Failure Analysis And Precautions Of PDM

Positive displacement mud motor(PDM)is one of the most widely downhole power tools.With the development of petroleum exploration technology in recent years,PDM is a necessary drill for directional well and horizontal well.However,with the increase of the frequency of use PDM,because of the failure of PDM,Sometimes it happens Downhole accident,and caused a lot of economic losses.The main purpose of this thesis is through a lot of research,we analyze the structure and working principle of PDM,from PDM failure data began to study,we analysis PDM failure and stress,and optimum its body structure and design,and provided PDM failure prevention measures,and increase the service life of PDM,reduce the cost of drilling operation.Through PDM failure analysis and stress analysis,we know that the stress of PDM in drilling is very complex,the screw motor and a transmission shaft is high incidence of PDM failure parts;the bypass valve and the cardan is the main components of PDM failure.The wear and fracture of the screw motor's lock,transmission shaft and universal shaft are the most prone to failure of PDM.Combined with the actual working conditions,we optimize the structure of PDM.We optimize the selection of the rotor and the stator of the screw motor,increase flexible shaft transition zone rounding radius and flexible shaft body diameter;shorten transmission shaft length and increase the transmission shaft section radius.A series of optimization effectively increased the use time of the screw motor,reduce the flexible shaft of the maximum stress,enhance the torsion resistance of the drive shaft main body,reducing moving axis maximum should force and deformation,and effectively prolongs the service life of PDM.In this paper,through PDM failure,combined with the actual conditions of drilling production,through of PDM choice and use,optimized drilling technology and other means to reduce PDM failure probability of occurrence,and to enhance the service life of PDM.