The repeated use of the mud during the excavation process is to simply separate the excavated mud and gravel from the mud base fluid, but not all the solid phase materials are separated. The mud recovery system only separates the drilling fluid. The useless solids in the mud.
The bentonite and other drilling fluid additives added during the slurrying process are also solid, but the added solids are all very small solids with a particle size of several micrometers or submicron, so the slurry recovery system is in the process of processing the slurry. The unit of measurement required for particle size is important. Micrometer-sized units are commonly used in the industry.
The size of the bentonite particles added during the preparation of non-digging drilling fluids are all submicron-sized particles. This is something that we need to keep in mind. It means that bentonite is not easily separated from the slurry during the process of purifying the mud using the mud recovery system. For different formations in different regions, the size range of the soil or grit excavated by drilling is also different. The basic range can be from 1000 μm to sub-micron. Our selection of screens is generally below 120 mesh, because the 120 mesh screen means that he may separate 100 micron and larger particles.
In our actual excavation process, the particle size of the clay is smaller than that of sandy soil, and the size of the cuttings is larger than the former two. The smaller the particles are, the more difficult it is during the mud recovery process. Separation of particles smaller than 20 microns is generally not economical in the trenchless industry, so submicron bentonite or chemical additives will not be separated from conventional mud recovery systems. The objective of the mud recovery system is to separate the mud and gravel in the drilling fluid mud, and then ensure that the mud can be recycled, so as to save costs and protect the environment.