Shunt Chamber Tracer Separation for Multi-Phase Downhole Surveillance
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Solution Overview
Problem
Existing methods for monitoring fluid rates in petroleum wells with multi-phase flows, such as oil, gas, and water, are limited by the complexity and cost of well shut-ins, and lack accurate control over tracer exposure to target fluids, leading to uncertainties in zonal flow rate measurements due to slip and gravity differences.
Innovation Solution
A shunt chamber apparatus with flow phase separation, tracer chambers, outlet ports, and flow restrictors is used to separate and flush out low-density and high-density phases with tracers, creating tracer transients for downstream detection, allowing calculation of inflow profiles based on tracer velocity fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional tracer injection methods are used in multi-phase flow, then tracer can be injected into the main flow path, but control over tracer exposure to target fluid is limited and measurement accuracy deteriorates due to slip and gravity differences
Solution Approach 1:
The invention divides the flow path into separate segments for different phases using a shunt chamber with distinct flow paths. Low-density phase (e.g., oil) and high-density phase (e.g., water) are separated and injected with tracers independently through separate restrictors, ensuring each tracer is exposed only to its target phase and eliminating measurement errors from phase mixing
Solution Approach 2:
The shunt chamber acts as an intermediary device between the multi-phase flow and the tracer injection system. It receives the mixed multi-phase flow, separates the phases through density differences, and provides controlled interfaces for tracer injection into each phase separately, thereby mediating the interaction between tracers and target fluids
2Measurement precision
If well shut-in is performed to build up tracer concentration at influx zones, then qualitative and quantitative production data can be obtained, but project complexity and cost increase significantly and production revenue is lost
Solution Approach 1:
The shunt chamber is pre-installed in the well completion with tracer injection capabilities built in. This preliminary preparation allows tracer injection to occur during normal production without requiring well shut-ins, eliminating the need for complex project planning and revenue loss while maintaining measurement quality
Solution Approach 2:
The system enables continuous tracer injection and monitoring during ongoing production operations. The shunt chamber maintains flow separation and tracer injection functionality throughout the production lifecycle, allowing continuous data collection without interruption to production activities
3Ease of manufacture
If tracers are injected into the main flow path without phase separation, then injection is simple, but tracer exposure to target fluid cannot be controlled and measurement uncertainty increases
Solution Approach 1:
The shunt chamber segments the single main flow path into multiple phase-specific flow paths based on density separation. Each phase (low-density and high-density) has its own dedicated flow path with separate tracer injection points and restrictors, maintaining relative simplicity while enabling precise control over which tracers contact which phases
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, cost-effective, and continuous monitoring of multi-phase flow rates by forming tracer clouds that can be detected downstream, providing precise inflow profile calculations without well shut-ins, thus improving production surveillance.
Implementation Method 1
separating a shunt flow in the shunt chamber into a low-density flow phase and a high-density flow phase
Implementation Method 2
passing the separated low-density flow phase and high-density flow phase through each flow restrictor
Data Source
AI summary
The invention provides a method for quantitative downhole surveillance of a multi-phase flow, comprising at least two phases of either oil, water or gas, in a petroleum well. The method comprising providing at least one shunt chamber which comprises a flow phase separation section, a delay chamber, one or more outlet ports, at least one flow restrictor and a tracer release system with one or more tracers. The method comprises separating a shunt flow in the shunt chamber into a low-density flow phase and a high-density flow phase; releasing at least one tracer into the tracer delay chamber. The method also comprises passing the separated low-density flow phase and high-density flow phase through each flow restrictor and flushing out the low-density phase flow and the high-density phase flow with tracer from the shunt chamber through the outlet ports into the local flow inside the well. The method comprises monitoring the at least one tracer in the production flow at a detection point downstream of the outlet ports and measuring