Polymeric Tracers for Subterranean Flow Pathway Mapping
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Solution Overview
Problem
Current tracer technologies in oilfield applications face challenges due to overlapping fluorescence signals, limited detection range, sensitivity to environmental factors, and difficulties in detecting molecular tracers in saline aqueous matrices, which complicates understanding fluid connectivity between injection and production wells, leading to reduced oil production efficiency.
Innovation Solution
The use of polymeric tracers that undergo thermal decomposition, allowing for the generation of distinct pyrolysis products detectable by pyrolysis-GCMS, eliminating the need for expensive functionalized molecular taggants and enabling clear tracing of fluid flow pathways without interference from water or electrolytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fluorescence-based molecular tracers are used, then tracer detection is possible, but signal overlap and limited detection range reduce the number of distinguishable tracers
Solution Approach 1:
The patent changes the detection parameter from fluorescence emission wavelength to pyrolysis product mass-to-charge ratio. By thermal decomposing polymeric tracers and detecting the resulting monomer fragments via GCMS, the system achieves sharp quasi-discrete signals that eliminate the bandwidth overlap problem inherent in fluorescence detection, thereby increasing the number of distinguishable tracers.
2Ease of operation
If molecular tracers are used in saline aqueous matrices, then fluid flow tracing is possible, but water incompatibility with GCMS requires time-consuming and expensive isolation procedures
Solution Approach 1:
Instead of extracting the tracer from water before detection, the patent extracts water and other volatile interferents through pyrolysis. The thermal decomposition process removes water and electrolytes, leaving behind non-volatile polymeric tracer fragments that are directly compatible with GCMS analysis, thereby eliminating the need for separate isolation procedures.
3Measurement precision
If fluorescence detection is used, then tracer presence can be detected, but sensitivity to salinity, temperature, and dissolved organic matter makes quantitation difficult
Solution Approach 1:
The patent replaces the fluorescence detection mechanism with thermal decomposition and mass spectrometry. This substitution eliminates sensitivity to environmental factors because pyrolysis is a thermal process that breaks down the polymer into characteristic monomer fragments regardless of the original environmental conditions, providing robust quantitation.
4Measurement precision
If polymeric tracers undergo thermal decomposition, then distinct pyrolysis products generate sharp signals, but high pyrolysis temperatures are required
Solution Approach 1:
The patent changes the physical state of the tracer from small molecules to polymers. The polymeric structure requires higher temperatures for decomposition, but this trade-off is acceptable because it produces sharp, quasi-discrete pyrolysis signals that are easily distinguishable, overcoming the signal overlap problems of fluorescence detection.
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
This approach provides a rich barcoding scheme for tracing fluid flow in complex subterranean systems, enhancing the ability to map fluid pathways and optimize oil recovery by generating sharp, quasi-discrete signals and increasing the number of detectable tracers, while reducing material costs and simplifying detection protocols.
Implementation Method 1
pyrolyzing the first dehydrated sample to yield a first gaseous sample
Data Source
AI summary
Tracing subterranean fluid flow includes providing a first polymeric tracer to a first injector, collecting a first aqueous sample from a first producer, and assessing the presence of the first polymeric tracer in the first aqueous sample. The first polymeric tracer includes a first polymer formed from at least a first monomer. The presence of the first polymeric tracer in the first aqueous sample is assessed by removing water from the first aqueous sample to yield a first dehydrated sample. pyrolyzing the first dehydrated sample to yield a first gaseous sample, and assessing the presence of a pyrolization product of the first polymer in the first gaseous sample. The presence of the pyrolization product of the first polymer in the first gaseous sample is indicative of the presence of a first subterranean flow pathway between the first injector location and the first producer location.