Oval Pad Probe Screens for Unconsolidated Formation Sampling
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Solution Overview
Problem
Existing fluid sampling tools often cause poorly consolidated formations to crumble, leading to clogging and degradation of formation fluid analysis due to suction or pressure from the probe, resulting in incomplete or inaccurate sampling.
Innovation Solution
A fluid-sampling probe with an oval pad that contacts the borehole wall and features a plurality of screens between the wall and inlets, filtering particulates and preventing them from entering the inlets, thereby reducing clogging and enhancing fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If suction pressure is applied to draw fluid from the formation, then fluid sampling efficiency is improved, but unconsolidated formations crumble and particulates clog the probe
Solution Approach 1:
The patent introduces a screen as an intermediary component between the formation and the probe inlet. This screen acts as a mediator that allows fluid to pass through while blocking particulates, thereby resolving the contradiction between maintaining suction pressure for efficient sampling and preventing particulate clogging of the probe
2Productivity
If probe pressure is applied to sample from the formation, then sampling rate is improved, but formation structure degrades and sand is released
Solution Approach 1:
The screen serves as a protective intermediary that decouples the sampling function from the formation contact function. It allows the probe to apply pressure for high sampling rates while the screen protects the probe interior and maintains formation structure by distributing the pressure across a larger area
3Reliability
If multiple probes are used to prevent clogging, then sampling reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the filtering function from the sampling function by introducing a separate screen component. This allows a single probe to achieve the reliability of multiple probes by dividing the functions: the probe handles sampling while the screen handles particulate rejection, avoiding the need for multiple complex probe assemblies
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 solution effectively filters out unconsolidated fines and particulates, preventing internal flow line clogging and ensuring accurate formation fluid sampling by creating a cross-flow region that allows formation fluids to reach the inlets from a larger surface area, thus improving sampling efficiency.
Implementation Method 1
a plurality of screens between the borehole wall and the inlets which filter particulates from the formation fluid
Data Source
AI summary
A fluid-sampling system that includes a downhole tool string with a fluid-sampling tool coupled thereto, and a fluid sampling probe coupled to the tool via a probe extension arm, the fluid sampling probe having an oval pad that contacts a borehole wall, one or more fluid inlets which receive a formation fluid, and a plurality of screens between the borehole wall and the one or more fluid inlets which filter the formation fluid. The fluid-sampling system further including one or more offset arms coupled to the tool which contact the borehole wall.