Drilling technology for the first shale gas horizontal well in West Sichuan

XYHF-1 well is the first shale gas prospecting horizontal well in west Sichuan. However, there are many difficulties in its drilling process, such as the low ROP, difficulty in controlling the well body quality, difficulty in selection of drilling fluid, high risk of well control and poor stability of well wall. This paper mainly elaborates the key drilling technologies and application effects, such as optimizing well structure, controlling wellbore track, optimizing drilling tools, safely drilling and reservoir protecting technology based on the analysis of drilling difficulties. At the same time, this paper briefly introduces application of some new technologies in this well, such as rotary guide drilling, oil-based drilling fluid and sleeve cementing techniques. The drilling cycle time is 253.17d for full hole, average ROP is 1.6m/h (including the pilot hole), the enlargement rate of full hole diameter is below 12%, and the maximum well deviation of the upper part is 0.87°, the construction effect is good. The application results show that reasonable well structure and borehole trajectory design is the basic premise of smooth drilling of shallow horizontal wells; and strengthening the prediction of friction and torque and using safety measures and good performance drilling fluids are the important guarantee for the safety drilling. The successful finish drilling of this well provides practical experience for similar wells.