基于数值模拟的套管受力单因素分析

Single Factor Analysis of Casing Force Based on the Numerical Simulation

套管损坏一直是油田开发过程中的棘手难题,对套管受力及影响因素进行研究对保证套管安全具有重要意义。考虑开发过程中储层渗流场与应力场的耦合作用,基于流-固耦合理论,建立了套管-水泥环-围岩组合体系的数学力学模型,根据单因素理论,通过数值模拟,揭示了套管的径向挤压力随注水压力、套管参数、地层参数和地应力的变化规律:套管的径向挤压力随注水压力、套管壁厚、地层泊松比、弹性模量的增大而减小;随着套管弹性模量、直径、地层渗透系数、地应力的增大而增大。研究成果将为油田套管保护和预防套损提供理论指导。

Casing damage is always a problem in the process of oil field development, so it is significance for the study of casing failure mechanism and its influencing factors to ensure the casing security. Based on fluid-solid coupling theory, a new mathematical model which was used to simulate the stress distribution of the combination about casing-cement sheath -formation was established considering seepage and stress interaction during oil development process. Besides, the numerical simulation was carried out by the finite element software ABAQUS that describes radial compressive force of casing under different water injection pressure, formation parameters, casing parameters and in-situ stress. The results show that radial compressive force of casing will increase as the water injection pressure, casing wall thickness and poisson＇s ratio and elasticity modulus of formation increasing. However, radial compressive force of casing will decrease with elastic modulus and diameter of casing, formation permeability and in-situ stress increasing. The results can provide the theoretical guidance for protecting and preventing casing damage.