Citation: | DING Xin,GAO Feitong,CUI Jingzhi,et al. Investigation on pyrolytic, fracture evolution and seepage of oil shale under high temperature[J]. Coal Science and Technology,2023,51(S2):175−182. DOI: 10.13199/j.cnki.cst.2022-1591 |
Oil shale resources are rich in China, and kerogen-dominated organic matter in the oil shale is transformed into shale oil after heating, which is expected to make up the “short board” of China’s energy structure. It is of great scientific value to exploring the evolution of pores, fractures and the law of fluid migration in oil shale under the influence of pyrolysis final temperature and high temperature to promote the commercial development of it in-situ exploitation in China. In this paper, the influence of multiple pyrolysis final temperature and heating duration was considered, the physical experiment method and the introduction of electron microscope observation technology (SEM) are used, the pyrolysis of oil shale samples and gas seepage tests were carried out, and the pyrolysis property, pore and fissure evolution and permeability were investigated. The results show that, with the increase of pyrolysis temperature, the pyrolysis rate of organic matter mainly kerogen increases exponentially, the remolding of the internal structure of oil shale heated include the pores produced by organic pyrolysis and cracks formed by non-uniform deformation of inorganic materials. The SEM results showed that the pyrolytic areas originally distributed in discrete spots are connected with each other, and the dark area keeps expanding. The uneven change of the materials in the pyrolytic and non-pyrolytic areas leads to cracks at the interface between them. The pyrolysis process had a development process of “small-scale discontinuous fissure -- penetrating distributed fissure -- penetrating main fissure”, which improves the fracture rate in oil shale reservoir. Under the influence of Klinkenberg effect, the permeability of oil shale after pyrolysis decreases with the increase of gas injection pressure in an exponential function law, and it increases with the heating temperature in an approximate “S” shape, which is almost opposite to the TG curve of Balikun oil shale pyrolysis. Organic matter in oil shale has the highest pyrolysis efficiency and enhanced effective permeability in the range of 450−500 ℃. The research results provide a certain experimental basis for improving the theory of oil shale pyrolysis mining.
[1] |
中国煤炭网. 十八大以来我国能源发展状况[Z]. [2016-3-21]. http://nyj.guizhou.gov.cn/xwzx/xydt/ 201704/ t20170426_27673639.html.
|
[2] |
康志勤,赵阳升,孟巧荣,等. 油页岩热破裂规律显微 CT 实验研究[J]. 地球物理学报,2009,52(3):842−848
KANG Zhiqin,ZHAO Yangqheng,MENG Qiaorong,et al. Micro-CT experimental research of oil shale thermal cracking laws[J]. Chinese Journal of Geophysics,2009,52(3):842−848.
|
[3] |
孟巧荣,康志勤,赵阳升,等. 油页岩热破裂及起裂机制试验[J]. 中国石油大学学报(自然科学版),2010,34(4) 95−98,104.
MENG Qiaorong,KANG Zhiqin,ZHAO Yangsheng,et al. Experiment of cracking and crack initiation mechanism of oil shale[J]. Journal of China University of Petroleum,2010,34(4) 95−98,104.
|
[4] |
GENG Y,LIANG W,LIU J,et al. Evolution of pore and fracture structure of oil shale under high temperature and high pressure[J]. Energy & Fuels,2017,31(10):7b01071.
|
[5] |
RABBANI A,BAYCHEV T G,AYATOLLAHI S,et al. Evolution of pore-scale morphology of oil shale during pyrolysis:a quantitative analysis[J]. Transport in Porous Media,2017:1−20.
|
[6] |
韩向新,姜秀民,崔志刚,等. 油页岩颗粒孔隙结构在燃烧过程中的变化[J]. 中国电机工程学报,2007,27(2):26−30.
HAN Xiangxin,JIANG Xiumin,CUI Zhigang,et al. Evolution proe structure of oil shale particles during combustion[J]. Proceedings of the CSEE,2007,27(2):26−30.
|
[7] |
SUN L,TUO J,ZHANG M,et al. Formation and development of the pore structure in Chang 7 member oil-shale from Ordos Basin during organic matter evolution induced by hydrous pyrolysis[J]. Fuel,2015,158(1):549−557.
|
[8] |
SAIF T,LIN Qingyang ,BRANKO B,et al. Microstructural imaging and characterization of oil shale before and after pyrolysis[J]. Fuel,2017,197:562–574.
|
[9] |
SAIF T,LIN Q,SINGH K,et al. Dynamic imaging of oil shale pyrolysis using synchrotron X-ray microtomography[J]. Geophysical Research Letters,2016,43:6799−6807. doi: 10.1002/2016GL069279
|
[10] |
SAIF T,LIN Qingyang ,ALAN R,et al . Multi-scale multi-dimensional microstructure imaging of oil shale pyrolysis using X-ray micro-tomography,automated ultra-high resolution SEM,MAPS Mineralogy and FIB-SEM[J]. Applied Energy,202 :628–647.
|
[11] |
BAI F,SUN Y,LIU Y,et al. Evaluation of the porous structure of Huadian oil shale during pyrolysis using multiple approaches[J]. Fuel,2017,187:1−8. doi: 10.1016/j.fuel.2016.09.012
|
[12] |
YANG L,YANG D,ZHAO J,et al. Changes of oil shale pore structure and permeability at different temperatures[J]. Oil Shal,2016,33(2):101−110. doi: 10.3176/oil.2016.2.01
|
[13] |
董付科,杨 栋,冯子军. 高温三轴应力下吉木萨尔油页岩渗透率演化规律[J]. 煤炭技术,2017,36(8):165−166.
DONG Fuke,YANG Dong,FENG Zijun. Thermal deformation characteristics of Jimusar oil shale in Xinjiang under high temperature and triaxial stresses[J]. Coal Engineering,2017,36(8):165−166.
|
[14] |
杨 栋,薛晋霞,康志勤,等. 抚顺油页岩干馏渗透实验研究[J]. 西安石油大学学报(自然科学版). 2007,22(2):23−25.
YANG Dong,XUE Jinxia,KANG Zhiqin,et al. Study on the seepage characteristics in fractured network porous media[J]. Journal of Xi’an Shiyou University (Nature Science Edition),2007,22(2):23−25.
|
[15] |
刘中华,杨 栋,薛晋霞,等. 干馏后油页岩渗透规律的实验研究[J]. 太原理工大学学报,2006,37(4):414−416
LIU Zhonghua,YANG Dong,XUE Jinxia,et al. Experimental study on seepage law of distilied oil shale[J]. Journal of Taiyuan University of Technology,2006,37(4):414−416.
|
[16] |
赵丽梅. 油页岩原位热解与煤地下气化耦合过程研究[D]. 北京:中国矿业大学(北京),2013.
ZHAO Limei. Properties of oil shale in-situ pyrolysis and couoling process of underground coal gasification[D]. Beijing:China University of Mining & Technology,Beijing,2013.
|
[17] |
耿毅德. 油页岩地下原位压裂—热解物理力学特性试验研究[D]. 太原:太原理工大学,2018.
GENG Yide. Experimental study on the physical and mechanical properties of oil shale during in-situ fracturing and pyrolysis [D]. Taiyuan:Taiyuan University of Technology,2018.
|
[18] |
赵 静. 高温及三维应力下油页岩细观特征及力学特性试验研究[D]. 太原:太原理工大学,2014.
ZHAO Jing. Experimental study on the microscopic characteristics and mechanical property of oil shale under high temperature& three -dimensional stress[D]. Taiyuan:Taiyuan University of Technology ,2014.
|
[19] |
李 强. 油页岩原位热裂解温度场数值模拟及实验研究[D]. 长春:吉林大学,2012.
LI Qiang. Simulation of temperature field experiment of in-situ oil shale pyrolysis[D]. Changchun:Jilin University2012.
|
[20] |
张红鸽,赵阳升,杨 栋,等. 温度对油页岩热解-力学-渗流特性的影响研究[J]. 太原理工大学学报,2021,52(6):945-952.
ZHANG Hongge,ZHAO Yangsheng,YANG Dong,et al. Study on the effect of temperature on the pyrolysis- mechanics- seepage characteristics of oil shale[J]. Journal of Taiyuan University of Technology,2021,52(6):945-952.
|
[21] |
王 磊,杨 栋,康志勤. 高温水蒸汽作用后油页岩渗透特性及各向异性演化的试验研究[J]. 岩石力学与工程学报,2021,40(11):2286−2295.
WANG Lei,YANG Dong,KANG Zhiqin. Experimental study on permeability characteristics and anisotropy evolution of oil shale after high-temperature water vapor treatment[J]. Chinese Journal of Rock Mechanics and Engineering,2021,40(11):2286−2295.
|