Abstract : This article introduces the application of frequency converters in oil drilling rigs. It briefly discusses the characteristics of drilling technology, control schemes, system composition, and precautions.
Keywords : Oil drilling rig frequency converter system
1. Introduction to Drilling Technology
The drilling process is divided into several major steps, including raising and lowering the derrick, drilling, mud circulation, drill string replacement, casing installation, and logging. It mainly consists of winches, rotary tables, and mud pumps. The winch comprises drums, a gearbox, a clutch, a brake, a motor, and control equipment. It is used to raise and lower the derrick and to lift and lower the drill pipe and casing. As well depth increases, the drill string becomes longer and heavier, placing a greater load on the winch. Currently, some oil wells in my country are 7000m deep, with drill strings weighing nearly 600 tons. Since the drill string needs to be raised and lowered approximately every 9m of drilling, the winch operation time accounts for a larger proportion of the total operation time as the well depth increases. To reduce costs, it is desirable to minimize operation time in the field or at sea. This requires not only high-speed operation of the winch and smooth start-up and shutdown to prevent damage to drilling equipment and improve well quality, but also good dynamic characteristics of the drive equipment. This is especially important when operating in inner-line well areas. The power supply can be connected to the well site power grid. When the drill pipe is lowered, the motor works in generator mode, and the energy can be fed back to the power grid, resulting in significant energy savings.
The rotary table and winch can share the same drive system and motor. With the drill pipe extended, the drive mechanism switches to the rotary table, which rotates the drill string to perform drilling operations. The driller adjusts the rotary table speed and pressure to change the drilling speed. The rotary table rotates forward normally, but reverses to retract the drill bit when dealing with stuck drill bits. To prevent the drill pipe from breaking during forward rotation or disengaging during reverse rotation, the motor output torque must be stable, flexible, and have a set limit value. A braking component for the motor is also essential.
For details, please click: Application of Frequency Converters in Domestic Oil Drilling Rigs
