METHOD AND SYSTEM FOR DETERMINING RELATIVE DEPTH OF AN ACOUSTIC EVENT WITHIN A WELLBORE

摘要

The present disclosure is directed at a method and system for determining relative depth of an acoustic event within a wellbore. The method includes obtaining two acoustic signals at two different and known depths in the wellbore, in which each of the acoustic signals includes the acoustic event; dividing each of the acoustic signals into windows; determining cross-correlations of pairs of the windows, in which each of the pairs includes one window from one of the acoustic signals and another window from the other of the acoustic signals that at least partially overlap each other in time; and determining the relative depth of the acoustic event relative to the two known depths from the cross-correlations. The acoustic event may represent, for example, fluid flowing from formation into the wellbore (or vice-versa) or fluid flowing across any casing or tubing located within the wellbore.

主权项

1. A method for determining relative depth of an acoustic event within a wellbore, the method comprising:
(a) obtaining two acoustic signals at two different and known depths in the wellbore, wherein each of the acoustic signals includes the acoustic event; (b) dividing each of the acoustic signals into windows, each of which has a certain duration; (c) determining cross-correlations of pairs of the windows, wherein each of the pairs comprises one window from one of the acoustic signals and another window from the other of the acoustic signals that at least partially overlap each other in time; and (d) determining the relative depth of the acoustic event relative to the two known depths from the cross-correlations, wherein the acoustic event comprises fluid flowing from formation into the wellbore, fluid flowing from the wellbore into the formation, or fluid flowing across any casing or tubing located within the wellbore.