滩坝沉积研究进展综述

滩坝是发育于滨岸带非常重要的一种沉积相类型和油气储集体,是滩和坝的总称。国外关于滩坝的研究,多集中于对现代沉积与野外露头的考察,侧重于成因机理的解释;中国的沉积学家、石油地质学家则偏重于陆相湖盆滩坝的沉积特征与油气地质意义的研究。作者从滩坝的成因出发,对滩坝的分类、沉积模式、控制因素、古地理及油气意义进行了总结梳理,提出滩坝是"风(风浪)-源(物源)-盆(盆地演化)"系统内综合作用下的产物,表现在:波浪是滩坝形成的动力;物源是滩坝形成的物质基础;盆地层序—构造演化过程中古地貌与古水深决定了滩坝的发育位置与范围。研究滩坝发育的控制因素,有利于为其在垂向上和平面上的分布预测提供有力的支持,具有重要的油气勘探意义。滩坝砂体记录了其形成时的古地理条件。特别地,通过对滩坝砂体沉积特征的解剖,可以一定程度上定量反映其形成时的古风浪条件,进而可以恢复古大气流场,这对古气候的恢复起到了重要的补充作用。

Advances in beach-bar research: A review

The beach-bar deposits,which is a general term of the beach and bar,is an important kind of facies and petroleum reservoir developed in the nearshore zone. Most of the foreign researches on beach-bar deposits are focused on the interpretation of their formation mechanisms via geology investigation of modern deposits and field outcrops;while Chinese sedimentologists and petroleum geologists have focused on their sedimentary characteristics and petroleum significances,especially those formed in lake environments. In this paper,we reviewed and refined the advances in beach-bar researches. Firstly,we summarized the origin of beach-bars,and then followed by their classification,depositional model,controlling factors,and the palaeogeography and petroleum significances. We propose that the beach-bar is formed in the system combined of wind(wind wave),provenance and basin(basinal evolution), i.e.,waves are the original power of beach-bar formation,while the provenance provides the material base,and the evolution of tectonic and sequence of the basin determines the position and extent of beach-bars. Study on controlling factors of beach-bar formation could provide powerful supports in prospecting the distribution position of beach-bar sandbodies vertically and horizontally,which is of great significance in petroleum reservoir exploration. Ancient beach-bar deposits recorded the palaeogeographic conditions during their formation. Especially,palaeo-wave conditions could be quantitatively recovered based on sedimentology analyses on beach-bar deposits,and in turn,the palaeo-atmospheric flow field. This plays an important,promotive and supplemental role in the study area of palaeoclimatic recovery.