Relative to the use of drilling fluids within the oil and gas industry, the use of drilling fluids within the horizontal directional drilling (HDD) industry is new. Even today, the amount of research and development aimed at HDD drilling fluids is considered a rounding error in the oligopoly of drilling fluid manufacturers. However, the trends strongly suggest that the future of HDD drilling will follow a similar evolution as experienced by the traditional oil and gas industry.
Couple the evolution of drilling fluids with the escalating cost of waste management and disposal, the economic practicality of utilizing drilling fluids, is fully dependent on the ability to recover and recycle. Though the cost of barite and bentonite continue to be commoditized, additives continue to become more and more expensive. Add the escalating cost of qualified personnel, HDD rig operators are left with a critical challenge: making profits, when the cost of business is increasing.
In addressing the economics of drilling fluids, HDD rig operators must clearly understand the basic operating principals behind the available recycling processes. The following provides for a practical understanding of the key principles behind HDD solids control and drilling fluid management. With that said, the following discussion should not be considered exhaustive. Ultimately, the manufacturer of the drilling fluid and the solid control and waste management equipment should be consulted.
When deploying a “solids control system,” there are several key hydraulic design factors that must be considered. These factors simply provide a “hydraulically balanced” solids control system, however, buyers of solids control systems should not overlook the durability, dependability and return on investment that the features and benefits bring.
A typical 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. Located directly downstream from the shaker will likely be a hydrocyclone assembly that will employ desilters, desanders or both. Though still considered rare, centrifuge-enable solids control systems are becoming more popular. By adding a centrifuge, the solids control system will achieve the highest level of cut available within the market today.