Derivative Ratio Test for Fluid Sampling Cleanup
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Solution Overview
Problem
Current methods for obtaining a clean formation fluid sample in boreholes are inefficient, as they often require prolonged pumping, leading to high costs and potential contamination issues, especially when dealing with miscible fluid mixtures, which can result in wasted time and resources.
Innovation Solution
A method and system utilizing a downhole fluid tester that analyzes the sample's absorbance data to calculate the ratio of the first derivative to the second derivative, allowing for real-time determination of whether a clean sample will be obtained, enabling early decision-making on when to stop or relocate the sampling process, thereby optimizing the fluid extraction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pumping continues for extended periods to achieve clean sample collection, then sample purity is improved, but operational time and cost increase significantly
Solution Approach 1:
The patent applies preliminary action by performing derivative ratio calculations on real-time spectral data during the pumping process. This allows operators to predict future sample quality trends and make informed decisions about when to stop pumping before actually reaching the desired sample purity, thereby avoiding unnecessary pumping time while still achieving clean samples.
Solution Approach 2:
The patent implements feedback by continuously monitoring spectral data, calculating derivative ratios, and using this information to adjust pumping duration decisions. The system provides real-time feedback on whether the fluid is cleaning up properly, allowing dynamic optimization of pumping time based on actual formation conditions rather than fixed time schedules.
2Manufacturing precision
If pumping time is extended to ensure sample cleanliness, then sample quality is improved, but operational cost increases due to rig time
Solution Approach 1:
The patent applies preliminary action by calculating derivative ratios from spectral data obtained during early to mid-stage pumping. This preliminary analysis allows operators to predict whether continued pumping will yield a clean sample, enabling cost-effective decision-making before committing to extended pumping operations that would increase operational costs.
Solution Approach 2:
The system provides real-time feedback on sample cleanup progress through derivative ratio calculations. When the ratio indicates poor cleanup trends, operators can terminate pumping early, avoiding unnecessary operational costs. When the ratio shows good cleanup trends, operators can confidently continue pumping to achieve high-quality samples, optimizing the balance between sample quality and operational cost.
3Manufacturing precision
If pumping duration is increased for miscible fluid cleanup, then sample purity improves, but the risk of contamination and waste increases
Solution Approach 1:
The patent implements feedback by continuously monitoring derivative ratios of spectral data throughout the pumping process. This real-time monitoring provides reliable indicators of whether the fluid is properly cleaning up or if contamination issues are developing, allowing operators to adjust pumping duration to achieve pure samples while minimizing contamination risks associated with overly prolonged pumping.
Solution Approach 2:
The patent replaces reliance on mechanical timing methods with optical spectral analysis. Instead of using fixed time schedules or mechanical indicators to determine when to stop pumping, the system uses spectral derivative ratio calculations to objectively assess sample purity, providing more reliable contamination detection and reducing the risk of collecting contaminated samples.
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
This approach reduces unnecessary pumping time and costs by providing an early indication of sample cleanliness, preventing waste and potential contamination issues, and allowing for informed decisions on when to terminate or relocate sampling operations.
Implementation Method 1
analyzing the sample using the fluid tester to provide test data... analyzing the sample's absorbance data
Data Source
AI summary
A method for performing a formation fluid test in a borehole penetrating a subsurface formation includes disposing a fluid tester in the borehole, extracting a sample of fluid from the subsurface formation using the fluid tester, and analyzing the sample using the fluid tester to provide test data for a process used to analyze the sample. The method also includes fitting an equation to the test data and calculating a ratio of a first derivative of the equation to a second derivative of the equation. The method further includes continuing to extract the sample from the subsurface formation in response to the ratio indicating a clean sample will be forthcoming and terminating the extracting of the sample from the subsurface formation in response to the ratio indicating a clean sample will not be forthcoming.