Multi-phase fluid measurement using low activity sources
Methods and apparatus for using exempt gamma photon sources to measure fluid properties are described herein. The gamma photon sources are used with detectors in an arrangement that provides a short photon path length between source and detector. Fluid measurement devices described herein have a fluid container defining an interior, an exempt gamma-ray source located outside the fluid container, and a gamma-ray detector located outside the fluid container, the exempt gamma photon source and the gamma-ray detector defining a photon path that traverses the interior of the fluid container along a non-diametric chord of the fluid container.
1 . A fluid measurement device, comprising:
a fluid container comprising an inlet side and an outlet side opposite the inlet side, the fluid container configured to direct a fluid in a non-horizontal direction from the inlet side to the outlet side, the fluid container defining an interior and having a diameter line perpendicular to the non-horizontal direction;
an exempt gamma-ray source located outside the fluid container; and
a gamma-ray detector located outside the fluid container, the exempt gamma-ray source and the gamma-ray detector defining a photon path that traverses the interior of the fluid container in a direction parallel to, and spaced apart from, the diameter line.
2 . The fluid measurement device of claim 1 , wherein the fluid measurement device is a portable static fluid device and the fluid container is a static fluid container.
3 . The fluid measurement device of claim 1 , wherein a length of the photon path is from 3 cm to 6 cm.
4 . The fluid measurement device of claim 1 , wherein the fluid measurement device is a fluid flow measurement device and the fluid container is a fluid flow conduit.
5 . The fluid measurement device of claim 1 , wherein the fluid comprises a non-separated multi-phase fluid.
6 . The fluid measurement device of claim 1 , wherein the fluid measurement device is a Venturi device and the fluid container is a fluid flow conduit of the Venturi device.
7 . The fluid measurement device of claim 6 , wherein:
the fluid flow conduit has a narrow portion;
the photon path is a first photon path;
the first photon path is positioned at the inlet side;
the fluid measurement device further comprises:
a microwave source; and
a microwave detector;
the microwave source and the microwave detector define a second photon path; and
the microwave source and the microwave detector are positioned to dispose the second photon path at the narrow portion.
8 . The fluid measurement device of claim 7 , wherein a length of the first photon path is from 3 cm to 6 cm.
9 . The fluid measurement device of claim 8 , wherein the first photon path is angled with respect to the second photon path.
10 . A fluid measurement device, comprising:
a fluid container comprising an inlet side and an outlet side opposite the inlet side, the fluid container configured to direct a fluid in a non-horizontal direction from the inlet side to the outlet side, the fluid container defining an interior and having a diameter line perpendicular to the non-horizontal direction;
an exempt gamma-ray source located external to an outer wall of the fluid container to emit photons into the interior of the fluid container; and
a gamma-ray detector located external to the outer wall of the fluid container, the exempt gamma-ray source and the gamma-ray detector defining a photon path having a photon path length of from 3 cm to 6 cm, wherein at least a portion of the photon path traverses the interior of the fluid container in a direction parallel to, and spaced apart from, the diameter line, and the photon path is along a non-diametric chord of the fluid container.
11 . The fluid measurement device of claim 10 , wherein the photon path has an extent, in a width direction thereof, from 20% of a radial distance of the fluid container to 80% of the radial distance of the fluid container.
12 . The fluid measurement device of claim 10 , wherein the fluid measurement device is a fluid flow measurement device, and wherein the fluid container is a fluid flow conduit.
13 . The fluid measurement device of claim 10 , further comprising a microwave transmission measurement device.
14 . The fluid measurement device of claim 10 , wherein the fluid measurement device is a Venturi device and the fluid container is a fluid flow conduit of the Venturi device.
15 . The fluid measurement device of claim 14 , further comprising a microwave transmission measurement device, wherein the microwave transmission measurement device is located at a narrow portion of the fluid container and the exempt gamma-ray source and the gamma-ray detector are located at the inlet side of the fluid container.
16 . The fluid measurement device of claim 15 , wherein the photon path is a first photon path, the microwave transmission measurement device has a microwave transmission antenna and a microwave receiving antenna that together define a second photon path, and the second photon path extends along a diameter of the fluid container.
17 . The fluid measurement device of claim 16 , wherein the first photon path and the second photon path are respectively angled.
18 . A method of fluid flow measurement, comprising:
disposing an exempt gamma-ray source and a gamma-ray detector outside a fluid container to define a first photon path between the exempt gamma-ray source and the gamma-ray detector that traverses an interior of the fluid container along a non-diametric path;
disposing a microwave transmitting antenna and a microwave receiving antenna outside the fluid container to define a second photon path between the microwave transmitting antenna and the microwave receiving antenna that traverses the interior of the fluid container;
flowing a non-separated multi-phase fluid through the fluid container in a vertical direction from an inlet side to an outlet side of the fluid container, the fluid container having a diameter line perpendicular to the vertical direction;
while flowing the non-separated multi-phase fluid through the fluid container, obtaining a count rate of gamma photons propagated through the non-separated multi-phase fluid using the exempt gamma-ray source and the gamma-ray detector and measuring dielectric properties of the non-separated multi-phase fluid using the microwave transmitting antenna and the microwave receiving antenna;
measuring pressure drop as the non-separated multi-phase fluid flows through a flow restriction of the fluid container;
determining water-liquid ratio of the non-separated multi-phase fluid from the count rate of gamma photons;
determining a gas fraction of the non-separated multi-phase fluid from the dielectric properties and the water-liquid ratio;
calculating a mixture density of the non-separated multi-phase fluid based on the water-liquid ratio and the gas fraction;
determining volumetric flow rate of the non-separated multi-phase fluid from the measured pressure drop and the mixture density; and
determining volumetric flow rates of gas, water, and oil in the non-separated multi-phase fluid from the volumetric flow rate of the non-separated multi-phase fluid, the gas fraction, and the water-liquid ratio.
19 . The method of claim 18 , further comprising measuring a density of water, oil, and gas in the non-separated multi-phase fluid and determining mass flow rates of the water, the oil, and the gas in the non-separated multi-phase fluid from the volumetric flow rates of the water, the oil, and the gas and the density of the water, the oil, and the gas.
20 . The method of claim 18 , wherein the exempt gamma-ray source, the gamma-ray detector, the microwave transmitting antenna, and the microwave receiving antenna are all located at the flow restriction of the fluid container.