What is the hoisting system in oil drilling?
Apr 02, 2025
The hoisting system in oil drilling is a crucial component of oil drilling equipment, mainly used for tripping drill strings and casings, as well as suspending drill strings during drilling operations. The following are some of the main equipment in this system:
Ⅰ. DerrickStructural Features: The derrick is a large-scale steel structure, usually including types such as the tower-shaped derrick, A-shaped derrick, and mast derrick. The tower-shaped derrick has an overall tower-like structure, with high stability and load-bearing capacity, capable of withstanding large loads. However, it is large in size, heavy in weight, and relatively complex in disassembly, assembly, and transportation. The A-shaped derrick is composed of two inclined brackets and a top crossbeam, resembling the letter "A" in shape. It has a compact structure, is convenient for disassembly and assembly, and is widely applied. The mast derrick is relatively low and has a small footprint, suitable for places with limited space.Function: The derrick provides support and fixation for the entire hoisting system. Through its steel structure framework, it bears the weights of equipment such as the crown block, traveling block, and drill string, as well as various tensile forces and pressures generated during the hoisting process. It enables the drill string to be raised and lowered vertically, and provides installation positions for hoisting equipment and tools such as the crown block, traveling block, rotary swivel, (top drive) power tongs, and elevator. It also ensures that operators have sufficient space for drilling operations.
Ⅱ. Crown Block
Structural Composition: Installed at the top of the derrick, it is a fixed sheave block composed of multiple sheaves.The crown block sheaves are usually made of high-quality steel, with high wear resistance and strength to withstand the huge tensile forces generated by frequent hoisting and lowering operations.Function: It changes the direction of the wire rope, transmits the pulling force of the drawworks to the traveling block, and realizes the hoisting and lowering of the drill string. Through the combination of multiple sheaves, it can effectively distribute the pulling force, reduce the load borne by a single sheave, and improve the reliability and safety of the system.
Ⅲ. Traveling BlockStructural Features: Connected to the crown block by a wire rope, it is a movable sheave block, usually composed of multiple sheaves, which cooperates with the sheave block of the crown block through the wire rope to form a labor-saving hoisting system. The number and size of the sheaves are determined according to the load-bearing capacity of the traveling block and the requirements of the drilling operation. The lower part of the traveling block is connected to the drill string through the traveling block hook. Under the action of the hoisting system, it drives the drill string to move up and down. The structural design of the traveling block should ensure its flexibility and stability during movement, and it should be able to withstand the weight of the drill string and the impact force during the hoisting process.Function: Driven by the drawworks, it moves the drill string up and down through the pulling of the wire rope. Since the traveling block is a movable sheave block, according to the principle of labor-saving of the sheave block, it can amplify the pulling force of the drawworks, enabling the hoisting of heavier drill strings.
Ⅳ. HookStructural Composition: The hook is connected below the traveling block, suspending the drill string through the hook body, and forms a hoisting system together with the traveling block, crown block, and drawworks. The hook has a rotatable hook body and a safety locking device.Function: Its working principle is relatively simple. It mainly uses its own structural features and connection devices to transmit the pulling force of the traveling block to the drill string, facilitating the connection and separation with the joint of the drill string, and preventing the drill string from accidentally falling off during the hoisting process. The rotating function of the hook body allows the drill string to rotate as needed during the hoisting and lowering process. For example, when connecting or disassembling drill pipes, it enables the threads of the drill pipes to be accurately aligned. The safety locking device of the hook prevents the hook body from accidentally opening after the drill string is suspended, ensuring that the drill string will not fall off and guaranteeing the safety of the operation. The load-bearing capacity of the hook varies according to the depth of the well and the weight of the drill string, generally ranging from several dozen tons to several hundred tons.
Ⅴ. DrawworksThe drilling drawworks is not only the main equipment of the hoisting system but also the core part of the entire drilling and workover rig, and it is one of the three major working units of the drilling and workover rig. A classic three-axis electric-driven drilling rig.Structural Features: As the power equipment of the hoisting system and the power source, it is usually driven by an electric motor or a diesel engine. The drawworks contains components such as a transmission device, a drum, and a braking system.Function: It controls the lifting speed and position of the traveling block and the drill string by winding and unwinding the wire rope. The transmission device can transmit power to the drum at different rotation speeds and torques according to different operation requirements. When the drill string needs to be hoisted, the drum rotates forward and winds the wire rope, thus pulling the traveling block and the connected drill string upward; when lowering the drill string, the drum rotates in reverse and releases the wire rope, and the drill string slowly descends under its own gravity. The braking system uses components such as brake pads or brake discs to quickly stop the rotation of the drum when necessary, making the drill string stop at the specified position and achieving the hovering function, ensuring the safety and precise control of the operation.
Ⅵ. Wire RopeStructural Features: Made of high-strength and corrosion-resistant steel, it has high breaking tensile force and good flexibility. Generally, it is twisted by multiple strands of steel wires, and the outer layer may also have a protective layer to improve its wear resistance and corrosion resistance. In order to ensure the service life and safety of the wire rope, it is necessary to regularly inspect, lubricate, and replace it. When selecting a wire rope, an appropriate one should be determined according to factors such as the depth of the well and the load.Function: It connects the crown block, traveling block, and drawworks, transmits the pulling force, and suspends the drill string. During the drilling process, the wire rope needs to bear a huge pulling force, so its quality and performance directly affect the safety and reliability of the hoisting system. The wire rope bypasses multiple sheaves of the crown block and traveling block to form a multi-strand rope system. According to the principle of labor-saving of the sheave block, in this way, the drawworks only needs to provide a pulling force smaller than the gravity of the drill string to achieve the hoisting of the drill string. For example, a crown block and traveling block system composed of multiple sheaves can amplify the pulling force of the drawworks several times, enabling the hoisting of drill strings weighing dozens of tons or even hundreds of tons. At the same time, the sheave block can also change the direction of the force, allowing the drawworks to be operated in a more convenient position while the drill string can be raised and lowered vertically.
In addition, the oil drilling hoisting system may also include some auxiliary equipment, such as the anti-collision device for preventing the traveling block from rising too high and colliding with the crown block, and the dead rope anchor for fixing one end of the wire rope. These devices work together to ensure that the oil drilling hoisting system can operate safely and efficiently, and complete the operations such as tripping drill strings and casings during the oil drilling process.
اقرأ أكثر