Eight systems of drilling rigs and their functions

Drilling rigs are the general term for a series of mechanical equipment that drives the drilling tools to drill into the formation during the oil drilling process, also known as drilling machines. The towering derricks that we often see standing on the ground are only part of the drilling rig. Let's learn about the eight systems of the drilling rig!

Drilling rigs generally have eight systems (lifting system, rotation system, drilling fluid circulation system, transmission system, control system and monitoring display instrument, power drive system, drilling rig base, drilling rig auxiliary equipment system), which must have the ability to lift and lower drilling, rotary drilling, and circulation well washing. Its main equipment includes: derrick, overhead crane, winch, traveling pulley, big hook, turntable, faucet (power faucet) and drilling pump (usually called the eight pieces of drilling rigs on site), power machine (diesel engine, electric motor, gas turbine), linkage machine, solid control equipment, well control equipment, etc.

Lifting system

In order to lift and lower drilling tools, lower casing, control drilling pressure, and feed drilling tools, drilling tools are equipped with a lifting system. The lifting system includes winch, auxiliary brake, crown block, traveling block, hook, wire rope, and various tools such as lifting ring, elevator, tongs, slips, etc. During lifting, the winch drum is wound with wire rope, the crown block and traveling block form a secondary pulley group, and the hook rises to lift the drilling tool through tools such as lifting ring and elevator. During lowering, the drilling tool or casing string descends by its own weight, and the lowering speed of the hook is controlled by the brake mechanism and auxiliary brake of the winch. During normal drilling, the feeding speed of the drilling tool is controlled by the brake mechanism, and part of the weight of the drilling tool is applied to the drill bit as drilling pressure to break the rock formation.

Rotation system

The rotation system is a typical system of a rotary drilling rig. Its function is to drive the drilling tool to rotate to break the rock formation. The rotation system includes a rotary table, a faucet, and a drilling tool. Depending on the well being drilled, the composition of the drilling tool is also different. It generally includes square drill rods, drill pipes, drill collars and drill bits, in addition to centralizers, shock absorbers, and matching joints. The drill bit is a tool for directly crushing rocks, and there are scraper bits, roller bits, diamond bits and other types. The weight and wall thickness of the drill collar are very large, and it is used to apply drilling pressure to the drill bit. The drill pipe connects the ground equipment with the bottom hole equipment and transmits torque. The cross section of the square drill rod is generally square. The turntable drives the entire drill string and drill bit to rotate through the square drill rod. The faucet is a typical component of the rotary drilling rig. It must not only bear the weight of the drill tool, but also realize the rotational motion, and also provide a channel for high-pressure mud.

Circulation system

In order to bring the rock cuttings broken by the bottom hole drill bit to the ground in time for continued drilling, and to cool the drill bit to protect the well wall and prevent drilling accidents such as well collapse and leakage, the rotary drilling rig is equipped with a circulation system. The circulation system includes drilling pumps, ground manifolds, mud tanks, mud purification equipment, etc. Among them, the ground manifold includes high-pressure manifolds, risers, and hoses. The mud purification equipment includes vibrating screens, desanders, desilters, centrifuges, etc.

The drilling pump sucks the mud from the mud tank. The mud pressurized by the drilling pump passes through the high-pressure manifold, riser, and hose, enters the faucet, goes down to the bottom of the well through the hollow drill bit, and sprays out from the water hole of the drill bit. It returns to the ground through the annular space between the wellbore and the drill bit with rock cuttings. The mud returned from the bottom of the well passes through various levels of mud purification equipment to remove the solid content and then reuse it.

Power equipment

The lifting system, circulation system, and rotation system are the three major working units of the drilling rig. They can complete the drilling operation by coordinating their work. In order to provide power to these working units, the drilling rig needs to be equipped with power equipment. The power equipment of the dth drilling rig includes diesel engines, AC motors, and DC motors. Diesel engines are suitable for drilling wells in remote areas without power grids. AC motors rely on industrial power grids or require diesel engines to generate AC power. DC motors require diesel engines to drive DC generators to generate DC power. At present, the more common situation is that diesel engines drive AC generators to generate AC power, and then thyristor rectification is used to convert AC power into DC power.

Transmission system

The transmission system transforms the force and motion provided by the power equipment, and then transmits and distributes it to each working unit to meet the different power requirements of each working unit. The transmission system generally includes a reduction mechanism, a speed change mechanism, a forward and reverse mechanism, and a parallel mechanism between multiple power machines. Drilling rigs directly driven by diesel engines mostly adopt a unified drive form, and the transmission system is relatively complex. Drilling rigs driven by AC and DC motors mostly adopt the form of individual or group drive of each unit, and the transmission system has been greatly simplified.

Control system

In order to ensure the coordinated work of the three major working units of the drilling rig to meet the requirements of the drilling process, the drilling rig is equipped with a control system. The control methods include mechanical control, gas control, electric control and hydraulic control. At present, the commonly used control method on the drilling rig is centralized gas control. The driller can complete almost all drilling rig controls through the driller console on the drilling rig: such as the clutch of the total clutch; the paralleling of each power machine; the start and stop of the winch, turntable and drilling pump; the high and low speed control of the winch, etc.

Derrick and base

The derrick and base are used to support and install various drilling equipment and tools and provide a place for drilling operations. The derrick is used to install the overhead crane, the traveling block, the big hook, the faucet and the drilling tools, bear the drilling load, and discharge the stand; the base is used to install the power unit, the winch, the turntable, and the support derrick. The turntable is used to suspend the drilling tools and provide a height space between the turntable and the ground to install the necessary blowout preventer and facilitate mud circulation.

Auxiliary equipment

In order to ensure the safety and normal progress of drilling, the drilling rig also includes other auxiliary equipment, such as the blowout preventer group, the generator set that provides lighting and auxiliary electricity for drilling, the air compression equipment that provides compressed air, and the water and oil supply equipment.