A drilling fluid system is often discussed in terms of solids control: shale shakers remove drilled cuttings, hydrocyclones separate finer solids, and centrifuges provide further separation. But separation is only part of the process.
The drilling fluid still needs to move continuously between tanks, separation equipment and other treatment stages. When the fluid contains a high concentration of solids, pumping becomes a technical consideration of its own.
Drilling Mud Is More Than a Liquid
Drilling mud is a complex mixture of liquid and solid components. Depending on the drilling formation and treatment stage, it may contain drilled cuttings, sand and other suspended particles.
This changes the conditions under which the pumping equipment operates.
A pump designed primarily for clean liquids may not always be the most appropriate choice when the medium contains a significant amount of solids. The flow passage, impeller configuration and submerged components all need to be considered in relation to the characteristics of the fluid.
This is where slurry pumping becomes relevant to drilling fluid management.
Where Does Slurry Pumping Fit into Solids Control?
The main purpose of solids control equipment is to remove unwanted solids from drilling fluid. However, the fluid must be transferred before, between and after these separation stages.
For example, drilling fluid may need to be pumped:
- From a mud tank to a separation unit
- Between different treatment stages
- From collection areas back into the circulation system
- Together with fluids containing a relatively high concentration of solids
The pump therefore acts as a connection between different parts of the system.
In this context, slurry pumping is not a separate process from solids control. It is part of the fluid-handling infrastructure that allows the overall treatment system to operate continuously.
What Makes High-Solids Pumping Different?
The most important difference is the presence of solid particles in the pumped medium.
Solids can influence flow conditions and may create a greater risk of blockage when the internal flow passage is not suitable for the application. The concentration, size and characteristics of the particles should therefore be considered when selecting pumping equipment.
Pump structure also matters.
For high-solids applications, configurations such as semi-open impellers can provide a more suitable flow passage for particle-containing fluids. The design of submerged components is another consideration, particularly where the pumped medium comes into direct contact with the pump shaft and related components.
Selecting the Right Pump for Drilling Mud
There is no universal pump for every drilling fluid application.
The selection should take into account the characteristics of the drilling mud, including its solids content, particle characteristics and viscosity, together with the required flow and installation conditions.
For applications involving high-solid-content fluids, a pump specifically designed for slurry handling can provide a more appropriate solution than equipment intended primarily for clean-liquid service.
KOSUN LSP Series: An Example of Slurry Pumping Equipment
For oil drilling mud systems, KOSUN’s LSP Series Vertical Slurry Pump is designed to transport fluids containing a high concentration of solid particles.
The pump uses a vertical, single-stage, single-suction cantilever centrifugal configuration with a semi-open impeller. Its pump shaft in the submerged portion has sufficient rigidity, with no bearings installed between the impeller and pump casing and no shaft seal.
The LSP Series is one example of how pump design can be adapted to the requirements of high-solids fluid handling within a drilling fluid system.
Ultimately, effective solids control is not only about separating solids. It also depends on moving the drilling fluid reliably through each stage of the process.