Research on the Control Methods of a Drilling Fluid Continuous Wave Signal Generator

Abstract

In order to control the drilling fluid continuous waves generated by the reciprocating main valve, and achieve the efficient and rapid transmission of downhole information, the control methods of reciprocal continuous wave generator were studied. While selecting the beveled cam as the control actuator, the motor was selected and optimized, and the speed control method of changing armature voltage was determined. Then the calculation model of the motor speed and load torque when the reciprocating main valve generated the continuous wave of drilling fluid was established. After making the calculation, the motor speed that were capable of generating a continuous sinusoidal wave, and the variation rules of load torque and armature voltage along with time were obtained. In the half cycle, the motor rotary speed decreased nonlinearly, while the motor torque increased nonlinearly, where the maximum load of motor was 0. 46 N·m and the armature voltage tended to decrease first and then increase. The research results showed that the speed control method of changing the armature voltage was feasible, and the frequency modulation of continuous wave could achieve the transmission of downhole information. The proposed control method for drilling fluid continuous wave signal generator could provide reference and serve as a model for design and field applications of the downhole signal generator.

AAPG Datapages/Search and Discovery Article #130004© Petroleum Drilling Techniques, Issue 5, 2018