环空幂律液体旋流研究与应用  

STUDY AND APPLICATION OF VORTEX FLOW FORMED BY POWER-LAW FLUID IN ANNULUS

作　　者：舒秋贵[1] 刘崇建[2] 刘孝良[2] 冷如波[3] 

机构地区：[1]西华师范大学 [2]西南石油大学 [3]上海交通大学

出　　处：《天然气工业》2006年第10期74-76,94,共4页Natural Gas Industry

基　　金：西华师范大学科研启动基金项目(编号:04B035)

摘　　要：在油气井固井注水泥顶替技术中,多用一维轴向流顶替方式进行顶替。该顶替方式理论与实践证明不能有效替净环空被顶替液。轴向流顶替存在的最主要的缺点是顶替液对近井壁区的驱动能力弱,对边壁的高粘附钻井液及虚滤饼清除效果差,造成二界面附近难以被替净;对于变径、不规则环空流道,由于存在涡流而滞留的钻井液,轴向流顶替效果更差。而通过使用旋流扶正器不但可以提高套管居中度,而且可以改变液体流速剖面,产生螺旋流,从而增加周向剪切驱动力,这有利于将环空窄间隙钻井液和井壁附着虚滤饼驱替干净,从而提高水泥与地层的胶结质量,提高固井质量。为此,研究了旋流扶正器作用下形成的环空幂律液体螺旋流边壁剪切应力,提出了旋流扶正器安放间距设计的新理念,即根据旋流周向剪切驱动力与近壁滞留钻井液粘滞阻力相平衡的原则确定旋流扶正器安装位置。推导出了旋流扶正器安放间距设计理论公式,该公式简单,利于现场施工应用。One-dimensional axial flow is mostly used to displace the cement slurry during oil/gas well cementing. While both the theoretical analysis and the practice prove this displacement mode cannot effectively displace all the fluid in the annulus. The major disadvantage is the low drive force of the displacement fluid applied to the near-wellbore region, which results in poor sweep of highly sticky drilling fluid and the mud cake at the side bore and thus the incomplete displacement nearby the 2 interfaces. For irregular or undergauged/overgauged annulus, the displacement effects of the axial flow is especially poor because the drilling fluid is still lagged behind due to the vortex flow. However, by using spiral centralizer or stabilizer, not only the centrality of the casing can be improved, the velocity profile of the fluid can also be changed, to produce a spiral flow which will increase the circumferential shear force, helpful to displace the drilling fluid in the narrow annulus and the mud cake stuck at the wellbore, so as to improve the bond quality between the cement and the formation. In this paper, it is studied both the spiral flow produced by installing spiral stabilizers, and the shear stress exerted on the side wellbore by the spiral flow of the annulus power-law fluid. And according to the balance between the circumferential shear force of the spiral flow and the lag force of the near-wellbore drilling fluid, it is also discussed the distance between the spiral stabilizers. A simple theoretical calculation equation is derived which will be much easier for field service design.

关 键 词：油井 气井 幂律液体 注水泥 钻井液 固井 扶正器 

分 类 号：TE256[石油与天然气工程—油气井工程]