石油与天然气地质 ›› 2005, Vol. 26 ›› Issue (6): 786-791,799.doi: 10.11743/ogg20050616

• 论文 • 上一篇    下一篇

库车冲断带巴什基奇克组砂岩自生高岭石成因与油气成藏

邹华耀1, 郝芳1, 柳广弟1, 隋成2   

  1. 1. 中国石油大学资源与信息学院,北京昌平,102249;
    2. 长庆石油分公司研究院,陕西西安,710021
  • 收稿日期:2005-07-27 出版日期:2005-12-25 发布日期:2012-01-16
  • 基金资助:

    国家基础研究发展规划(973)项目(2001CB209103);中国石油中青年科技创新基金项目(04E7020)

Genesis of authigenic kaolinite and gas accumulation in Bashijiqike Fm sandstone in Kuqa thrust belt

Zou Huayao1, Hao Fang1, Liu Guangdi1, Sui Cheng2   

  1. 1. China University of Petroleum, Beijing;
    2. Petroleum Exploration and Development Research Institute of Changqing Oilfield Company, Xi'an, Shaanxi
  • Received:2005-07-27 Online:2005-12-25 Published:2012-01-16

摘要:

克拉2构造是该区最大的气田,白垩系储层自生高岭石也最为发育,平均相对含量大于20%,以书页状和蠕虫状分布于骨架颗粒间。克拉3、克拉1和吐北1等勘探失利的圈闭,高岭石均不发育。克拉2构造自生高岭石是长石颗粒在地层酸性介质中溶解的沉淀产物,同时伴随次生孔隙的形成。其成岩环境处于开放或半开放流体系统。这一成岩环境既能保证来源于下伏源岩层系酸性流体的注入,又要允许长石等溶解物质的排出。自生高岭石与次生孔隙的形成过程与天然气的充注,为两个机理上紧密联系的共生过程。贯通-贯穿型断裂向下贯通烃源岩、向上又断穿膏盐岩盖层,构成超压流体运移的主通道。有贯通-贯穿型断裂发育的地区,不仅具备了自生高岭石与次生孔隙的形成条件,而且有利于天然气成藏。断裂输导通道的类型对比表明,克拉苏构造带比秋里塔克构造带更有利于天然气的成藏。

关键词: 自生高岭石, 次生孔隙, 贯通-贯穿断裂组合, 天然气成藏, 库车冲断带

Abstract:

Kela 2 structure is the largest gas pool in Kuqa thrust belt and authigenic kaolinites are best developed in Cretaceous reservoir,with an average relative content of over 20%,and occur as book and vermicular kaoli-nites between the skeletal grains.While authigenic kaolinites are underdeveloped in Kela 3,Kela 1 and Tubei 1 traps where exploration failed.In Kela 2 structure,authigenic kaolinites have been precipitated from the dissolution of feldspar in the stratal acidic media,which have been associated with the formation of secondary pores.The diagenetic environment was in an open or half-open flow system,which allowed both the charge of acidic fluid from the underlying source rocks and the discharge of dissolved feldspar and other materials.The formation of authigenic kaolinite and secondary pores and charging of natural gas are two associated processes with closely related mechanisms.Through-going and linking-up faults pierced downward through source rock and broke upward through gypsum and halite cap rocks and constituted the major migration pathway of overpressured fluid.Areas with through-going faults had not only been provided with conditions for formation of authigenic kaolinite and secondary pores,but were also favorable for gas accumulation.Comparison of fault carrier types shows that Kelasu structural zone is more favorable for gas accumulation than Qiulitake structural zone.

Key words: authigenic kaolinite, secondary pore, through-going and linking-up fault combination, gas accumulation, Kuqa thrust belt

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