Online Tracer Injection and Optical Sensing for Multiphase Well Flow
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Solution Overview
Problem
Existing methods for tracer injection and flow characterization in petroleum wells are inefficient in simultaneously injecting and detecting tracers in multiple phases, leading to inaccurate flow characterization due to misinterpretation and lack of precise time resolution.
Innovation Solution
A method and system for injecting and detecting tracers in petroleum wells that involves synchronized injection of water-affine and hydrocarbon-affine tracers at multiple positions, followed by optical monitoring and detection, calculating slip times, and back-calculating zonal slip times to characterize flow behavior, using optical inline tracer detection probes and tracer injection devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tracers are injected simultaneously into all target fluids at multiple positions, then flow characterization accuracy is improved, but device complexity and injection system requirements increase
Solution Approach 1:
The injection system is divided into multiple independent injection devices positioned at different locations along the wellbore. Each device can independently inject tracers into specific fluid phases, allowing simultaneous multi-position injection without requiring a single complex centralized system. This segmentation enables accurate flow characterization while distributing system complexity across multiple simpler units.
Solution Approach 2:
The injection devices are designed with multi-functionality to handle both water-affine and hydrocarbon-affine tracers, as well as to inject into multiple fluid phases simultaneously. This universal design reduces the need for separate specialized injection systems for each tracer type and position, thereby managing device complexity while maintaining measurement precision.
2Measurement precision
If synchronized injection of multiple tracer types is performed, then time resolution for flow characterization is improved, but injection control difficulty increases
Solution Approach 1:
The injection devices are pre-programmed with synchronized injection timing before deployment. This preliminary configuration ensures that water-affine and hydrocarbon-affine tracers are injected simultaneously at multiple positions without requiring complex real-time control operations. The synchronization is established in advance, maintaining high time resolution while simplifying operational control during the actual injection process.
3Measurement precision
If optical detection is used for tracer detection, then detection sensitivity is improved, but device complexity and cost increase
Solution Approach 1:
The detection system replaces complex mechanical sampling and laboratory analysis methods with optical detection technology. Optical sensors can directly detect tracer presence and concentration in the flowing fluids, providing high sensitivity without requiring mechanical sampling systems, laboratory equipment, or complex signal processing infrastructure. This substitution maintains detection sensitivity while reducing overall device complexity.
4Measurement precision
If tracers are injected at multiple positions along the well, then flow distribution characterization is improved, but injection time and operational duration increase
Solution Approach 1:
The injection process uses periodic action by injecting tracers in synchronized pulses at multiple positions rather than continuously. Each injection device delivers tracer in a controlled pulse sequence, allowing simultaneous injection events at different positions. This periodic approach maintains comprehensive flow distribution characterization while minimizing total injection time compared to continuous or sequential injection methods.
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 accurate and efficient characterization of multi-phase petroleum well flow by ensuring rapid mixing and detection of tracers, allowing for precise determination of inflow distribution and flow regimes, even in long distances without disrupting the flow regime.
Implementation Method 1
a light source for generating light capable of generating luminescent light in the tracers
Implementation Method 2
one or more optical fibres through the sensor body for receiving backscattered luminescence
Implementation Method 3
the tracers being optically detectable... allowing transport of the production flow from the downhole injection points
Implementation Method 4
one or more optical fibres through the sensor body for guiding the light to and through the windows into the flow
Data Source
AI summary
The invention is a method, a system, tools for use by the system, and an interpretation method for injecting and detecting tracers and conducting flow characterizing of a petroleum well. The method describes monitoring of travel time and slip velocity between two/three different phases (oil/water and possibly gas) in the well. The travel time and slip velocity are determined using an injection too for injection of an over pressurized injection of the partitioning tracers each of which would follow certain phase. The tracers are detected by an optical detection probe in the pipe. The slip velocity is obtained from the difference of travel time of two tracers which partition to two different phases.