The terrain and geological condition to horizontal directional drilling and its countermeasures

In the design of long-distance oil and gas pipelines project, loess tableland, wandering large rivers, mountain and other different topographies such as sand, gravel layer of rock strata, pebbles and many kinds of formation conditions and their combination are frequently encountered.According to different terrains and geomorphic conditions, the design in crossing curve and mud process is analyzed. The results show that the crossing curve design is the foundation of directional drilling technique. It is considered that one-fit-all crossing curve is the key to realize the crossing technique program, combined with topography and landforms. According to the different structure lithology of strata, available mud ratio can effectively reduce the risks in sticking of tool, seizeing of tool and backtow drag. In directional drilling, the combination of one-pass drilling, opposite-pass and directional drilling should be adopted so as to make up the traditional technology.