As it is shown that by employing a theoretically enhanced centrifuge (CEC) Treatment for drilling fluids, the volume of fluid can be dramatically reduced. Additional cost savings arise from the elimination of sumps, the reuse of fluid for Multiple production holes and increased penetration rates, while the environmental Impact of fluid systems and fluid waste disposal are brought to a minimum.
Drilling through rock requires a fluid to perform the following functions:
Lubricate the bit
Cool the bit
Carry away cuttings
Stabilize the walls of the hole
Minimize fluid loss into formation
Hold the cuttings in suspension when the fluid is not in motion.
The cost of making, handling, processing and disposing of drilling fluids (or muds, as they are sometimes known) can range from $10,000 to more than $1,000,000 per hole, depending on the size and depth of the hole and types of formation encountered. Cuttings are removed mechanically from fluids so they can be re-used as much as possible, but mechanical systems only remove the larger cuttings: ultra-fines(particles less than 20micros in diameter) remain. These are recirculated, accumulate and are ground still finer. Consequently, the quality ofthe drilling fluid deteriorates until a portion of the fluid has to be disposed of and new fluid is used as a diluents to the contaminated mud in the system. In addition, the mechanical solids removal systems require large volumes of drilling fluid to operate properly, and so a considerable amount of fluid is wasted.
In the fall oof 1984, while engaged in a sump clean-up for a major Canadian oil company. Hitec began to consider the possibilities of tackling the clean-up problem of its source, the drilling fluid system. It was surmised that the Hitec equipment and chemistry could be modified to provide greater benefits in this regard. The aim was to make the equipment more mobile and use a new proprietary chemistry that would allow for the processing of fluid during the drilling operation, returning the fluid to the mud with most if the original qualities. If this could be accomplished, then the sump could be eliminated and the volume of waste at the end of the job would be considerably reduced. It further followed that if the waste could be reduced, the cost of the drilling fluid, its handling and disposal should also be reduced. In addition, by continuously cleaning the fluid, penetration rates could be increased.
To this end, in October of 1984 Hitec completed its first "Active Closed Circuit" Unit, which was immediately put to work in southwest Oregon for a major U.S. oil company. Thi application proved completely successful. The unit has since been adopted by a major U.S. resource company in a potash mining operation in Michigan using oil drilling rigs. In January of 1985 a major Canadian oil company tested the unit on two holes in a drilling operation near Inuvik, N.W.T. The purpose of thisarctic operation was to evaluate the unit for later drillship applications.
