A system and method for installing casing in a blind horizontal well for blind horizontal directional borings. The system and method may include an example of an offset transmitter sonde assembly that contains an open central passage through which well casing can be inserted, and an example of a drill bit assembly that may be remotely uncoupled from a drill string, leaving the bit in the bore created. Remote uncoupling of the drill bit assembly tends to allow a casing to be installed in the bore while the drill string and bit remain in the bore for support during casing installation. After installation of the casing the drill bit assembly may be uncoupled from the drill string, allowing the drill string to be withdrawn from the bore, with the drill bit assembly remaining in the bore.