摘要
为准确预测套管环空上方的持续环空压力,以水泥环裂隙与固井界面微环隙为环空窜流通道,用一维不稳定渗流描述气体在水泥环中的运移过程,基于物质守恒和体积守恒,将环空窜流等效渗透率计算方法补充到持续环空压力预测模型中,依此建立了套管环空压力计算模型,并给出了迭代求解方法,实现了对水泥环真实密封性的定量评价。通过与现场实测数据的对比,验证了模型预测套管环空压力的准确性。研究结果表明:窜流通道等效渗透率和初始环空压力只会影响套管环空压力的上升速度;而气层泄漏压力和水泥环封隔长度会同时影响上升速率和环空压力极值;改善水泥浆配方以及合理调控水泥返高是现场防治套管环空压力较为可行的措施。研究结果可为现场套管环空压力的风险评价与管理控制提供理论依据。
In order to accurately predict the sustained annular pressure in the upper part of casing annulus, taking the fracture of cement sheath and the micro-annulus of cementing interface as the annular channeling paths, the 1D transient seepage flow was used to describe the migration process of gas in the cement sheath;then, based on the conservation of matter and volume, the equivalent permeability calculation method of annular channeling was supplemented into the sustained annular pressure prediction model, and based on which, the casing annular pressure calculation model was built;moreover, the iterative solution method was presented, and the quantitative evaluation on the real sealing capacity of the cement sheath was realized. By means of comparing with the field measured data, the accuracy of the model in predicting casing annular pressure was verified. The research results show that the equivalent permeability of channeling path and the initial annular pressure only affect the rising velocity of casing annular pressure;the gas layer leakage pressure and the cement sheath packed-off length affect the rising velocity and the maximum annular pressure;and improving cement slurry formula and reasonably controlling cement top are feasible measures to control the casing annular pressure on site. The research results provide theoretical basis for risk evaluation and management control of casing annular pressure on site.
作者
阎卫军
赵效锋
闫炎
管志川
Yan Weijun;Zhao Xiaofeng;Yan Yan;Guan Zhichuan(No.1 Drilling Company,CNPC Greatwall Drilling Company;Petroleum Engineering Research Institute,Sinopec Zhongyuan Oilfield Company;School of Petroleum Engineering,China University of Petroleum(Huadong))
出处
《石油机械》
北大核心
2022年第1期27-33,共7页
China Petroleum Machinery
基金
国家自然科学基金面上项目“钻井井下气液固多相流中超声波传播特性及气侵监测方法研究”(52074326)。
关键词
套管
环空压力
窜流
水泥环
微环隙
等效渗透率
casing
annular pressure
channeling
cement sheath
micro-annulus
equivalent permeability
