阿克库勒凸起南部辫状河三角洲砂体尖灭圈闭预测

阿克库勒凸起南部辫状河三角洲砂体尖灭圈闭,可通过下述方法预测:(1) 将上三叠统标志层对齐,制作不同方向的钻井剖面对比图,发现中油组存在着两处相变尖灭;(2) 将中油组顶底界标定在半个反射周期内,顶界标在正极性波峰附近,底界标在波谷附近,因尖灭与波峰、波谷的振幅有关,中油组对应的弱 空白反射即为尖灭;(3)根据上、中、下油组砂岩及间互泥岩的厚度、速度及密度,结合今构造北倾的单斜背景,分别制作中油组砂体陡倾短距离尖灭,缓倾长距离尖灭时含油、气、水的地质模型及选用30 Hz 主频子波制作褶积地震模型验证,中油组和下油组上段砂体均向南尖灭。据此预测在中下油组有两个面积为56 km² 和160 km² 的砂岩尖灭圈闭,且显示出良好的含油气前景。

PREDICTION ON PINCH TRAPS OF BRAIDED DELTAIC SANDBODIES IN SOUTHERN PART OF AKEKULE RISE

Following methods were adopted to predict the pinch out traps of braided deltaic sandbodies in southern part of Akekule Rise:1.drilling profile correlation was made in the study area and two pinch out were found on the top of Akekule Rise and Paleo sag respectively;2.seismic response was used to trace the pinch outs and the weak blank reflection corresponded well with the pinch outs;3.forward model was made to verify the pinch outs.The results indicate that short distance rapid pinch outs developed in the braided river deltaic sandbodies in southern Akekule Rise.It thus predicted that there are two sandstone pinch out traps with the areas of 56 km 2 and 160 km 2 respectively in the middle and lower oil reservoir set.The traps,situated on the passageway of multiphase oil migration since late Cretaceous with fractures as the passageways,are easy to trap oil and gas and are prospects in oil and gas exploration.