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深水水道沉积是深水油气勘探开发中重要的沉积类型。利用高分辨率三维地震、钻测井等资料,通过地震资料综合解释和地质分析,对南海北部白云深水区珠江组上段发育的大型深水水道的展布特征及成因模式进行识别、刻画和预测。研究认为,该体系近SN向展布,具低弯度蛇曲形态,体系内发育3类深水重力流沉积单元,其中块体搬运沉积发育于白云凹陷东北端,呈丘状外形、内部杂乱反射特征,底部发育侵蚀擦痕;水道为体系主体搬运通道,按成因可分为侵蚀型、侵蚀/加积型和加积型,受控于物源供给及古地貌特征,具“上下分期,南北分段”发育特征,为典型的复合水道沉积构型,复合水道内叠置迁移关系复杂;位于水道前端的朵体发育于荔湾凹陷南部,剖面上表现为强振幅平行—亚平行反射,在平面上具有朵状特征。从古水深、古地形、触发机制及古源头沉积体系等方面综合分析,探讨了该深水水道体系的成因模式,推测古珠江三角洲为其主力物源,东沙隆起碳酸盐岩沉积为次级物源。这一研究对研究深水重力流沉积过程具有重要的参考价值。
Deepwater channel deposition is an important sedimentary type in deepwater oil and gas exploration and development. Based on the data of high resolution 3D seismic and drilling logging, the distribution features and genetic models of the large-scale deepwater channel developed in the upper part of the Zhujiang Formation in the Baiyun deep-water area of the northern South China Sea are identified, characterized and predicted through comprehensive interpretation of seismic data and geological analysis. The study shows that the system is distributed in the near SN direction and has a low curvature serpentine morphology. There are three types of deep-water gravity flow sedimentary units developed in the system. The sediment transport and sedimentation developed in the northeastern tip of Baiyun Sag with mound-shaped and internal messy reflections , The bottom of the development of erosion scratches; waterway system for the main channel, according to the causes can be divided into erosion, erosion / plus accumulation and accumulation, controlled by the provenance and paleogeomorphology, with “up and down staging, north and south The characteristics of the ”section" development are typical composite channel sedimentary configurations, and the superimposed migration in the composite channel is complex. The body located at the front of the channel develops in the southern part of Liwan Sag with strong amplitude parallel- The plane has a flower-like features. Based on the comprehensive analysis of palaeo-water depth, palaeogeomorphology, triggering mechanism and palaeotectonic depositional system, the genetic model of the deepwater channel system is discussed. It is speculated that the ancient Pearl River Delta is the main source of sediment, and the carbonate sediments of the Dongsha uplift are secondary source. This study has important reference value for the study of deep water gravity flow deposition process.