Polymer Injection Well Flow Measurement Using Periodic Tracer Transit
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Solution Overview
Problem
Existing flow rate measurement technologies for polymer injection wells in enhanced oil recovery (EOR) are unreliable due to laminar flow rates causing irregular tracer mixing and inconsistent signal interpretation, especially in wells with varying depths and fluid properties.
Innovation Solution
A fluid transit-based flow rate measurement tool with controlled tracer ejection, sealing, and recharging system, combined with signal processing methods, to ensure repeatable and reliable flow rate determination in polymer injection wells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional tracer logging is used in polymer injection wells, then flow rate measurement is attempted, but the high viscosity of polymer solution induces laminar flow that hinders homogeneous tracer mixing and produces unclear or contradictory results
Solution Approach 1:
The patent employs periodic injection of tracer pulses at controlled intervals into the polymer stream. This periodic action creates distinct tracer bursts that can be individually tracked by detectors, allowing for reliable flow rate calculation even in laminar flow conditions where continuous mixing would be ineffective.
Solution Approach 2:
The patent changes the tracer injection parameters by using multiple injection points spaced along the wellbore and adjusting injection timing and duration. This parameter modification allows the tracer to effectively mark different segments of the polymer flow, enabling accurate flow rate measurement despite the challenging laminar flow regime.
2Measurement precision
If tracer injection is performed in polymer injection wells, then flow rate measurement is attempted, but the tracer penetration distance and jet shape depend on injection pressure and main flow rate, making controlled injection difficult
Solution Approach 1:
The patent divides the tracer injection system into multiple separate injection points or nozzles positioned at different locations along the wellbore. This segmentation allows for distributed tracer introduction that compensates for variations in local flow conditions, ensuring more consistent tracer distribution throughout the polymer stream without requiring precise control at any single point.
Solution Approach 2:
The patent introduces an intermediary injection mechanism that delivers tracer through a controlled delivery system rather than direct injection into the high-velocity polymer stream. This intermediary approach buffers the tracer injection from the harsh flow conditions, making the injection process easier to control while maintaining consistent tracer distribution.
3Measurement precision
If tracer-based flow rate measurement is used in multilayer systems with varying intake capacities, then flow rate determination is attempted, but the system intake profile causes total injected flow rate to partially escape through different layers, complicating readings
Solution Approach 1:
The patent uses periodic tracer pulse injection that creates distinct, time-separated tracer arrivals at detectors. This periodic signaling allows for clear identification of tracer transit times corresponding to different flow paths through the multilayer system, simplifying the interpretation of complex signals from multiple layers with varying intake capacities.
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 tool provides accurate flow rate measurements with an error below 20% by employing multiple signal processing techniques and a sealing system, ensuring consistent tracer distribution and reliable data interpretation.
Implementation Method 1
an actuator that drives, through a reduction gearbox, a rod connected to a plunger
Implementation Method 2
a retraction chamber and an ejection chamber separated by the plunger
Implementation Method 3
the retraction chamber comprises a plurality of pressure equalization holes
Implementation Method 4
the ejection body comprises a plurality of angularly spaced ejection holes
Implementation Method 5
Two radiation detectors are placed downstream to measure the transit time between both detectors
Implementation Method 6
the lower body having a plurality of centering projections, preferably two centering projections, wherein the centering projections are evenly distributed around the clamp and extend radially inward the clamp allowing to hold and keep the tool centered with respect to the clamp
Implementation Method 7
a quick-closing mechanism comprising a spring and linking the upper and lower bodies of the clamp, ensuring its closure
Implementation Method 8
a funnel located in the through-hole of the upper body of the clamp, said funnel allowing for the storage of radioactive tracer fluid
Implementation Method 9
the high viscosity of the polymer solution induces laminar flow rate within the injector well
Implementation Method 10
the flow rate can be calculated by processing the sensor signals using the theoretical framework developed by G. I. Taylor
Data Source
AI summary
A fluid transit-based flow rate measurement tool for polymer injection wells. A sealing and refilling system for said tool. A flow rate measurement method that utilizes said tool. A signal processing method for the fluid transit-based flow rate measurement for polymer injection wells