System and method for measuring a multiphase flow by measuring density and electrical impedance for correcting the measurement due to effect of deposits on inner surface of pipe walls
AssigneeRoxar Flow Measurement AS
InventorDag Erik Laumann
Life of this patent
Estimating the term…
Abstract
A method for measuring conditions in a pipe includes measuring a chosen electrical characteristic in the flow, measuring the density in essentially the same flow volume, and calculating a curve representing the relationship between the density and the electrical characteristic. The method further includes at least one of calculating the derivative of the curve, indicating the water to liquid ratio of the flow volume, and extrapolating the curve to the value representing density at no liquid, the value of the electric characteristic representing the characteristic of a possible deposit layer on the inner surface of the pipe.
Claims19
A measuring system comprising:
- at least two electrodes on an inner wall of a pipe for conducting a multiphase fluid flow, the pipe having a deposit layer covering the inner wall, the flow having a stable water liquid ratio (WLR) over a time span, the at least two electrodes being positioned on an inner surface of the pipe and being connected to a measuring instrument for measuring electric characteristics in a fluid flow volume between the at least two electrodes;
- a flow density sensor measuring the same fluid flow volume measured by the at least two electrodes;
- and
- an analyzing unit in the measuring instrument sampling density and electric measurements at a predetermined rate, and calculating a best fit curve representing the sampled data as a function between the corresponding density and electric measurement data and based on the best fit curve determining an effect of the deposit layer.
A measuring system comprising:
- at least two electrodes on an inner wall of a pipe for conducting a multiphase fluid flow, the flow having a stable water liquid ratio (WLR) over a time span, the at least two electrodes being positioned on an inner surface of the pipe and being connected to a measuring instrument for measuring electric characteristics in a fluid flow volume between the at least two electrodes;
- a flow density sensor measuring the same fluid flow volume measured by the at least two electrodes;
- and
- an analyzing unit in the measuring instrument sampling density and electric measurements at a predetermined rate, and calculating a best fit linear curve representing the sampled data as a function between the corresponding density and electric measurement data and based on a curve slope determining the constant water liquid ratio in the multiphase fluid flow.
A method for measuring conditions in a pipe containing a fluid flow, the method comprising :
- measuring a chosen electrical characteristic in a volume of the fluid flow;
- measuring a density in the same fluid flow volume;
- calculating a curve representing a relationship between the density and the electrical characteristic;
- and
- at least one of:
- calculating a derivative of the curve, indicating water to liquid ratio of the flow volume;
- and
- extrapolating the curve to a value representing density at no liquid present, the value of the electric characteristic representing the characteristic of a possible deposit layer on an inner surface of the pipe.
Dependencies are inferred from the claim text.