石油与天然气地质 ›› 2020, Vol. 41 ›› Issue (4): 824-837.doi: 10.11743/ogg20200415

• 油气地质 • 上一篇    下一篇

东海陆架盆地西湖凹陷平湖组断层组合样式及其控砂机制

陈哲1(), 张昌民1,*(), 侯国伟2, 冯文杰1, 徐清海1   

  1. 1. 长江大学 地球科学学院, 湖北 武汉 430100
    2. 中海石油(中国)有限公司 上海分公司, 上海 200335
  • 收稿日期:2019-04-29 出版日期:2020-08-01 发布日期:2020-08-11
  • 通讯作者: 张昌民 E-mail:1990cz@sina.com;zcm@yangtzeu.edu.cn
  • 第一作者简介:陈哲(1989-),男,博士研究生,储层沉积学。E-mail:1990cz@sina.com
  • 基金项目:
    国家科技重大专项(2016ZX05027-002-007);国家自然科学基金项目(41772094);国家自然科学基金项目(41802123)

Fault distribution patterns and their control on sand bodies in Pinghu Formation of Xihu Sag in East China Sea Shelf Basin

Zhe Chen1(), Changmin Zhang1,*(), Guowei Hou2, Wenjie Feng1, Qinghai Xu1   

  1. 1. School of Geosciences, Yangtze University, Wuhan, Hubei 430100, China
    2. Shanghai Branch, CNOOC, Shanghai 200335, China
  • Received:2019-04-29 Online:2020-08-01 Published:2020-08-11
  • Contact: Changmin Zhang E-mail:1990cz@sina.com;zcm@yangtzeu.edu.cn

摘要:

东海陆架盆地西湖凹陷是中国沿海重要的含油气区,勘探实践中发现其内部断层及砂体分布规律复杂、勘探难度大,亟待解决砂体分布控制因素问题,深化砂体分布规律认识。运用岩心、测井及三维地震资料,采用古地貌和地震属性叠合精细砂体解释技术,对西湖凹陷平湖组同沉积断层分布及组合特征对砂体的控制作用开展了研究。根据同沉积断层发育规模的差异,划分出3个级别的断层,分别控制了凹陷格局、斜坡特征及砂体展布3个层次,分析了三级同沉积断层组合样式对砂体垂向沉积特征及平面展布方向的控制作用。研究表明,研究区发育6种断层控砂模式,分别为正向断阶阶梯型、正向断阶掀斜型、正向断阶叠覆型、墙角型、反向断阶型和正反向断阶复合型控砂模式。其中由正向断层构成的断层组合样式有利于砂体向凹陷中央搬运,扩大了储层在凹陷内的分布规模,而由反向断层构成的断层组合样式,其富砂作用显著、油气聚集条件优越。在6种断层控砂模式的指导下,有利于发现砂体垂向富集段及横向富集带,判断砂体展布方向及预测储层发育位置。

关键词: 同沉积断层, 反向断层, 控砂机制, 砂体分布, 平湖组, 西湖凹陷, 东海陆架盆地

Abstract:

Xihu Sag in the East China Sea Shelf Basin is an important petroliferous area along the coast of China. Exploration activities in the sag reveal complex distribution of (syndepositional) faults and sand bodies but the controlling factors on the distribution of the sand bodies are still unclear. In this study, core observation, logging and 3D seismic data are combined with fine sand body interpretation based on paleogeomorphology and seismic attributes to study the effect of synsedimentary faults on the sand bodies in the Pinghu Formation of the sag. According to the different development scale, the syndepositional faults can be divided into three levels, which serve to control the sag pattern, slope characteristics and sand body distribution, respectively. In addition, the controlling effect of the three levels of the syndepositional fault distribution patterns on the vertical sedimentation and plane extension of the sand bodies is analyzed. The results show that there are six fault combination patterns controlling the sandstone development in the study area, namely the forward fault-step type, forward fault-step-tilt type, forward fault-step overlying type, corner type, reverse fault step type, and composite type with both forward and reverse faults and steps. Of which, forward types facilitated the transportation of sand bodies to the center of the sag and enlarged the distribution of reservoirs within the sag, and reverse types had significant sand-rich effect and provided superior conditions for hydrocarbon accumulation. The six combination patterns are helpful in guiding the finding of vertical and horizontal enrichment zones of sand bodies, determining the distribution of sand bodies and predicting the locations of reservoirs.

Key words: syndepositional fault, reverse fault, sand body control mechanism, sand body distribution, Pinghu Formation, Xihu Sag, East China Sea Shelf Basin

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