大斜度井筒条件下沉积砂床表面颗粒起动临界条件研究  

Research of Critical Condition for Grains at Bed Surface in Highly Deviated Wells

作　　者：董长银[1] 邓珊[1] 李爱萍[2] 周生田[3] 武龙[1] 

机构地区：[1]中国石油大学(华东)石油工程学院,山东东营257061 [2]中国石化中原油田分公司采油五厂,河南濮阳457001 [3]中国石油大学(华东)数学与计算科学学院,山东东营257061

出　　处：《石油钻探技术》2010年第3期22-26,共5页Petroleum Drilling Techniques

基　　金：国家高技术研究发展计划("863"计划)项目"大斜度井砾石充填模拟及工艺技术"(编号:2006AA09Z351);国家自然科学基金项目"复杂条件下大斜度井砾石充填机理"(编号:50704035)资助

摘　　要：石油工程领域中,涉及到大斜度井筒条件下固液两相流动的作业,有大斜度井的钻井岩屑运移、管内砾石充填以及冲砂作业等,这些作业的过程其实质都是沉积砂床条件下的固体颗粒运移,其中固相沉积床表面的颗粒起动是其核心问题之一。将固相颗粒视为球形颗粒,考虑颗粒重力、水流推力、上举力、水柱静压力和粒间粘结力,以及各力臂与沉没度的关系,通过力矩平衡分析建立了井筒倾斜条件下沉积床表面颗粒起动的临界流速模型,并进行了计算结果分析。该模型考虑了沉积床表面颗粒沉没位置的随机性及由此引起的颗粒起动的随机性,引入颗粒无因次沉没度随机变量,将其概率密度视为均匀分布,结合无因次沉没度的概率分布函数,在临界流速与颗粒直径及颗粒起动百分比之间建立了定量关系。该模型用于预测大斜度井条件下砂床表面颗粒在水流作用下的起动临界条件以及给定水流条件下的起动百分比。Solid-liquid two-phase flow in deviated pipeline exist in many oil fields,including drilling cuttings bed moving,gravel-packing and sand washing in highly deviated wells,while the essential process is activating and moving of the solid grain at bed surface.The critical velocity model for grains at bed surface in highly deviated well was developed based on the analysis of torque equilibrium considering the gravity,buoyant weight,fluid thrust force,upthrust force and cohesive force between grains along with the assumption of round particle.The calculated results were analyzed.The model considers the randomicity of settlement location of grains on the bed surface and the associated randomicity of grains starting.Dimensionless submergence with a uniform probability distribution is used to denote the location randomicity.Combined the critical velocity equation and submergence probability distribution equation,the quantitative relationship between critical velocity and the percentage of starting grains was created.This model can be used to calculate the critical starting condition under water for grains at the surface bed in highly deviated wells and to calculate the starting percentage at given water flow velocity.

关 键 词：大角度斜井 两相流动 沉积砂床 颗粒 临界速度 砾石充填 

分 类 号：TE358.1[石油与天然气工程—油气田开发工程]