石油与天然气地质 ›› 2015, Vol. 36 ›› Issue (1): 111-117.doi: 10.11743/ogg20150114

• 层序与储层 • 上一篇    下一篇

砂质辫状河岩相与构型特征——以山西大同盆地中侏罗统云冈组露头为例

陈彬滔1,2, 于兴河3, 王天奇1, 马凤良1, 李顺利3, 杨丽莎1   

  1. 1. 中国石油 勘探开发研究院 西北分院, 甘肃 兰州 730020;
    2. 中国石油天然气集团公司 油藏描述重点 实验室, 甘肃 兰州 730020;
    3. 中国地质大学 能源学院, 北京 100083
  • 收稿日期:2013-12-11 修回日期:2014-10-17 出版日期:2015-02-08 发布日期:2015-02-11
  • 第一作者简介:陈彬滔(1985-), 男, 工程师, 储层沉积学.E-mail:tobychencugb@foxmail.com.cn.
  • 基金项目:

    国家自然科学基金项目(41072084).

Lithofacies and architectural characteristics of sandy braided river deposits:a case from outcrops of the Middle Jurassic Yungang Formation in the Datong Basin, Shanxi Province

Chen Bintao1,2, Yu Xinghe3, Wang Tianqi1, Ma Fengliang1, Li Shunli3, Yang Lisha1   

  1. 1. Research Institute of Petroleum Exploration & Development-Northwest (NWGI), PetroChina, Lanzhou, Gansu 730020, China;
    2. Key Laboratory of Reservoir Description, CNPC, Lanzhou, Gansu 730020, China;
    3. School of Energy Resources, China University of Geosciences, Beijing 100083, China
  • Received:2013-12-11 Revised:2014-10-17 Online:2015-02-08 Published:2015-02-11

摘要:

砂质辫状河沉积具有极好的储集性能,是重要的油气储层。为了阐明砂质辫状河储层的岩相与构型特征,定量表征构型单元的几何属性和物性特征,采用露头实测、精细构型解释以及实验分析等方法对山西大同盆地中侏罗统云冈组砂质辫状河露头进行了系统研究,共识别出7种岩相类型和5种岩相组合。砂质辫状河中发育河道(CH)、心滩(CB)、边滩(PB)、废弃河道(ACH)及漫溢沉积(OF)5种典型构型单元,以河道和心滩构型单元为主,两者的累积分布频率高达78%。河道构型单元的厚度介于2.5~6.5 m,宽厚比约为25~30,平均孔隙度为7.1%。心滩构型单元的厚度介于2.5~7.0 m,宽厚比约为30~35,平均孔隙度为7.8%。同一沉积时期,砂质辫状河中存在4种基本构型单元组合,分别为CH-OF,CH/ACH-PB,CH-CB-CH和CH/ACH-PB-OF。不同沉积时期的构型单元空间分布可表示为4种基本组合类型及河道构型单元在垂向和横向的重复或叠加。河道和心滩构型单元为砂质辫状河的主要储层类型,但心滩构型单元的规模和储层物性优于河道构型单元。

关键词: 构型单元, 油气储层, 储集物性, 露头, 砂质辫状河, 岩相, 大同盆地

Abstract:

Sandy braided river deposits have excellent physical properties, thus are important oil/gas reservoirs.In order to demonstrate the lithofacies and architectural characteristics of the sandy braided river reservoirs, and quantify the geometric properties and physical properties of architectural units, a systematic study for outcrops of sandy braided river deposits in the Middle Jurassic Yungang Formation in the Datong Basin has been conducted on the basis of outcrop observation, detailed interpretation of architectures, and laboratory analysis.Seven types of lithofacies in five associations have been identified.Five typical architectural units were identified in the sandy braided river deposits, including channel (CH), channel bar (CB), point bar (PB), abandoned channel (ACH), and overflowing sediments (OF).Among these architectural units, the channel and channel bar are the main architectural units with accumulative distribution frequency up to 78%.The thickness of channels ranges from 2.5 m to 6.5 m, width/thickness ratio is about 25-30, and the average porosity is 7.1%.The thickness of channel bars ranges from 2.5 m to 7.0 m, width/thickness ratio is about 30-35, and the average porosity is 7.8%.During the same depositional period, four basic combination types of the architectural units developed in the sandy braided river, namely CH-OF, CH/ACH-PB, CH-CB-CH, and CH/ACH-PB-OF.The spatial distribution of the architectural units in the different depositional periods is characterized by superposition or repetition of these four basic combination types in vertical and lateral.Channel and channel bar are the major reservoir types in the sandy braided river deposits, but the scale and physical properties of the later are better than the former.

Key words: architectural unit, oil/gas reservoir, reservoir property, sandy braided river, lithofacies, outcrop, Datong Basin

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