摘要
琼东南盆地南部隆起属于深水勘探潜力区,距其南部40~100km的西沙群岛中新统—第四系均系碳酸盐岩礁滩地层。通过对该盆地的古构造、古地理分析,认为中新世南部隆起具备发育碳酸盐岩礁滩的地质条件。高波阻抗碳酸盐岩在地震剖面上表现为强低频振幅反射,礁滩体分布在古构造高部位,且厚度大于同期地层。从邻区钻井岩性、速度建立的碳酸盐岩厚度变化正演模型模拟出碳酸盐岩不同厚度时的地震响应,找出地震剖面上识别碳酸盐岩厚度的几个重要控制点:尖灭点、λ/4点、λ/2点,据此制作了琼东南盆地南部深水区碳酸盐岩厚度图。根据碳酸盐岩厚度图和古构造、古地理背景以及礁滩地震响应特征可以看出,琼东南盆地南部隆起中新统发育的碳酸盐岩主要为西沙群岛向北伸出的一个半岛式的孤立碳酸盐岩台地和斜坡沉积,由缓坡台地、陡坡台地、台洼、重力流、礁滩等相带组成。
The south deepwater horst in Qiongdongnan Basin is one of potential exploration areas and the Xisha Islands is carbonate reef flat strata developed from Miocene to Quaternary. Based on the palaeogeographic and palaeostructure analysis, the southern horst had proper conditions for carbonate, reef and tide flat generated during the Miocene. Carbonates show high-amplitude and low-frequency reflection on seismic section. Reef flats distributes on structure high and they are thicker than other strata in the same period. Based on velocity lithology extracted from drilling data in adjacent areas, we perform a forward modeling to simulate reflection of carbonates with different thickness. Then we identify several important thickness control points on seismic sections such as pinch point, λ/4 point, λ/2 point. Finally we construct carbonate thickness maps of the south deepwater area in Qiongdongnan Basin. Based on the palaeogeographic principle, palaeostructure dominate carbonate sedimentation, and seismic response of reef flat, we can draw a conclusion: Carbonate rocks of Miocene developed in the south horst, Qiongdongnan is mainly a peninsula isolated carbonate flat and slope sediment towards the north of Xisha Islands, and the carbonate platform facies is composed of platform gentle slope, platform steep slope, gravity facies, platform hollow, reef, and tide flats. © 2017, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2017年第2期381-391,共11页
Oil Geophysical Prospecting
基金
国家科技重大专项(2011ZX05025-006-02)
国家自然科学基金课题(41390451)联合资助
