Drilling practice of shale gas parameterswells in Baojing block, Hunan

Shale gas resources are a kind of clean energy resources. Drilling is one of the main technologies for shale gas pre exploration.In 2013, the original Shenhua Group was was awarded the Baojing shale gas block, Hunan.On the basis of investigation & analysis of the two dimensional seismic exploration results and outcrop of the field in the early period of Baojing. Through the optimization and peer review for well locations, 3 small size parameters wells along the syncline wings are deployed in the Longmaxi group. Because the Baojing block belongs to the complex and high steep structural area, it has high formation dip, the local fault development and the poor drillability. Hence the borehole is instability, stuck pipe, lost circulation and other accidents occur occasionally.In order to improve drilling efficiency and shorten drilling cycle, achieve excellent and fast drilling, the formation pressure evaluation, drillability researching and borehole structure design are carried out in pre-drilling, and the drilling parameters, drilling fluid performance and drilling tools combination are continuously optimized during drilling, preventive inclination ofvertical well, rope coring and storage logging are adopted, the rich drilling results have been obtained, and the layerproperty and gas bearing characteristics of the Longmaxi group are revealed. It is found that better shale gas shows and the maximum gas content is 1.59 m³/t, which provides the basis for the evaluation of the potential of shale gas resources in Baojing block and the optimization of the optimization of the "sweet spot" area.