Key Drilling Technology for Deep Shale Gas Reservoirs in the Southeastern Sichuan Region

Due to deep burial depth,high rock strength and complex geological structures of shale reservoirs in Southeastern Sichuan,shale gas drilling in this region has encountered the challenges of low rate of penetration and long drilling period.Through a comparative analysis of deep shale gas drilling technologies in China and abroad,and by reviewing a summary of the main technical challenges faced by deep shale gas drilling in Southeastern Sichuan,we determined the key technologies to drill in deep shale gas formations in the Southeastern Sichuan Region.Factors included casing program optimization,rapid drilling,wellbore trajectory control,high-density oil-based drilling fluids,and deep shale gas cementing optimization,while considering research results and applications of middle-shallow shale gas drilling technologies.These technologies have been used in deep shale gas wells in blocks like Pingqiao,Jiangdong of Fuling Area and area like Dingshan,Weirong,Yangchuan,and achieved significant positive results.Among them,the rate of penetration of Well JY74-2HF was increased by 73.48%,and the drilling cycle was shortened by 42.89%; the rate of penetration of Well JY187-2HF was increased by 37.26%,and the drilling cycle was shortened by 25.79%.The research results are significant in that they can provide reference points and excellent guidance for and drilling plan design,rapid drilling and efficiency enhancements of deep shale gas wells in China.