NUMERICAL SIMULATION OF PRESSURE PULSATION CHARACTERISTICS OF VIBRATION-REDUCING DRILLING TOOLS

Abstract

During the drilling process of complex structure wells, the "thrust" problem is encountered, which affects the transmission of WOB. This issue can be addressed by installing a hydraulic oscillator. The pulse generator is the power unit of downhole stimulation tools, represented by the hydraulic oscillator, whose pressure fluctuation characteristics significantly impact the application effectiveness of downhole stimulation tools. This study takes the structure of an interleaved flat blocking valve as the research object and obtains the rotor movement law through theoretical analysis. This law is then imported into Ansys Fluent software platform for secondary development, simulating pressure fluctuation characteristics and influencing factors. The optimal structure under given conditions is determined using orthogonal experimental design method. The results show that pressure wave amplitude has a positive correlation with the eccentricity of the screw rotor, eccentricity of the eccentric hole, and displacement, while having a negative correlation with the aperture of the stator and rotor. As the initial installation angle increases, pressure wave amplitude first decreases and then increases. The primary and secondary relationships of the factors affecting pressure wave amplitude are: aperture of the stator/rotor, eccentricity of the screw rotor, eccentricity of the eccentric hole, displacement, and initial installation angle. This study provides reference for the design and optimization of pulse generators.