井壁坍塌破坏过程的数值模拟及井径扩大率预测

Numerical Simulation of Borehole Collapse Procedure and Prediction on Well-hole Enlargement

用有限元法对钻井过程中的井壁坍塌进行了数值模拟计算 ,研究了不同钻井液密度下的井壁坍塌破坏过程、稳定的井眼形状及井径扩大率。

The borehole collapse is analyzed by use of the Finite Element Method, and the procedure, the stable shape and the enlarging ratio of the borehole are studied. The result shows the wellbore collapse takes place step by step before the stable borehole shape is formed. The stable borehole shape is an ellipse with sharp angle. The wellhole enlarging ratio can be calculated in different mud density. The conclusions are conducive to analyzing the wellbore collapse mechanism and resolving the hole problem.