Downhole Fluid Phase Sensor Saturation Pressure Measurement
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Solution Overview
Problem
Current methods for sampling subterranean formation fluids face challenges in maintaining flowline pressure above the saturation pressure, leading to inefficient pumping and contamination issues due to the formation of gas bubbles or liquid condensate.
Innovation Solution
A downhole sampling tool with a fluid flowline and a fluid phase sensor that measures saturation pressure by heating or cooling the fluid, estimating temperature, and processing pressure and temperature data to compute saturation pressure, allowing for real-time adjustment of pumping rates to maintain pressure above the saturation threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pumping rate is increased to improve sampling efficiency, then the productivity is improved, but the flowline pressure drops below the saturation pressure causing gas bubble formation and reducing pumping efficiency
Solution Approach 1:
The system continuously measures flowline pressure and compares it to the saturation pressure of the formation fluid. When the pressure approaches the saturation pressure, the system provides feedback to reduce the pumping rate, preventing gas bubble formation. This closed-loop control enables the system to operate at maximum efficiency without crossing into the two-phase region.
Solution Approach 2:
The pumping rate is dynamically adjusted based on real-time pressure measurements and fluid composition analysis. The system transitions from a static pumping rate to a dynamic one that adapts to changing conditions, allowing maximum productivity while maintaining single-phase flow conditions.
2Loss of time
If the pumping rate is increased to reduce sampling time, then the loss of time is reduced, but gas bubbles form due to pressure drop below saturation pressure
Solution Approach 1:
Real-time pressure monitoring provides continuous feedback on the proximity to saturation pressure. This feedback mechanism allows the system to identify the maximum safe pumping rate that prevents gas bubble formation, enabling rapid sampling without the harmful effects of two-phase flow.
Solution Approach 2:
The system changes the pumping rate parameter dynamically based on measured fluid composition and pressure conditions. By adjusting this parameter in real-time, the system achieves rapid sampling while maintaining conditions that prevent gas bubble formation.
3Productivity
If pumping is performed rapidly to improve productivity, then the productivity is improved, but optical spectroscopy measurements are degraded due to bubble formation
Solution Approach 1:
The system monitors pressure and fluid composition continuously, providing feedback that ensures pumping operations remain within the single-phase region. This feedback control maintains measurement quality by preventing bubble formation that would interfere with optical spectroscopy measurements.
Solution Approach 2:
The system performs preliminary analysis of fluid composition and saturation pressure before initiating rapid pumping. This preliminary action establishes the safe operating parameters that maintain measurement precision while enabling high-speed sampling.
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 enables rapid and efficient sampling by maintaining a single phase fluid in the flowline, improving pumping speed and reducing contamination, while allowing for continuous saturation pressure measurement and optimal pumping rate adjustment.
Implementation Method 1
The saturation pressure may be measured in the flowline, for example, by heating or cooling formation fluid in the flowline while pumping
Implementation Method 2
The saturation pressure may be measured in the flowline, for example, by heating or cooling formation fluid in the flowline while pumping
Implementation Method 3
The fluid phase sensor includes a temperature sensor and at least one of a heating element and a cooling element deployed on a substrate
Implementation Method 4
evaluating the temperature estimates to determine a temperature indicative of bubble or dew formation in the flowline
Data Source
AI summary
A method for sampling a downhole formation fluid includes pumping formation fluid into the flowline of a downhole sampling tool While pumping, a saturation pressure of the formation fluid is measured. The pumping rate is adjusted such that the fluid pressure in the flowline remains above a threshold saturation pressure.