| 摘要 |
A drilling fluid composition for horizontal directional drilling is a flowable aqueous slurry of biodegradable, non-toxic, preferably edible plant particles. The particle size of the plant-derived particles depends on the drill bit used. The particles should be small enough not to clog the fluid jet orifices in normal use. The slurry is pumped through to the drill bit in a warm or preferably hot state, e.g. 80-100° C. After ejection, the slurry cools rapidly, causing solidification and creating a lining on the tunnel wall. |
