What are Solids Control Equipment For Oilfields?

In oilfield drilling operations, a series of solid control equipment is essential to ensure smooth and efficient processes.  The solid control system utilizes physical methods to remove solid particles from drilling mud, thereby maintaining the performance of drilling mud, reducing the occurrence of drilling accidents, effectively saving drilling costs, and maximizing economic benefits.

Oilfields Solids Control Equipment refers to key equipment used in drilling operations to separate and remove solid particles and gases from drilling mud.  Common solid control equipment includes shale shakers, mud tanks, agitators, decanter centrifuges, vacuum degassers, mud cleaners, hydrocyclone desanders, and desilters.  These equipment can effectively reduce waste generated from drilling mud.  The treated mud becomes clean and recyclable, minimizing environmental pollution and lowering project costs.

All equipment that helps remove solid waste is referred to as solid control equipment.  Among them, the shale shaker is indispensable, operating through vibration.  When drilling mud flows through shale shaker, the screen collects the liquid part and smaller solid components.  This process can remove up to 80% of solid particles from the drilling mud.  The mud tank provides settling space for large particles in the fluid, allowing them to settle to bottom.  The vacuum degasser can help remove trapped gas molecules, restoring the mud to usable state. Hydrocyclones, namely desanders or desilters, mainly function to convert the pressure generated by centrifugal pump into centrifugal force.  This helps separate suspended solids from the liquid in drilling mud.

Another important piece of equipment is mud cleaner.  The mud cleaner is combination of shale shaker and desander/desilter.  The mud cleaner has both cleaning and sand/mud removal functions.  There is also type of solid control equipment called decanter centrifuge, which can help remove heavy solids and can also be used to remove light components by utilizing centrifugal force.  This equipment is equipped with dual-screw conveyor that helps change the conveying direction of materials during operation.  

There is wide variety of solid control equipment, each with its unique advantages and characteristics.  In actual oilfield drilling operations, the solid control system is usually composed of multi-stage equipment working together to form complete purification process.

Shale Shaker

When drilling mud flows onto shale shaker, drill cuttings are discharged from the bottom of the shaker.  It achieves solid-liquid separation through high-frequency shaker screen, focusing on separating larger solid particles with particle size greater than 74μm from the drilling mud.  Shale shakers can be divided into two types: translational elliptical motion shale shakers and linear motion shale shakers.

Hydrocyclone

Desander：Separates solid phases with particle size >40μm.  The desander is used at the wellhead to help reduce mud density.

Desilter：Separates solid phases with particle size of 15-40μm and adopts conical structure.

The centrifugal pump injects drilling mud into hydrocyclone at high speed, causing the fluid to produce intense rotational motion.  Under the action of centrifugal force, media with different densities are separated.  According to the separation particle size, it can be divided into sand removal hydrocyclones (separating particles of 20-74μm) and mud removal hydrocyclones (separating particles of 2-20μm).  It can flexibly adapt to different grading requirements of the solid control process and is often used in conjunction with equipment such as shale shakers and centrifuges to form multi-stage purification system.

Centrifuge

Separates ultra-fine solid phases (such as clay) with particle size of 2-10μm to further purify the drilling mud.

The centrifuge is deep purification equipment.  Driven by motor, the drum rotates at high speed to generate strong centrifugal force.  Utilizing the density difference between solid particles and drilling mud, it completely separates tiny solid particles as fine as 2-20μm from the drilling mud.  It has high separation efficiency and large processing capacity, which can greatly improve the cleanliness of the drilling mud.  It is one of the core equipment to ensure the long-term stable performance of the drilling mud and meet the drilling needs of deep wells and complex wells.

Vacuum Degasser

Removes gases entrained in the drilling mud (such as natural gas and air) to prevent a decrease in drilling mud density caused by gas invasion.

Negative pressure is formed through suction by vacuum pump, allowing gas to separate from the liquid phase and be discharged. If the gas entrained in the drilling mud is not removed in time, it will lead to decrease in drilling mud density, abnormal viscosity, and increase safety risks such as well kick and blowout. Therefore, the vacuum degasser can effectively avoid the interference of gas on the performance of the drilling mud and ensure the safe and stable drilling process.

Agitator

Maintains the uniformity of drilling mud, prevents solid phase settlement, and ensures the continuous and stable operation of solid control equipment.

It is usually installed in containers such as mud tanks and circulation tanks. Driven by motor, the stirring paddle rotates at high speed to keep the drilling mud in uniform mixed state. Its function is to prevent the separated solid particles from settling and accumulating at the bottom of the tank again, and at the same time ensure that the chemical additives in the drilling mud are evenly dispersed, avoiding performance fluctuations caused by local concentration imbalance, and providing stable drilling mud medium for subsequent drilling operations.

Mud Cleaner

Combines hydrocyclone and shale shaker to form two-stage purification system.

The mud cleaner is integrated high-efficiency solid control equipment that integrates multiple units such as hydrocyclone, shale shaker, and slurry storage tank, and can realize the synergistic effect of "graded purification + secondary filtration". The drilling mud is first initially separated from fine particles by the hydrocyclone, and then further filtered by the built-in shale shaker, which does not require the series connection of multiple independent equipment, improves purification efficiency, and reduces equipment floor space. It is suitable for drilling scenarios with high requirements for purification effect and operation efficiency.

Settling Tank

Also known as sedimentation tank, it uses the principle of gravity sedimentation to allow fine solid particles still suspended in the drilling mud after treatment by the shale shaker to settle slowly in the tank and finally accumulate at bottom to achieve separation. To improve the sedimentation effect, the tank is usually equipped with guide plates, buffer devices and other structures to reduce the interference of drilling mud flow on the sedimentation process and further improve the purification accuracy of the drilling mud.

Mud Tank

The mud tank is used to store, mix and circulate drilling mud, and is equipped with monitoring equipment such as liquid level sensors and flow meters. According to different uses, mud tanks can be divided into overflow tanks, circulation tanks, weighting tanks, mixing tanks, storage tanks, etc., to meet different operation needs.

Auxiliary Equipment in Solid Control System

In addition to the above equipment, the solid control system is also equipped with some auxiliary equipment, such as centrifugal pumps, jet mixing devices, mud shear pumps, dryers, mud guns, pipelines, etc. The entire system can meet different mud treatment situations during drilling operations.

By rational configuration of solid control equipment, drilling mud performance can be significantly improved, accidents such as stuck pipe and lost circulation can be reduced, and at the same time, drilling costs (such as drilling mud supplement costs and waste disposal costs) can be reduced, and environmental impact can be minimized, realizing safe, efficient and green drilling operations.

TR Solid Control is manufacturer of oilfield solid control equipment.  Our solid control equipment is used in natural gas drilling mud purification systems, construction mud treatment systems, and trenchless mud recycling systems.  Please feel free to contact us for inquiries; we will provide you with one-stop service.