基于欧拉双流体模型的微小井眼环空岩屑运移数值模拟研究  

Numerical simulation research of cuttings transport in microhole annulus based on Eulerian two-fluid model

作　　者：张鑫鑫 毛纯芝 信伟卫 张绍和[1,2] 吴冬宇 贺勇[1,2] ZHANG Xinxin;MAO Chunzhi;XIN Weiwei;ZHANG Shaohe;WU Dongyu;HE Yong(Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,Central South University,Changsha 410083,China;School of Geosciences and Info-physics,Central South University,Changsha 410083,China;Jiangxi Nonferrous Metal Geology and Mineral Resources Exploration and Exploitation Institute,Nanchang 330001,China)

机构地区：[1]中南大学有色金属成矿预测与地质环境监测教育部重点实验室,湖南长沙410083 [2]中南大学地球科学与信息物理学院,湖南长沙410083 [3]江西有色地质矿产勘查开发院,江西南昌330001

出　　处：《中南大学学报（自然科学版）》2023年第11期4413-4423,共11页Journal of Central South University:Science and Technology

基　　金：中南大学创新驱动项目(2023CXQD044);中南大学中央高校基本业务费专项资金资助项目(2022ZZTS0502);国家自然科学基金资助项目(42302354);湖南省自然科学基金资助项目(2023JJ30664)。

摘　　要：为了探究微小井眼环空内岩屑运移规律,基于欧拉双流体模型,采用计算流体动力学(CFD)数值模拟方法建立井眼环空固液两相流模型,研究岩屑运移过程中的岩屑特征、操作参数和井筒环境变化对岩屑运移规律的影响,分析钻杆振荡频率和振荡幅度对岩屑运移的效果。研究结果表明:岩屑在环空运移的过程中,当机械钻速(ROP)、岩屑特征和井筒环境保持不变时,增加液相在环空的初始速度能增大流体对颗粒的作用力,进而达到提高携岩效率的目的;在微小井眼钻井工况下,单个岩屑颗粒所受重力和颗粒碰撞造成的能量损失协同影响岩屑运移过程,粒径为1.5 mm的岩屑最难被运移出环空;机械钻速增加虽会使岩屑初始速度有所提升,但同时也会使环空内堆积的岩屑数量增多;随着偏心度增加,岩屑固定床占比升高,运移效率显著降低;倾斜井段携岩效率明显比水平井段和垂直井段的低,且当井斜角为60°时管内岩屑体积分数最高;相比于无振荡工况,钻杆振荡能对钻杆附近岩屑起到扰动作用,使岩屑床高度降低,在流速为1 m/s、振荡频率为15 Hz、振荡幅度为9 mm的工况下钻井液携岩效果最佳。In order to investigate the cuttings transport law in the microhole annulus,a solid-liquid two-phase flow model of the borehole annulus was developed based on the Eulerian two-fluid model using computational fluid dynamics(CFD)numerical simulation method.Firstly,the influences of cuttings characteristics,operating parameters and wellbore condition changes on cuttings transport law were studied,and then the beneficial effect of drill pipe oscillation frequency and oscillation amplitude on cuttings transport was analyzed.The results show that as other conditions remain unchanged,increasing the initial velocity of the liquid phase in the annulus can increase the force of the fluid on the particles and thus improve the cuttings-carrying efficiency during the process of cuttings transport.Under microhole drilling conditions,the gravity of individual cuttings particles and the energy loss synergistically affect the cuttings transport process due to particle collision,and the cuttings with 1.5 mm diameter are the most difficult to be transported out of the annulus.Although increasing the rate of penetration(ROP)can increase the initial velocity of cuttings,it also increases the accumulation of cuttings in the annulus.With the increase of eccentricity,the proportion of stationary bed of cuttings increases and the transport efficiency significantly decreases.The cuttings-carrying efficiency of the inclined section is significantly lower than that of the horizontal and vertical sections,and the volume fraction of cuttings in the pipe reaches its highest value at the inclination angle of 60°.Compared with the no-oscillation condition,the oscillation of the drill pipe can disturb the cuttings near the drill pipe and reduce the height of the cuttings bed.When the velocity of the liquid phase is 1 m/s,the best cuttings-carrying efficiency of drilling fluid is achieved with an oscillation frequency of 15 Hz and an oscillation amplitude of 9 mm.

关 键 词：微小井眼 CFD数值模拟 水平井 固液两相流 岩屑运移 

分 类 号：TE21[石油与天然气工程—油气井工程]