【作者】 王颖；

【导师】 王英民；

【作者基本信息】 石油大学（北京） ， 矿产普查与勘探， 2005， 博士

【摘要】 本文旨在通过对松辽盆地南部层序地层学和坡折带古地貌的研究,建立大型坳陷湖盆坡折带背景下的沉积层序叠置模式以及相的演化规律,分析坡折带古地貌背景对沉积、层序的控制作用。认为多级坡折带-沟谷体系,共同控制了沉积体系分布,其中,坡折带对低位域发育有明显的控制作用,低位坡折控制了湖底扇体系的分布,高位坡折和低位坡折共同控制了三角洲前缘的分布,高位坡折上下发育的沟谷明显控制了下切水道充填的厚层砂岩的分布。通过重点地区精细的沉积砂体研究,确定坡折带控制重力流形成的坡度,试图建立不同古地貌背景下的沉积响应模式。通过本地区地层厚度变化的研究,以及经过压实校正和古水深校正等的恢复,认为在斜坡梯度大致为6m/km 的坡折带即可以发生砂质碎屑流。结合大型水槽沉积物理模拟实验,发现砂质碎屑流形成时地形高差与坡度之间具有强烈的互补性,坡度小所需要的高差就大,坡度大所需要的高差就小。并且结合本地区实际钻测井和地震资料综合分析,建立了缓坡条件下的沉积模式。短缓坡和长缓坡在形成重力流的位置、规模、展布以及发育深切谷的形态特征等均存在明显的不同。在此基础上,结合本地区已发现油气藏的勘探成果和海陀子三维区岩性地层圈闭的发育情况,建立了坡折带背景下的圈闭发育模式,认为低位坡折带的斜坡和坡脚是湖底扇和下切水道岩性圈闭、地层超覆圈闭和断层-岩性复合圈闭发育的有利地区。水进域、高位域分流河道和河口坝砂体发育区是寻找高丰度岩性-断块复合圈闭和构造圈闭的有利层位和地区。低位坡折之上的地区是寻找水进域地层超覆圈闭的主要地区,为岩性地层圈闭发育的有利区带预测提供了有利的保证。更多还原

【Abstract】 Through the study of sequence stratigraphy and the geomorphology of slope belt, the dissertation aims to establish the stacking patterns and the evolvement of facies in the south of the Songliao basin and to analyze the controls of slope geomorphology on sedimentology and sequences. The study has shown that incisions and valleys of mutli-grade slopes govern the sedimentary systems. Slope belt have apparent controls on the development of low-stand system tracks. Low-stand slope belt govern the development of bottom-lacustrine fans, and high-stand and transgressive slope belt co-govern the development of delta front. The distribution of thick sands that fill in the channels are largely controlled by the ravines and valleys formed during high-stand systems. Based on accurate and thorough analysis of sandstones in the key area, the critical angle that could form gravity flows under slope belt conditions is established. An attempt was made to establish the model of sedimentary response to different geomorphologies. With a comprehensive study of the change in strata thickness, revision of compaction and reestablishing of paleo water depth, the study proved that debris flow could form under a critical grade of 6m/km. These, coupled with physical simulation, have further proven that mutual compensation exits in the course of forming debris flows: low angle and gradient needs larger height, high angle and gradient needs smaller height. Sedimentary models under low-gradient environment are established based on analysis of drilling, logging and seismic data, and further study proved that the occurrence, scale and distribution of debris flows and the shape of incised valleys all have obvious difference under long and short distance of low gradient slopes. All of these, coupled with exploration fruits and distribution of lithological and stratigraphic traps in the Haituozi area, a model for the developing of different traps under slope belt background is established. Slopes and toe of slopes of low-stand slope belt are the favorable sites for the developing of bottom-lacustrine fans and channel-filling related lithological traps, stratigraphic onlapping traps and fault-lithology composite traps. Regions that develop high-stand and transgressive distributary channel and mouth bars are favorable sites that could form potential high-saturated lothology-fault composite and structure straps. The upside of low-stand slope belt is favorable region where transgressive onlapping stratigraphic traps could develop. These roles provided valuable references for the forecasting of lithological and stratigraphic traps under slope belt backgrounds in down warped lacustrine basins.更多还原