Modification And Application Of Mechanical Specific Energy Model

In drilling engineering,the formation lithology and formation pressure system are complex and changeable.Selecting the bit suitable for the formation and the matching drilling parameters is an effective means to improve the drilling speed.The mechanical specific energy can overcome the difference of the formation,as a measure of the bit performance,and also as a tool to evaluate the rationality of drilling parameters in real time.On the basis of the previous research results,this thesis comprehensively considers the influence of mechanical energy and hydraulic energy on rock breaking and clearing of the drill bit,optimizes and corrects the parameters of the commonly used mechanical specific energy model.The application of bit selection,formation pressure monitoring and optimization of drilling parameters while drilling is studied;and field data analysis is carried out on the application of the modified mechanical specific energy model in the target well area.The application of the modified mechanical specific energy model shows that the drill bit with the lowest mechanical specific energy in each formation can be regarded as the drill bit with the lowest drilling cost in the formation;the real-time wear of the drill bit can be evaluated based on the modified mechanical specific energy model.At the same time,the wear correction is made to the d_c index method,and the formation pressure monitoring profile can be drawn by combining the inverse algorithm;based on the corrected mechanical specific energy model,the working state of the drill bit and the downhole working condition can be identified,and the drilling pressure and rotational speed can be adjusted to keep the drilling parameters in the mud.Near the wrapping point,the drill can keep drilling efficiently.