Downhole Thermal Conductivity Detectors for Transient Flow Measurement
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Solution Overview
Problem
Current methods for measuring fluid flow characteristics during and after perforation in wellbores lack accuracy and efficiency, particularly in determining transient inflow profiles and fluid velocities across multiple layers in subterranean formations.
Innovation Solution
A downhole tool equipped with a thermal insulating body and a pair of recessed thermal conductivity detectors (TCDs) spaced laterally apart, embedded in a shaped charge package, which measures thermal characteristics of the flowing fluid by detecting temperature changes caused by Joule Thomson and Adiabatic effects, allowing for precise determination of fluid flow velocities and profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spinner type flow meters are used for production logging, then fluid flow rates can be measured, but measurement accuracy is insufficient for transient inflow profiles and fluid velocities across multiple layers
Solution Approach 1:
The patent replaces mechanical spinner type flow meters with a thermal-based measurement system using thermal conductivity detectors (TCDs). This substitution eliminates mechanical moving parts that limit accuracy in transient conditions, using instead thermal field measurements to detect fluid flow characteristics, achieving superior measurement precision for transient inflow profiles and multi-layer fluid velocities.
2Measurement precision
If thermal conductivity detectors are placed directly in fluid flow path, then fluid velocity measurement is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent embeds the thermal conductivity detectors within a nested structure consisting of a thermal insulating body containing a cavity, which itself contains the TCDs. This nested arrangement protects the sensitive detectors from direct fluid exposure while maintaining measurement capability through the insulating body's thermal properties, simplifying manufacturing compared to direct placement methods.
3Loss of information
If multiple thermal conductivity detectors are spaced laterally apart to measure multi-layer flow, then flow profile determination is improved, but device complexity increases
Solution Approach 1:
The patent designs the thermal insulating body with a cavity structure that can accommodate multiple TCDs spaced laterally apart, where each detector serves the same function of thermal conductivity measurement but at different spatial positions. This universal design approach allows the same basic detector unit to be replicated and positioned strategically, capturing comprehensive flow profile information without proportionally increasing overall device complexity.
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 solution enables accurate measurement of fluid flow velocities and profiles, including transient conditions, across multiple layers, enhancing the understanding of fluid flow dynamics and optimizing hydrocarbon production by providing detailed flow rate and phase distribution data.
Implementation Method 1
a thermal insulating body having an exterior surface to be disposed in use such that a fluid flows across the exterior surface and a recessed thermal conductivity detector (TCD) having a sensor face of a thermally conductive pane
Implementation Method 2
measuring a velocity of the fluid flowing from the perforations across the downhole tool toward the surface using a measuring device arranged in shaped charge package
Implementation Method 3
measuring thermal characteristics of the flowing fluid by detecting temperature changes caused by Joule Thomson and Adiabatic effects
Data Source
AI summary
A measurement device is configured in a shaped charge package to be utilized in a perforating gun section tool string. The measurement device may include for example thermal conductivity detectors (TCD) configured to measure fluid flow velocity and/or thermal characteristics of the flowing fluid. The measurement device may include for example a pair laterally spaced TCDs each having sensor faces positioned co-planar with a surface across which the fluid flows. The measurement device may include a recessed TCD, having a sensor face recessed below an opening in the exterior surface.