摘要
为了研究注水蒸汽原位热解油页岩过程中岩体内部的细观结构以及评价注蒸汽热解油页岩的效率,通过结合压汞测试和显微CT的方法对热解后油页岩的孔隙和裂隙参数进行测试,通过数值模拟方法对不同加热方式下油页岩矿层的温度演化特征和产油量进行分析和讨论。研究结果显示:(1)热解后油页岩的有效孔隙率至少达到了自然状态下油页岩有效孔隙率的12.2倍,同时热解后油页岩内部孔隙的迂曲度较小,比表面积较大,孔隙结构发生了质的改变,整体上,热解后油页岩内部孔隙主要为毛管孔隙;(2)热解后油页岩内部裂隙以微裂隙为主,微裂隙数量在185~293范围,在高温蒸汽作用下油页岩内部发生明显的热破裂;(3)注水蒸汽热解油页岩过程中,油页岩发生了显著的层理面的破裂,形成了贯通整个三维空间的裂隙面,为热解和产物的运移提供了良好通路;(4)注水蒸汽热解油页岩的效率要远高于传导加热,热解时间为19个月时,注水蒸汽热解油页岩形成有效热解区域可达传导加热的22.4倍,而且注水蒸汽热解油页岩的产油量要远高于传导加热;(5)综合试验测试和数值模拟结果证明了注蒸汽热解油页岩技术的高效性和可行性。
In order to study the micro-structure of rock mass and to evaluate the pyrolysis efficiency of oil shale by in-situ steam injection,the pore and fracture parameters of oil shale after pyrolysis were tested by mercury injection test and micro-CT,and the temperature evolution characteristics and oil production of oil shale under different heating modes were analyzed and discussed by numerical simulation. The results show that,after pyrolysis,the effective porosity of oil shale is at least 12.2 times of that of natural oil shale,and the structure of pores with smaller tortuosity and larger specific area,being mainly capillary pores,is changed fundamentally.After pyrolysis,the internal fractures of oil shale are mainly micro-fractures,and the fracture number of the samples is between 185 and 293. Under the action of high temperature steam,there is obvious thermal cracking in the oil shale. In the process of oil shale pyrolysis by steam injection,significant fracture of the bedding plane of the oil shale occurs,forming a fracture plane through the whole three-dimensional space and hence providing a good path for pyrolysis and product migration. It is also found that the efficiency of oil shale pyrolysis by steam injection is much higher than that of conduction heating. When the pyrolysis time is 19 months,the effective pyrolysis area of the oil shale can reach 22.4 times of conduction heating and the oil production of oil shale pyrolysis by steam injection is much higher than that by conduction heating. The experimental test and numerical simulation results show that the technology oil shale pyrolysis by in-situ steam injection is efficient and feasible.
作者
王磊
赵阳升
杨栋
WANG Lei;ZHAO Yangsheng;YANG Dong(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of In-situ Property Improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;The In-situ Steam Injection Branch of State Center for Research and Development of Oil Shale Exploitation,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2020年第8期1634-1647,共14页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(11772213)
国家重点研发计划项目(2019YFA0705501)。
关键词
石油工程
水蒸汽
对流加热
油页岩
孔隙结构
微裂隙
有效热解
petroleum engineering
steam
convection heating
oil shale
pore structure
microfracture
effective pyrolysis
