持续套管环空压力风险预警与防治措施  

Risk-alert and control measures of sustained casing annulus pressure

作　　者：徐申奇 管志川[1] 张波[1] XU Shenqi;GUAN Zhichuan;ZHANG Bo(School of Petroleum Engineering,China University of Petroleum,Qingdao,Shandong 266580,China)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580

出　　处：《中国科技论文》2018年第3期253-258,共6页China Sciencepaper

基　　金：国家自然科学基金资助项目(51574275);教育部长江学者创新团队项目(IRT-14R58)

摘　　要：针对气窜引起的套管持续环空压力,建立了基于气体不稳定渗流理论、气液两相流动理论及气体PVT状态方程的环空含液持续环空压力预测模型;通过与现场实测数据的对比,验证了模型的准确性,并对水泥环密封性进行了定量评价,提出了基于压力-时间关系的持续环空压力风险预测管理方法,并分析了各因素对环空压力的影响规律。结果表明:较大的初始环空气顶能有效延缓环空压力上升速度;环空压力上升速度随环空液体压缩性和黏度的增大而降低,环空压力极限值随环空液体密度的增大而减小;环空压力随着水泥环等效渗透率的增大而加快上升,环空压力极限值和上升速度随水泥返高的降低而减小。配置高压缩性高粘高密度的环空液体、注入堵漏材料形成环空气体封隔段、合理调控水泥返高以及注入热激活封隔物等措施能够防治持续环空压力。Aiming at the problem of sustained annulus pressure caused by gas channeling,the theory of gas transient seepage flow and gas-liquid two-phase flowandgas PVT equation were used to establish a prediction model of sustained annular pressurewhen there is liquid in the annulus.Through the comparative analysis between predicted results and field measured data,the accuracy of this model was verified and the cement sealing property was evaluated quantitatively,then the method of annulus pressure risk profile and management was proposedbased on the pressure-time relationship.After analyzing the effects of various factors on thesustained annulus pressure,the results show that the increase of the initial annulus gastop volume will slows down the annular pressurerising velocity.The rising velocity of annular pressure will declines with the increase of annular liquid compressibility and viscosity.Annulus pressure rising rate will decreases with the increase of air ring of liquid compressibility and viscosity.The annular ultimate pressurewill decreases with the increasing of gas liquid density.The increase of cement sheath’s equivalent permeability will acceleratesthe rising of annulus pressure,the increase of cement return height will reduces the ultimate value and increases velocityof annular pressure.High compression,high viscosity,high density annulus liquid is needed,controlling cement return height reasonably,cementing plug and heat activated packer can be used to prevent and control the risk of sustained annulus pressure.

关 键 词：气井 持续环空压力 气体渗流 气-液两相流 压力预测 压力防治 

分 类 号：TE2[石油与天然气工程—油气井工程]