偏心环空循环压耗的数值模拟与验证  

Numerical Simulation and Verification of Pressure Loss in Eccentric Annulus

作　　者：钟成旭 赵鹏超 李郑涛 赵文奎[3] 李积学 王旭东 陈烨 杨谋[2] ZHONG Chengxu;ZHAO Pengchao;LI Zhengtao;ZHAO Wenkui;LI Jixue;WANG Xudong;CHEN Ye;YANG Mou(Shale Gas Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610056,China;State Key Laboratory for Oil&Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China;No.7 Oil Production Plant of PetroChina Changqing Oilfield Company Xi′an,Shaanxi 710018,China;No.2 Oil Production Plant of PetroChina Qinghai Oilfield Company,Haixi,Qinghai 816400,China)

机构地区：[1]中国石油西南油气田分公司页岩气研究院 [2]油气藏地质及开发工程国家重点实验室·西南石油大学 [3]中国石油长庆油田分公司第七采油厂 [4]中国石油青海油田公司采油二厂

出　　处：《钻采工艺》2023年第3期37-42,共6页Drilling & Production Technology

基　　金：国家自然科学基金“干热岩型地热泡沫钻井流体相变行为下井筒温度压力响应特性研究”(编号:52174008);中国石油西南油气田分公司科技项目“长宁区块小井眼水平井钻完井及配套技术研究”(编号:20210302-12)。

摘　　要：在水平井和复杂结构井中,井斜角和方位角随井深不断变化,套管在井内不易居中,影响流体在环空中的流动状态和循环摩阻。现有的偏心摩阻压耗计算模型是基于特定井眼尺寸和流体性能条件下建立的,不具备普适性。为此,结合某水平井井眼尺寸和流体性能,基于计算流体力学(CFD)的仿真理论与方法,分析了不同套管偏心度和直径比对环空流态与摩阻压耗的影响,对比了套管居中和套管偏心工况下环空摩阻压耗与当量循环密度(ECD)分布特征。结果表明:随着偏心度增大,宽间隙中心流速增大,壁面低流速域增多,增加了流体滞留量;直径比越小,有助于提高窄间隙流速;环空间隙越小,套管偏心对摩阻压耗影响越大。实例井偏心环空摩阻压降比同心环空低2.16 MPa;文章建立的摩阻压降计算模型比现有经典模型误差更小,为偏心环空下摩阻压降的准确计算提供了可靠的计算方法。In horizontal wells and complex-structure wells,the inclination angle and azimuth angle constantly change as the depth of well increases,resulting in casing eccentricity,further affecting the fluid flow state and circulating friction in the annulus.The existing calculation model of eccentric friction and pressure loss was developed based on the specific wellbore size and fluid properties,which is not universal.Therefore,based on CFD simulation theory and method,combing with a horizontal well borehole size and fluid properties,the effect of different casing eccentricities and diameter ratios on the annulus flow pattern and friction pressure loss was analyzed;the friction pressure loss and the ECD distribution were investigated under the concentric and eccentric annulus.The results indicate that with the increase of casing eccentricity,the central velocity in wide gap increases and the low velocity region of walls increases,which increases the fluid retention.The smaller the diameter ratio is,the higher velocity in the narrow gap is.The influence of casing eccentricity on friction pressure loss increased with the decrease of the annular gap;the friction pressure drop of eccentric annulus is 2.16 MPa lower than that of concentric annulus.The calculation model of friction pressure drop established in this paper has less error than the existing classical model,which provides a reliable theoretical method for accurate calculation of friction pressure drop under the eccentric annulus.

关 键 词：偏心环空 同心环空 摩阻压耗 数值仿真 数学模型 

分 类 号：TE24[石油与天然气工程—油气井工程]