X-ray Tomography System for Three-Phase Flow Imaging
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Solution Overview
Problem
Current X-ray tomography systems for three-phase gas-oil-water flows in large diameter pipes face challenges in achieving high temporal and spatial resolution, leading to inaccurate phase distribution measurements due to low sampling rates and insufficient energy discrimination, which complicates the prediction of phase inventory and pressure loss in multiphase pipeline flows.
Innovation Solution
A three-phase X-ray tomography system with two independent channels, each equipped with an X-ray source and high-resolution detectors, uses a copper filter to differentiate between X-ray energy bands, allowing for high sampling rates of up to 300 frames per second and precise measurement of phase distributions by discriminating between gas, oil, and water based on their distinct absorption coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If moving filters are used to provide alternating high and low energy exposures, then energy discrimination is achieved, but temporal resolution decreases to a maximum sampling rate of 5 Hz
Solution Approach 1:
The detector is divided into multiple independent detector elements that can simultaneously measure different energy bands. This segmentation allows parallel measurement of multiple energy ranges without requiring mechanical filter movement, thereby achieving both energy discrimination and high temporal resolution at 300 Hz sampling rate.
Solution Approach 2:
The system transitions from temporal multiplexing (sequential measurements with moving filters) to spatial multiplexing (simultaneous measurements across different detector elements). By adding the spatial dimension of energy band separation across detector elements, the system achieves both energy discrimination and high sampling rates without mechanical movement.
2Device complexity
If conventional measurement techniques are used, then equipment complexity is reduced, but measurement precision of phase distribution decreases
Solution Approach 1:
The patent introduces specialized detector elements with energy discrimination capability as an intermediary between the X-ray source and the flow phases. These detector elements act as mediators that can distinguish between different phases (gas, oil, water) based on their distinct X-ray absorption characteristics at different energy bands, thereby improving measurement precision while maintaining manageable system complexity.
Solution Approach 2:
The system utilizes changes in X-ray energy parameters to differentiate between phases. By measuring attenuation at multiple energy bands and analyzing the distinct absorption characteristics of gas, oil, and water phases, the system achieves precise phase distribution measurement without requiring complex mechanical or chemical intervention.
3Quantity of substance
If dual-energy gamma densitometer is used, then bulk parameters can be measured, but detailed flow structure information is insufficient
Solution Approach 1:
The detector array is segmented into multiple detector elements that can simultaneously measure bulk parameters and provide detailed spatial information about flow structures. This segmentation allows the system to capture both overall phase holdups and local flow pattern details, including interfaces and distribution patterns, without requiring separate measurement systems.
Solution Approach 2:
The system transitions from one-dimensional bulk parameter measurement to two-dimensional cross-sectional imaging capability. By utilizing the spatial arrangement of detector elements and analyzing attenuation patterns across multiple energy bands, the system reconstructs detailed flow structure information including phase distribution, interface locations, and flow patterns in the cross-section.
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 system provides detailed and accurate measurements of three-phase flow structures and phase distributions at high temporal and spatial resolution, reducing errors in holdup calculations and improving the understanding of complex multiphase flow behaviors, essential for validating flow models and ensuring safe and efficient pipeline operations.
Implementation Method 1
a thin copper filter is placed on the top of one section of each detector to harden the X-ray beams so as to give two different energy bands required for distinguishing oil and water
Implementation Method 2
providing vertical and horizontal projections through the test pipe section
Implementation Method 3
discriminating between gas, oil, and water based on their distinct absorption coefficients
Data Source
AI summary
A method of estimating chordal holdup values of gas, oil, and water (εG, εO, εW) for tomographic imaging of a three-phase flow through a volume, including:providing an X-ray source for irradiating through said volume and X-ray sensors for discriminating between a first and a second radiation bands,conducting first calibration measurements (IGS, IOS, IWS) of said first radiation band,conducting second calibration measurements (IGH, IOH, IWH) of said second radiation band,arranging a mixture of two or more fluids,irradiating said volume and conducting X-ray measurements (IS, IH) in said radiation bands,establishing a relationship between a function of holdup values f(εG, εW) of at least gas and water and said X-ray measurements (IS, IH),searching holdup values (εG, εW) that minimize said function of holdup values f(εG, εW) under the constraints of the sum of said holdup values is more than or equal to zero and less than or equal to one, i.e. that 0≦εG+εW≦1.