应用古地貌分析方法进行有利区带预测——以琼东南盆地②号断裂带为例

Palaeogeomorphologic prediction of favorable zones: Take Fault ② of Qiongdongnan Basin as an example

古地貌不仅对沉积盆地后期层序的发育起着重要的控制作用,对沉积体系类型及其展布同样也有重要的控制作用。利用古地貌分析方法,对琼东南盆地②号断裂带附近区域进行了坡折带类型的识别和古沟谷的判别与追踪,分析了不同坡折带控制的沉积体系类型及其形成机制。在研究区松涛凸起上识别出大量下切谷沉积,在此基础上判断出该区域的主要物源通道;②号断裂和②-1号断裂控制着该区域的沉积填充,按控制方式可划分为挠曲坡折和断裂坡折两种类型,控制着不同的沉积相类型。通过进一步分析认为,坡折带控制的低位扇体发育带是油气储集的有利区带。

Palaeogeomorphology plays an important role in the development of sequences in the later filling stage of a sedimentary basin, and it also controls the pattern of the sedimentary system and its distribution. Using the measure of palaeogeomorphologic analysis, this paper identifies the types of slope breaks and paleo-ravines that are developed near the fault （2） of the Qiongdongnan Basin, and classifies the types of the sedimentary systems controlled by the slope breaks. In the study area of Songtao High, a great amount of incised valley sedimentation is identified, from which the provenance is determined. The faults （2） and （2）-1 control the sediments infill in the area, and according to control pattern, the slope breaks can be divided into two types, bend slope break and fault slope break. Lowstand fans controlled by the slope break are the most favorable zone for oil and gas accumulation.