| In recent years,shale gas development has become a new energy industry,good shale gas formation and enrichment of geological conditions in China are also available,shale gas development in China has a real strategic significance,but the development of oil-based drilling fluid and high-performance water-based drilling fluid system is relatively slow and can’t meet the requirement of shale gas horizontal well drilling,so it is necessary to carry out the drilling fluid technical research to improve the efficiency of shale gas development.In this paper,the drilling fluid system is used to study the existing drilling fluid system in the construction of shale gas horizontal well drilling at home and abroad.In view of the different geological characteristics of Weiyuan block and Zhaotong block in southern Sichuan,the main difficulties of drilling fluid in shale gas horizontal well are analyzed,and the indoor research and performance evaluation of oil-based drilling fluid,KCl drilling fluid and high performance water-based drilling fluid are carried out in different sections of wells.It manifests that the drilling fluid system is excellent in rheology,lubricity,resistance to temperature,pollution resistance,wall formation and suppression ability,and realizes field application technology.The field test results delicate that the performance of the drilling fluid system is excellent,which solves the problems such as the instability of the borehole in the construction of the horizontal well of the shale gas in southern Sichuan,the difficulty of well collapse,leaks and so on.It has completed the drilling fluid technology required for the "factory" construction of the shale gas horizontal well in southern Sichuan.At present,there are 45 horizontal wells in the south of Sichuan,with an average well depth of 4973 m and an average completion period of 93 days.The drilling construction efficiency could be effectively improve. |
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