Turbo-coring device equipped with a following pipe

This turbo-coring device comprises a tubular body provided with a coring bit and surrounded by a following pipe provided by a reaming bit. The tubular body is connected to the turbine through a fluid distributor having a side opening for discharging above the following pipe in the annular space between the device and the borehole wall a fraction of the fluid leaving the turbine, while the remaining fraction feeds the tubular body. The following pipe is connected to the outer wall of the fluid distributor through releasable bayonet type latching means. Means are provided for automatically closing the fluid discharge opening when the lower part of the tubular body becomes obturated by ground formations and an annular sealing packer is positioned between the tubular body and the following pipe.