Adjustable Guard Probe Inlet for Downhole Sampling
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Solution Overview
Problem
Conventional down hole sampling methods face challenges in achieving accurate and efficient fluid sampling in geological formations, particularly in low permeability conditions, due to fixed inlet areas and limited control over drawdown pressures, which can lead to contamination and prolonged sampling times.
Innovation Solution
The implementation of a processor-implemented method using a geological formation probe with a surrounding pad and adjustable guard probe inlet area, allowing incremental and dynamic variation of the inlet size, combined with straddle packers to capture fluid at different flow rates, enabling precise control of drawdown pressures and permeability determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed inlet area is used in down hole sampling, then the device structure is simple, but sampling efficiency is low and sampling time is prolonged
Solution Approach 1:
The inlet area of the guard probe is made dynamically adjustable through a mechanism that allows the inlet area to be changed during operation. This enables optimization of sampling efficiency for different formation conditions without requiring multiple fixed devices, resolving the contradiction between sampling efficiency and device complexity.
Solution Approach 2:
The inlet area parameter of the guard probe is made variable to adapt to different formation permeability conditions. By changing this geometric parameter, the system achieves higher sampling efficiency across diverse conditions while maintaining a single versatile device structure.
2Productivity
If drawdown pressure is increased to improve sampling rate, then sampling efficiency improves, but contamination risk increases
Solution Approach 1:
The guard probe is deployed in advance to establish a sealed zone around the sampling probe before actual sampling begins. This preliminary sealing action prevents contamination while allowing the sampling probe to operate at optimal drawdown pressures for high sampling rates.
Solution Approach 2:
The guard probe acts as an intermediary structure between the formation and the sampling probe. It creates a controlled flow path that directs fluid toward the sampling probe while filtering out contaminants, enabling high sampling rates without increasing contamination risk.
3Productivity
If inlet area is increased to draw more fluid, then sampling rate improves, but drawdown pressure control becomes difficult
Solution Approach 1:
The flow path is segmented into two zones: the guard probe inlet area for capturing fluid at controlled rates, and the sampling probe inlet for actual sampling. This segmentation allows independent optimization of each zone, enabling high fluid draw rates while maintaining precise drawdown pressure control through the adjustable guard probe inlet.
Data Source
Figure 1A~1D
Figure 2A~2B
Figure 3A
AI summary
In some embodiments, an apparatus and a system, as well as a method and an article, may operate to advance a sampling and guard probe (100) with a surrounding sealing pad (108) against a borehole wall, to adjust the size of the area associated with a fluid flow inlet of the probe, where the size of the inlet area (104) is selectably and incrementally variable, and to draw fluid into the fluid flow inlet by activating at least one pump (344) coupled to at least one fluid passage (128) in the probe. Additional apparatus, systems, and methods are disclosed.