白云凹陷东南部晚渐新世陆架边缘三角洲沉积特征及沉积地貌演化  

Sedimentary features and sedimentary evolution of the shelf-margin delta in late Oligocene of southeast Baiyun sag

作　　者：王思琦[1] 张忠涛 林畅松[3] 秦成岗 邢作昌[1] 

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国海洋石油(中国)有限公司深圳分公司,广东深圳510240 [3]中国地质大学(北京)海洋学院,北京100083

出　　处：《东北石油大学学报》2017年第1期33-42,共10页Journal of Northeast Petroleum University

基　　金：国家自然科学基金项目(91328201;91528301)

摘　　要：综合利用岩心、测井及三维地震资料,应用地震沉积学和地震地貌学方法,建立白云深水区晚渐新世三级层序地层格架,揭示白云凹陷东南部晚渐新世大型陆架边缘三角洲的沉积结构和沉积地貌特征。结果表明:珠海组至珠江组下段可划分7个层序,中上部ZHSQ5、ZHSQ6和ZHJSQ1时期发育三期陆架边缘三角洲沉积,其中ZHSQ5时期陆架边缘三角洲发育范围较小且相对富泥,前三角洲在地震剖面上呈约300m厚的斜交前积反射;ZHSQ6时期陆架边缘三角洲展布最广,前缘水下分流河道微相呈网状交织,横向展布达5km,三角洲前缘在地震剖面上为S型前积反射,前积体的高度向盆地方向逐渐减薄,前三角洲斜坡远端发育多个小型滑塌浊积体;ZHJSQ1时期继承早期陆架边缘三角洲的沉积特点,同时前缘下斜坡伴生较大规模的滑塌浊积扇。估算三角洲沉积古水深为600m,三角洲前缘斜坡倾角为4°~7°,反映三角洲形成于深水陆架边缘环境。晚渐新世相对海平面变化和沉积物供给共同作用控制研究区陆架边缘三角洲的形成期次和展布规模,而同沉积断裂活动对陆架边缘三角洲的发育位置及沉积形态具有制约作用。陆架边缘三角洲前缘砂坝、分流河道砂体及前三角洲浊积砂体可构成重要的油气储层。We established the third-order sequence stratigraphic framework and revealed the structures and geomorphology of a large-scale shelf-margin delta in the deep-water area of the late Oligocene Baiyun sag,based on an integrated analysis of cores,well-logs and three dimensional seismic data.Result shows:Seven third-order sequences are recognized in Zhuhai and the lower Zhujiang formation of the sag,three stages of shelf-margin deltas were revealed in contain distribute in the upper part of ZHSQ5,ZHSQ6and ZHJSQ1,respectively.The shelf-margin delta of the ZHSQ5period was small and mudrich,with the pre-delta was 300 mthick and an oblique progradation configuration in the front-delta.The shelf-margin delta in the ZHSQ6period was wide lateral distribution about 5km,S-shape progradation in seismic data,a thinning phenomenon in the foreset body toward the basin,and some small-scale slump bodies in the distal slope of the pre-delta.The shelf-margin delta in the ZHJSQ1period inherited the depositional characteristics of that in of ZHJSQ1period,but with some larger slump turbidite fan in the fore-slope.The delta was deposited in a paleo-water depth about 600m,with the calculated front slope angle 4°~7°.It indicates a deep-water shelf-edge environment.The relative sea-level changed and sediment supply co-controlled the formation time and scale of the shelf-margin delta,and the syn-depositional faults controlled its morphology and location.The barrier bar,distributary channel and turbiditic sand in the shelf delta are potential reservoir.

关 键 词：白云凹陷 晚渐新世 陆架边缘三角洲 沉积结构 沉积地貌 

分 类 号：TE121.3[石油与天然气工程—油气勘探]