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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.

The hoisting sheaves are an important part of the hoisting system of oil drilling rigs. The sheaves of crown block and traveling block jointly form a sheave block, which is connected to the drawworks through wire ropes. By utilizing the principles of the sheave block to save force and change the direction of the force, the hoisting and lowering of the drilling tools are achieved to meet the needs of oil drilling operations. The following is the relevant introduction: Ⅰ. Structure and Principle Structure: The hoisting sheave is usually composed of parts such as the sheave body, bearings, sheave shaft, and rope groove. The sheave body is generally made of high-strength alloy steel or cast steel to withstand huge loads. The bearings are installed on the shaft to enable the sheave to rotate flexibly. The rope groove is used to accommodate the wire rope, and its shape and size are matched with the wire rope to ensure that the wire rope will not jump out of the groove during operation. Principle: The sheaves of the crown block and the traveling block form a sheave block, which is connected to the drawworks through wire ropes. When hoisting, the drum of the drawworks winds the wire rope, and through the action of the sheave block, the drilling rig hook and the drilling tools are lifted. When lowering, the drilling tools descend under their own weight, and the lowering speed of the hook is controlled by the braking mechanism and auxiliary brakes of the drawworks. Ⅱ. Functions Saving Force: Through the combination of the sheave block, the amplification of force can be achieved, enabling the drawworks to hoist or lower heavier drilling tools with less force, reducing the requirements for the power and driving force of the drawworks. Changing the Direction of Force: It changes the pulling force direction of the wire rope from the horizontal direction of the drawworks to the vertical direction, adapting to the hoisting and lowering requirements of the drilling tools, and can transmit the force to the required position. Improving Hoisting Efficiency: The coordinated operation of multiple sheaves increases the number of winding turns of the wire rope, reduces the wear of the wire rope, and also improves the stability and reliability of the hoisting system, thus improving the efficiency of drilling operations. Ⅲ. Crown Block Sheaves Location and Function: Installed at the top of the derrick, it is a set of fixed sheaves and is the highest point of the entire hoisting system. Its main function is to change the direction of the wire rope and transmit the pulling force of the drawworks to the traveling block and the drilling tools to achieve the hoisting and lowering of the drilling tools. There are usually a large number of crown block sheaves, and the number and size of the sheaves vary according to the model of the drilling rig and the hoisting capacity. Structural Features: The crown block sheaves are usually composed of multiple sheaves, which are installed on a common frame or wheel shaft. The number of sheaves is determined according to the drilling depth, hoisting weight, and system design requirements. Common configurations include 3 wheels, 4 wheels, 5 wheels, etc. The sheaves are generally made of high-strength alloy steel to withstand huge pulling forces and wear. Their surfaces are specially treated, such as quenching and chrome plating, to improve hardness and wear resistance and reduce the wear of the wire rope. The bearings of the sheaves are high-performance rolling bearings, which can withstand large radial and axial loads, ensure the flexible rotation of the sheaves, and reduce the frictional resistance. Working Principle: When the drawworks pulls the crown block sheave through the wire rope, the sheave rotates around the shaft. Due to its fixed position at the top of the derrick, the direction of the wire rope is changed, allowing the wire rope to be vertically connected to the traveling block downward, converting the horizontal pulling force of the drawworks into the vertical pulling force for hoisting the drilling tools. Ⅳ. Traveling Block Sheaves Location and Function: The traveling block sheaves are located below the crown block, and they are movable sheaves. They are connected to the crown block through wire ropes and are also connected to the hook, which in turn suspends the drilling tools. The function of the traveling block sheaves is to cooperate with the crown block sheaves to jointly complete the hoisting, lowering, and suspension operations of the drilling tools. At the same time, during the hoisting process, they share the pulling force of the wire rope, reducing the load borne by a single sheave. Structural Features: The structure of the traveling block sheaves is similar to that of the crown block sheaves, and they are also a sheave block composed of multiple sheaves. The material, manufacturing process, and surface treatment method of its sheaves are basically the same as those of the crown block sheaves to meet the same strength and wear resistance requirements. The frame structure design of the traveling block needs to consider the connection with the hook and the overall stability to ensure smooth operation during the hoisting and lowering of the drilling tools and reduce shaking and swinging. Working Principle: In the drilling operation, the wire rope passes around the crown block sheave and the traveling block sheave to form a closed system. When the drawworks pulls the wire rope, the crown block sheave and the traveling block sheave rotate simultaneously. Since the traveling block can move up and down along the derrick guide rails, it can drive the hook and the drilling tools to move in the vertical direction. During the hoisting process, multiple rope strands are formed between the crown block and the traveling block sheaves, and each rope strand shares a part of the weight of the drilling tools, thus reducing the pulling force borne by each sheave and improving the safety and reliability of the entire hoisting system. Ⅴ. To select suitable crown block and traveling block sheaves for specific oil drilling operations, the following multiple factors need to be comprehensively considered: Drilling Depth: The drilling depth directly affects the required hoisting force and the length of the wire rope. Generally speaking, the greater the depth, the greater the required hoisting force, and sheaves with higher bearing capacity should be selected. At the same time, the size of the sheave may also need to be larger to accommodate a longer wire rope. For example, for ultra-deep well drilling, large-diameter and high-strength sheaves may be required to meet the hoisting requirements. Hoisting Weight: Accurately calculate the maximum hoisting weight including the drilling tools, casing pipes, drilling fluid, etc. Select sheaves that can bear the corresponding load according to this weight. Usually, the rated load of the sheave should be 1.2 to 1.5 times greater than the maximum hoisting weight to ensure a safety margin. For example, if the maximum hoisting weight is 200 tons, the rated load of the sheave should be between 240 and 300 tons. Wire Rope Specifications: Different specifications of wire ropes need to be matched with sheaves of corresponding sizes and groove shapes. The diameter of the rope groove of the sheave should be suitable for the diameter of the wire rope. Generally, the diameter of the rope groove is 1 to 2 mm larger than the diameter of the wire rope to ensure that the wire rope can be well embedded in the rope groove and reduce wear and sliding. At the same time, the rope capacity of the sheave should also meet the length requirements of the wire rope in the drilling operation. Working Environment: If the drilling operation is carried out in special working conditions such as high temperature, high humidity, corrosive environment, or offshore, sheaves with corresponding protective performance need to be selected. For example, on offshore platforms, the sheaves should have good corrosion resistance, and stainless steel materials or sheaves treated with anti-corrosion coatings can be used. In high-temperature environments, high-temperature-resistant bearings and lubricating materials should be selected to ensure the normal operation of the sheaves. Drilling Speed: A higher drilling speed will make the sheave bear greater impact and wear. Therefore, sheaves with flexible rotation and good wear resistance need to be selected. Sheaves can be manufactured using high-precision bearings and high-quality wear-resistant materials to meet the requirements of high-speed drilling. Derrick Space: The space size of the derrick limits the size of the crown block and the traveling block, and thus affects the selection of the sheaves. According to the height, width, and bearing capacity of the derrick, select sheaves of appropriate size and structure to ensure that they can be reasonably installed and operated within the derrick without causing excessive load on the derrick. Economy: On the premise of meeting the requirements of the drilling operation, consider the cost, service life, and maintenance cost of the sheaves. Select sheaves with high cost performance to reduce the overall cost of the drilling operation. For example, although some imported high-end sheaves are more expensive, they have a longer service life and better performance, and may be more economical in the long run. While some domestic sheaves have a relatively low price and can be given priority if they can meet the operation requirements. Brand and Quality: Select sheaves from well-known brands and with reliable quality to ensure their performance and safety. Sheaves of well-known brands usually go through strict quality inspection and certification, have better stability and reliability, and can reduce drilling accidents and downtime caused by sheave failures. You can refer to the usage experience and evaluations of other drilling operators to select suitable brands and models. Ⅵ. Maintenance Daily Inspection: Before and after each day's operation, check whether there are cracks, wear, and deformation on the surface of the sheave, whether it rotates flexibly, and whether the position of the wire rope in the rope groove is normal. Regular Lubrication: Select suitable lubricating grease. According to the equipment instruction manual and the actual working situation, lubricate once every 100 to 200 working hours or once a week. When injecting oil, ensure that the lubricating grease is fully filled into the bearing and journal parts. Cleaning and Maintenance: Regularly remove impurities such as oil stains, dust, and drilling fluid on the surface of the sheave. Disassemble and clean the sheave at regular intervals, clean the internal oil stains and impurities, dry it, and then reassemble it and add lubricating grease. Regular Detection and Calibration: Use professional measuring tools to regularly measure the dimensions of the sheave rope groove and hub, monitor the wear situation, and replace the sheave in time when the wear amount reaches the limit standard. Regularly calibrate the crown block and traveling block sheave block to ensure that all sheaves are in the same plane and that the levelness and perpendicularity of the sheaves meet the requirements.