真三维套管-水泥环-岩层系统力学模型研究

二维力学模型很难真实反映套管的受力状态,三维力学模型没有考虑地质构造形态对套管损坏的影响。为了克服上述力学模型的缺陷,提出了真三维套管-水泥环-岩层系统力学模型。采用ANSYS软件中自底向上的建模方法建立真三维套损力学模型。根据地质勘探获得的三维地质构造信息,在井眼附近取出一定大小范围内的三维地质构造数据点,以获取不同层位各离散点的高度数据,用这些数据建立井眼周围的三维地质构造曲面,在此基础上生成三维实体的粗糙模型。研究结果表明,真三维套管-水泥环-岩层系统力学模型能够真实地模拟套管实际变形,可与有限元分析方法相结合用于套损的预测。

Study of true 3D casing-cement sheath-rock system mechanics model

The two-dimensional mechanics model is very difficult to truly reflect the force condition of casing, and the three-dimensional mechanics model doesn’t consider the influence of geological structural configuration on casing damage. For that reason, the true three-dimensional casing-cement sheath-rock system mechanics model is put forward. The three-dimensional casing damage mechanics model is established by means of the method of establishing model from bottom to top in ANSYS software. According to the three-dimensional geological structure information obtained from geological exploration, the three-dimensional geological structure data point within a certain scope is taken near the wellbore to obtain the height data of each discrete point at different zones, which are used to establish the three-dimensional geological structure camber near the wellbore. Then on the basis of it, the three-dimensional solid coarse model is developed. The result indicates that true three-dimensional casing-cement sheath-rock system mechanics model overcomes the drawback of plane model which cannot truly reflect the force condition of casing, and fully considers the influence of multilayer rock zone combination and rock geological structural configuration on casing damage. The model can be combined with finite-element analysis method to be used for predicting casing damage.