Abstract: In order to further clarify the differences among long horizontal section wells,extended reach wells and conventional horizontal wells,and explore drilling technologies and relative developing strategy for long horizontal section wells,the technical characteristics of these kinds of wells were analyzed.The analysis and comparison shows the main differences among the three kinds of wells are as follows:the problem of drag and torque in long horizontal section wells is not serious in conventional horizontal wells;long horizontal section wells feature a long horizontal section,which is beyond the range of extended reach well in many cases;the relative technologies have been focused on the drilling ability for the long horizontal section with deviation of more than 86°,it is different from the drilling and completion capability in extended reach wells that aimed at getting a long displacement.Based on the findings above,preliminary definition of long horizontal section wells was presented,and some specific suggestions on basic drilling design theory,drilling technology for improving ROP of long horizontal section and economic drilling model have been proposed.