苏丹国穆格莱德盆地构造特征及演化

Structure characteristic and evolution in Muglad Basin of Sudan

用盆地分析的方法确定了穆格莱德盆地的原型为伸展断陷盆地.由于改造状况不同,出现3种类型:第一类是未受改造的伸展断陷盆地,第二类是挤压反转的伸展断陷盆地,第三类是走滑改造的伸展断陷盆地.盆地内半地堑、半地垒不对称地交替变化是通过调节带调节其变形或位移,该盆地调节带有6种类型,其构造样式为地垒状凸起、鼻状构造和走向斜坡,具有纵向、横向和斜向3种走向.盆地构造演化有3期:(1)早白垩世早期,随着非洲-南美泛大陆裂开,产生了第一期伸展断陷盆地;(2)早白垩世晚期到晚白垩世,随着原始大西洋的扩张,形成了第二期伸展断陷盆地;(3)新生代,随着区域沉降,演化为伸展坳陷盆地.油气储量主要分布在第二期伸展断陷盆地,油气具有跨时代聚集、高产富集的特点.

There are three types of basin,which are typical rift basin,the rift basin with reversal structure and rift basin modified by strike-slip movement.There are six types of accommodation zone in Muglad Basin,and in the basin,their structure styles are of horst-shaped uplift,nosing structure and strike ramps with longitudinal,horizontal or oblique trends.There are 3 stages in the structure evolution of Muglad Basin,which are pre-rift period,rift period and post-rift period.At the end of late Cretaceous,Muglad Basin is modified by strike-slip movement and negative flower shaped structures,and by compressional movement,which causes some reversal anticlines and semi-anticlines to be formed.Semi-deep-deep lacustrine shale filled in the basin at the early stage of early Cretaceous controls the distribution of source rock,and the high-quality thick shale formed at the end of late Cretaceous is the cap rock and high-quality hydrocarbon reservoir.