Horizontal well drilling technology for Dixi volcanic complex formation

The geology structure of Dixi volcanic gas field is complex. Cretaceous and Jurassic unconsolidated formation tend to loss circulation, and Triassic and Permian clay formation and Carboniferous carbargilite and coal bed tend to collapse. Carboniferous formation is developed with vertical fractures, so it tends to loss circulation. The sealing agents in drilling fluid affect the transmission of MWD signals, which makes difficulties to trace control. The gas bearing layer distribution is complex, so it need adjust trajectory significantly when horizontal well is penetrated. Therefore, a series of technical treatments are taken to deal with the issues, including leak protection and sealing techniques, leaking section trace control technique, wellbore sloughing mechanism description for deviated well section and the anti-slough treatment, deviation section drifting and reaming techniques, winding horizontal well friction reducing technique, etc. Through the application of these techniques in field, the horizontal well drilling process is speeded up, which supplies an experience for the similar drilling operations.