Downhole Fluid Sampling Saturation Pressure Prediction
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Solution Overview
Problem
Current downhole sampling methods for formation fluids are costly and prone to contamination, leading to inaccuracies in fluid analysis due to errors during separation and remixing at the well site, which can be mitigated by predicting fluid sample contamination using saturation pressure measurements.
Innovation Solution
A method involving the measurement of saturation pressure over specific intervals, plotting these measurements against fluid composition, and using sensors to determine when a clean sample is obtained, allowing for the prediction of ultimate saturation pressure and contamination levels, thereby ensuring accurate sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If downhole sampling is performed to obtain accurate formation fluid samples, then sample representation accuracy is improved, but sampling cost and time increase
Solution Approach 1:
The patent applies preliminary action by measuring saturation pressure at multiple intervals during the sampling process to predict future contamination levels before actually capturing the sample. This allows the system to determine in advance whether a sample will be contaminated, avoiding unnecessary downhole sampling operations and reducing time loss while maintaining accuracy.
Solution Approach 2:
The patent implements feedback by continuously monitoring saturation pressure measurements and using them to update predictions of sample contamination. This feedback loop allows the system to adjust sampling decisions based on real-time data, optimizing the balance between sample accuracy and sampling time/cost.
2Measurement precision
If downhole sampling is performed to obtain accurate formation fluid samples, then sample representation accuracy is improved, but operational cost increases
Solution Approach 1:
The patent performs preliminary saturation pressure measurements at multiple intervals to predict sample quality before committing to expensive downhole sampling operations. This preliminary assessment prevents wasteful spending on sampling operations that would yield contaminated samples, thereby reducing operational costs while maintaining accuracy.
Solution Approach 2:
The system uses feedback from saturation pressure measurements to guide sampling decisions, only proceeding with costly downhole sampling when predictions indicate high sample quality. This feedback-driven approach optimizes operational costs by avoiding unnecessary expensive operations.
3Measurement precision
If saturation pressure measurements are taken at multiple intervals to predict contamination, then sample quality prediction accuracy is improved, but measurement complexity increases
Solution Approach 1:
The patent employs a multi-functional saturation pressure sensor that serves both as a contamination prediction tool and as a quality control mechanism throughout the sampling process. This universal measurement approach consolidates multiple measurement functions into a single integrated system, improving prediction accuracy without proportionally increasing overall measurement complexity.
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 enables the capture of reservoir fluid samples with reduced contamination, improving analysis accuracy and reducing operational costs by determining the quality of the final flowing fluid for sample capture.
Implementation Method 1
predicting when a sufficiently clean sample can been taken. For example, a method of predicting fluid sample contamination may involve using one or more measured properties of the fluid, such as saturation pressure
Data Source
AI summary
In some embodiments, an apparatus and a system, as well as a method and an article, may operate to obtain a formation fluid sample from a formation adjacent to a wellbore disposed in a reservoir, determine the sample saturation pressure of the formation fluid sample, repeat obtaining the formation fluid sample and determining the sample saturation pressure over a selected time period or number of samples, and determine a predicted ultimate formation fluid saturation pressure based on multiple determinations of the sample saturation pressure. The sample saturation pressures measured over selected time periods can be used to determine fluid sample contamination. Additional apparatus, systems, and methods are disclosed.