In-situ Phase-Change Pressure Detection via Light Scattering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining phase-change pressures of formation fluids in wellbores are limited by the need for laboratory analysis or require measuring fluid volume, which can be difficult or unreliable, especially when fluids are not sealed or are compressible.
Innovation Solution
A system using a wireline assembly with a fluid isolation and analysis tool that induces a controlled pressure change and measures light scattering to detect phase-change pressures, allowing in-situ analysis without requiring fluid volume measurement, using sensors like photo-detectors or acoustic sensors to identify gas bubbles, liquid droplets, and asphaltene particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laboratory analysis is used to determine phase-change pressures, then measurement precision is improved, but loss of time increases and device complexity increases
Solution Approach 1:
The patent replaces mechanical/lab-based phase-change pressure measurement systems with an optical detection system. A light source emits light through the formation fluid, and a detector measures light transmittance. When phase change occurs (bubble point, dew point, asphaltene onset), the fluid's optical properties change, causing detectable variations in light transmittance. This substitution eliminates the need for retrieving fluid to the laboratory while maintaining measurement precision.
Solution Approach 2:
The patent introduces light as an intermediary substance to detect phase-change pressures. Instead of directly measuring pressure changes or fluid composition, the system uses light transmittance as a mediator that responds to phase changes in the formation fluid. The light source and detector act as intermediaries that translate complex phase-change phenomena into measurable optical signals, enabling in-situ measurement without laboratory analysis.
2Measurement precision
If fluid volume measurement is used to determine phase-change pressures, then measurement precision may be improved, but device complexity increases and reliability decreases when fluids are compressible or not sealed
Solution Approach 1:
The patent replaces mechanical volume measurement methods with optical detection. Instead of measuring fluid volume changes during pressure variation, the system measures light transmittance through the fluid. Phase changes affect the fluid's optical density and light scattering properties, providing a reliable detection method that works regardless of fluid compressibility or sealing conditions, eliminating the reliability issues associated with volume measurement of compressible fluids.
3Productivity
If in-situ analysis is implemented to reduce laboratory analysis needs, then loss of time is reduced and productivity increases, but measurement precision may worsen
Solution Approach 1:
The patent employs optical detection methodology that enables in-situ measurement of phase-change pressures. By measuring light transmittance variations caused by phase changes directly in the wellbore, the system achieves both rapid results and high measurement precision. The optical method is sensitive to subtle phase changes, maintaining accuracy while eliminating the time delay associated with laboratory analysis.
Solution Approach 2:
The use of light as an intermediary enables precise in-situ detection of phase changes. The light source and detector system translates phase-change phenomena into optical signals that can be measured accurately in the field. This intermediary approach maintains measurement precision while enabling rapid in-situ analysis, as the optical detection is sensitive to the physical changes occurring during phase transitions.
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 accurate and efficient determination of phase-change pressures, such as bubble point, dew point, and asphaltene onset pressure, directly in the wellbore, reducing the need for laboratory analysis and overcoming challenges related to fluid volume measurement and compressibility.
Implementation Method 1
measuring a plurality of transmittances of a signal through the formation fluid... measures a plurality of transmittances of light through the formation fluid
Data Source
AI summary
Example methods and apparatus to determine phase-change pressures are disclosed. A disclosed example method includes capturing a fluid in a chamber, pressurizing the fluid at a plurality of pressures, measuring a plurality of transmittances of a signal through the fluid at respective ones of the plurality of pressures, computing a first magnitude of a first subset of the plurality of transmittances, computing a second magnitude of a second subset of the plurality of transmittances, comparing the first and second magnitudes to determine a phase-change pressure for the fluid.