Subterranean Fluid Sampling Apparatus with Pressure Buffer
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Solution Overview
Problem
Conventional fluid sampling methods from subterranean formations result in sample degradation due to temperature decrease and pressure reduction during retrieval, making the sample no longer representative of the downhole environment.
Innovation Solution
A fluid sampling apparatus with a sample chamber and a housing that includes a compressible fluid-filled annulus to maintain sample pressure, allowing the compressible fluid to pressurize the sample and maintain it near reservoir conditions, using a system that can be conveyed via slickline, wireline, or coiled tubing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sampling tool is retrieved to the surface, then the fluid sample can be analyzed, but the temperature and pressure of the fluid sample decrease causing shrinkage and loss of representativeness
Solution Approach 1:
The patent introduces an intermediary substance (gel or viscous fluid) that fills the space between the sampling chamber and the outer housing. This intermediary acts as a thermal and pressure buffer, maintaining reservoir conditions during retrieval. The gel/viscous fluid transmits pressure from the annulus to the sample while providing thermal insulation, thus preserving sample integrity without requiring direct thermal contact or complex heating systems.
Solution Approach 2:
The patent employs hydraulic pressure transmission through a compressible fluid in an annulus surrounding the sampling chamber. By pressurizing this annular space, the system maintains external pressure on the sample chamber, counteracting the pressure drop during retrieval. This hydraulic pressure system works in conjunction with the gel intermediary to maintain both pressure and temperature stability of the fluid sample.
2Reliability
If the sampling tool is retrieved to the surface, then the fluid sample can be analyzed, but the pressure of the fluid sample reduces causing sample degradation
Solution Approach 1:
The gel or viscous fluid serves as a pressure transmission medium between the annular pressure system and the sampling chamber. This intermediary ensures uniform pressure distribution across the sample chamber walls while absorbing pressure fluctuations during retrieval. The gel's viscosity provides damping effects that prevent pressure shocks to the sample, maintaining sample integrity throughout the retrieval process.
Solution Approach 2:
The system uses a hydraulic pressure maintenance mechanism where compressible fluid in an annulus is pressurized to counteract the external pressure reduction during retrieval. This hydraulic system continuously applies compensating pressure to the sampling chamber, ensuring the fluid sample remains at reservoir pressure conditions from downhole environment through surface retrieval.
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
The apparatus effectively maintains the fluid sample at reservoir pressure, ensuring its representativeness and integrity during retrieval, minimizing sample degradation and allowing for accurate analysis.
Implementation Method 1
An annulus can be defined between at least part of the housing and at least part of the sampler. The annulus can include a compressible fluid... the compressible fluid can be operable to pressurize the fluid sample received in the sample chamber
Data Source
AI summary
An assembly capable of being disposed in a subterranean bore for obtaining a fluid sample is described. The assembly can include an apparatus having a sample chamber and a housing encasing the sample chamber and providing a pressure source. The pressure source can be disposed of in an annulus defined by the sample chamber and the housing. The assembly can be attached to a slick line or wire line and conveyed into a wellbore.