基于数字图像处理的孔喉内三相接触角自动测量方法  

Automatic measurement of three-phase contact angles in pore throats based on digital images

作　　者：臧传贞 王利达[1] 周凯虎 于馥玮 姜汉桥 李俊键 ZANG Chuanzhen;WANG Lida;ZHOU Kaihu;YU Fuwei;JIANG Hanqiao;LI Junjian(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China;PetroChina Xinjiang Oilfield Company,Karamay 834000,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China)

机构地区：[1]油气资源与探测国家重点实验室(中国石油大学(北京)),北京102249 [2]中国石油新疆油田公司,新疆克拉玛依834000 [3]中国石油勘探开发研究院,北京100083

出　　处：《石油勘探与开发》2023年第2期391-397,共7页Petroleum Exploration and Development

基　　金：国家自然科学基金面上项目(51674271);中国石油天然气集团有限公司重大技术现场试验(2019F-33)。

摘　　要：借助数字图像处理技术,以微流控水驱油实验视频为数据源,建立了微流控模型孔喉内三相接触角的自动批量测量计算方法;采用人工测量数据验证了新方法测量结果的可靠性,在此基础上,利用接触角概率密度曲线、均值变化曲线揭示了三相接触角在流动条件下的动态变化规律。研究表明:对于水湿岩石,水驱油过程中,驱替前期接触角均值以锐角为主,随驱替时间的延长,油相受力逐渐由黏滞力为主导向毛细管力为主导过渡,接触角均值不断增大,至驱替中后期以钝角为主。剩余油中的滴状流赋存于孔喉通道中央,不存在三相接触角;多孔流和柱状流在整个驱替过程中接触角变化幅度较小且均值皆为钝角,该类剩余油形成后流动性差,动用难度较大;簇状流在驱替过程中三相接触角均值整体呈上升趋势,剩余油动用难度逐渐升高;膜状流整体呈钝角,水驱后期接触角均值最大,动用难度最大。驱替结束后,不同流态剩余油仅受毛细管力作用的影响,接触角均为钝角,在原油作用下模型孔喉壁润湿性呈油湿特征。With the help of digital image processing technology,an automatic measurement method for the three-phase contact angles in the pore throats of the microfluidic model was established using the microfluidic water flooding experiment videos as the data source.The results of the new method were verified through comparing with the manual measurement data.On this basis,the dynamic changes of the three-phase contact angles under flow conditions were clarified by the contact angles probability density curve and mean value change curve.The results show that,for water-wetting rocks,the mean value of the contact angles is acute angle during the early stage of the water flooding process,and it increases with the displacement time and becomes obtuse angle in the middle-late stage of displacement as the dominant force of oil phase gradually changes from viscous force to capillary force.The droplet flow in the remaining oil occurs in the central part of the pore throats,without three-phase contact angle.The contact angles for the porous flow and the columnar flow change slightly during the displacement and present as obtuse angles in view of mean values,which makes the remaining oil poorly movable and thus hard to be recovered.The mean value of the contact angle for the cluster flow tends to increase in the flooding process,which makes the remaining oil more difficult to be recovered.The contact angles for the membrane flow are mainly obtuse angles and reach the highest mean value in the late stage of displacement,which makes the remaining oil most difficult to be recovered.After displacement,the remaining oils under different flow regimes are just subjected to capillary force,with obtuse contact angles,and the wettability of the pore throat walls in the microfluidic model tends to be oil-wet under the action of crude oil.

关 键 词：微流控模型 水驱油实验 图像处理 三相接触角 测量方法 剩余油流态 

分 类 号：TE319[石油与天然气工程—油气田开发工程]