Downhole Fluid Sampling Holdup Detection With Dual-Resolution Sensors
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Solution Overview
Problem
Fluid holdups during downhole fluid sampling operations lead to unreliable measurements and sampling due to trapped gas bubbles or liquid droplets on the pipe wall, affecting optical and chemical analysis, with conventional flushing methods lacking assurance of complete clearance.
Innovation Solution
Utilizing a combination of high and low spatial resolution sensors to monitor fluid holdups by comparing fluid ratios derived from optical and density measurements, enabling real-time identification and guided mechanical flushing to clear trapped fluids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical flushing procedures are used to clear fluid holdups, then trapped fluids may be removed, but there is no assurance of complete clearance and measurements may still be unreliable
Solution Approach 1:
The patent employs feedback by continuously monitoring fluid properties (optical measurements, density, capacitance) and using this information to determine when holdups have been cleared. The system adjusts flushing operations based on real-time measurement feedback, ensuring complete clearance while avoiding unnecessary flushing cycles.
Solution Approach 2:
The patent replaces purely mechanical flushing procedures with a hybrid system that uses optical sensors, density measurements, and capacitance measurements to detect and monitor holdups. This substitution allows for precise detection of holdup conditions and verification of clearance without relying solely on mechanical flushing intensity.
2Reliability
If periodic flushing is performed to clear holdups, then trapped fluids may be removed, but time is lost and productivity decreases
Solution Approach 1:
The patent performs preliminary detection of holdup conditions using optical and density measurements before they significantly impact sampling reliability. By detecting holdups early, the system can initiate targeted flushing only when necessary, preventing unnecessary productivity loss while maintaining sampling reliability.
Solution Approach 2:
The system uses real-time feedback from multiple measurement channels to determine when flushing is actually needed. This feedback-driven approach eliminates periodic flushing schedules, allowing continuous productive operation while maintaining measurement reliability through on-demand clearance only when holdups are detected.
3Measurement precision
If high spatial resolution optical measurements are used to detect holdups, then detection precision improves, but the measurements become more sensitive to holdup interference
Solution Approach 1:
The patent merges multiple measurement techniques (optical measurements, density measurements, capacitance measurements) into a unified detection system. By combining these methods, the system achieves high detection precision while compensating for the sensitivity of individual methods to holdup interference through cross-validation of results.
Solution Approach 2:
The patent uses density measurements and capacitance measurements as intermediary indicators that are less sensitive to optical interference from holdups. These intermediary measurements provide corroborating evidence of holdup conditions without being as severely affected by the presence of trapped fluids as direct optical measurements.
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
Enhances the accuracy and reliability of downhole fluid sampling by providing real-time monitoring and reducing unnecessary flushing procedures, ensuring reliable fluid composition analysis.
Implementation Method 1
optical measurements including, but not limited to, optical spectroscopy, index of refraction, florescence
Implementation Method 2
optical measurements including, but not limited to, optical spectroscopy, index of refraction, florescence
Implementation Method 3
density measurements
Implementation Method 4
capacitance measurements
Implementation Method 5
a pump operable to pressurize and circulate the fluids through the sampling system
Data Source
AI summary
Methods to identify fluid holdups during downhole fluid sampling operations includes obtaining, using a sampling tool positioned within a wellbore, one or more fluid measurements using at least one sensor having a first set of spatial resolution, obtaining one or more second fluid measurements having a second spatial resolution, calculating a first fluid ratio using the at least one sensor having the first set of spatial resolution measurements, calculating a second fluid ratio of the second fluid measurements using the at least one sensor having the second set of spatial resolution, wherein the second set of spatial resolution is lower than the first set of spatial resolution, and identifying fluid holdup within the sampling tool when the differences between the two fluid ratios are higher than a limit or a similarity of the two fluid ratios are lower than a limit.