Lanthanide Complex Tracers for Time-Gated Reservoir Flow Mapping
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Solution Overview
Problem
Existing cross-well tracers for petroleum reservoirs face challenges such as high retention in rock, thermal instability, chemical reactivity, and difficulty in detecting low concentrations amidst background noise, which hinders accurate fluid flow path analysis and water flood management.
Innovation Solution
Complexing agents that form lanthanide ion complexes, emitting fluorescence signals with temporal delay, allowing for time-gated detection and background-free measurement of tracer concentrations as low as parts-per-quadrillion, enabling precise fluid flow path mapping and reservoir connectivity evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cross-well tracers are used, then tracer can be detected in reservoir fluid, but tracer exhibits high retention in rock and thermal instability
Solution Approach 1:
The patent changes the chemical parameters of the tracer by using complexing agents that form stable complexes with lanthanide ions. This chemical transformation enables the tracer to withstand high temperatures and resist adsorption onto rock surfaces, simultaneously improving thermal stability and reducing rock retention.
Solution Approach 2:
The invention creates a composite tracer system by combining complexing agents with lanthanide ions to form stable complexes. This composite approach leverages the unique properties of both components: the complexing agent provides structural stability while the lanthanide ion enables fluorescence detection and resistance to thermal degradation.
2Measurement precision
If conventional tracers are used, then fluid flow paths can be traced, but detection of low concentrations is difficult amidst background noise
Solution Approach 1:
The patent utilizes fluorescence emission as an optical signal change property. The lanthanide ion complexes exhibit characteristic fluorescence that can be detected at extremely low concentrations. By measuring this optical emission, the system achieves high sensitivity detection capability that overcomes background interference from natural constituents.
Solution Approach 2:
The invention replaces conventional detection methods with fluorescence-based optical detection. This substitution enables detection of tracer concentrations as low as parts-per-quadrillion, providing superior measurement precision compared to traditional mechanical or chemical detection approaches.
3Measurement precision
If purer tracer detection is achieved, then measurement precision improves, but time and resources for purification increase
Solution Approach 1:
The patent employs a detection system that can measure tracer concentrations directly in the extracted fluid without requiring prior purification steps. The fluorescence detection method is sufficiently sensitive to detect tracer signals even in the presence of natural constituents, eliminating the need for time-consuming purification and derivatization procedures.
4Measurement precision
If tracer concentration is reduced to increase sensitivity, then detection limit improves, but signal strength decreases
Solution Approach 1:
The patent changes the detection parameter by utilizing the unique fluorescence properties of lanthanide ion complexes. These complexes exhibit long fluorescence lifetimes and characteristic emission wavelengths that allow for time-gated detection. This enables differentiation of the tracer signal from background fluorescence, maintaining signal strength even at extremely low concentrations.
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 detection of tracer concentrations down to 10 picomolar or less, reducing time and costs associated with reservoir mapping and water flooding management by providing accurate fluid flow path information.
Implementation Method 1
The complexes formed, when exposed to excitation light, emit a fluorescence signal that is temporally delayed relative to fluorescence signals from other components of the extracted reservoir fluid
Data Source
AI summary
The disclosure features methods of analyzing a fluid extracted from a reservoir, the methods including introducing a first composition featuring a first complexing agent into a reservoir at a first location, extracting a fluid from the reservoir at a second location different from the first location, combining the fluid with a second composition featuring a concentration of a lanthanide ion to form a third composition featuring a concentration of a complex formed by the first complexing agent and the lanthanide ion, exposing a quantity of the complex to electromagnetic radiation for a first time period ending at a time t0, detecting fluorescence emission from the quantity of the complex for a second time period starting at a time t1>t0, where t0−t0 is greater than 2 microseconds, and determining information about a fluid flow path between the first location and the second location.