【摘要】 南沙海域是重要的含油气盆地发育区,其西部的万安盆地新生代沉积了陆相—海陆过渡相碎屑岩和海相灰岩。目前,万安盆地的油气勘探进展甚微,建立完善的层序地层格架并分析层序发育主控因素对研究盆地构造-沉积演化史、预测砂体分布以及落实油气勘探目标均具有重要意义。综合利用钻井、测井和二维地震资料,运用层序地层学原理与方法,结合南海海域新生代构造-沉积演化背景,将万安盆地新生界划分为3个亚一级层序、6个二级层序和10个三级层序。SQ1—SQ2(古新统—始新统)发育范围有限;SQ3—SQ10(渐新统—第四系)地层发育完整,主要为海陆过渡相砂泥岩和海相灰岩。分析认为,构造运动、海平面升降和物源供给共同影响盆地层序地层发育,其中构造运动是最主要的影响因素。更多还原

【Abstract】 Wan’an Basin is one of the uppermost basins in the western part of Nansha Islands which develops several significant petroliferous basins. The sedimentary layer mainly consists of conglomerate, sandstone and mudstone of Cenozoic continental facies, marine-continental transitional facies and marine facies. So far, because of the restriction of many factors,the oil and gas exploration progress in Wan’an Basin is slow. A reasonable and reliable sequence stratigraphic framework is necessary and important for analyzing tectonic-sedimentation evolution history and predicting the distribution of sandstone and implementing lithological reservoirs. Based on the drilling, logging and2 D seismic data, under the guidance of sequence stratigraphic theory and method, combined with the tectonicsedimentation evolution background of Cenozoic in South China sea, this paper divided the Cenozoic into three subfirst-order sequences, six second-order sequences and ten third-order sequences(SQ1-SQ10) in Wan’an Basin. SQ1 and SQ2, corresponding to Paleocene-Eocene, can’t be identified completely because of erosion and the limit of seismic quality. The strata of SQ3-SQ10(Oligocene-Quaternary) were developed completely and mainly composed of sand-shale and marine limestone of marine-continental transitional faceis. The controlling factors of sequence stratigraphic development include tectonic movement, sea level change and sediments supply, among which the tectonic movement is the most important factor.更多还原