HDD Mud Recycling System for Israel Directional Drilling

An Israeli horizontal directional drilling contractor needed a closed-loop mud treatment system for their job site. The site operates on 230/400V, 50Hz power and ExdIIBt4 explosion-proof electrical equipment. The existing setup used a single shaker with no downstream separation. It removed coarse cuttings, but finer solids continued to circulate with the drilling fluid.

As fine solids accumulated, mud density and viscosity became harder to control, particularly in abrasive formations.

TR Solids Control built a three-stage HDD mud recycling system around a single integrated mud tank. The HDD system was assembled and tested in working condition at TR factory before disassembly and shipment. 

System Overview

All processing equipment is installed on a 6000 × 2000 × 1800 mm mud tank. The tank uses 8 mm base plates and 6 mm side walls on a 200mm I-beam frame with 100 mm square tube top framing. The compact layout was required to simplify transportation and fit the available space at the Israeli HDD site.

Solids Control System Design

Each stage was sized with more capacity than the one after it. The TRZS584 shaker handles 136 m³/h, the cleaner 120 m³/h, and each centrifugal pump 112 m³/h.  In HDD operations, return flow spikes during reaming passes when the borehole diameter increases. If the primary shaker is the tightest point in the system, it overflows and sends untreated mud downstream. Sizing each stage larger than the next gives the system room to absorb those peaks.

The TRZS584 and TRZS583 use MI SWACO Mongoose-compatible screens. The same screen type can therefore be stocked for both shakers. The supplied screens included 60-, 80-, and 120-mesh options, allowing the operator to adjust screening according to drilling conditions.

The two centrifugal pumps are connected in parallel with isolation valves. The centrifugal pumps operate in duty/standby configuration. If the duty pump requires maintenance, the standby unit can be brought into service without changing the cyclone feed arrangement.

Each pump provides 37 m head, covering the pressure required by the hydrocyclone circuit while allowing for piping losses.

The TRJBQ7.5 agitator runs at 75 r/min with two 650 mm impellers. This speed provides solids suspension and tank circulation while limiting excessive shear on polymer-based HDD drilling fluids.

Separation Process

During HDD operation, drilling fluid follows a continuous recycling path:

HDD return mud

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TRZS584 shale shaker

Coarse drilled cuttings are removed

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TRQJ200×2S-100×8N mud cleaner

2 × 8" desander hydrocyclones

8 × 4" desilter hydrocyclones

↓

TRZS583 underflow shaker

Screens cyclone underflow solids

↓

Mud tank

Treated mud is kept in suspension by the TRJBQ7.5 agitator

↓

TRSB5×4-12J centrifugal pump

Feeds the hydrocyclone circuit

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Treated drilling fluid returns to the HDD operation

The shale shaker handles the coarse solids fraction, while the hydrocyclones provide finer separation. The 8-inch desander cones are designed for a nominal separation point of approximately 44 μm, while the 4-inch desilter cones target approximately 15 μm, depending on feed pressure and drilling fluid properties.

Factory Assembly and Acceptance

The customer required the system to arrive with the equipment layout already established. No field layout or major equipment assembly was required.

The system was assembled at TR's factory in its final working configuration before shipment. The shaker, mud cleaner, underflow shaker, centrifugal pumps, agitator, control panel and explosion-proof lighting were installed and wired as they would be at site.

Inspection covered the mechanical interfaces, electrical system, piping, and equipment operation.

Mechanical checks included mounting points, bolt connections, flange alignment, and piping installation. The electrical system was energized at 230/400 V, 50 Hz. Motor rotation and current draw were checked, and the Ex d IIB T4 documentation for the electrical components was verified.

The shaker was run without load to verify its linear motion, 7.1 G vibration intensity, and 7 mm peak-to-peak amplitude. The hydrocyclone feed circuit was checked at 0.25–0.4 MPa for leakage. Valve positions, tri-clamp couplings, and expansion joints were also checked for correct installation and access.

The customer inspected the assembled system and completed the factory acceptance before shipment.

After approval, the system was disassembled for export. Connection points, pipe joints, and cable connections were marked with reference numbers to guide site reassembly. The main equipment was shipped as bare-loaded units, while spare parts were packed in export wooden cases.

Spare Parts of HDD Mud System

The spare parts package covers the main wear and maintenance items for the shakers, centrifugal pumps, hydrocyclones, and piping. The package included replacement shaker springs, seal frames, screens, pump bearings and seals, hydrocyclone cones, tri-clamp couplings, expansion joints, and butterfly valves. Spare parts were packed separately in export wooden cases for transport.

Project Value

Compared with the previous single-shaker setup, the new arrangement adds secondary and fine-solids separation through the mud cleaner. Coarse solids are removed by the shale shaker, while the desander and desilter target the finer fraction.

This helps limit fine-solids buildup in the active mud system and maintain more stable mud density and viscosity during HDD operations. It can also reduce fluid replacement and disposal compared with primary shaker separation alone.

TR Solids Control has supplied mud solisd control systems and solids control equipment to projects in Romania, the UAE, Nigeria, Indonesia, India, Argentina, and Israel.

TR Solids Control supplies complete HDD mud recycling systems as well as individual solids control equipment for directional drilling projects.