Downhole Fiber Optic Flow Sensing Tool
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Solution Overview
Problem
Existing systems for measuring fluid properties in wells, such as venturi meters and passive acoustic sensing, are prone to component failures and have limitations in detecting silent flow, leading to costly downtime and inaccurate parameter monitoring.
Innovation Solution
A downhole flow sensing tool utilizing two fiber optic cables for discrete or distributed acoustic signal generation and sensing, allowing precise measurement of flow parameters by comparing generated and received signals, which enhances detection capabilities for silent flows and simplifies the system by eliminating the need for multiple components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If venturi meters and separate electronic sensors are used to measure flow and parameters, then measurement capability is improved, but system complexity and component failure risk increase
Solution Approach 1:
The patent combines multiple measurement functions (flow rate, pressure, temperature) into a single integrated fiber optic sensing system. The distributed acoustic sensing capability along the fiber optic cable eliminates the need for separate venturi meters, pressure sensors, and temperature sensors, reducing system complexity while maintaining comprehensive measurement capability.
Solution Approach 2:
The fiber optic cable serves multiple functions simultaneously: it acts as both the acoustic signal generation medium and the sensing element for measuring flow parameters. This multi-functional approach replaces multiple specialized components with a single universal sensing system that can measure various parameters along its entire length.
2Device complexity
If passive acoustic sensing is used to monitor fluid flow, then system simplicity is improved, but detection capability for silent flow deteriorates
Solution Approach 1:
The system performs preliminary action by generating acoustic signals through the fiber optic cable before attempting to detect flow. This active signal generation creates a reference acoustic field that interacts with the fluid, enabling detection of flow conditions that would be invisible to passive sensing alone.
Solution Approach 2:
The system uses feedback by comparing the generated acoustic signal with the signal received after propagation through the fluid. Changes in the received signal provide feedback about flow conditions, enabling reliable detection of both noisy and silent flows by measuring perturbations in the acoustic field.
3Measurement precision
If multiple components are used for flow measurement, then measurement accuracy is improved, but reliability and downtime risk worsen
Solution Approach 1:
The patent merges multiple measurement functions into a single fiber optic sensing system, eliminating multiple potential failure points. The distributed sensing capability along the fiber optic cable provides comprehensive measurement of flow parameters without requiring separate components that could fail independently.
Solution Approach 2:
The fiber optic cable serves itself by acting as both the signal generation medium and the sensing element. This self-service approach eliminates the need for separate transducers, sensors, and electronic components that require maintenance and can fail, improving system reliability while maintaining measurement accuracy.
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
The system provides accurate and reliable measurement of wellbore parameters like pressure, temperature, and fluid flow rate, improving the monitoring of well performance and reducing the risk of component failures, while enabling real-time adjustments for optimized production and equipment operation.
Implementation Method 1
multiple signal generation gauges, each located at a predetermined location along the first fiber optic cable for producing a generated acoustic signal by tapping out a light of a predetermined wavelength of the first fiber optic cable
Implementation Method 2
A second fiber optic cable extends axially along a second surface portion of the tubing and is operable to receive a resulting signal of the generated acoustic signal
Data Source
Figure 1
Figure 2
AI summary
A system for measuring conditions in a wellbore (10) includes tubing (12) extending into the wellbore. A first fiber optic cable (20) extends axially along a fist surface portion of the tubing and has at least one signal generation gauge (24) located at a predetermined location for producing a generated acoustic signal (26) that propagates outward from the generation gauge and through the tubing. A second fiber optic cable (22) extends axially along a second surface portion of the tubing and is operable to receive a resulting signal of the generated acoustic signal so that wellbore parameters proximate to the predetermined location can be determined. The second fiber optic cable (22) is spaced apart from the first fiber optic cable (20) and is operable to transmit data of the resulting signal to a receiver (30).