Downhole Pumpout Contamination Prediction via Multi-Parameter Correlation
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Solution Overview
Problem
Current methods for collecting clean formation fluid samples during oil and gas exploration are limited by contamination from drilling fluid, as existing techniques rely on curve fitting methods that assume stable properties, which can lead to inaccurate contamination level estimation even at high contamination levels.
Innovation Solution
A downhole formation testing tool that performs pressure and pumpout operations to identify the optimal time for capturing a clean fluid sample by using a combination of pumpout data and formation properties, such as density and drawdown mobility, to build a predictive model for contamination levels, allowing for more accurate contamination estimation and sample acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If curve fitting methods are used to determine clean fluid sample timing, then the sampling process is simplified, but contamination level estimation becomes inaccurate
Solution Approach 1:
The patent transitions from using single-property curve fitting to monitoring multiple fluid properties (density, GOR, viscosity, chlorides) simultaneously. By changing from one-dimensional to multi-dimensional parameter monitoring, the system achieves more accurate contamination detection while maintaining operational simplicity through automated multi-parameter analysis.
2Manufacturing precision
If pumping continues to reduce contamination, then clean fluid samples can be obtained, but the steady state effect masks high contamination levels
Solution Approach 1:
The system continuously monitors multiple fluid properties during pumping and uses this feedback to detect contamination levels. By tracking changes in density, GOR, viscosity, and chloride content in real-time, the system can identify when clean fluid is achieved despite the steady state effect, providing accurate contamination detection throughout the pumping process.
Solution Approach 2:
The patent combines multiple measurement techniques (density measurement, GOR analysis, viscosity testing, chloride detection) into a composite monitoring system. This multi-property approach compensates for the limitations of individual measurements and provides robust contamination detection even when steady state conditions obscure single-parameter changes.
3Measurement precision
If multiple fluid properties are monitored to improve contamination detection, then accuracy increases, but system complexity increases
Solution Approach 1:
The system uses a multi-functional monitoring approach where a single integrated system measures multiple fluid properties (density, GOR, viscosity, chlorides) simultaneously. This universal monitoring system achieves high contamination detection accuracy without proportionally increasing complexity, as the same basic measurement infrastructure supports multiple property assessments.
Data Source
AI summary
A method may comprise positioning a downhole fluid sampling tool into a wellbore; performing a pressure test operation within the wellbore; performing a pumpout operation within the wellbore; identifying one or more formation parameters at least in part from the at least one pressure test operation or the at least one pumpout operation; building a correlation model that relates a pumpout trend to the one or more formation parameters; determining a time when the downhole fluid sampling tool takes a clean fluid sample utilizing at least the correlation model; and acquiring the clean fluid sample with the downhole fluid sampling tool from the wellbore. Additionally, a system may comprise a downhole fluid sampling tool configured to: perform a pressure test operation within a wellbore; and perform a pumpout operation within the wellbore.