石油与天然气地质 ›› 2009, Vol. 30 ›› Issue (4): 438-443.doi: 10.11743/ogg20090408

• 古近系层序地层与隐蔽圈闭 • 上一篇    下一篇

渤中坳陷古近系中、深部碎屑岩储层碳酸盐胶结物分布特征及成因机制

王清斌1, 臧春艳2, 赖维成1, 王波1, 王雪莲1, 赵小娇3   

  1. 1. 中海石油(中国)有限公司, 天津分公司, 勘探开发研究院, 天津, 300452;
    2. 中海油能源发展股份右限公司采油工程研究院, 天津, 300452;
    3. 中国地质大学海洋学院, 北京, 100083
  • 收稿日期:2009-05-05 出版日期:2009-08-25 发布日期:2012-01-16
  • 基金资助:

    中海石油(中国)有限公司"十一五"重大基础研究项目(SC06TJ-TQL-004-BH02).

Distribution characteristics and origin of carbonate cements in the middle and deep clastic reservoirs of the Paleogene in the Bozhong Depression

Wang Qingbin1, Zang Chunyan2, Lai Weicheng1, Wang Bo1, Wang Xuelian1, Zhao Xiaojiao3   

  1. 1. Exploration and Development Research Institute, CNOOC Tianjin Company, Tianjin 300452, China;
    2. Oilfield Engineering Research Institute, CNOOC Energy Development Company, Tianjin 300452, China;
    3. School of Ocean Sciences, China University of Geosciences, Beijing 100083, China
  • Received:2009-05-05 Online:2009-08-25 Published:2012-01-16

摘要:

碳酸盐胶结物是渤中坳陷古近系砂岩储层中最重要的胶结物.薄片分析表明,中、深部储层中碳酸盐胶结物主要为菱铁矿、白云石、方解石、铁白云石、铁方解石.统计显示,随着层位和深度加深,碳酸盐含量逐渐增加,含量突增段主要发生在东营组;碳酸盐含量超过10%,对储层物性影响较大.由薄片分析及碳、氧同位素分析可知,菱铁矿多以孔隙充填和颗粒环边方式产出,主要形成于同生到早成岩早期;方解石主要以粒状或呈连生胶结方式产出,方解石相对含量与δ18O值呈明显的负相关关系,说明大部分方解石形成较晚;铁方解石主要以粒状产出,以铁方解石为主的样品对应着较低的δ18O值,且沉淀温度高;白云石主要以斑块状充填粒间孔隙,其相对含量与δ18O值呈明显正相关性,且沉淀温度较低、形成较早;铁白云石主要以分散的粒状产出,其相对含量与δ18O值呈明显的正相关关系,且沉淀温度相对较低.

关键词: 碳、氧同位素, 碳酸盐胶结物, 碎屑岩储层, 古近系, 渤中坳陷

Abstract:

Carbonate cements are the most important cements in the Paleogene sandstone reservoirs of the Bozhong depression.Analysis on thin sections shows that the main cements of the middle and deep clastic reservoirs are siderites,dolomites,calcites,ferrodolomites and ferrocalcites.According to the statistical data,carbonate content gradually rises with the increase of depth.A sharp increase of carbonate content occurs in the Paleogene Dongying Formation.When the carbonate content exceeds 10%,it will have a great impact on physical properties of reservoirs.Analysis on thin sections and isotopes reveals that the siderites mainly occur as pores fillings and particle rim cements and were mainly formed in the synsedimentary period or at the early stage of the early diagenesis.The calcites mainly occur as particles or poikilitic cements.The relative calcite content has negative correlation with δ18O values,indicating that most of the calcites were formed late.The ferrocalcites mainly occur as particles.The ferrocalcite-dominant samples correlate with low δ18O values and relatively high temperature of precipitation.The dolomites mainly occur as intergranular pore-filling particles in patches,and its relative content has obvious positive correlation with δ18O value.Its temperature of precipitation is relatively low and the time of forming is relatively early.The ferrodolomites mainly occur as dispersed particles,and its relative content has obvious positive correlation with δ18O value and its temperature of precipitation is relatively low.

Key words: carbon and oxygen isotope, carbonate cement, clastic reservoir, Paleogene, Bozhong Depression

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