The invention discloses a method and device for testing rock drillability of deep
well drilling and extra-deep
well drilling. The device comprises a
machine frame (1), a high temperature and
high pressure loading mechanism and a micro
drill bit
rock breaking drilling depth measurement mechanism, wherein the high temperature and
high pressure loading mechanism and the micro
drill bit
rock breaking drilling depth measurement mechanism are arranged on the
machine frame (1). The device exerts confining pressure, pore pressure and fluid column pressure on rock samples in cavities in three axes,
overburden pressure is exerted on the rock samples through a
hydraulic pump, and therefore the
high pressure environment of the stratum of the bottom of a well can be simulated, the relation between the drilling depth and the time is tested through a displacement sensor at the position of a micro
drill bit, optimization of the drilling pressure, the rotating speed and the
drilling fluid type and drilling machinery drilling speed prediction are achieved. The method and the device have the advantages that the requirements for the bottom hole temperature and the pressure can be met in the deep
well drilling process and the ultra-deep well drilling process, the function of testing multiple sets of rock drillability values through a single time of
experimental testing of deep well drilling is achieved, the efficiency of the single time of
experimental testing is greatly improved, and experimental cost is reduced.