A mud gun is a device used to agitate drilling mud on a drilling rig. More of a nozzle than a gun, a mud gun is connected to a pump to circulate the drilling mud and prevent the solids from settling in the mud tank. The mud is mixed by being sucked into a pipe by a powerful pump and expelled back into the mud tank by being pushed through the nozzle of the mud gun. The process is similar to how a water jet works on a power washer.
Drilling mud is a wet substance that resembles a thick clay and is used to cool the drill head and carry the remnants of drilling to the surface in water well drilling and oil or gas drilling operations. The mud is recycled by passing it through several filters or screens as it is circulated into the drill hole and back into the mud tanks on the drilling rig. In order to keep the mud as fluid as possible, a mud gun is used to keep the tank agitated and mixed. Mud is made by mixing water or oil with a clay-like substance that also contains numerous other chemicals into a large tank called the mud tank on a drilling rig.
The type of mud used when drilling is dependent on the type of drilling that is being done. The mud gun is the same for whatever type of mud is being used. Often made by adding a type of nozzle onto a piece of pipe, the mud gun works much like placing a thumb over the end of a water hose. This applies pressurized mud into the tank, causing it to create a mixing action. Agitating the mixture also aids in the removal of the cuttings from the mixture as it is filtered through the various screens in the tank.
The viscosity of the mud is very critical, with a thin mixture being unable to keep the cuttings from the drill head suspended until they reach the surface and can be screened out of the mixture. A mixture that is too thick can waste profits and can even slow the drilling productivity. Another function of the mud gun is to maintain the suspension of the drilling cuttings so that they can be removed on the first pass through the screens. Cuttings that are not removed on the first pass through the screens can become broken up into smaller pieces that are more difficult to remove from the mixture.