External Optical Coils for Downhole Fluid Flow Sensing
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Solution Overview
Problem
Existing fluid flow measurement technologies in the oil and gas industry face challenges in accurately sensing fluid flow parameters in harsh downhole environments due to interference from gas bubbles, particulates, and localized concentration variations, while also being prone to erosion, corrosion, and leakages, and are limited in distinguishing fluid sources from multiple wells.
Innovation Solution
A sensing system utilizing low and high sensitivity optical coils to measure fluid flow parameters, switching between coil types based on phase change rates to avoid phase over-ranging and ensure accurate measurements across varying acoustic signal environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If venturi type devices are used to measure fluid flow parameters, then bulk velocity can be sensed, but the device creates flow impediment and potential leak paths
Solution Approach 1:
The patent replaces mechanical venturi flowmeters with an optical sensing system using coils wrapped around the pipe exterior. This substitution eliminates the need for mechanical intrusion into the fluid stream, removing flow impediment and leak path issues while maintaining measurement capability through optical detection of fluid motion effects on the pipe.
Solution Approach 2:
The patent introduces the pipe itself as an intermediary medium between the fluid and the sensor. By wrapping coils around the pipe exterior, the system detects fluid flow parameters indirectly through the pipe wall, avoiding direct contact with the fluid while still obtaining accurate measurements of bulk velocity and other flow characteristics.
2Measurement precision
If ultrasonic transceivers are used for flow measurement, then speed of sound can be determined, but gas bubbles and particulates interfere with signal transmission
Solution Approach 1:
The patent uses the pipe wall as an intermediary that transmits acoustic vibrations from the fluid to external coils without requiring direct line-of-sight through the fluid. This indirect coupling method allows acoustic signals to pass through the pipe wall to the sensors, avoiding interference from gas bubbles and particulates that would block direct ultrasonic transmission paths.
Solution Approach 2:
The patent employs mechanical vibration detection through coils that sense vibrations transmitted through the pipe wall from acoustic waves in the fluid. This approach converts acoustic energy into mechanical vibrations detectable by the coils, providing a reliable measurement method that is not blocked by gas bubbles or particulates in the fluid.
3Measurement precision
If multiphase flowmeters are installed at wellhead, then constituent ratios can be measured, but information from individual sources cannot be distinguished
Solution Approach 1:
The patent segments the measurement process by installing multiple sensors at different locations along the pipe, each monitoring specific flow characteristics. By distributing sensors throughout the system rather than relying on a single wellhead instrument, the system can track fluid properties and source characteristics at multiple points, enabling identification of individual sources while maintaining constituent ratio measurement capability.
4Measurement precision
If sensors are placed in direct contact with fluid flow, then accurate measurements can be obtained, but sensors are subject to erosion and corrosion
Solution Approach 1:
The patent uses the pipe wall as a protective intermediary barrier between the sensors and the harsh fluid environment. Sensors are mounted externally and couple to the fluid through the pipe wall, which protects them from direct exposure to erosive and corrosive fluids while still allowing accurate measurement of flow parameters through vibration and acoustic signal transmission.
Solution Approach 2:
The patent replaces direct mechanical contact sensors with external optical and acoustic sensors that detect fluid motion through the pipe wall. This substitution eliminates sensor exposure to harsh fluid conditions while maintaining measurement accuracy through non-contact detection methods that sense fluid dynamics indirectly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable, non-intrusive, and accurate measurement of fluid flow parameters, including speed of sound and bulk velocity, in hostile downhole conditions without requiring prior knowledge of well layouts or equipment profiles.
Implementation Method 1
acoustic waves are propagating through a fluid in a tubing
Implementation Method 2
low sensitivity coils comprising optical coils for sensing one or more fluid flow parameters
Implementation Method 3
measuring a speed of sound through the fluid in the tubing
Implementation Method 4
measuring a bulk velocity of the fluid in the tubing
Data Source
AI summary
Examples are disclosed herein for sensing one or more fluid parameters of a flowing fluid. A flowmeter can include high and low sensitivity coils. The low sensitivity coils can include optical coils for sensing one or more fluid flow parameters of flowing fluid. The high sensitivity coils can include optical coils for sensing the one or more fluid flow parameters of the flowing fluid. The low sensitivity coils can be selected so that an instrument receives data from the low sensitivity coils indicative of the one or more fluid flow parameters over a first period of time. The high sensitivity coils can be selected so that the instrument receives data from the high sensitivity coils indicative of the one or more fluid flow parameters over a second period of time.