APPLICATION OF DIRECTIONAL DRILLING TECHNOLOGY IN LAYING NATURAL GAS PIPELINE ACROSS THE QINGJIANG RIVER
LI Xiao-sheng;LIU Xian-quan;Anhui Bureau of Coal Geology;
The qingjiang River natural gas pipeline project is laying 1500m long Φ1016×26.2 natural gas steel pipe andΦ114 silica casing across the river beneath the riverbed. The river is open to navigation, with river bottom elevation at a minimum of-5.90m and water depth at a maximum of 6.0-8.6m. The strata consist of land fills, sludge silt, silty clay intercalated with silt and fine sand. After optimizing construction scheme, some effective technical measures have been taken in lead hole trail control, directional drilling deviation correction, big-size hole reaming and clearing, and long-distance big-size pipeline back-dragging, which ensured success of back dragging at one time.