Bentonite tunnelling products , filtration additives, stabilizers and lubricants for tunnel drilling
Micro tunneling is a digging technique used to construct small tunnels, varying from 600 mm up to 4000 mm. Cebo offers proven CEBOGEL® solutions to ensure successful tunneling operations.
As the length of a tunnel increases, the friction of the ground around the pipe increases as well. To minimize this friction, firstly, over-cutting is used to create a slight annular between the inner edge of the tunnel and the outer edge of the liner. A well formulated Bentonite-based lubrication fluid is injected into the annular to decrease the friction and stabilize the formation.
In some occasions, it is necessary to utilize a Bentonite-based stabilization fluid in front of the cutter wheel to stabilize the formation until the lubrication fluid is injected into the created annular.
Bentonite Microtunneling Products
Bentonite tunneling products are used as a primary drilling fluid in tunnelling operations due to their excellent suspension, filtration, and lubrication properties. They also help to cool and clean the drilling bit, reduce friction, and prevent the entry of water or other fluids into the borehole.
TUNNEL-GEL® PLUS is a high-yield Bentonite, defined by its increased polymer volume, and is used predominantly as a viscosifier. TUNNEL-GEL PLUS promotes rapid viscosity development and subsequent high gel strength, allowing for effective suspension and transportation of drilled solids.
TUNNEL-GEL PLUS is ideal for conventional drilling operations, enhancing filtration control and maintaining borehole stability throughout.
Microtunneling Filtration Control Additives
Tunneling Filtration Control Additives help to prevent the loss of drilling fluid into the formation, which can cause borehole instability, reduce drilling performance, and affect the quality of the tunnel walls. The use of effective filtration control additives can minimize the risks associated with fluid loss and help maintain a stable drilling environment, which is critical for safe and efficient tunnelling operations.
QUIK-TROL® is an additive that provides filtration control in most water-based drilling fluids.
Specialist Microtunneling Additives
Sodium Bicarbonate (NaHCO₃) is a white crystalline powder, used as an additive to precipitate Calcium.
The product is commonly introduced to Diaphragm & Slurry Wall operations after cementing or when cement contamination occurs, where it will effectively decrease pH and Calcium ions content.
Microtunneling Clay/Shale Stabilizers
Tunneling Clay/Shale Stabilizers maintain the structural stability of the surrounding ground and prevent collapse during excavation, ensuring worker safety and minimizing project delays and costs. These stabilizers also improve the strength and durability of tunnel walls.
EZ MUD® is a polymer emulsion, primarily used as a borehole stabilizer to prevent reactive shale and clay from swelling and sloughing.
Tunneling Lost Circulation Materials
Cebo F-SEAL is an acid-soluble, fibrous lost circulation material, composed of synthetic resin-bound stone wool. Cebo F-SEAL is used as an additive for preventing and resolving loss of circulation in concentrations of up to 20 kg/m³.
The product’s fibrous composition builds a structure against high-permeable formations on which a Bentonite fluid can create a filter cake; this effectively prevents drilling fluids from seeping into the surrounding formation. Cebo F-SEAL is an inorganic, non-fermenting product and can be easily mixed.
Microtunneling Lubricants
The use of lubricants in tunnelling operations is crucial for reducing friction and wear on the tunnel boring machine and other equipment, increasing efficiency and speed while minimizing energy consumption. Proper lubrication also promotes the longevity and reliability of equipment, reducing maintenance costs and downtime.
Cebo Tunnel-Lube is a torque reducer that helps to provide friction reduction and improve lubrication characteristics of water-based drilling fluids.