松辽盆地北部埋藏历史对大庆长垣油藏成藏的控制

Controls of Buried History on Oil Accumulation Processes in Daqing Placanticline of Northern Songliao Basin

利用 8 90余口钻井资料 ,综合应用埋藏历史、盆地数值模拟、成藏年代学研究方法 ,查明了松辽盆地北部埋藏历史对大庆长垣油藏成藏过程的控制 .松辽盆地北部普遍经历了 3次沉降、2次抬升 .青山口组到嫩江组、四方台组到明水组、新第三系泰康组到第四系沉积时期 ,构成 3次沉降 ,其中以嫩江组沉积后期 (嫩三～五段沉积时期 )和明水组沉积时期沉积速率最大 ,分别达 16 0m/Ma和 180m/Ma .而 2次区域抬升分别发生于嫩江组沉积后和明水组沉积后 ,大庆长垣背斜构造主要是在这 2次构造抬升过程中形成的 .青山口组主力烃源岩具有漫长的生排油历史 ,而且生排烃过程与构造活动及圈闭增长过程在时间和数值上具有良好的匹配关系 .在 73Ma左右和 6 5～ 4 0Ma之间为大庆长垣油藏的成藏高峰期 .盆地沉降过程是油气生成量积累的过程 ,盆地抬升。

Based on data of more than 890 drilling wells, the controls of buried history on oil accumulation processes in the Daqing placanticline of northern Songliao basin have been elaborated by means of basin simulation and dating technique of oil reservoir. Northern Songliao basin had been undergone 3 subsidences and 2 uplifts. The 3 subsidences are Qingshankou-Nenjiang, Sifangtai-Mingshui and Tertiary-Quaternary periods, of which the biggest depositional rates with respectively 160 m/Ma and 180 m/Ma occur at Late Nenjiang and Mingshui periods. The 2 uplifts respectively betide in the end of Nenjiang and Mingshui periods, which results in the formation of the Daqing placanticline. The oil generation and expulsion of the major source rocks of Qingshankou Formation maintained for a very long period, which started from about 77.4 Ma, and matched well with tectonic activity and formation of trap. The results indicate that two oil accumulation peaks occur respectively about 73 Ma and 65-40 Ma, which are in agreement with the processes of basin uplifts and structure formation.