柴达木盆地东部石炭系页岩渗流机理研究

发布时间：2018-02-13 02:55

  本文关键词： 渗流 页岩 纳米孔隙 表观渗透率　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：页岩的渗流与许多资源与环境问题相关。深入的研究页岩中气体渗流特征对于页岩气的形成与开采问题、核废料地下储存安全性评价以及CO2、CH4等温室气体封存性能评价油重要的理论意义和现实意义。本文在广泛的研究了国内外现有的研究成果,选取具有代表性的柴达木盆地东部石炭系克鲁克组页岩进行研究。利用实验室自主设计的仪器,在模拟实际地层温度压力的情况下,对页岩进行了CH4、N2、He三种气体的渗流实验,研究页岩纳米孔隙中复杂的气体渗流问题。根据国家相关的测试标准,测定研究区内页岩的TOC含量几乎都大于1%,达到了产气的标准且生烃能力强;但是热成熟度相对来说比较低,干酪根类型以Ⅱ型为主;矿物成分主要包括石英等碎屑矿物、白云石等碳酸盐矿物、伊/蒙混层为主的粘土矿物,说明研究区内页岩是具有一定开发价值的烃源岩。利用压汞法、氮气吸附法及二氧化碳吸附法来测量页岩纳米孔径,结果表明研究区页岩宏孔范围主要分布在50nm-100nm,所占比例在35%-60%;微孔所占比例较少,在10%左右;中孔分布密集,所占比例也在37%-54%。通过克努森数(kn)的大小将页岩纳米孔隙中气体的流动状态分为达西流、滑脱流以及扩散流,建立了页岩纳米孔隙气体流动数学模型。通过模型得出页岩纳米孔隙的表观渗透率与平均压力的倒数呈现正比例关系。根据页岩渗透率测试的实验数据,本文得出达西渗透率不随着压力的变化而变化,滑脱流以及扩散流对表观渗透率的贡献值随着压力的增大而减小。本文还发现同一块岩样氦气所测得的表观渗透率最大,其次是甲烷,氮气所测得的值最小。对页岩进行了不同方向的渗透率的研究,发现平行于地层切割的页岩比垂直于地层切割的页岩表观渗透率大。最后综合分析了压力、页岩孔径及页岩岩性对渗透率的影响,发现页岩的表观渗透率随着压力的增大而减小,并且与页岩的孔径分布、矿物成分以及气体分子平均自由程有关。
[Abstract]:The percolation of shale is related to many resource and environmental problems. The characteristics of gas percolation in shale are deeply studied on the formation and exploitation of shale gas. The important theoretical and practical significance of nuclear waste underground storage safety evaluation and evaluation of greenhouse gas storage performance such as CO _ 2C _ (2) H _ (4). In this paper, the existing research results at home and abroad have been extensively studied. The typical carboniferous Kruke formation shale in the eastern Qaidam Basin was studied. The seepage experiments of three kinds of gas Ch _ 4 and N _ 2H _ 2He were carried out on the shale under the condition of simulating the actual formation temperature and pressure by using the instrument designed independently by the laboratory. The complex gas percolation problem in shale nano-pores is studied. According to the national relevant test standards, the TOC content of shale in the study area is almost more than 1, which has reached the standard of gas production and has strong hydrocarbon generation ability. However, the thermal maturity is relatively low, the type of kerogen is mainly type 鈪，

本文编号：1507161