李智高,丁琳,杜家元,等. 珠江口盆地恩平凹陷中新统沉积特征及河道型岩性圈闭潜力[J]. 海洋地质前沿,2022,38(10):13-21. DOI: 10.16028/j.1009-2722.2021.235
    引用本文: 李智高,丁琳,杜家元,等. 珠江口盆地恩平凹陷中新统沉积特征及河道型岩性圈闭潜力[J]. 海洋地质前沿,2022,38(10):13-21. DOI: 10.16028/j.1009-2722.2021.235
    LI Zhigao, DING Lin, DU Jiayuan, et al. Sedimentary characteristics and potential of channel-type lithologic traps in Miocene in Enping Sag, Pearl River Mouth Basin[J]. Marine Geology Frontiers, 2022, 38(10): 13-21. DOI: 10.16028/j.1009-2722.2021.235
    Citation: LI Zhigao, DING Lin, DU Jiayuan, et al. Sedimentary characteristics and potential of channel-type lithologic traps in Miocene in Enping Sag, Pearl River Mouth Basin[J]. Marine Geology Frontiers, 2022, 38(10): 13-21. DOI: 10.16028/j.1009-2722.2021.235

    珠江口盆地恩平凹陷中新统沉积特征及河道型岩性圈闭潜力

    Sedimentary characteristics and potential of channel-type lithologic traps in Miocene in Enping Sag, Pearl River Mouth Basin

    • 摘要: 珠江口盆地恩平凹陷中浅层近年来相继有商业油气发现,虽目前仍然以构造圈闭为主,但古珠江三角洲相关岩性目标的评价亟待展开。基于高品质井、震资料,本次研究以恩平凹陷中新统珠江组上段—韩江组下段(T50—T35)为主要目的层,以三级层序界面和最大海泛面为界,建立了恩平凹陷T50—T35间的四级层序格架。在高精度层序地层格架的约束下,进一步采用地震沉积学手段揭示了恩平凹陷以分流河道为主的沉积特征,并建立了不同海平面背景下的河道沉积模式:海侵早期和高位末期河道规模较大,延伸距离较远,平面上常连片发育;海侵晚期和高位早期的河道规模适中,平面上孤立性较强,且前缘常被波浪改造。研究发现,不同类型的河道砂体与特定的构造背景结合可发育“河道切割型”岩性圈闭,并且最大海泛面上下更适合于相关圈闭的发育。据此,研究锁定了恩平A油田西侧斜坡带、E油田东侧斜坡带和G油田西侧披覆构造带等3个岩性圈闭有利区及2个有利勘探目标,为盆地岩性油气藏勘探提供了新思路。

       

      Abstract: Commercial petrol resources have been discovered in the middle and shallow layers of Zhuyi Depression in the Pearl River Mouth Basin in recent years. Although structural traps are still the main ones, the evaluation of related lithologic targets in the paleo Pearl River delta needs to be carried out urgently. Based on high-quality well and seismic data, a fourth-order sequence framework between T50-T35 in Enping Sag is established with the upper member of Zhujiang Formation and the lower member of Hanjiang Formation (T50-T35) in Enping Sag as the main target layer, using a set of third-order sequence boundary and the maximum flooding surface as the boundary. With the constraint of high-resolution sequence stratigraphic framework, the sedimentary characteristics of distributary channel in Enping Sag are further revealed by seismic sedimentology method, and the channel sedimentary models under different sea-level backgrounds are established: the channel scale is larger in the early stage of transgression and the end of highstand, the extension distance is longer, and often developed continuously on the plane; in the late transgression and early highstand, the scale of the river channel moderate, the plane isolation is stronger, and the front edge is often transformed by waves. It is found that different types of channel sand bodies combined with specific structural background can develop "channel cutting" lithologic traps, and about the maximum flooding surface are more suitable for the development of related traps. Therefore, three favorable areas for lithologic trap: east slope of Enping A Oilfield , east slope of Enping E Oilfield and west slop of Enping G Oilfield. Two favorable exploration targets are proposed, which provided new ideas for lithologic reservoir exploration in the basin.

       

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