A petroleum stream measurement system includes a cell made of non-conductive material for passing a flowing petroleum stream. First and second sensors, spatially arranged with the cell and spaced at a predetermined distance apart, sense the capacitance of the petroleum stream and provides representative signals. A third sensor senses the capacitance of the petroleum stream and provides a corresponding signal. A fourth sensor senses the capacitance of the petroleum stream and provides a signal corresponding thereto. Apparatus receiving the signals from all the sensors derives the distribution of the different fluids within the petroleum stream.