克拉玛依油田石炭系火山岩油气成藏期次及成藏演化

Hydrocarbon accumulation period and evolution of Carboniferous volcanic in Karamay Oilfield

通过对克拉玛依油田石炭系若干流体包裹体样品进行岩相学和均一温度的测定,结合烃源岩生排烃史和地层埋藏热演化史,分别对3个典型井区的成藏期次进行分析,综合判断了石炭系火山岩的油气成藏期.结果表明:研究区石炭系火山岩油气成藏期次可划分为3期,分别为中三叠世、三叠纪末—早侏罗世、中侏罗世—晚侏罗世.在恢复各成藏期构造演化史的基础上,结合烃源岩演化史和断层活动规律,恢复了石炭系火山岩3期油气成藏演化过程:第一期为T2原生成藏,第二期为T末—J1早期混合成藏,第三期为J2—J3晚期混合成藏.

Carboniferous volcanic reservoirs in Karamay Oilfield have been explored for a long time,but its hydrocarbon accumulation period is not known,which restricts the further study of hydrocarbon accumulation mechanism of the volcanic reservoirs. Through combing the study on petrography and homogenization temperature of several fluid inclusions in Carboniferous with the generation and expulsion hydrocarbon history and thermal evolution history of the strata,the hydrocarbon accumulation periods of 3 representative wellblocks are analyzed to synthetically identify the accurate hydrocarbon accumulation period of Carboniferous volcanic. The results show that hydrocarbon accumulation period of Carboniferous volcanic in the studied area should be divided into 3 stages,that is,Middle Triassic,the end of Triassic to Early Jurassic and Middle Jurassic to Late Jurassic. Combining the recover of tectonic evolution history corresponding to 3 hydrocarbon accumulation stages with the source rock evolution history and the fault activity law,3 hydrocarbon accumulation evolution stages of Carboniferous volcanic are identified,which are the protogenous accumulation stage in T2,the early mixed accumulation stage from the end of T to J1 and the late mixed accumulation stage from J2 to J3.