As an auxiliary device for cleaning mud tanks, the mud gun plays an irreplaceable role in the solids control system. Also known as a drilling fluid gun or mud tank cleaning gun, the mud gun is specialized equipment designed to prevent mud sedimentation in mud tanks. It can flush and agitate dead corners that mud tank agitators cannot reach, preventing mud from settling and enabling 360-degree cleaning inside the tank. This ensures the removal of residual materials, maintains tank cleanliness, and extends the service life of the tank.
Power Source of Mud Guns
Mud guns can be powered by the discharge branch of a drilling pump or a centrifugal sand pump, eliminating the need for a dedicated power source. Typically, the power source for a mud gun can be either a mud pump or a jet mixing device.
Types of Mud Guns
Mud guns can be classified based on pressure into low-pressure, medium-pressure, and high-pressure mud guns. Based on their structure, they are divided into fixed mud guns and rotary mud guns.
- Fixed Mud Guns: These are commonly used in solids control systems for drilling tanks abroad. Fixed mud guns are installed at two diagonal corners approximately 200 mm from the tank bottom, with nozzles parallel to the longitudinal tank wall, creating a rotational flow of the drilling fluid layer. For example, the solids control system of the American IDEAL drilling rig uses fixed mud guns.
- Rotary Mud Guns: These are further divided into manually adjustable and self-rotating types. Manually adjustable mud guns include swinging and rotating types. Rotary mud guns are fixed at the top of the drilling fluid tank, with the gun barrel extending into the tank and nozzles positioned 200–300 mm from the tank bottom. The rotation of the mud gun creates a rotational flow of the drilling fluid layer for agitation. In China, manually adjustable rotary mud guns are predominantly used.
Working Principle Judd of Mud Guns
The working principle of a mud gun is similar to that of a high-pressure water gun. The clean water pipeline inside the tank is connected to the mud gun. When the valve is opened, water is sprayed from the three nozzles of the mud gun under pressure, forming an umbrella-shaped spray that covers the tank walls and dead corners.
Selection of Mud Guns
Selecting the appropriate mud gun requires understanding its specifications and model. Mud guns generate high-speed flow through a nozzle to agitate drilling fluid. Since most systems use low-pressure mud guns, the following factors must be considered for proper operation:
- Size and type of the nozzle.
- Number of elbows, tees, valves, and reducers.
- Length of the pipeline.
- Size of the pipeline.
These parameters are critical, and their impact must be determined before selecting a pump. In most systems, the fluid loses most of the total dynamic head provided by the pump as it passes through the nozzle. Additionally, the pipeline length, pipe diameter, and fittings must be compatible with the pump and motor. To achieve the desired flow rate through the nozzle, a specific total dynamic head is required to overcome system friction. The longer the pipeline, the more fittings, and the smaller the pipe diameter, the greater the required total dynamic head. General guidelines include:
- Fluid velocity should be maintained between 5 ft/s (to avoid solid sedimentation) and 10 ft/s (to prevent excessive pipe erosion), equivalent to 1.5–3 m/s.
- Use as few fittings and joints as possible.
- Keep the pipeline as short as possible.