| Popis: |
Horizontal Directional Drilling (HDD) as the first candidate for petroleum and natural gas pipeline in East-west natural gas transmission project have been wildly used to install pipes and conduits for more than 30 years. However, large-diameter borehole increases the risk of drilling accident in weak cementation stratum such as sands, cobbles, and gravel. There are a few researches or studies on large-diameter (up to 1000mm) horizontal bore-hole while drilling slurry and reamer design. The objective of this paper is to analyze the effect of slurry permeability on the borehole instability and improving elastic-plastic model of horizontal bore-hole by citing permeability theory. |
