How the Double-Layers Shale Shaker be used in mud recycling system?

In drilling engineering, pile foundation construction, and tunnel boring, drilling mud plays a crucial role in cooling the drill bit, carrying cuttings, and stabilizing the wellbore. A mud recycling system separates solid particles from the mud, enabling its recycling. A double-layer shale shaker uses two layers of screens with different mesh sizes to classify and separate solid particles in drilling mud, significantly improving mud utilization, reducing drilling costs, and minimizing environmental pollution. The following section, based on the product characteristics of TR Solids Control's double-layer shale shaker, details its application in mud recycling systems.

I. Application and Positioning of Double-Layer shale shaker

During drilling, the solid particles (rock cuttings, sand) carried by the drilling mud can be classified into large particles (>74μm), medium particles (45-74μm), and fine particles (<45μm)  according to their particle size. A single-layer shale shaker can only achieve a single level of screening, while a double-layer shale shaker, through a combination design of "coarse screening + fine screening," solves three core requirements:

1. The tiered purification process involves an upper screen separating large rock fragments (to prevent clogging of subsequent centrifuges and desanders) and a lower screen filtering out medium-sized solid particles, allowing the mud to initially meet recyclability standards.

2. Protecting downstream equipment: If slurry containing large particles is directly allowed into the desander, desilter, or centrifuge, it will cause impeller wear and pipeline blockage. The double-layer shale shaker can intercept more than 80% of the harmful solid phase in advance.

3. Improved mud performance: After removing excess solids, the mud's viscosity, shear stress, and water loss are more stable, effectively cooling the drill bit, lubricating the drill string, stabilizing the wellbore, and improving drilling efficiency.

II. Installation and Work Process of the Mud Recovery System

1. System installation location

   The double-layer shale shaker is installed at the front end of the mud recovery system. Upstream, it connects to the mud return pipeline at the wellhead, and downstream, it connects to the feed inlet of the desander and desilter, forming a closed loop of "wellhead mud return → double-layer shale shaker → desander → desilter → centrifuge → mud tank → drilling pump".

2. Workflow (grading and screening + mud recovery)

   (1) Mud introduction: Distribute the mud evenly to avoid local overload of the screen.

   The sand-containing mud returned from drilling enters the feed box of the shale shaker through the guide pipe. TR Solid Control's double-layer shale shaker is equipped with an "eight-shaped diversion plate" which can evenly distribute the mud to the entire screen surface and prevent local mud accumulation from causing incomplete screening.

   The feed pressure needs to be controlled between 0.1-0.3MPa (which can be achieved by adjusting the feed valve) to avoid high pressure impacting the screen and extend the screen's service life.

   (2) Double-layer grading screening: coarse screening removes large particles and fine screening removes medium particles, which are completed simultaneously.

   Upper screen (coarse screen): A wear-resistant polyurethane screen with a mesh size of 10-40 (0.45-2.0mm) is selected. It mainly separates large rock fragments with a particle size >74μm. The separated rock fragments are discharged through the slag discharge port at the end of the screen and can be directly collected or transported for processing.

   Lower screen (fine screen): Use 60-120 mesh (0.12-0.25mm aperture) stainless steel woven screen or polyurethane screen to filter medium particle solid phase with a particle size of 45-74μm. At this time, the "purified mud" (containing fine particle solid phase) after double-layer screening flows out from the collection tank below the screen.

   Key technology: TR Solid Control adopts "dual-motor self-synchronous vibration technology" with a vibration frequency of 50-60Hz and an amplitude of 3-6mm. Through the reciprocating vibration of the inclined screen surface (inclination angle of 15-20°), it ensures that the mud stays on the screen surface for ≥3 seconds and the screening efficiency reaches over 95%.

   (3) Mud diversion and purification

   The qualified mud after double-layer screening is introduced into the mud recovery tank through the collection tank, and then pumped to the desander and desilter to further remove fine particulate solid phase.

   If the solid content of the mud is still too high, a centrifuge can be connected for further purification to ultimately form "regenerated mud that meets drilling requirements" which can then be pumped back into the wellhead for recycling.

   (4) Solid emissions and environmental protection treatment

   Large rock cuttings separated by the upper coarse screen can fall directly into the cuttings box for recycling (some can be used for well site paving).

   The fine sand separated by the lower fine screen is collected through a dedicated sand discharge channel, dried, and then transported to a designated environmental protection treatment point to avoid polluting the soil or water source.

III. Key Technical Points of Double-Layer shale shaker

1. Screen selection: Match the double-layer mesh size according to drilling conditions.

   
   

   Drilling scene	Upper sieve mesh size (coarse sieve)	Lower layer screen mesh size (fine screen)	separation effect
   Surface drilling (large cuttings particle size)	10-20 mesh	60-80 mesh	Separate large rock fragments >100μm, retain medium and fine mud.
   Intermediate well section (conventional operating conditions)	20-40 mesh	80-100 mesh	Separate solid phases >74μm, mud solids content ≤15%.
   Deep well / Horizontal well	40 mesh	100-120 mesh	Separating solid phases >45μm, the slurry can be directly fed into a centrifuge.

   
   

   TR Solids Control Screen Advantages: It adopts "polyurethane wear-resistant screen + stainless steel frame", which has a service life of 3 times that of ordinary screens and supports quick replacement, and is suitable for different drilling mud types (water-based, oil-based, synthetic-based).

   
   

2. Vibration parameter adjustment: optimized based on mud viscosity

   Vibration frequency: For high-viscosity mud (such as oil-based mud), the frequency should be adjusted to 55-60Hz to enhance the penetration of the screen surface; for low-viscosity water-based mud, the frequency can be adjusted to 50-55Hz to prevent the mud from flowing away too quickly.

   Amplitude adjustment: When the solid content is high, adjust to 4-6mm to improve slag discharge efficiency; when the solid content is low, adjust to 3-4mm to protect the screen.

   Screen inclination angle: The inclination angle is controlled between 15-20° by adjusting the height of the support. Too large an inclination angle will easily lead to mud loss, while too small an inclination angle will result in poor slag discharge.

3. System Integration: Key Points for Coordination with Other Fixed Equipment

   Start-up sequence: First turn on the double-layer shale shaker → then turn on the Desander → Desilter → centrifuge, to avoid downstream equipment running idle or overloaded;

   Shutdown sequence: Reverse operation, first stop the centrifuge → desilter → desander → finally stop the double-layer shale shaker to ensure that the mud in the system is emptied;

   Pressure linkage: If the feed pressure of the shale shaker suddenly increases, it is necessary to immediately check whether the screen is blocked or whether the amount of slurry returning from the wellhead exceeds the standard to avoid equipment damage.

4. Routine maintenance: Extends service life + ensures screening efficiency

   Regular inspections: Check if the screen is damaged, if the tension is sufficient (TR Solid Control is equipped with a quick tensioning device), and if the fixing bolts of the vibration motor are loose;

   Regular cleaning: Use a high-pressure water gun to rinse the screen during working breaks to prevent solid particles from clogging the screen holes;

   Replacement of vulnerable parts: Vulnerable parts such as shaker screens, vibrating motor bearings, and shock absorber springs should be stocked regularly and replaced immediately upon discovery of wear to avoid affecting the purification effect.

IV. Application Advantages of TR Solid Control Double-Layer shale shaker

High-efficiency screening: Dual-motor self-synchronization design, with a processing capacity of 80-240m³/h, meeting the mud treatment needs of different drilling depths (vertical wells, horizontal wells, shale gas wells);

Wear-resistant and energy-saving: The screen surface is made of polyurethane wear-resistant material, the motor power is only 3-5.5kW, which saves 30% energy compared with traditional equipment, and the operating noise is<85dB;

Highly adaptable: It can be seamlessly connected with TR solids control desanders, desilters, centrifuges, mud tanks and other equipment, and supports modular combination to meet the mud recovery system configuration of different well sites;

Environmental compliance: Through efficient solid-phase separation, the mud reuse rate is increased to over 90%, reducing drilling waste fluid emissions and meeting environmental standards.

In mud recycling systems, the application of double-layer shale shakers can reduce costs, improve efficiency, and meet oilfield environmental protection requirements. TR Solids Control's double-layer shale shaker, with its "grading and screening + high-efficiency adaptation + wear-resistant and energy-saving" product design, has become the preferred equipment for oilfield mud recovery systems. It can provide customized solutions according to different drilling conditions, helping drilling projects reduce costs, increase efficiency, and achieve green compliance.