206 the sensor or sensors are disposed in a suitable position to detect the acoustic disturbances generated within the borehole fluid for example a sensor could be disposed near the head or a sensor may be disposed closer to the feature of interest further the sensor may be either fixed e g to the casing or mobile e g connected to coiled tubing a variety of techniques may be employed to detect and process tubewave arrival times and arrival delays examples include but are not limited to manual picking automatic thresholding algorithms and autocorrelation based approaches more sophisticated approaches may be utilized if the typical noise field is more complex modeling may be employed to interpret the acoustic disturbance as received by the sensor in order to determine a prediction of some attribute of the recorded data where the attribute includes at least one of amplitude frequency attenuation dispersion and travel time the response of the system is generally characterized by reflections of alternating polarity which decrease in amplitude over time in the case where a series of pulses are being transmitted it is useful for the processing unit to process the received disturbance to filter noise distinguish the initial pulse from reflections of earlier pulses and otherwise account for changes in the transmitted disturbance more particularly the processing unit is operable to account for various parameters of the borehole system which can cause changes in the acoustic disturbance between the transmitter and the receiver including but not limited to wellbore system geometry viscoacoustic properties of the fluid and entrained solids contained in the wellbore system locations of boundaries and entrained solids.