Downhole Sampling System Contamination Correction
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Solution Overview
Problem
Oil-based mud filtrate contamination affects the accuracy of fluid properties measured downhole in hydrocarbon reservoirs, making it difficult to obtain uncontaminated fluid samples for precise analysis, which is crucial for reservoir development and production optimization.
Innovation Solution
A downhole sampling system and methodology that corrects for contamination by measuring oil-based mud filtrate contamination and extrapolating saturation pressure measurements to zero contamination levels, allowing for the determination of uncontaminated fluid properties and formation volume factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fluid samples are obtained downhole for analysis, then fluid properties can be determined for reservoir optimization, but oil-based mud filtrate contamination affects measurement accuracy
Solution Approach 1:
The patent applies this principle by using the contamination data itself to correct the measurements. The system measures contamination levels and then uses this information to mathematically correct the fluid property measurements, converting the harmful contamination into a correctable parameter that improves overall measurement accuracy.
Solution Approach 2:
The patent introduces correction algorithms and computational models as intermediaries between the contaminated measurements and the true fluid properties. These computational tools act as mediators that process the contaminated data and extract accurate reservoir fluid characteristics by removing the contamination effects.
2Adaptability or versatility
If fluid samples are obtained at multiple stations along the borehole, then realistic models of fluid distribution can be developed, but contamination makes it difficult to obtain uncontaminated samples
Solution Approach 1:
The system converts the contamination present in samples from multiple stations into useful information by measuring contamination levels at each station and using this data to correct the fluid property measurements, enabling accurate multi-location modeling despite universal contamination exposure.
Solution Approach 2:
The patent changes the approach from seeking pure samples to working with contaminated samples by measuring and correcting contamination effects. This parameter change allows the system to obtain accurate fluid distribution data across multiple stations by treating contamination as a correctable variable rather than a disqualifying factor.
Data Source
AI summary
Embodiments of the disclosure can include systems, methods, and devices for determining saturation pressure of an uncontaminated fluid. A technique facilitates fluid analysis in situ at a downhole location. Downhole saturation pressure measurements and downhole OBM filtrate contamination of a contaminated fluid may be obtained and a relationship may be determined between the saturation pressure measurements and OBM filtrate contamination. The relationship may be extrapolated to zero OBM filtrate contamination to determine the saturation pressure of the uncontaminated fluid. According to an embodiment, a sample of oil is obtained at the downhole location from oil in a reservoir. A downhole sampling system is used to determine whether a sample has contamination and other selected characteristics of the sample. The data obtained may be processed to provide a formation volume factor of the oil.