Non-invasive Perforation Flow Logging via Ultrasonic Phased Array
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Solution Overview
Problem
Current methods for logging perforation flow in wellbores are invasive, unreliable, and lack detailed perforation-by-perforation analysis, especially in inclined wellbores, due to mechanical complexities and inaccuracies in fluid velocity measurements.
Innovation Solution
A downhole measurement apparatus with a staggered arrangement of transducers that transmit and detect acoustic pulses, using range-gated Doppler measurements to determine perforation size and fluid velocity, providing a 360° view with minimal transducers and no moving parts, allowing non-invasive, accurate logging of perforation flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a motor driven rotation head with transducer is used to perform azimuthal scan, then the transducer can be aligned to the centre of the perforation, but the system has mechanical complexities, reliability issues, and wear from moving parts
Solution Approach 1:
The patent replaces the mechanical rotation head system with an ultrasonic phased array that uses electronic beam steering to achieve azimuthal scanning. Instead of physically rotating a transducer mounted on a motor-driven head, the system electronically steers the ultrasonic beam across different azimuthal angles by controlling the phase and timing of multiple fixed transducer elements. This eliminates all moving parts while maintaining the ability to align measurements with perforation centers through computational focusing.
2Reliability
If ultrasonic phased arrays with many transducer elements are used, then electronic beam forming and azimuthal scan can be achieved without moving parts, but the system complexity, cost, and number of electrical connections increase significantly
Solution Approach 1:
The patent divides the ultrasonic transducer system into multiple discrete elements arranged in an array around the tool body. Each element can be independently controlled to contribute to the overall beam formation. This segmentation allows electronic steering and focusing of the ultrasonic beam by selectively activating and phase-shifting individual elements, replacing the need for a single complex rotating transducer while reducing the total number of elements compared to a full phased array.
Solution Approach 2:
The ultrasonic transducer array is designed to perform multiple functions: it can focus beams at different azimuthal angles, steer beams electronically to track perforations, and potentially operate at different frequencies or modes. This multi-functionality is achieved through a unified electronic control system that manages all transducer elements, eliminating the need for separate mechanical scanning systems while maintaining measurement capabilities across the entire azimuthal range.
3Productivity
If conventional production logging velocity measurements are used in inclined wellbores, then flowrate can be measured at points along the wellbore, but strong gradients in fluid velocities and holdup cause inaccurate measurements
Solution Approach 1:
The patent introduces an ultrasonic Doppler measurement system as an intermediary between the flowing fluid and the measurement process. Instead of relying on conventional velocity measurements that are affected by strong gradients in inclined wellbores, the system uses ultrasonic waves to directly measure fluid velocity through Doppler shift of scattered ultrasound. This intermediary measurement technique is less sensitive to the adverse effects of inclination and velocity gradients, providing more accurate flow measurements in challenging wellbore geometries.
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 precise, non-invasive logging of perforation flow and size on a perforation-by-perforation basis, improving accuracy and reliability while reducing complexity and wear, suitable for various wellbore orientations and sizes.
Implementation Method 1
range-gated Doppler measurements to determine perforation size and fluid velocity
Implementation Method 2
transducers that are adapted to transmit and detect an acoustic pulse
Data Source
AI summary
A measurement apparatus for non-invasively logging the flow of perforations in a well casing lining a wellbore. The measurement apparatus includes a plurality of transducers arranged adjacent an outer surface of the measurement apparatus and at predefined azimuthal angular positions with respect to a longitudinal axis of the measurement apparatus, where the transducers are adapted to transmit and detect an acoustic pulse, and where each transducer is arranged at a different azimuthal angle with respect to each of the remaining transducers.