1. Drilling rig power system

Power is the energy required to start an engine. Drilling rig power system provides required power for drilling by internal combustion engines that use diesel fuel. The use of gas fuel engines is also becoming popular. Number of required engines depends on the depth of the well being drilled.

The power generated by mechanical and electrical actuators is transmitted to the components of the rig. In mechanical rigs, power is transmitted to the rig components by a set of belts, chains, and wheels. The drilling rig power system in most drilling rigs for deep and semi-deep wells is electric. This is because maintenance and installation of these types of rigs is easier than mechanical rigs.

2. Hoisting system in drilling rig

Drilling rig systems, with the help of a hosting System, guide the drill pipe string into or out of the well. The Hosting System is also responsible for piping the well. The hosting system includes Substructure rig (steel structure), drilling draw works (sometimes called hoist), Crown Block, Traveling Block, hook and drilling cable. The hosting system includes substructure rig (steel structure), drilling draw works (sometimes called hoist), Crown Block, Traveling Block, hook and drilling cable.

Substructure provides the necessary support for the rig and rotary table structure. Therefore substructure and rotary table can withstand the load applied by the drill pipe string either when suspended in the well or when it is placed on the rig structure. In addition, the height of the substructure is adjusted to provide space under the drilling rig for large blow out valves. Drilling draw works, drilling control panels, doghouse and other equipment are located at the bottom of the drilling rig. These equipments are located at suitable distance from the ground due to the height of the Substructure).

Draw works in the drilling rig systems are also called hoists. Drilling draw works is a very large winch that twists the drill wire to move the drill pipe and drill string up or down.

Drilling cable, called a cable or wire rope, is made by twisting several steel wires. This cable is designed to withstand heavy loads in the drilling rig. Drilling wire or cable must be wrapped around a Draw works on the rig, so stringing-up is required.

3. Rotary system in drilling rig

The rotary system, as an important part of the drilling system, is responsible for rotating the drill pipe and drill bit.The rotary system includes:

  1. Drilling mud pumps

  2. Rotating hose pipe

  3. Rotary Hose

  4. Drill pipe string

  5. Drill

  6. Drilling mud return path

  7. Drilling mud tanks

4. Recirculation system in drilling rigs

Recirculation system circulates the drilling fluid to the drill and then transfer it to the ground for treatment and reuse. For rotary drilling, the fluid must circulate downward through the drill pipe string around the drill and then flow upward through the annular space between the drill pipe string and the well wall. Drilling mud after passing through the drill pipe string, comes out of the drill nozzles and moves from the annular space to the wellhead.

The recirculation system uses the following equipment to circulate, purify, and recirculate the fluid:

  1. Drilling mud pumps

  2. Rotating hose pipe

  3. Rotary Hose

  4. Drill pipe string

  5. Drill

  6. Drilling mud return path

  7. Drilling mud tanks

If the recycling system uses air or gas to circulate the fluid, the compressor must also be added to the above equipment. The main purpose of using the mud circulation system is:

  1. Cleaning the bottom of the well

  2. Cooling and lubrication of the drill and drill pipe string

  3. Preventing lost circulation in drilling fluids

  4. Preventing fluid ingress In the formations into the well and its eruption.

  5. Remove drilling cuttings from the well

The drilling fluid is usually liquid and sometimes it can be air or gas. Most of the liquid fluid is water with oil (usually diesel fuel). Drilling mud pump is one of the most essential components of a fluid circulation system. The pump pressure pushes the fluid from the fluid chamber through the drill pipe string to the drill and the depth of the well. It then returns to the pit through the empty space between the well wall and the drill pipe string.

5. Control system

Well control system is used to prevent eruptions. Well eruption is the uncontrolled flow of gas, oil or other fluids in the well into the space outside the well or underground layers. This condition occurs when the pressure inside the formation is greater than the pressure applied to it by the drilling mud. A well eruption can destroy a drilling rig, waste oil, and possibly damage the environment. Fluid (oil, gas or salt water) erupts at very high pressure from the wellhead. The fluid coming out of the well often ignites, especially in cases where the fluid contains gas, and becomes a roaring fire. Well control equipment includes the following components: B.O.P., Accumulators, Chokes, Choke Manifolds. The drilling rig system uses the following equipment in the control section: B.O.P., Accumulators, Chokes, Choke Manifolds.

6. Additional equipment

In addition to the main equipment of drilling rig system, other additional is required. Power, lifting, rotating, recycling and well control systems have additional equipment that is added to the main equipment and prepares the drilling rig for drilling operations. The number and type of this additional equipment depends on the type of drilling rig. In addition to these effects, other factors such as land conditions, weather, distance from service centers and transportation should also be considered.

7. Electric generators

To start the operation of modern drilling rigs, AC generators are used, which mostly work with the help of diesel fuels or natural gas. This motor-generator set is used to generate the required power of drilling catapults, rotary tables and drilling mud pumps. In addition to the above, the energy produced by this system is used to set up the rig, shale shaker motors, mud pit agitators, centrifugal pumps, engine cooling fans and other ventilation systems.

Most of these generators are capable of generating 50 to 350 kW of energy. In some cases, larger units with more power are also used. In general, one of these generators is responsible for generating the required power of a drilling rig without considering the energy required for the Hosting system, rotary and pumping. The second unit of the generator motor system is used as the first set of storage. The second unit of the generator motor system is used as reserve the first set of storage.

8. Air compressors

In mechanical rigs a small compressor producing compressed air, provides the required air for clutches and pneumatic controls. The compressor has a tank to store compressed air. Diesel-electric drilling rigs are rigs that supply their required power through diesel engines that drive electric generators. In these rigs, an electric compressor is used to produce compressed air with a pressure of 650 to 1000 kPa. Compressed air is used to start pneumatic controls, start main engines, pneumatic elevators, air pumps on the BOP unit and etc.

9. Drilling instrumentation system

The instrumentation system is the key part of a drilling rig system. Drilling instrumentation system measures the weight of the drill pipe string, drilling mud level, pump pressure, rotational speed and other variables are measured.

Significance of Drilling Fluid in Rig Operations

Drilling fluid, also known as drilling mud, is an integral component of the drilling process, playing multiple crucial roles. It serves as a coolant and lubricant for the drill bit and drill string, preventing overheating and reducing friction during drilling operations. Additionally, the drilling fluid helps in maintaining wellbore stability by exerting hydrostatic pressure to counterbalance formation pressure, thereby preventing blowouts and well collapses. Moreover, drilling fluid carries drill cuttings to the surface, facilitating their removal from the wellbore, which is essential for maintaining drilling efficiency and preventing equipment damage. Overall, the careful selection and management of drilling fluid are essential for ensuring smooth and safe drilling operations, underscoring its importance alongside other critical components of drilling rig systems.


Due to the high cost of maintenance and operation of drilling rig systems, the best possible type of equipment should be used. This can only be achieved by employing a skilled, experienced workforce familiar with the drilling equipment so that they can, prevent possible damages during drilling operation. Also, using up-to-date and safe equipment, in addition to reducing the operation risks associated with the work, also significantly reduces the costs of equipment failure. Safety, skilled labor and up-to-date equipment are therefore the most important issues regarding drilling rig systems and equipment.