Downhole Fluid Phase Transition Detection via Pressure Deviation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining phase transition pressures of downhole fluids face challenges due to unknown fluid compressibility, leading to inaccurate measurements and prolonged testing times, as they often require constant volume expansion rates and measurement of fluid properties versus pressure.
Innovation Solution
The implementation of a fluid analysis tool that induces a prescribed pressure change according to a predetermined pressure versus time profile, allowing for phase transition pressure determination without measuring fluid volume or property variations, using a pressure changing device and sensors to monitor pressure changes over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If constant volume expansion rate methods are used to determine phase transition pressure, then measurement can be performed, but measurement accuracy deteriorates due to unknown fluid compressibility
Solution Approach 1:
The patent changes the control parameter from constant volume expansion rate to prescribed pressure change rate. By controlling the pressure change rate according to a predetermined profile rather than maintaining constant volume expansion, the method eliminates the need to know fluid compressibility while achieving accurate phase transition pressure determination through deviation detection from the prescribed pressure profile
Solution Approach 2:
The patent replaces the mechanical measurement approach (measuring volume changes and fluid properties versus pressure) with a pressure-controlled approach using prescribed pressure versus time profiles. This substitution eliminates the need for volume measurement devices and complex property analysis while improving measurement reliability
2Measurement precision
If fluid properties versus pressure measurements are performed to determine phase transition pressure, then phase transition can be detected, but testing duration is prolonged
Solution Approach 1:
The patent extracts and eliminates the time-consuming step of measuring fluid properties versus pressure. By using only pressure measurements at different times and comparing them to a prescribed pressure profile, the method achieves phase transition detection without requiring extensive property measurements, thereby reducing testing duration
Solution Approach 2:
The patent skips the intermediate step of measuring fluid properties at various pressure points. Instead of gradually measuring properties versus pressure, the method directly detects phase transition by monitoring deviations from the prescribed pressure versus time profile, accelerating the testing process
3Measurement precision
If fluid volume measurement is required for phase transition pressure determination, then accurate results can be obtained, but device complexity and measurement difficulty increase
Solution Approach 1:
The patent replaces volume measurement mechanisms with a pressure-based detection system. By using a prescribed pressure versus time profile and monitoring pressure deviations, the method eliminates the need for volume measurement devices and complex volumetric analysis apparatus
Solution Approach 2:
The patent uses a predetermined pressure versus time profile as a reference model. By comparing actual pressure measurements against this prescribed profile, the method determines phase transition pressure without directly measuring fluid volume or properties, simplifying the measurement system
Data Source
AI summary
Methods and apparatuses for analyzing a downhole fluid are disclosed. An example method may involve the steps of admitting the downhole fluid in a test volume, controllably inducing a pressure change in the test volume based on at least one prescribed rate, measuring pressures in the test volume at a plurality of times, using the pressures measured at the plurality of times to determine a time at which an actual rate of the pressure change in the test volume deviates from the at least one prescribed rate, and detecting an occurrence of phase transition of the downhole fluid based on the determined time.