Patent ID: 7186971
Filing Date: 2007-03-06
Classification: E21B,G01F,G01P

Abstract:
1. A method of determining a flow velocity of a first fluid in a borehole in an earth formation, the method comprising: (a) irradiating said earth formation wit a pulsed radiation source; (b) obtaining a first temporal signal resulting from said irradiation at a first detector; (c) obtaining at least one second temporal signal resulting from said irradiation at at least one second detector spaced apart from said first detector; the first and second temporal signals indicative of the flow velocity; (d) time differentiating the first temporal signal to provide a first time differentiated signal and time differentiating the at least one second temporal signal to provide a second time differentiated signal; and (e) determining said flow velocity based on analysis of said first time differentiated signal, said second time differentiated signal, and a distance between one of (A) said first detector and said at least one second detector, and, (B) said source and said at least one second detector.