Predicted Bias Correction for Gas Extractor Sampling
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Solution Overview
Problem
Current gas extraction and fluid sampling systems in wellbore drilling operations face challenges in accurately representing reservoir compositions due to system bias, which affects the analysis of gases such as methane through pentane, necessitating real-time bias correction during drilling.
Innovation Solution
A method involving obtaining a drilling fluid sample, flushing it with a hydrocarbon blend, and using a gas chromatograph to determine concentration over time, generating an area per concentration curve, fitting a response curve, and applying it to correct bias in real-time, thereby improving the accuracy of gas analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gas extraction and fluid sampling systems are used during drilling operations, then gas analysis can be performed to determine formation characteristics, but system bias causes inaccurate representation of reservoir compositions
Solution Approach 1:
The system performs preliminary calibration by injecting known concentrations of hydrocarbon gases into the drilling fluid sample before actual measurement. This preliminary action establishes a response curve that characterizes system bias, which is then used to correct subsequent measurements, ensuring accurate representation of reservoir compositions.
Solution Approach 2:
The system implements feedback by continuously comparing measured gas concentrations against the pre-established response curve derived from known standards. This feedback mechanism allows real-time correction of system bias, maintaining measurement precision and reliability throughout drilling operations.
2Measurement precision
If real-time bias correction is implemented during drilling operations, then accuracy of gas analysis is improved, but system complexity increases
Solution Approach 1:
The system creates a simplified copy or model of the measurement process by establishing a response curve from known standards. This curve serves as a reference model that captures system behavior, allowing complex bias correction to be performed through simple curve comparison and interpolation during real-time operations.
Solution Approach 2:
The system manages complexity by focusing correction on key parameters - specifically, it adjusts concentration values based on the response curve rather than attempting to correct all possible measurement variables. This parameter-focused approach maintains accuracy while limiting system 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 more accurate representation of reservoir compositions by correcting for system bias in real-time, enhancing the reliability of gas analysis during drilling operations.
Implementation Method 1
using a gas chromatograph to determine concentration over time
Data Source
AI summary
A system can flush a drilling fluid sample with a hydrocarbon blend, which includes a determined concentration of at least one chemical species to generate a flushed drilling fluid sample. The system can extract a dissolved gas from the flushed drilling fluid sample. The system can determine a concentration over time of at least one chemical species of the dissolved gas. The system can generate an area per concentration curve based on the concentration over time of the at least one chemical species. The system can determine at least one concentration value of the at least one chemical species. The system can modify the at least one concentration value based on the area per concentration curve. The system can then correct bias caused by the gas extractor and fluid sampling system.