正密度差对水平井偏心环空顶替影响规律研究  

Cement Displacement Flow Law Affected by Positive Density Difference in the Eccentric Annulus of the Horizontal Well

作　　者：张松杰[1,2] 薛亮[1] 汪志明[1] 张文华 

机构地区：[1]中国石油大学(北京)石油工程学院,北京102249 [2]中国石油集团渤海钻探工程有限公司,天津300280

出　　处：《科学技术与工程》2013年第4期1011-1015,共5页Science Technology and Engineering

摘　　要：在地层压力许可的条件下,固井顶替流体之间的密度差可以提高水平井顶替效率。基于计算流体相关理论与方法,建立水平井偏心环空浆体顶替模型。数值模拟正密度差对水平井顶替的影响规律。数值实验结果表明:正密度差顶替条件下,重力作用使宽边高密度流体在顶替界面附近向下方低速的窄边流动,提高了窄边的流量,克服了水平井偏心度的影响,提高了窄边的顶替效率。重力作用超过宽窄边效应的影响,形成分层的顶替界面,顶替界面长度随顶替时间增加而增长,但增长的越来越缓慢,有利于提高水平井的顶替效率。顶替界面长度随密度差增大而增大,适当降低顶替流体与被顶替流体之间的正密度差,有利于减小顶替界面长度提高顶替效率。以上研究结果揭示了正密度差顶替克服水平井偏心度影响,提高水平井顶替效率的机理与规律,对提高水平井固井顶替效率具有理论指导意义。In the license conditions of formation pressure, the density difference between the cementation re- placement fluid can improve the overdisplace efficiency of the horizontal wells. Based on the theories and methods of fluid computation, slurry replacement model in eccentric annulus of horizontal well is established, simulated the law of overdisplace influenced by positive density difference in horizontal well annulus. The numerical experiment results show that： in the conditions of positive density difference about horizontal wells displacement, the force of gravity lead to high-speed broadside high density fluid flow to nether low-speed narrow hem in the vicinity of the displacement interface, improve the flow of the narrow side and overdisplace efficiency, prove that positive density difference can overcome effect by the eccentricity and improve the horizontal well cementing displacement efficien- cy. Action of gravity exceeds the wide-narrow effect and form a high-density replacement fluid in layered displace- ment interface below, the displacement interface length grows with the increase of replacement time, and more and more slowly. This is conducive to improve the displacement efficiency of horizontal wells. Displacement interface length grows with the increase of density difference, lower positive density difference suitably between the replacing fluid and replaced fluid, is conducive to reducing the length of the displacement interface and improve the displace- ment efficiency. The above results reveal the mechanism and law about horizontal well displacement efficiency in- creased by positive density difference that overcome eccentricity effect of horizontal wells, has theory guiding signifi- cance for improving cementing displacement efficiency in the horizontal wells.

关 键 词：水平井 偏心度 正密度差 固井顶替 顶替界面长度 

分 类 号：TE256.1[石油与天然气工程—油气井工程]