Dielectric Spectroscopy for Non-Linear Water Cut Measurement
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Solution Overview
Problem
Current methods for determining water cut values in hydrocarbon production, especially in mature fields using water injection techniques, face challenges due to non-linear permittivity effects caused by the conductivity of brine, leading to inaccurate measurements and economic inefficiencies when water content exceeds 80% relative to hydrocarbons.
Innovation Solution
A method and apparatus that utilize ratiometric mixture permittivity values, induced frequency, and salinity measurements to accurately determine water cut values, accounting for complex permittivity components and non-linear effects, thereby improving the reliability and accuracy of hydrocarbon production monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water injection techniques are used to enhance hydrocarbon production, then productivity increases by up to 50%, but measurement precision deteriorates when water content exceeds 80% due to non-linear permittivity effects
Solution Approach 1:
The patent applies parameter changes by transitioning from traditional capacitance measurement at fixed frequency to dielectric spectroscopy that measures permittivity across a spectrum of frequencies. This frequency domain transformation allows differentiation between linear hydrocarbon responses and non-linear brine responses, enabling accurate water cut determination even at high water cuts exceeding 80% where traditional methods fail
Solution Approach 2:
The patent introduces another dimension by adding frequency as a new measurement dimension. Instead of single-point capacitance measurement, the system measures permittivity across multiple frequencies, creating a frequency spectrum signature. This dimensional expansion allows the system to distinguish between the non-monotonic behavior caused by conductive brine and the monotonic behavior of hydrocarbons, resolving the measurement ambiguity at high water cuts
2Device complexity
If traditional capacitance measuring devices are used, then device complexity remains low, but measurement precision deteriorates due to inability to account for non-linear permittivity effects of conductive brine
Solution Approach 1:
The patent replaces traditional mechanical/electrical capacitance measurement systems with dielectric spectroscopy that operates in the frequency domain. By substituting single-frequency capacitance sensing with multi-frequency permittivity spectral analysis, the system can mathematically deconvolve the non-linear contributions of conductive brine from the total measured signal, achieving accurate water cut determination without requiring complex physical separation or sampling systems
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 robust and reliable technique for determining water cut values, reducing measurement drift and enhancing hydrocarbon production by optimizing water and hydrocarbon ratios, thus improving the efficiency of enhanced oil recovery (EOR) processes.
Implementation Method 1
detecting a mixture permittivity value associated with the induced frequency value
Implementation Method 2
Reduced frequency (≤1 MHz) permittivity measuring devices are based upon detecting the capacitance of a fluid
Data Source
AI summary
The present disclosure relates to a method for determining a water cut value of a composition comprising a hydrocarbon. In some embodiments, the disclosure relates to an apparatus for determining the water cut value of the composition that comprises one or more of a capacitance probe, a temperature probe, a salinity probe, and a computer.