Entropy based multiphase flow detection

A method for characterizing multiphase fluid flow (MPF) to enhance measuring and monitoring of a flow regime in a segment of pipe for hydrocarbon-production operations, the method comprising the steps of:

• transmitting an acoustic signal through a MPF;
• receiving an acoustic signal transmitted through the MPF, the segment of pipe operable to support the MPF in hydrocarbon-production operations including at least two physical phases;
• converting the acoustic signal to an electrical signal;
• segmenting the electrical signal into short term, medium term, and long term time series;
• assigning positive real numbers to the time series, the positive real numbers including larger values and smaller values, the larger values corresponding to process randomness, and the smaller values corresponding to instances of recognizable patterns in the electrical signal;
• categorizing certain positive real numbers as outlier values;
• calculating short term, medium term, and long term approximate entropy values for the MPF responsive to the short term, medium term, and long term time series from the electrical signal by performing the following steps:
• assigning each of the short term, medium term, and long term time series of data to variables each representing raw data values measured at equally spaced time intervals,
• forming a sequence of vectors using the variables each representing raw data values,
• using the sequence of vectors to construct scalar components representing the distance between each respective vector sequence given by the maximum difference in their respective scalar components,
• calculating each of the short term, medium term, and long term time series approximate entropy values using the scalar components,
• comparing the short term, medium term, and long term approximate entropy values for the MPF to pre-determined short term, medium term, and long term approximate entropy values;
• and
• determining characteristics of the MPF responsive to similarities between the short term, medium term, and long term approximate entropy values for the MPF and the pre-determined short term, medium term, and long term approximate entropy values.