白云-荔湾深水区新生界生物礁识别与发育模式及主控因素探讨

白云-荔湾地区新生界是否发育大型生物礁一直是珠江口盆地(东部)碳酸盐岩油气勘探的核心问题之一。根据已有的地质资料,总结了该区新生界碳酸盐岩及生物礁发育层段的规律性,并在此基础上首次总结了研究区生物礁地震识别特征、发育模式及其主控因素。研究表明:①白云-荔湾地区发育的大型生物礁在不同层段零星分布,多呈丘形、透镜体状外形,顶部具有强-中反射特征,底部连续可追踪,侧向上多见超覆不整合接触,内部多见加积、进积或退积地震发射特征、偶见杂乱至空白反射;②基于构造活动及古隆起背景,本区建立了3种类型的生物礁发育模式:Ⅰ台地边缘礁发育模式、Ⅱ古隆起斜坡礁发育模式、Ⅲ古隆起顶部礁发育模式;③构造运动及全球海平面变化是该区碳酸盐岩及生物礁发育的主控因素。

Reef recognition,development mode and main controlling factors in Baiyun-Liwan deep water area

Whether there are carbonate platforms or large reefs is the core problem of the oil-gas exploration in the Baiyun-Liwan deep-water area of the east part of Pearl river mouth basin.Based on the existing geological data,we summarize the regularity of carbonate development in deep water,and preliminary analysis the carbonate recognition,development mode and main controlling factors in the area.The results can be concluded as follows:(1) Large biological reef always has mound,lens appearance,coping with strong reflection characteristics on the top,continuous tracked on the bottom,unconformity contact on the surrounding,and accretion,prograde,retrogradation or blank reflection characteristics in the inside.(2)Three types of reef development modes have been recognized and characterized based on their basinal and tectonic setting:reef developed on margin platform,reef developed on the ramp,reef developed on the paleohigh.(3)The tectonic movement and the change of sea level are the main controlling factors of the development of biological reef in Baiyun-Liwan deep water area.