石油学报 ›› 2013, Vol. 34 ›› Issue (5): 820-825.DOI: 10.7623/syxb201305002

• 地质勘探 • 上一篇    下一篇

富有机质Woodford页岩孔隙演化的热模拟实验

胡海燕   

  1. 长江大学地球科学学院 湖北武汉 430100
  • 收稿日期:2013-02-16 修回日期:2013-07-01 出版日期:2013-09-25 发布日期:2013-08-01
  • 通讯作者: 胡海燕
  • 作者简介:胡海燕,男,1977年4月生,2000年毕业于中国地质大学地质学专业,2007年获中国地质大学矿产普查与勘探专业博士学位,现为长江大学副教授,从事石油地质学的教学和科研工作。Email:hyhucom@163.com
  • 基金资助:

    国家自然科学基金项目(No.41072192)和国家重点基础研究发展计划(973) 项目(2012CB214702)资助。

Porosity evolution of the organic-rich shale with thermal maturity increasing

HU Haiyan   

  1. School of Geosciences, Yangtze University, Wuhan 430100, China
  • Received:2013-02-16 Revised:2013-07-01 Online:2013-09-25 Published:2013-08-01

摘要:

通过高温热模拟实验加热未成熟的露头样品,获得5个不同成熟阶段的页岩样品,然后用比表面积分析仪测试这5个页岩样品的纳米孔隙,从而研究富有机质页岩的孔隙演化。结果表明,随着成熟度的增加,富有机质页岩发育大量纳米孔隙,孔隙度随着热成熟度增高而增加,完全不同于基质孔隙度的演化规律。随着成熟度增加,有机质不断转化为油气,基于有机质转化为油气过程中的物质平衡理论计算的孔隙度增加量与测试的孔隙度增加量吻合。因此,富有机质页岩孔隙度随着成熟度增高而增加,与有机质转化为油气的热降解过程有关。

关键词: 孔隙演化, 富有机质页岩, 成熟度, 热模拟, 页岩气

Abstract:

To study porosity evolution of organic-rich shale, five immature shale samples collected from outcrops were analyzed by pyrolyzing them in a thermal simulation experiment. Organic-rich shale samples with different thermal maturities were obtained in the lab and their maturities referred to immature, early bitumen-formation, late bitumen-formation, late oil-formation and oil-cracking stages, respectively. Nano-pores in these five shale samples were then measured on a specific surface area analyzer. A series of nitrogen adsorption isotherms were measured, which showed that nano-pores increase with thermal maturity increasing and so does the porosity in the organic-rich shale, which is obviously different from the porosity evolution in matrix. The porosity changes little at the oil window, but drastically increases in the gas window, which is consistent with calculated value based on the mass balance theory. Therefore, it can be concluded that increase in porosity of the organic-rich shale results dominantly from the organic matter conversion of oil to gas.

Key words: pore evolution, organic-rich shale, maturity, thermal simulation experiment, shale gas

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