PLT Data Interpretation via Inverse Method Smoothness Link
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Solution Overview
Problem
Current methods for interpreting data from Production Logging Tools (PLT) in oil wells are noisy and user-dependent, leading to inconsistent results and lack of uniform discretization, especially during the production step where thermal balance is established between the well and the formation.
Innovation Solution
A method that automatically interprets PLT data using an inverse approach with smoothness regularization, eliminating user influence and providing higher resolution by fitting raw curves, allowing for better comparison across different wells and scales, and optimizing the process by eliminating the pre-processing phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If user-defined zoning is used for direct analysis of PLT data, then the interpretation process is simple and fast, but the results are inconsistent and dependent on user perception, lacking uniform discretization
Solution Approach 1:
The patent applies the inverse method by inverting the traditional interpretation approach. Instead of directly analyzing PLT data to determine flow rates (forward problem), the method formulates an inverse problem where a smoothness-constrained optimization algorithm automatically determines the flow rate distribution that best fits the observed spinner velocity data, eliminating user-defined zoning and achieving consistent, uniform discretization results
Solution Approach 2:
The patent changes the parameter representation by introducing a smoothness constraint parameter (regularization parameter) that controls the trade-off between fitting the data and maintaining smooth flow rate variations. This parameter transformation enables the optimization algorithm to automatically determine appropriate discretization without user intervention, resolving the contradiction between interpretation simplicity and result consistency
2Reliability
If conventional smoothing methods are applied to PLT data, then noise is reduced, but the pre-processing phase adds complexity and user influence remains
Solution Approach 1:
The patent merges the smoothing operation with the flow rate calculation process itself. The smoothness constraint is integrated into the objective function of the inverse method, combining noise reduction and flow rate determination into a single unified optimization process, thereby eliminating the separate pre-processing phase and reducing overall process complexity
Solution Approach 2:
The optimization algorithm performs self-service by automatically determining the appropriate smoothing level and flow rate distribution without user intervention. The smoothness constraint enables the system to self-regulate the balance between noise reduction and data fidelity, eliminating user influence while maintaining reliability
Data Source
AI summary
The present invention is applied in the interpretation and processing of data from the PLT (Production Logging Tool) tool that are obtained during a cased well formation test. The present invention reduces the randomness of interpretation using an inverse method that does not require user zoning. For this, it is assumed that the function is increasing (valid in the vast majority of cases, otherwise there would need to be a cross flow) and that the solution is smooth, which is valid for the discretization used by this invention.