Drilling technologies for deep wells and ultra-deep wells

Lots of advanced modern high technologies are applied in the drilling of deep and ultra deep wells, including the vertical drilling system (VDS), top drive drilling rig, aluminum drill pipe, and wire line coring without tripping, as well as the use of drilling fluid with temperature tolerance of over 250℃, etc. On data and information processing, large scale of real time tracing and electric simulation technologies are applied, making the analysis to various data more direct, e. g. , monitoring of downhole troubles by computer terminations has been realized in modern deep well drilling, and the drilling engineers can determine the treating plans according to the information supplied by the monitor rapidly, thus minimize the time and the difficult degree of downhole troubles and improve efficiency. However, with the increasing of well depth, the possibilities of various problems increase, such as the application of ultra-high density drilling fluid, the determination of a reasonable hole structure, the proper use of advanced technologies and tools in field condition, the manufacture of long life bit, the optimization of drilling methods and borehole quality, and wellbore stability in the deep formation, etc. Combined with the case histories of the deep wells and ultra deep well drilled in abroad, the drilling technology plans for solving the problems encoun tered during the drilling of deep and ultra-deep wells are concluded, i. e. , drilling fluid technology plan, machinery technology plan, formation stability technology plan, drilling technical plan, sampling technical plan, and some recommendations were also presented.