深水高弯度水道—堤岸沉积体系形态及特征

Morphology and characteristics of deep water high sinuous channel-levee system

在海底扇研究及油气勘探中,不断发现一种形态类似曲流河的高弯度水道—堤岸沉积体系,其在形态及沉积特征方面与海底扇有较大差异。在国内外研究成果的基础上,结合对重力流的实际研究工作,对该体系的沉积模式及沉积特征等开展了进一步的研究,并从沉积环境、流体类型、形态等方面与曲流河进行比较。深水高弯度水道—堤岸沉积体系主要包括水道、废弃水道、堤岸、决口扇及朵叶5个部分。其中,水道分支少,弯度大,岩性主要为砂岩,局部见砾岩;堤岸多为细砂岩和粉砂岩;朵叶主要为砂泥互层;整个沉积体系外部形态为条带状。深水高弯度水道—堤岸沉积体系的发现及研究将丰富深水沉积研究内容,为深水油气勘探提供新的思路。

High sinuous channel-levee system with morphology similar to the meandering river has been found during the submarine fan study and hydrocarbon exploration.This system is different from submarine fan in the aspect of morphology and sedimentary characteristics.Based on the achievements from the foreign and domestic researches,combining with the practical researches on gravity flow,a further research on the sedimentary model and sedimentary characteristics of the system has been carried out,including comparison to the meandering river with sedimentary environment,type of flow,morphology and so on.Channel,abandoned channel,levee,crevasse splay and lobe are included in the system.The number of branch of the channel is less,but always be high sinuous.The lithology of channel is mostly sandstone,while conglomerate can be found locally.The main lithology of levee is fine-sand or siltstone while lobe mudstone intercalated with sandstone.The whole morphology of the system is band-belt-like.The discovery and research on the deep water high sinuous channel-levee system not only enrich the content of the deep water deposition study,but also provide a new prospect for oil and gas exploration.