A method, comprising: substantially simultaneously measuring acoustic signals with each of at least two sensors disposed in an array within a wellbore; computing one or more parameter values for one or more respective specified parameters, the one or more specified parameters comprising at least one of one or more parameters indicative of a type of flow causing the acoustic signals or one or more parameters indicative of a quantitative flow parameter of the flow causing the acoustic signals; and based on the one or more parameter values, at least one of classifying, when the one or more specified parameters comprise the one or more parameters indicative of a type of flow causing the acoustic signals, the type of flow, or, when the one or more specified parameters comprise the one or more parameters indicative of a quantitative flow parameter of the flow causing the acoustic signals, quantifying the quantitative flow parameter; characterized in that the method further comprises: using an array signal processing technique to combine the measured acoustic signals into a fused signal, the array signal processing technique including a spatial filtering method such as conventional beamforming, Capon's beamforming, multiple signal classification, a parametric method, and/or time-delay estimation; wherein the one or more parameter values for one or more respective specified parameters are computed from the fused signal. substantially simultaneously measuring acoustic signals with each of at least two sensors disposed in an array within a wellbore; computing one or more parameter values for one or more respective specified parameters, the one or more specified parameters comprising at least one of one or more parameters indicative of a type of flow causing the acoustic signals or one or more parameters indicative of a quantitative flow parameter of the flow causing the acoustic signals; and based on the one or more parameter values, at least one of classifying, when the one or more specified parameters comprise the one or more parameters indicative of a type of flow causing the acoustic signals, the type of flow, or, when the one or more specified parameters comprise the one or more parameters indicative of a quantitative flow parameter of the flow causing the acoustic signals, quantifying the quantitative flow parameter; characterized in that the method further comprises: using an array signal processing technique to combine the measured acoustic signals into a fused signal, the array signal processing technique including a spatial filtering method such as conventional beamforming, Capon's beamforming, multiple signal classification, a parametric method, and/or time-delay estimation; wherein the one or more parameter values for one or more respective specified parameters are computed from the fused signal. using an array signal processing technique to combine the measured acoustic signals into a fused signal, the array signal processing technique including a spatial filtering method such as conventional beamforming, Capon's beamforming, multiple signal classification, a parametric method, and/or time-delay estimation; wherein the one or more parameter values for one or more respective specified parameters are computed from the fused signal. <EOS>