M走滑盆地形成演化与油气勘探

Forming & Evolution of Hydrocarbon and Its Exploration of the Strike-Slip M Basin

张亚敏^{1 ,2},王婧韫²,李玉荣³,丁　颖⁴

Zhang Yamin,Wang Jingyun, Li Yurong, et al

1.中国地质大学,北京,2. 中原油田分公司勘探开发科学研究院,3.中原石油勘探局地质录井处,4. 中原油田分公司规划处

China University of Geoscience , Beijing 100083. P. R. China

M 盆地形成演化可分为两期:早白垩世(130～96 Ma) 随着大西洋的分段、分期扩张,中非大断裂右行走滑并且产生了早期的M 盆地;晚白垩世(96～75 Ma) 非洲大陆东侧印度洋尤其红海扩张加剧,中非大断裂由早白世的右行变为晚白垩世的左行,其形成演化史可概括为“早期右行成盆,晚期左行改造”。晚白垩世区域地质应力场的变化产生了挤压运动,对盆地构造有较大的改造,使盆地的构造很复杂,主要构造样式有压性背斜、正、负花状构造、直立断层、旋转断块等。左旋压扭作用在盆地内尤其在南区形成了一系列压性背斜,成为油气富集的主要场所。由于构造演化史的变化,沉积中心不断向南转移,在南区沉积了上白垩统优质的厚层泥岩,形成了大油田的区域盖层,控制油气的分布与富集。

The forming & evolution history of M basin can be generalized by in early stages dextral forms basin , in late stages sinistral modifies it ;in late Cretaceous ,the changes of regional geological stress field create compressional movement , this modifies the structure of basin greatly and make it complex. The main structure style is compressional anticline ,positive and negative flower structure ,vertical fault and rotary fault block , etc. Sinistral transpression creates a series of compressional anticline in the basin , especially in south area , this make it the main area of hydrocarbon enrichment. Because of the changes of structural evolution history ,sedimental center continuously moves southerly ,good thick upper Cretaceous mudstone deposited in south area ,and forms regional caprock of giant oil field which controls the distribution and accumulation of oil and gas.