Systems and methods relating to subterranean drilling while maintaining
containment of any contaminants released during the drilling. A thrust
block installed over a zone of interest provides an overflow space for
retaining any contaminants and excess sealant returns. Negative air
pressure may be maintained in the overflow space by a ventilation system.
Access ports in the thrust block seal the overflow space from the
surrounding environment with a membrane seal. A flexible sack seal in the
access port may be connected to a drill shroud prior to drilling,
providing containment during drilling after the drill bit penetrates the
membrane seal. The drill shroud may be adapted to any industry standard
drilling rig and includes a connection conduit for connecting to the
flexible sack seal and a flexible enclosure surrounding the drill shaft
and of a length to accommodate full extension thereof. Upon withdrawal,
the sack seal may be closed off and separated, maintaining containment of
the overflow space and the drill shroud.
