extends along a path generally oblique to one of the tool axis a t the well axis a w or both by estimating the fluid properties within the well 2 the sound speed within the wellbore fluid can be estimated thereby providing an estimated value of distance between each of the sensors 45 and the wellbore wall w p these distances can be calculated within the processor 41 optionally provided within the tool 38 stored within the tool 38 or communicated to the surface for real time analysis subsequent cycles of acoustic signal generation and detection can be performed at different depths within the wellbore 2 this can be an incremental or a continuous fashion it is believed it is well within the capabilities skilled in the art to devise a suitable method of disposing the tool 38 within the wellbore while making acoustic estimations within the wellbore using the data collected the wellbore dimensions adjacent the tool 38 can be estimated fig8 illustrates an overhead schematic view of the tool 38 in the wellbore wherein the lateral detector 44 is disposed adjacent the intersection i to form the acoustic path 54 as shown generated signals 56 directed towards the wellbore wall w p and the primary wellbore will generate reflected signals 58 similar to those of fig7 both in direction and arrival time to the sensor 45 however generated signals 56 a 56 b directed towards the intersection are shown extending past the line representing the primary wellbore wall w p into the wellbore wall lining the lateral wellbore 5 the reflected signals 58 a 58 b produced by reflecting signals 56 a 56 b on the wellbore wall w.