基于热传递作用的环空圈闭压力预测与分析

Prediction and Analysis of Annular Trap Pressure Induced by Heat Transfer

环空圈闭压力上升是深水油气井钻采过程中水泥环密封完整性面临的主要问题之一,基于此研究井筒高温流体热传递引起的环空圈闭压力上升问题。根据PVT状态方程和弹塑性力学理论,建立了环空温度、体积变化耦合的环空圈闭压力预测模型,并采用迭代法对模型进行求解。分析了环空温度、环空流体的膨胀、压缩系数及套管的泊松比、线性膨胀系数、弹性模量、壁厚参数对环空圈闭压力的影响。通过误差分析表明,迭代结果逐步收敛,且随着温度的增加,迭代次数也逐渐增加,迭代结果收敛变缓。

The pressure rise of annular trap is one of the main problems in the drilling and production process of deep water oil and gas wells.This paper mainly studies the pressure rise in annulus trap caused by heat transfer of high temperature fluid in wellbore.Based on the PVT equation of state and the theory of elastoplastic mechanics,a prediction model of annular trap pressure coupled with annular temperature and volume changes is established,and the iterative method is used to solve the model.The effects of annulus temperature,annulus fluid expansion,compression coefficient,Poisson s ratio of casing,linear expansion coefficient,elastic modulus and wall thickness on annulus trap pressure are analyzed.Furthermore,the calculation error analysis shows that the iteration results converge gradually,and with the increase of temperature,the number of iterations also increases gradually,and the convergence becomes slow.