The invention relates to a device for removal and filtration of drilling
fluid at top hole drilling, where a suction module (10) comprises an
extended, pipe-formed body (30), open at the top and which is arranged to
an ocean-bottom penetrating pipe, through which a drill stem is led for
drilling of the top hole, and where the pipe-formed body (30) comprises
at least one outlet passage (32) in the pipe wall for export of return
drilling fluid from the bore hole to a pump module (12). The invention is
characterized in that the pipe-formed body (30) comprises a filtration
device with through openings, where the mentioned openings are arranged
to let through, to at least one outlet passage (32), return drilling
fluid containing suspended material, such as swelling clay and stones,
having a size that is less that the diameter of the inlet pipe of the
pump or the openings of the pump.