Downhole Fluid Analyzer Extrapolates Clean Properties
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Solution Overview
Problem
Current methods for evaluating formation fluid properties in wells face challenges in accurately determining uncontaminated fluid properties due to contamination from drilling mud filtrate, which affects real-time analysis and sample interpretation.
Innovation Solution
A downhole fluid analysis method involving a probe and fluid analyzer within a downhole tool that samples formation fluid, measures properties across a range of contamination levels, identifies data clusters, and develops a model to estimate clean fluid properties through extrapolation, enabling real-time estimation of uncontaminated formation fluid properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If downhole fluid analysis is performed on sampled formation fluid, then real-time fluid property information is obtained, but contamination from drilling mud filtrate affects measurement accuracy
Solution Approach 1:
The patent converts the harmful effect of contamination into a beneficial tool by using the contamination model to mathematically separate and estimate clean fluid properties from contaminated measurements. The contamination, rather than being discarded as noise, becomes the basis for an extrapolation process that recovers accurate formation fluid properties.
Solution Approach 2:
The patent introduces a contamination model as an intermediary mathematical framework that mediates between the contaminated measurements and the desired clean fluid properties. This model serves as a bridge, allowing the system to account for and compensate for the effects of drilling mud filtrate contamination.
2Measurement precision
If fluid samples are retained for later testing at the surface, then detailed analysis can be performed, but sample contamination and loss of real-time information occur
Solution Approach 1:
The downhole fluid analyzer performs self-service analysis by conducting fluid property measurements directly at the wellbore location. This eliminates the need to transport samples to the surface, providing both real-time information and maintaining measurement capability without contamination from handling and transport.
Solution Approach 2:
The patent performs fluid analysis preliminarily at the downhole location before samples would be transported to the surface. By conducting the analysis in situ, the system obtains both timely results and avoids the contamination issues associated with sample handling during transport.
3Reliability
If multiple measurements are taken at different sampling times to account for contamination variation, then more data for extrapolation is obtained, but measurement time and complexity increase
Solution Approach 1:
The patent changes the parameter being measured from direct fluid properties to contamination indicators (such as optical properties that correlate with contamination levels). By measuring these surrogate parameters, the system can track contamination variation over time and use it to drive the extrapolation process, simplifying the overall measurement approach.
Data Source
AI summary
According to certain embodiments, formation fluid properties, such as gas-oil ratio (GOR), formation volume factor (FVF), and density, may be measured at multiple times during sampling. In one embodiment, data representing the measured properties is analyzed and a characteristic of interest is determined through extrapolation from the analyzed data. Various other methods and systems are also disclosed.