套管损坏的力学分析及动力学机制探讨

为预防和治理油田开发套管损坏，以弹塑性力学变形破坏理论为基础，通过建立套管损坏的概念模型，模拟了油层厚度变化、水平应力场不均匀变化、套管外形成空洞以及单、双油层注水井等条件下的套管损坏现象。从力学机理上揭示了采油井和注水井套管损坏的原因，分析了套管损坏的动力学机制。研究表明，随着油层厚度的增加，采油井套管和套营外围岩被破坏的程度逐渐增加，并从整个层位的套管损坏过渡到套管中上部的局部损坏。水平应力场的不均匀变化也加大了套管损坏的程度。当套管外围岩被掏空时，所形成的空洞范围越大，套管损坏的程度也就越严重。单油层注水井套管的破坏程度较双油层注水井严重，双油层注水井中上部油层套管的破坏程度较下部油层严重。据此，套管损坏的机制分为区域动力学机制和局部动力学机制，前者受构造应力场控制，后者受非构造应力场控制，对油井周围环境的改变更为敏感，并且受控干区域动力学机制。

Mechanical analysis on casing damage and discussion on dynamic mechanism

Based on the theory of elastoplastic mechanical deformation and damage,the concept model of casing damage was established.Phenomenon of casing damage was simulated under the conditions of different reservoir thickness,unequal alternation of the horizon stress field,cavity around the casing and injection well of individual or double reservoir.The reason of casing damage of production wells and injection wells were revealed with the mechanical mechanism and the dynamic mechanism.Research shows that the destru...