小间隙偏心环空注水泥顶替效率研究  

Displacement Efficiency of Cementing in Eccentric Annulus with Small Clearance

作　　者：马越 王宏彦 孙巧雷[1,2] 罗有刚 侯灵霞[1,2] 冯定 Ma Yue;Wang Hongyan;Sun Qiaolei;Luo Yougang;Hou Lingxia;Feng Ding(School of Mechanical Engineering,Yangtze University;Hubei Engineering Research Center for Oil&Gas Drilling and Completion Tools;No.5 Oil Production Plant,PetroChina Changqing Oilfield Company;National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields,Oil and Gas Technology Research Institute,PetroChina Chang-qing Oilfield Company)

机构地区：[1]长江大学机械工程学院,湖北省荆州市434023 [2]湖北省油气钻完井工具工程技术研究中心 [3]中国石油长庆油田分公司第五采油厂 [4]长庆油田分公司油气工艺研究院低渗透油气田勘探开发国家工程实验室

出　　处：《石油机械》2022年第6期22-28,共7页China Petroleum Machinery

基　　金：湖北省技术创新专项(重大项目)“智能油气钻采井眼轨迹控制工具研究”(2019AAA010);国家采油装备工程技术研究中心资助项目“自动化管柱运移系统关键技术研究”(ZBKJ2021-A-03)。

摘　　要：在小间隙环空注水泥固井过程中,当套管偏心严重时,除了在环空两壁面上有钻井液滞留外,在环空窄间隙处可能会出现钻井液的整体滞留现象。为了改善固井质量,从钻井液发生整体滞留条件出发,通过分析流体受力特性,建立了小间隙偏心环空钻井液滞留模型。基于该钻井液滞留模型并结合长庆某区块实例井作业工况,分析套管偏心度、水泥浆与钻井液密度差、钻井液屈服值等因素对小间隙偏心环空内顶替效率的影响规律。分析结果表明:随着套管偏心度的增加,注水泥顶替效率逐渐降低,当套管偏心度大于0.5后,环空窄间隙处发生钻井液的整体滞留现象,顶替效率急剧降低且套管偏心越严重,通过增加顶替压差来改善钻井液整体滞留角的效果越不明显;提高套管的居中度,增大顶替压差和钻井液与水泥浆的密度差,降低钻井液的屈服值均有利于提高小间隙偏心环空内注水泥顶替效率。研究结果可为准确便捷预测小间隙偏心环空内顶替效率提供理论依据。In the process of cementing in a small annular clearance,if the casing is eccentric seriously,drilling fluid might be detained in the narrow clearance of the annulus generally besides retention on both walls of the annulus.In order to improve the cementing quality,considering the conditions of drilling fluid retention,the fluid force characteristics were analyzed and the retention model of drilling fluid in eccentric annulus with small clearance was established.Based on the drilling fluid retention model and the operation conditions of a well in a block of Changqing Oilfield,the influences of casing eccentricity,density difference between cement slurry and drilling fluid,yield value of drilling fluid on displacement efficiency in eccentric annulus with small clearance were analyzed.The results show that with the increase of casing eccentricity,the displacement efficiency of cementing decreases gradually.When casing eccentricity is greater than 0.5,the overall retention of drilling fluid occurs in the narrow clearance of the annulus,and the displacement efficiency decreases sharply.The higher the casing eccentricity is,the less effective to improve the overall retention angle of drilling fluid by increasing the displacement pressure difference is.Improving the centrality of casing,increasing the displacement pressure difference and the density difference between drilling fluid and cement slurry,and reducing the yield value of drilling fluid are all effective to improve the displacement efficiency of cementing in eccentric annulus with small clearance.The results provide a theoretical basis for accurate and convenient prediction of displacement efficiency in eccentric annulus with small clearance.

关 键 词：小间隙 偏心环空 钻井液滞留 注水泥 顶替效率 

分 类 号：TE256[石油与天然气工程—油气井工程]