Application of lengthen kelly stand in MWD drilling

In the process of popularizing combined steering drilling technology and new type of PDC,drill string contrarotation occurs from time to time which is caused by reverse torque of downhole motors.As a result,a series of negative consequences will take place such as wire line wringing,wreathe of hose and wired MWD cables,and other downhole accidents.A new method was presented to solve the above-mentioned problem.According to the type of derrick,two or three self-processed kellys were connected together;so the reverse torque caused by the motor can be controlled by the interaction of kelly and rotary table.The onsite application of this technology in Jidong oilfield manifests that drilling speed can be increased and drilling accident drops off dramatically.The goal of drilling safely,effectively and economically can be achieved by popularization of this technology.