一期成藏距今100-70Ma（K2）,主要以莫西庄、征沙村地区的I幕发黄色荧光原油充注为标志;第二期成藏距今62-0Ma（E—Q）,油气充注活动频繁且持续时间长,发黄色和蓝色、蓝色和白色荧光的烃类包裹体依次在较长的统一地质时期内叠置共存。表明各含油区块内三工河组油气藏随盆地构造演化发生了多次动态充注与调整,具有残留型、调整改造型及持续充注型等多种油气藏在空间上复合叠加的成藏特征。

The fluid inclusions, captured during the alternation of the diagenesis and the hydrocarbon charge, can provide reliable evidences for hydrocarbon accumulation. Through a series of inclusion tests including microscopic identification, micro-XRF analysis and homogenization temperature measurement, this paper tested 56 fluid inclusion samples from the oil-bearing reservoir of Sangonghe Formation of No. 1 Block,middle Junggar Basin; combined with basinal tectonic-thermal evolution analysis and hydrocarbon generation and expulsion simulation,the periods and time of hydrocarbon charge and adjustment are stud led. The results show that. the hydrocarbon inclusions are mainly liquid hydrocarbon inclusions, and their fluorescence colors are yellow,blue and white,whose main peak wave length were 535-545/μm, 475-485μm and 505-515μm,showing the captured period became newer correspondingly. The carbonaceous bitumen indicated destroyed paleo-oil-reservoir which formed in the earliest hydrocarbon accumulation during the Middle-Late Jurassic,and the reason was successive tectonic uplift and erosion occurring in the Late Jurassic. Present hydrocarbon reservoirs experienced two times of hydrocarbon charge, and these periods were after the Permian source rock generation peak time. The first charge event happened 100-70Ma（K2） ago. The hydrocarbon inclusions were characterized by the yellow fluorescence inclusions and mainly distributed in Moxizhuang and Zhengshacun. The second charge event continued from 62Ma（K2） to present（E-Q）, showing a long time lasting and multi-phased hydrocarbon accumulation. The hydrocarbon inclusions were characterized by the yellow-blue and blue-white fluorescence, and they coexisted in a long period. All the evidences above proved the hydrocarbon accumulation in the Sangonghe Formation was a combination of three kinds of processes,which were characterized by the residue of bitumen,the adjustment and reformation of oil distribution and the continuous charging of oil reservoir.