| Top drives have been applied and developed for more than 30 years up to now. At present, electric drive top drives are still used more. However, the electric drive top drives have the disadvantages of huge motor physical dimension, speed regulation dependence on complicated and expensive electrical system, heavy total weight, big rotary inertia and insufficient output torque, meanwhile, high-power motors are difficult to be explosion-proof highly, and the heavy current of the motor also influences the precision of high-precision logging while drilling apparatuses to some extent. Moreover, there is no top drive which can meet the demands of 10000m research and study wells yet at home, the overseas procurement costs are too high, and furthermore, the procurement of oversea top drives cannot promote the research and development abilities of Chinese top drive equipment and is also contrary to the national aim of strongly advocating self science and technology. Since the twenty-first century, the modern mechanical-electrical-hydraulic integration technology has been rapidly developed and maturely applied in engineering machinery field, and thus, it is a quite good choice to research hydraulic top drive suitable for the 10000m research and study wells at this time.By researching the structures of the international representative VARCO TDS11A top drive with single-stage drive structure, IDS-1 compact top drive, HH existing direct-drive top drive with hollow motor structure and Terra 350T trial-produced top drive, and by combining the validity of international patents and the actual technical abilities of domestic matching component manufacturers, the main body structure the HTD-70 top drive is determined. This top drive makes use of a main drive device comprising 4 sets of high-speed hydraulic motors, planetary reducers and 4 symmetrical external gearing mute helical gears. The main drive device, hoisting device, swivel assembly, hydraulic backup tong, BOP and swivel-washpipe assembly constitute the main body structure of the HTD-70 top drive. In combination with the drilling process demands of the 10000m research and study well and the economy of equipment procurement, the economical equipment matching mode of using traveling block and hook when running large-tonnage casings and using the hydraulic top drive when drilling is determined; the main parameter 4500kN, max. speed 300rpm (corresponding torque 58500N.m) and max. torque 12000N.m (corresponding speed 75rpm) of the HTD-70 top drive are determined; and drilling parameters are superior to those of the TDS11A top drive, IDS-1 top drive and Terra 350T top drive.The Simulation X software is used for performing simulation analysis on hydraulic system of such high-power hydraulic top drive to determine the detailed form and control mode of the hydraulic system and to optimize the hydraulic system. As this technique is applied to hydraulic equipment with so big power for the first time, its accuracy is to be verified.The tests of the hydraulic top drive in the factory verify the correctness of design parameters and meanwhile provide references for the applications in industrial fields. |
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