琼东南盆地中央峡谷西段充填体系沉积演化与砂体分布

Filling evolution and sand distribution in the west part of Central Canyon,Qiongdongnan Basin

依据三维地震资料和钻井资料，通过分析地震剖面反射特征和均方根振幅属性，对琼东南盆地中央峡谷充填体系西段沉积演化和砂体分布进行了研究。结果表明：①中央峡谷主要充填时期为距今5．5～1．8Ma，可划分为三个阶段，分别为峡谷轴向充填期（LST30）、低弯度水道发育期（LST29）和块状搬运复合体沉积（MTCs）充填期（I—ST28和LST27）；②峡谷充填体系主要受峡谷走向物源、海南岛物源和峡谷南部物源控制，并在峡谷充填过程中呈现单一物源与双物源相互转化的复杂变化过程；③中央峡谷西段发育峡谷轴向充填砂体、水道砂体、朵叶状砂体以及堤岸砂体，其中峡谷轴向充填砂体主要分布于LST30之内，水道砂体在研究区东部发育于LST30晚期，并在LST29时期最为发育，朵状砂体发育于LST29，主要集中分布于研究区的东部，堤岸砂体主要发育于LST30晚期水道沉积的两侧；④峡谷轴向充填砂体、朵叶状砂体以及堤岸砂体分布较广，可作为该区的有利储层。

Based on the 3D seismic and well data,we have studied filling evolution and sand distribution in the west part of Central Canyon by using seismic reflection characteristics and RMS amplitude attribute.The following observations are obtained: ① The canyon filling can be divided into three stages:canyon axial filling(LST30),low sinuosity channel(LST29)and MTCs(LST28and LST27), ② The fillings are controlled by canyon axial provenance,Hainan provenance and south provenance, ③ Canyon axial filling sands are located in LST30. Channel sands are mainly developed in the LST29 and the eastern part of the area during the later LST30.Lobe sands are located in the eastern part, and only developed in the LST29.In the later LST30,levee sands located on both sides of the channel.④ Canyon axial filling sand,lobe sand and levee sand are wider distribution and can be considered as good reservoirs.