东非鲁伍马盆地渐新统深水水道-朵体沉积特征及控制因素

发布时间：2018-04-23 04:24

本文选题：水道-朵体沉积 + 控制因素　；参考：《石油学报》2017年09期

【摘要】：近年来在东非鲁伍马盆地深水区古近系深水沉积砂体中连续发现大型天然气藏,该盆地已成为全球天然气勘探热点地区。但是鲁伍马盆地勘探程度低,深水沉积砂体研究相对滞后,严重制约了下一步油气勘探工作。基于岩心、测井及三维地震资料,建立了东非鲁伍马盆地陆坡深水区渐新统层序地层格架,通过分析水道-朵体沉积特征,并结合区域地质资料,探讨了水道、朵体等富砂深水沉积的控制因素,并建立了相应的沉积模式。鲁伍马盆地渐新统自下而上划分为SQ1、SQ2和SQ3共3个三级层序,水道-朵体沉积发育在每个层序的低位域。研究区SQ1和SQ2层序发育水道、朵体沉积,SQ3层序以水道沉积为主。受始新世末东非大陆抬升及全球"冰室"气候影响,盆地物源供给增加,三角洲向海进积,引发陆坡水道-朵体等重力流沉积。向北流动的南极底流改造水道-朵体沉积,通过淘洗重力流沉积提高水道和朵体的砂地比,并在水道北侧形成侧积砂体和漂积体,限制了后期重力流沉积,导致水道向南侧向迁移、朵体向南延伸。研究结果可以为鲁伍马盆地乃至整个东非陆缘盆地深水储集砂体预测及油气勘探提供一定理论依据。
[Abstract]:In recent years large natural gas reservoirs have been continuously discovered in the Paleogene deep-water sedimentary sandbodies in the deep water area of the Ruwuma Basin in East Africa. The basin has become a hot spot for natural gas exploration in the world. However, the exploration degree of Luwuma basin is low, and the study of deep-water sedimentary sand bodies is lagging behind, which seriously restricts the further oil and gas exploration work. Based on the core, logging and 3D seismic data, the sequence stratigraphic framework of the Oligocene in the deep water area on the slope of the Luwu Ma Basin in East Africa is established. The watercourse is discussed by analyzing the sedimentary characteristics of the watercourse and the dolomite and combining with the regional geological data. The controlling factors of sand-rich deep water deposits such as dolomite have been established and the corresponding sedimentary models have been established. The Oligocene in the Luwu Ma Basin is divided into three third-order sequences SQ1SQ2 and SQ3 from the bottom to the top. The watercourse and dolomite deposits are developed in the low order domain of each sequence. In the study area, the SQ1 and SQ2 sequences developed waterways. Influenced by the continental uplift in East Africa at the end of the Eocene and the global "ice chamber" climate, the source supply of the basin increased and the delta protruding to the sea, which led to the gravity flow deposition such as the waterway and the dolomite on the slope of the land. The northward flow of the Antarctic bottom flow reconstructs the watercourse-dolomite deposition, improves the sand / land ratio of the channel and the dolomite through the washing gravity flow deposition, and forms the lateral sand and drift deposits on the north side of the watercourse, which limits the late gravity flow deposition. Causes the waterway to the south lateral migration, the flower body extends southward. The results can provide a theoretical basis for prediction of deep water reservoir sand bodies and oil and gas exploration in Luwuma basin and the whole East African continental margin basin.
【作者单位】：西安石油大学地球科学与工程学院;中国石油杭州地质研究院;中海油研究总院;
【基金】：中国石油天然气股份有限公司重大科技项目“海外海洋勘探技术与有利目标评价研究”(2014D-0908)资助
【分类号】：P618.13

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