How Do Mud Pumps Work?

As an integral part of onshore and offshore drilling, mud pumps circulate the drilling fluid used to facilitate the drilling of oil and gas wells. Drilling fluids are used to stabilize pressure and support the well during drilling, as well as to reduce friction and remove rock chips.

Drilling fluids have come a long way since the early days of drilling and offshore mud pumps are constantly being taxed to help operators find and develop hydrocarbons in tougher, deeper, and more difficult locations.

Drilling offshore with a mud pump

Depending on the drilling conditions and the type of rock formation encountered by the bit at each depth, drilling fluids consist of a variety of components, including clay, water, oil, and synthetic materials. When drilling offshore, the environmental impact of drilling fluids must be considered more carefully.

The mud pump is one of the keys and essential pieces of equipment on land or offshore drilling rig. Offshore, where real estate is at a premium, mud pumps are equipped with compact top-mounted drive systems, reducing the overall length in a smaller package and strategically placed in the pump room for permanent installation.

 Mud Pump For Drilling Rigs

There are many different situations that can be encountered when drilling offshore. For example, while jack-up rigs focus on waters up to 350 feet deep, drillships and semi-submarines can drill in waters up to 12,000 feet deep.

Both jack-up semi-subs and drillships use the same mud pumps; however, the number of pumps installed in the pump room will vary depending on the drilling specifications.

In addition, the formations and pressures encountered while drilling may vary; HT/HP and environmental conditions may also affect the drilling process, as well as the drilling fluid selected and the mud pump required.

As drilling projects require higher flow rates and higher pressures, it is necessary to increase the pressure rating, either by increasing the number of mud pumps required or by using larger capacity mud pumps. Most early jack-up rigs used two mud pumps and piping systems rated at 5000 psi and 1600 HP working pressure, while most jack-up rigs today have 7500 psi working pressure and up to four 2200 HP pump piping systems.

Hydraulic Mud Pump

How Do Mud Pumps Work?

Mud pumps are integrated into the rig, so they are not usually stand-alone units. The mud pump has a drive motor and is connected to a mixing tank to supply mud as required. The input and output fluid ends of the pump are piped directly to the drill column and borehole annulus. The pump usually has pulsation dampers at both the fluid inlet and outlet ends to eliminate pressure variations in the mud flow.

Mud pumps are usually driven by electric or diesel engines. Diesel engines are best suited to remote areas. The motor is slowed down as most pumps run at around 100 to 200 rpm as the motor usually spins much faster. Most electric pumps use AC motors, but DC motor units are also available. The largest mud pumps are rated at over 2,500 hp.

The drilling fluid or mud is circulated through the fluid end of the pump. It is pumped through the center hole of the drill pipe and through the drill column of its bit. The mud is returned to the surface through the borehole annulus or the space between the shaft and the borehole ID. Deep wells, such as offshore oil rigs, require 7,500 psi to force the mud downwards and backward. These wells can be at the surface and up to 10 miles below the seabed. Drilling mud is usually a water-based viscous slurry of suspended clay-like colloids, but it may vary depending on where it is used or the purpose of the well being drilled. It can also be a fluid mixture based on oil or synthetic fluids. The mud mixture is usually stored in a large mixing tank.