Mini-spinner flowmeter and downhole tool comprising an array of mini-spinner flowmeters for operation in hydrocarbon well

A downhole tool used to measure and analyze a fluid present in a hydrocarbon well, the tool being adapted for displacement along and within the hydrocarbon well comprising a plurality of angularly distributed mini-spinner flowmeters, each mini-spinner flowmeter being intended for measuring a fluid linear velocity and a fluid direction of a fluid present in the hydrocarbon well and comprising:

• an impeller formed with a plurality of axially extending vanes longitudinally secured to a shaft, the shaft extending along a longitudinal axis, the impeller being caused to rotate at an impeller angular velocity depending on the fluid linear velocity and in a rotational direction depending on the fluid direction;
• a support having a bearing positioned on each end of the shaft and a through-hole securing an optical section;
• said optical section comprising an emitting optical fiber, a first receiving optical fiber and a second receiving optical fiber, optical fiber distal ends directed towards the vanes defining an optical path offset from the shaft longitudinal axis and positioned such as to face a vane rotation trajectory;
• and
• the vanes are reflective such that, in use, a light energy emitted by the emitting optical fiber and reflected backward by anyone of the vanes is received by the first receiving optical fiber and the second receiving optical fiber, the reflected light energy containing information indicative of the fluid linear velocity and the fluid direction;
• wherein the emitting optical fiber is coupled to a light energy source and the first and second receiving optical fibers are coupled to respective first and second light energy detectors;
• and
• wherein a rate of reflected light energy measured by said detectors is related to the fluid linear velocity and a succession order of reflected light energy measured by the first and second light energy detectors is related to the fluid direction.

A method of measuring a fluid linear velocity and a fluid direction of a fluid mixture present in a hydrocarbon well by using a mini-spinner flowmeter comprising:

• an impeller formed with a plurality of axially extending vanes longitudinally secured to a shaft, the shaft extending along a longitudinal axis;
• a support having a bearing positioned on each end of the shaft and a through-hole securing an optical section;
• said optical section comprising an emitting optical fiber, a first receiving optical fiber and a second receiving optical fiber, optical fiber distal ends directed towards the vanes defining an optical path offset from the shaft longitudinal axis and positioned such as to face a vane rotation trajectory;
• and
• the vanes being reflective;
• said measuring method comprising the steps of:
• causing the impeller to rotate at an impeller angular velocity depending on the fluid linear velocity and in a rotational direction depending on the fluid direction;
• emitting a light energy by the emitting optical fiber towards the vanes and receiving a reflected light energy reflected backward by anyone of the vanes by the first receiving optical fiber and/or the second receiving optical fiber, the reflected light energy containing information indicative of the fluid linear velocity and the fluid direction;
• and
• analyzing the reflected light energy and determining the fluid linear velocity and the fluid direction based on the reflected light energy such that a rate of reflected light energy is related to the fluid linear velocity and a succession order of reflected light energy is related to the fluid direction.