Study On Auxiliary Plugging Technology By Lateral Rotary Jet

Tarim Basin is the largest exploration and development area northwest China of Sinopec,where drilling geological environment is complex,especially leakage,happened at Permian basalt formations in medium term well completion,is the key factor of restricting drilling speed and efficiency.To solve the problem,based on the existing technology,auxiliary plugging technology by rotary jet is studied.On the basis of the studies of the data collected at the scene,Permian formation leakage mechanism was studied.Plugging material & mud cake dropped off and stress changed on wellbore lead to micro cracks from "non induced leakage" to "leakage",which result leakage in medium term well completion;based on the theoretical analysis and simulation experiments in the laboratory,we analyse that plugging material can be prompted to micro crack near wellbore zone deeper and denser by rotary jet,which forms assistant plugging method by rotary jet;using numerical simulation method and theory analysis,auxiliary plugging tools used in well(Ф311.2mm and Ф215.9mm)were designed and machined.According to the states of the filed,process of plugging technology by rotary jet is optimized,and 9 wells were tested.The result showed that formation bearing capacity was enhanced by 8.5~11.0MPa or formation bearing capacity was enhanced by 0.15-0.20,which can meet requirement of medium term well completion.Compared with the adjacent wells,plugging time is saved by 6-15 d.