基于长效地应力机制下套管围压的分析计算方法

Theoretical Methods of Determining the Pressure Around Casing Under Long-Term In-Situ Stresses

针对长期服役套管被大量挤毁的工程实际,在分析固井状态套管-井壁边界条件的基础上,提出了固井状态套管围压可以进行理论计算的观点。在应用经典力学弹性理论的半逆解法和叠加法分析固井状态井眼周围地层应力分布的基础上,结合数值计算方法,提出了固井状态套管围压的分析方法及计算公式,给出了套管围压呈周期变化、变化周期是900的结论。该理论分析方法可以直接应用于套管围压的计算,对石油工程领域分析套管的抗挤强度十分重要。

In view of a large number of engineering cases that casing has been collapsed for long-term serving,the viewpoint was put forward that the pressure around casing could be determined directly by theoretical methods,based on analyzing of casing-well wall boundary conditions in cementing status.The analysis methods parse analyzing pressure around casing were brought forward by application of the theory of classical mechanics and semi-inverse method to analyze the contribution of stresses around borehole on cementing status,combined with numerical methods.And the calculating formula to determine pressure on casing was presented.The conclusion was given that the pressure was periods changing and the cycle 0 was 90°.The theoretical analysis method could be directly applied to calculate the pressure loads on casing.It would be of the significance for analysis anti-collapse of casing on field of petroleum engineering.