地学前缘 ›› 2016, Vol. 23 ›› Issue (1): 146-153.DOI: 10.13745/j.esf.2016.01.013

• 页岩储层特征与评价 • 上一篇    下一篇

鄂尔多斯盆地延长组长7段暗色泥页岩吸附特征及其影响因素

赵靖舟，王芮，耳闯   

  1. 1. 西安石油大学 地球科学与工程学院, 陕西 西安 710065
    2. 西安石油大学 陕西省油气成藏地质学重点实验室， 陕西 西安 710065
    3. 中国石油大港油田公司 第二采油厂， 河北 黄骅 061100
  • 收稿日期:2015-09-15 修回日期:2015-11-15 出版日期:2016-01-15 发布日期:2016-01-15
  • 作者简介:赵靖舟(1962—)，男，博士，教授，主要从事油气成藏地质学，非常规油气地质与勘探研究。E-mail：jzzhao@xsyu.edu.cn
  • 基金资助:

    国家油气重大专项专题“鄂尔多斯盆地及周边页岩气资源评价”(2011ZX05018001 - 004)；陕西省自然科学基金项目“鄂尔多斯盆地延长组陆相富有机质页岩孔隙特征及其控制因素”(2013JQ5003)

Adsorption characteristics of Chang 7 shales from Triassic Yanchang Formation and the controlling factors, the Ordos Basin.

  • Received:2015-09-15 Revised:2015-11-15 Online:2016-01-15 Published:2016-01-15

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摘要：

鄂尔多斯盆地三叠系延长组长7段在研究区志丹甘泉地区主要为一套深湖相暗色泥岩和页岩沉积，其TOC含量高、有机质类型主要为Ⅱ1型、Ro多在0.6%~1.2%，是该盆地已发现大量油藏的主要源岩。为了探讨长7段富有机质泥页岩的吸附特征，选取了研究区长7段16块泥页岩样品进行了等温吸附、总有机碳含量、X衍射、热成熟度及液氮吸附等配套分析测试，在此基础上探讨了长7段陆相富有机质泥页岩的吸附能力及其影响因素。结果表明：研究区长7段泥页岩的兰氏体积为0.56~4.43 m3/t，随着压力的增大，吸附能力迅速增加，当增至一定程度，达到饱和后，将不再增加；泥页岩的吸附能力与有机碳含量、黏土矿物含量、比表面和孔体积具有正相关关系；与许多海相泥页岩相反，研究区陆相泥页岩的吸附能力与石英含量呈负相关关系，这可能与石英来源不同有关，陆相泥页岩的石英为陆源碎屑成因；泥页岩的吸附能力与热成熟度在Ro <0.9%左右时呈负相关，而后当Ro >0.9%时呈正相关关系。综合评价认为，TOC含量、黏土矿物含量是影响泥页岩吸附能力最重要的因素，而比表面是最直接的因素。

关键词: 三叠系, 延长组, 陆相页岩, 等温吸附特征, 影响因素, 鄂尔多斯盆地

Abstract:

The Chang 7 Member in the ZhidanGanquan region of the Ordos Basin is a set of dark mudstones and shales deposited in a deep lacustrine setting. With high TOC, type Ⅱ1 organic matter and Ro mostly of 0.6%1.2%, the Chang 7 mudstones and shales are confirmed to be the principal source of the widely distributed oils in the Ordos Basin. In order to discuss the adsorption characteristics of Chang 7 organicrich shales, we analyzed the test results of isothermal adsorption, the content of organic carbon, XRD, thermal maturity and liquid nitrogen adsorption of 16 shale samples chosen from the study area. It turns out that the Langmuir volume of the Chang 7 shales varies between 0.56 m3/t and 4.43 m3/t. With the increase of pressure, the Langmuir volume rises correspondingly until the pressure reaches a certain level. The Langmuir volume has a positive correlation with the organic carbon content, clay mineral content, specific surface area and pore volume. In contrast to many marine shales, the Langmuir volume of the Chang 7 lacustrine shale has a negative correlation with quartz content, which is probably due to the fact that the source of the lakedeposited quartz is of terrestrial detrital origin. The relation of the Langmuir volume and thermal maturity (Ro) of the studied shales is negative when the Ro is less than 0.9% or so but becomes positive as the Ro is more than 0.9%. Based on the comprehensive evaluation, it is found that the TOC content and clay mineral content have the most significant effect on adsorption characteristics, while the specific surface area is a more direct factor.

Key words: Triassic, Yanchang Formation, continental shale, adsorption characteristic, controlling factors, Ordos Basin

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