Real-Time Droppable Object Position Tracking in Wellbores
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for monitoring the position of cementing plugs and the top of the cement sheath during cementing operations in wells are prone to inaccuracies due to factors like borehole rugosity, pump rate fluctuations, and differences in casing geometry, leading to potential issues with cement placement and well integrity.
Innovation Solution
The use of a Kalman filter-based data fusion system to combine different plug position measurements, including those from pressure pulse correlation and cepstrum analysis, to provide a more accurate real-time estimation of the plug position and casing diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional volumetric measurements and single-method monitoring are used to track plug position, then the system is simple and easy to operate, but measurement precision and reliability deteriorate due to borehole rugosity, pump rate fluctuations, and casing geometry variations
Solution Approach 1:
The patent combines multiple monitoring methods (volumetric measurements, pressure pulse correlation, and cepstrum analysis) into a unified system that integrates their results to determine plug position. This merging of multiple measurement approaches compensates for the weaknesses of individual methods, achieving higher measurement precision while managing system complexity through coordinated integration of the different techniques.
Solution Approach 2:
The patent introduces an intermediary processing system that receives data from multiple sources (volumetric measurements, pressure sensors, cepstrum analysis) and processes this information to produce a reliable plug position estimate. This intermediary layer reconciles the conflicting or imprecise data from individual methods, providing accurate measurements without requiring direct modification of the basic monitoring components.
2Reliability
If multiple measurement methods are combined to improve plug position accuracy, then measurement precision improves, but the difficulty of detecting and measuring increases due to the need to process and reconcile multiple data sources
Solution Approach 1:
The system implements feedback mechanisms where pressure pulse correlations and cepstrum analysis results continuously refine the plug position estimate based on volumetric measurements. This feedback loop allows the system to automatically adjust and reconcile measurements from different sources, improving reliability while managing processing difficulty through iterative refinement rather than complex simultaneous calculations.
Solution Approach 2:
The patent performs preliminary processing of pressure data through cepstrum analysis and pressure pulse correlation before integrating these results with volumetric measurements. This preliminary action prepares the data in advance, making the final integration simpler and reducing the overall processing difficulty while maintaining high reliability through multiple validation steps.
3Measurement precision
If real-time monitoring with multiple methods is implemented, then measurement precision and reliability improve, but loss of time increases due to the computational processing required
Solution Approach 1:
The system uses periodic pressure pulse measurements and correlates these with volumetric data at regular intervals during cement pumping. This periodic approach allows real-time monitoring without requiring continuous complex calculations, as the system updates plug position estimates at meaningful intervals rather than continuously, reducing processing time while maintaining accuracy.
Solution Approach 2:
The patent applies partial processing where cepstrum analysis and pressure pulse correlation are used selectively to validate and refine volumetric measurements rather than processing all data equally. This partial action approach focuses computational resources on the most critical verification steps, achieving high measurement precision without the time cost of exhaustive processing of all available data.
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 enhances the accuracy of cementing plug position tracking and top of cement sheath location, allowing for timely recognition and remediation of potential issues during cementing operations, thereby improving well integrity and cement placement efficiency.
Implementation Method 1
A downhole pressure transducer or a surface pressure data acquisition system may detect the pressure pulse(s)
Implementation Method 2
The pressure data comprises the pressure pulses generated by the droppable object passing casing collars, reflected pressure pulses or a combination thereof
Data Source
AI summary
The position of a droppable object (e.g., a cementing plug or drillpipe dart) in a cased wellbore may be determined in real time during a cementing operation. A pressure data acquisition system is installed at a wellsite and a pressure transducer is installed at the cementing head. As the droppable object travels through casing it encounters regions with a positive or a negative change of inner cross-sectional dimension. The droppable object generates a pressure pulse as it passes through the regions. The pressure pulse and associated reflections are detected by the pressure transducer, and the signals are processed mathematically by a Kalman filter to determine the current position of the droppable object.