摘要
在页岩气水平井压裂开发过程中,由于页岩弱面剪切活动导致套管变形损坏,严重影响生产的正常进行。分析了川南泸州地区页岩的地质背景,在围压和温度相同的状况下,以不同孔隙介质类型、不同孔隙压力的条件下,利用CT扫描技术探究了页岩三轴滑动摩擦的宏观和微观变形机理,并对此进行实验。研究结果表明:在孔隙压力80~100 MPa,孔隙压力为80 MPa的酸性溶液为介质的页岩样品整体立体分形维数增加的最大,从2.40增加到2.56,孔隙压力为100 MPa的酸性溶液为介质的页岩样品迂曲度上升最高,从1.95上升到3.56,孔隙压力是90 MPa介质为酸性溶液的样品经过实验后,其立体分形维数反而出现了下降,下降了0.011。在滑动摩擦的面上,实验过后,滑动摩擦面分形维数增长最低的是压力80 MPa。介质是酸性溶液,增长了0.02879。滑动摩擦面分形维数增长最高的介质为中性去离子水,孔隙压力是90 MPa的Y12样品,其分形维数增大了0.20575。
In the process of fracturing development of shale gas horizontal wells,the casing deformation and damage caused by shale weak surface shear activities seriously affect the normal progress of production.Therefore,this paper investigates and analyzes the geological background of shale in Luzhou area of southern Sichuan Province under the same confining pressure and temperature,under the conditions of different pore media types and different pore pressures.The macroscopic and microscopic deformation mechanisms of shale in triaxial sliding friction experiments were explored by CT scanning technology,and experiments were carried out.The results show that in the range of pore pressure from 80 MPa to 100 MPa,the overall stereo fractal dimension of shale samples with pore pressure of 80 MPa as the medium increases the most.From 2.40 to 2.56,the curvature of shale samples with pore pressure of 100MPa and acidic solution increased the most,from 1.95 to 3.56,and the stereo-fractal dimension of samples with pore pressure of 90MPa and acidic solution decreased by 0.011 after experiments.On the sliding friction surface,after the experiment,the lowest increase in the fractal dimension of the sliding friction surface is the pressure of 80MPa.The medium is an acidic solution,which grows by 0.02879.The highest increase in the fractal dimension of the sliding friction surface was that the Y12 sample with neutral deionized water and pore pressure of 90 MPa increased by 0.20575.
作者
徐锐
李小明
张宇
徐晓斌
王亚蓉
孔令涛
李媛媛
Xu Rui;Li Xiaoming;Zhang Yu;Xu Xiaobin;Wang Yarong;Kong Lingtao;Li Yuanyuan(School of Safety Engineering,North China Institute of Science and Technology,Langfang 065000,Hebei,China)
出处
《绿色科技》
2024年第18期238-244,251,共8页
Journal of Green Science and Technology
关键词
页岩
微观
CT
分形维数
shale
microcosmic
CT
fractal dimension
