Patent ID: 9581558
Date: 2017-02-28
CPC Classifications: G01N

Claim:
1. A method for determining at least one piece of information (Γ g , W) representative of a phase fraction of a multiphase fluid circulating in a pipe, the method comprising the steps of: (a) emitting a number of gamma photon counts at at least one energy through the fluid, and (b) measuring a number of counts (n (c) dividing a given measuring period (T (d) choosing an initial value of the or each piece of representative information (Γ (e) determining the or each piece of representative information (Γ (e 1 ) estimating a number of counts received ({circumflex over (n)} le,i , {circumflex over (n)} he,i ) at each energy in each interval (I i ) based on the or each piece of representative information (Γ g,i , W i ) determined at a preceding iteration, (e 2 ) calculating a residual (L 0 ) comprising a first criterion (C 1 ) calculated from probabilities according to a given statistical law to measure, for each energy, the number of counts (n le,i , n he,i ) measured at each interval, the given statistical law being parameterized based on the number of counts estimated ({circumflex over (n)} le,i , {circumflex over (n)} he,i ) in step (e 1 ) at each interval (I i ); (e 3 ) determining new values of the or each piece of representative information (Γ g,i , W i ) to minimize the residual (L 0 ); step (e) including, at each iteration, (e 4 ) calculating the average (Ê k 0 ), for each energy, of an estimated number of counts ({circumflex over (n)} k 0 ) for each interval (I i ) based on the representative information (Γ g,i , W i ) determined in a preceding iteration, the residual (L 0 ) calculated in step (e 2 ) comprising a second criterion (C 2 ) calculated from probabilities according to a given statistical law to measure, for each energy, an average number of counts (n k 0 ), the given statistical law being parameterized based on the average (Ê k 0 ) calculated in step (e 4 ).