A method for modifying a detected downhole condition in a well bore using a drill string comprising the steps of: introducing the drill string into the well bore such that a well bore annulus forms between an external surface of the drill string and a wall of the well bore, where the drill string includes a communications sub, a measurement sub and a circulation sub along its operable length, has an internal fluid conduit and the external surface for its operative length and has an open distal end that is operable to pass fluid between the internal fluid conduit and the well bore, where the circulation sub is operable to selectively modify a fluid circulation flow path for a fluid in the well bore upon receiving of a command signal, and where the well bore is defined by the well bore wall that extends from a surface into a hydrocarbon-bearing formation and contains the fluid; inducing circulation of the fluid in the well bore such that the fluid circulates through the drill string and the well bore annulus along a first fluid circulation flow path; operating the drill string such that the measurement sub detects a downhole condition and transmits wirelessly upstring a corresponding data signal associated with the detected downhole condition; operating the drill string such that the communications sub receives wirelessly the data signal from the measurement sub and retransmits the data signal wirelessly upstring, where the communications sub is located upstring of the measurement sub; transmitting wirelessly downhole to the circulation sub a command signal associated with modifying the fluid circulation flow path from the first fluid circulation flow path to a second fluid circulation flow path, where the second fluid circulation flow path directs fluid towards the detected downhole condition; operating the drill string such that the communications sub receives wirelessly the command signal from upstring and retransmits the command signal wirelessly downstring, where the communications sub is located upstring of the circulation sub; and introducing a modifying fluid that is operable to modify the detected downhole condition into the well bore such that the modifying fluid circulates in the well bore along the second fluid circulation flow path fluid and modifies the detected downhole condition. introducing the drill string into the well bore such that a well bore annulus forms between an external surface of the drill string and a wall of the well bore, where the drill string includes a communications sub, a measurement sub and a circulation sub along its operable length, has an internal fluid conduit and the external surface for its operative length and has an open distal end that is operable to pass fluid between the internal fluid conduit and the well bore, where the circulation sub is operable to selectively modify a fluid circulation flow path for a fluid in the well bore upon receiving of a command signal, and where the well bore is defined by the well bore wall that extends from a surface into a hydrocarbon-bearing formation and contains the fluid; inducing circulation of the fluid in the well bore such that the fluid circulates through the drill string and the well bore annulus along a first fluid circulation flow path; operating the drill string such that the measurement sub detects a downhole condition and transmits wirelessly upstring a corresponding data signal associated with the detected downhole condition; operating the drill string such that the communications sub receives wirelessly the data signal from the measurement sub and retransmits the data signal wirelessly upstring, where the communications sub is located upstring of the measurement sub; transmitting wirelessly downhole to the circulation sub a command signal associated with modifying the fluid circulation flow path from the first fluid circulation flow path to a second fluid circulation flow path, where the second fluid circulation flow path directs fluid towards the detected downhole condition; operating the drill string such that the communications sub receives wirelessly the command signal from upstring and retransmits the command signal wirelessly downstring, where the communications sub is located upstring of the circulation sub; and introducing a modifying fluid that is operable to modify the detected downhole condition into the well bore such that the modifying fluid circulates in the well bore along the second fluid circulation flow path fluid and modifies the detected downhole condition.