Although the use of drilling fluids within the HDD / trenchless industry is still relatively new, recent trends suggest that this standard is shifting as solids control is one of the most important phases in the drilling process. This shift is due to a growing awareness that drilling fluid maintenance and disposal can become exponential problems as they are both harmful to the environment and extremely costly. With the correct solids control system, fluid life can be doubled, if not tripled. Since whole mud dumping and dilution are unacceptable from both a cost and environmental standpoint, effective solids control equipment has become an increasingly important aspect in any drilling process.
Often good solids control practices are ignored simply because they are not understood. Typically, an HDD solids control system will employ a combination of shaker, hydrocyclone, mixing, pump, and compartmentalized tank technologies. The shaker is vital to the solids control system and is considered the first line of defense. Shakers are considered the “first line of defense” in a solids control system. Shakers act by removing solids from drilling fluid as the mud passes over the surface of a vibrating screen. Particles smaller than the openings in the screen pass through the holes of the screen along with the liquid phase of the mud. Particles too large to pass through the screen are thereby separated from the mud for disposal. Without proper screening of the drilling fluid during this initial removal step, downstream equipment will experience reduced efficiency and effectiveness. The downstream hydrocyclones and/or centrifuges (if elected) will simply be overloaded beyond their design capacity.