石油与天然气地质 ›› 2012, Vol. 33 ›› Issue (1): 50-60.doi: 10.11743/ogg20120107

• 储层与层序 • 上一篇    下一篇

沉积期火山作用对川西坳陷须家河组优质储层的意义

曾小英1, 张娟2, 刘远洋1, 李勇1   

  1. 1. 中国石化 西南油气分公司 勘探开发研究院, 四川 成都 610081;
    2. 西南石油大学 石油工程学院, 四川 成都 610500
  • 收稿日期:2011-06-12 修回日期:2011-12-12 出版日期:2012-02-28 发布日期:2012-03-22
  • 基金项目:

    国家"十一五"科技攻关项目(2008ZX05002-004)。

Significance of syndepositional volcanism to high quality reservoirs in the Xujiahe Formation,the western Sichuan Depression

Zeng Xiaoying1, Zhang Juan2, Liu Yuanyang1, Li Yong1   

  1. 1. Research Institute of Exploration & Development, SINOPEC Southwest Oilfield Company, Chengdu, Sichuan 610081, China;
    2. School of Petroleum Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China
  • Received:2011-06-12 Revised:2011-12-12 Online:2012-02-28 Published:2012-03-22

PDF (PC)

1125

被引次数

19

摘要：

须家河组是川西坳陷的区域气层,由于埋深大,储层普遍经历了复杂的成岩作用,造成了现今储层的致密-超致密化,但在致密-超致密背景下仍发育部分储集性能相对较好的孔隙性储层。通过对研究区30余口井、7 000余块岩石薄片、1 000余块铸体薄片的观察与鉴定及其相关储层研究表明,火山碎屑溶蚀孔是须家河组二段、须家河组四段砂岩主要储集空间,是形成该区优质储层的主要控制因素,母岩风化搬运沉积下来的长石溶蚀不是形成中、高孔隙性砂岩的主要原因。因为同沉积期火山喷发作用形成的火山碎屑物含有较多的"易溶组分",在成岩过程中易溶蚀脱玻化形成孔隙,从而控制了次生溶孔发育的较高渗透性砂岩储层的分布。因此,同沉积期火山作用的成分及其溶蚀作用强度是控制须家河组砂岩优质储层的发育、分布和形成本区中、高孔隙性砂岩的主要原因。甘孜-理塘陆间裂谷带上,晚三叠世火山活动强烈,是研究区火山物质的主要来源。

关键词: 同沉积期, 火山作用, 易溶组分, 次生溶孔, 孔隙成因, 优质储层, 须家河组, 川西坳陷

Abstract:

The Xujiahe Formation is a regional gas reservoir in western Sichuan Depression.Due to the great bu- rial depth,the reservoir generally experienced complicated diagenesis,resulting in tight to supertight reservoirs.Even so,porous reservoirs with relatively good storage capacity were also developed.From observation of more than 30 wells,over 7 000 ordinary thin sections and over 1 000 cast thin sections in the study area as well as the research of related reservoirs,it is demonstrated that volcanic debris dissolved pores are the major storage space of sandstones of of the 2nd and 4th member of Xujiahe Formation,and are the major controlling factor of high quality reservoirs in the area.Dissolution of feldspar deposited through weathering and transportation of parent rock is not the major reason for the forming of sandstone with medium-high porosity.Volcanic debris from syndepositional volcanic eruption contain many "soluble compositions",which tend to be dissolved and devitrified to form pores during diagenesis,thus controlling the distribution of high-permeability sandstone reservoirs with well-developed secondary dissolved pores.Therefore,the compositions of debries from the syndepositional volcanism and their dissolution intensity are the major factors controlling the development and distribution of high quality reservoirs of the Xujiahe Formation and the formation of sandstone with medium-high porosity.Ganzi-Litang inter-continental rift area where volcanisms were strong during the Late Triassic was the major source for volcanic debris in the study area.

Key words: syndepositional period, volcanism, soluble composition, secondary dissolution pore, pore genesis, high quality reservoir, Xujiahe Formation, western Sichuan Depression

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