Subterranean Fluid Sampler with Nitrogen Pre-Charge
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Solution Overview
Problem
During the retrieval and storage of subterranean fluid samples, the samples undergo temperature changes and pressure reductions, leading to phase changes such as asphaltene deposition and gas flashing, which compromises their representativeness of the formation fluids.
Innovation Solution
A single phase fluid sampling apparatus and method that pressurizes the fluid samples using a common pressure source, both downhole and on the surface, to maintain the samples above saturation pressure, preventing phase changes and ensuring sample integrity during retrieval and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fluid sample is retrieved to the surface without pressure maintenance, then the retrieval process is simple, but the temperature decrease causes shrinkage and pressure reduction leading to phase changes such as asphaltene deposition and gas flashing
Solution Approach 1:
The sample chamber is pre-charged with nitrogen gas at downhole conditions before sampling. This preliminary pressurization ensures that when the sample is retrieved to the surface, the pressure maintenance system is already in place to prevent phase changes, thereby maintaining sample representativeness while allowing simple retrieval operations
Solution Approach 2:
A nitrogen gas cushion is introduced as an intermediary substance between the formation fluid sample and the ambient environment. This nitrogen cushion maintains pressure and prevents direct contact with atmospheric conditions during retrieval, thereby preventing asphaltene deposition and gas flashing while allowing straightforward sample retrieval
2Reliability
If a pressure maintenance system is implemented during retrieval, then sample integrity is maintained, but the device complexity increases
Solution Approach 1:
The pressure maintenance function is merged with the sample collection chamber by pre-charging the chamber with nitrogen gas. This integration eliminates the need for separate complex pressure maintenance systems during retrieval, as the chamber itself provides both sampling and pressure maintenance functions, thereby maintaining sample integrity with minimal added complexity
Solution Approach 2:
The sample chamber is designed to self-maintain pressure through its pre-charge with nitrogen gas. The chamber automatically maintains downhole pressure conditions without requiring external active pressure control systems during retrieval, thereby ensuring sample integrity while minimizing device complexity
3Adaptability or versatility
If multiple fluid samples are collected in separate chambers, then comprehensive formation analysis is enabled, but the sampling apparatus volume increases
Solution Approach 1:
The sampling apparatus is divided into multiple discrete sample chambers, each capable of collecting individual fluid samples. This segmentation allows comprehensive formation analysis by capturing different fluid phases or samples from different depths, while each compact chamber maintains a space-efficient design that minimizes overall apparatus volume
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 method effectively prevents phase change degradation of fluid samples, maintaining their representativeness and integrity throughout the sampling and storage process, even after retrieval to the surface.
Implementation Method 1
pressurizing the fluid sample in the sample chamber using a pressure source to maintain the sample above saturation pressure
Implementation Method 2
a layer of thermal insulation between the sample chamber and the external environment
Data Source
AI summary
A fluid sampler operable for taking at least one fluid sample in a subterranean well and associated methods. A fluid sampling method includes the steps of disposing a fluid sampler at a first target location in the well, receiving the fluid sample into at least a first sample chamber of the fluid sampler, pressurizing the fluid sample in the first sample chamber using a pressure source of the fluid sampler, retrieving the fluid sampler to a surface location, isolating the fluid sample in the first sample chamber from the pressure source of the fluid sampler and supercharging the fluid sample in the first sample chamber using a pressure source on the surface.