WOB fuzzy control and experimental study on horizontal well experimental setup

This paper developed a horizontal drillstring-wellbore-bit experimental setup based on the similarity of physical behaviors. A data acquisition and control system was established to achieve real-time control over the Rotations Per Minute (RPM) and Rate of Penetration (ROP). Combining experts’ experience and practical drilling experiments, a constant Weight on Bit (WOB) fuzzy controller was designed for rock-breaking experiment. To validate the reliability of the control system, control tests were conducted with different WOB settings at varying RPM. The results indicated that the WOB control error was within 60 N, with an error rate below 3%. Rock drilling experiments were conducted on different rocks. In sandstone drilling experiments, as WOB increased from 600N to 900 N, the ROP, Torque on Bit (TOB), and Stick-slip Vibration Intensity (SSVI) increased significantly, reaching 114.12, 3.6, and 2.97 times of the original values, respectively. When the RPM increased from 21 to 30 RPM, TOB, SSVI, and ROP changed to 1.43, 0.89, and 3.84 times of the original values. The increase in ROP during sandstone drilling was evident, suggesting a moderate increase in drilling parameters, with caution against stick-slip vibrations, which can be mitigated by increasing RPM. In limestone drilling experiments, as WOB increased from 900 to 3300 N, TOB, SSVI, and ROP increased by 2.45, 3.17, and 56.34 times, respectively. When RPM was increased from 45 to 63 RPM, TOB, SSVI, and ROP changed by 0.88, 0.74, and 1.68 times, respectively. Under conditions of high WOB and RPM, the limestone drilling speed increased more significantly.