Application of air hammer plus mist drilling in low cost development of shale gas

The Qianjiang Shale Gas Block in Chongqing has obvious mountainous characteristics, serious surface water shortage, large dip angle of shallow strata and well-developed caverns and fractures. In result, conventional drilling is faced with difficulties in wellbore quality control, frequent occurrence of malignant loss of circulation, low success rate and high costs in plugging due to water source limitation. For this reason, the wellbore profile was optimized, the static water level and the leaky strata above it were all included in the first spud section. Three-spud system well profile was reduced to two-spud system well profile and air hammer plus mist drilling technology was explored and applied in the first spud wellbore of?444.5 mm. Field application shows that lost circulation has been effectively eliminated, the well bore quality has been controlled very well, the drilling cycle is greatly shortened, and more than 2 000 meters of casing of?244.5 mm is saved. This research has explored a new way for low cost and efficient development of shale gas wells in Qianjiang area.