考虑U型管效应的注水泥套管变形问题研究  

Study on Casing Deformation During Cementing Considering the U-tube Effect

作　　者：欧阳勇 李军[1] 赵国翔 刘金璐 江文龙 武志强 杨宏伟[1] 殷志明 OUYANG Yong;LI Jun;ZHAO Guoxiang;LIU Jinlu;JIANG Wenlong;WU Zhiqiang;YANG Hongwei;YIN Zhiming(College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China;No.110il Production Plant of Changqing Oilfield Company,Qingyang,Gansu 745000,China;CNOOC Research Institute Ltd.,Beijing 100028,China)

机构地区：[1]中国石油大学(北京)石油工程学院 [2]中国石油长庆油田分公司第十一采油厂 [3]中海油研究总院有限责任公司

出　　处：《钻采工艺》2023年第6期47-52,共6页Drilling & Production Technology

基　　金：国家自然科学基金重点项目(编号:52227804、52104012);中国石油大学(北京)科研基金(编号:2462023BJRC008);国家能源深水油气工程技术研发中心2023年自主前瞻基础研究课题(编号:2023-SSGC-ZZQZ);井控风险预警及应急关键技术(编号:KJGG-2022-17)联合资助。

摘　　要：注水泥过程中的套管变形问题给固井作业带来了巨大挑战。基于U型管效应产生的机理,给出了真空段长度和返出排量的描述方程。考虑温度场对套管变形的影响,推导了传热学方程,用于预测井筒温度场。通过分析注水泥时套管受力情况,建立了相应的套管变形程度计算模型。以新疆油田Z井为例,进行了泵压、真空段长度、注入返出排量等参数的计算。结果表明,当井筒内出现U型管效应时,返出排量不等于注入排量;最佳的注入排量为12~14 L/s,此时套管变形量较小,且不会发生疲劳破坏。当在井口观测到泵压为0时,井筒内就会产生真空段,此时应重视U型管效应可能引发井下复杂。根据敏感性分析,注入排量对套管变形程度的影响最大。在设计注入排量时,可考虑变排量注水泥的设计方法,以便更好地解决该类问题。The casing deformation problem during the cement injection process brings great challenges to cementing operations.Based on the mechanism of U-tube effect,the descriptive equations for the length of vacuum section and return displacement are given.Considering the influence of temperature field on casing deformation,the heat transfer equation is derived for predicting the wellbore temperature field.By analyzing the casing force during cement injection,the corresponding calculation model of casing deformation degree was established.The calculation of parameters such as pump pressure,vacuum section length,injection and return displacement was carried out taking Xinjiang Oilfield Z well as an example.The results show that when the U-tube effect occurs in the wellbore,the return discharge is not equal to the injection discharge;the optimal injection discharge is 12-14 L/s,at which time the casing deformation is smaller and fatigue damage does not occur.When the pump pressure is observed to be 0 at the wellhead,a vacuum section will be generated in the wellbore,at which time attention should be paid to the U-tube effect that may trigger downhole complexity.The temperature change at the bottom of the well is the largest,and the effect of thermal stress on casing deformation should not be neglected.According to the sensitivity analysis,the injection displacement has the greatest influence on the degree of casing deformation.When designing the injection displacement,the design method of variable displacement cement injection can be considered in order to better solve this kind of problem.

关 键 词：套管变形 U型管效应 传热过程 真空段长度 变排量注水泥 

分 类 号：TE931.2[石油与天然气工程—石油机械设备]