Portable EPR Spectrometer for Flowing Fluid Analysis
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Solution Overview
Problem
Existing EPR spectrometers are unsuitable for field use in the oil industry due to their large size, high cost, and weight, and they cannot perform real-time measurements of flowing fluids under actual wellhead conditions without exposing the fluid to air or changing its temperature and pressure.
Innovation Solution
A portable EPR spectrometer system that performs continuous EPR measurements on flowing fluids by integrating a tube with a cavity capable of receiving the fluid, a magnetic field generator, transmit and receive circuitry, and a processor to control frequency and impedance matching, allowing for real-time analysis without exposing the fluid to atmospheric conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional EPR spectrometers are used, then measurement precision is achieved, but device size and weight become too large for field use
Solution Approach 1:
The EPR spectrometer is divided into separate functional modules: a resonator assembly that can be positioned in the wellbore, a magnetic field generator, and a control system. This segmentation allows the measurement function to be separated from the heavy supporting infrastructure, enabling field deployment while maintaining measurement capability.
Solution Approach 2:
The patent transitions from conventional benchtop EPR instrumentation to a downhole wellbore-based measurement system. By moving the measurement environment from laboratory surfaces to the three-dimensional wellbore space, the system achieves portability and field applicability without compromising the fundamental EPR measurement precision.
2Measurement precision
If traditional EPR spectrometers are used, then measurement precision is maintained, but device complexity and cost increase
Solution Approach 1:
The resonator assembly serves multiple functions: it acts as both the electromagnetic resonant cavity for EPR measurements and the structural component that interfaces with the wellbore environment. This multi-functionality reduces the number of separate components needed, simplifying the overall system while maintaining measurement precision.
Solution Approach 2:
The system uses the existing wellbore infrastructure and native wellhead conditions as part of the measurement environment. The fluid sample is measured in situ without requiring external sampling, preparation, or transfer systems, thereby reducing device complexity and eliminating the need for complex sample handling apparatus.
3Ease of operation
If fluid is exposed to air for measurement, then measurement access is improved, but fluid properties change due to temperature and pressure changes
Solution Approach 1:
The resonator assembly acts as an intermediary measurement interface that can be positioned within the wellbore fluid environment. This intermediary structure allows electromagnetic penetration for EPR measurements while maintaining the fluid's native pressure and temperature conditions, avoiding direct exposure to atmospheric conditions that would alter fluid composition.
Solution Approach 2:
The measurement is performed in the native wellbore environment which maintains an inert, controlled atmosphere relative to the fluid sample. By conducting measurements in situ rather than exposing the fluid to atmospheric air, the system preserves the fluid's original composition and prevents oxidation or other atmospheric interactions.
4Productivity
If real-time measurements of flowing fluid are performed, then productivity is improved, but measurement precision becomes difficult to maintain
Solution Approach 1:
The resonator assembly enables continuous EPR measurements as fluid flows through the wellbore. The system maintains uninterrupted measurement capability by positioning the resonator in a fixed location where fluid continuously passes through the measurement zone, allowing real-time monitoring without sacrificing precision through continuous data acquisition.
Solution Approach 2:
The system performs preliminary frequency sweeps and resonance condition optimizations before actual EPR measurements to ensure optimal measurement conditions are established. This preliminary setup ensures that when real-time measurements begin, the system is already calibrated for precision, maintaining measurement quality throughout the continuous monitoring process.
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 continuous, real-time EPR spectroscopy of flowing fluids at wellhead conditions, maintaining the fluid's original temperature and pressure, and adapting to rapidly changing properties, improving the accuracy and reliability of oilfield fluid analysis.
Implementation Method 1
a polarizing static magnetic field B0 (also referred to as a DC magnetic field) is applied to a sample to align the magnetic moments of the electrons along the direction of the magnetic field B0
Implementation Method 2
a high-frequency oscillating magnetic field B1, often referred to as the transverse magnetic field or the radio frequency (RF) magnetic field, is applied along a direction that is perpendicular to the polarizing field B0
Implementation Method 3
EPR is a measurement technique that relies on the external manipulation of the direction of this electron paramagnetization, also referred to as a net electronic magnetic moment
Data Source
AI summary
Certain aspects of the present disclosure provide methods and apparatus for performing electron paramagnetic resonance (EPR) spectroscopy on a fluid from a flowing well, such as fluid from hydrocarbon recovery operations flowing in a downhole tubular, wellhead, or pipeline. One example method generally includes, for a first EPR iteration, performing a first frequency sweep of discrete electromagnetic frequencies on a cavity containing the fluid; determining first parameter values of reflected signals from the first frequency sweep; selecting a first discrete frequency corresponding to one of the first parameter values that is less than a threshold value; activating a first electromagnetic field in the fluid at the first discrete frequency; and while the first electromagnetic field is activated, performing a first DC magnetic field sweep to generate a first EPR spectrum.