振动固井对泥饼的剪切作用机理研究

钻井时钻井液会在井壁上形成泥饼，如果固井时泥饼没有被清除掉，就会在井壁上形成一个不可固化层，严重影响第二界面的胶结强度，而振动固井可以通过剪切作用清除泥饼，提高固井质量，但人们对其作用机理还缺乏认识。为此，利用有限元法，对振动固井中的泥饼剪切作用过程与规律进行了数值模拟分析。分析结果表明:振动固井产生的振动波对泥饼的剪切力比环空流动产生的剪切力大，可以直接剪切除去部分泥饼；振动波的频率比较低时，振动波可以剪除虚泥饼层与部分可压缩层；振动波的频率比较高时可以剪除泥饼可压缩层与部分密实层，泥饼致密层一般不会被破坏。由于频率高的振动波衰减较快，传播距离短，振动固井时为了提高泥饼的破坏程度，不能一味地提高振动波的频率，应在保证振动波传播距离足够的条件下，适当提高振动波的频率。 

Study on Mechanism of Cake Shear Failure in Hydraulic Vibration Cementing

Mud cakes will form on wellbore during drilling.If the mud cake is not removed before cementing,the non-solidified layer will form on wellbore which severely affect the cementing strength of second contact surface.Vibration cementing can remove the mud cake by shearing action and improve cement job quality,while the mechanism of vibration cementing has not been fully understood.The process of shearing action in vibration cementing was numerically simulated using finite element method.It is found that hydrau...