Permanent downhole gauges (PDGs) can provide a continuous record of flow rate and pressure, which provides extensive information about the reservoir and makes PDG data a valuable source for reservoir analysis. In previous work, it has been shown that kernel-ridge regression-based machine learning is a promising tool to interpret pressure transients from a single PDG. In this work, the machine-learning framework was extended to two applications: multiwell testing and flow-rate reconstruction.
Analysis of PDG data is challenging because of the inherent characteristics of the data, including continuously variable flow rate, noise, and the large data volume. Until now, most efforts in PDG-data analysis have been concentrated on pressure-transient analysis on single wells, although there have also been some studies on temperature-transient analysis and multiwall-data analysis. Recently, however, there have been some attempts to apply machine-learning techniques for PDG-data analysis. The fundamental idea is to learn the patterns behind PDG data, where the patterns contain the reservoir information implicitly. A previous study on single-well pressure analysis showed that machine learning has the potential to handle the complexities in PDG-data analysis, and learn the reservoir model successfully.
In this work, the authors use machine learning as the tool for investigation, but address two different problems—namely, multiwell testing (multiwell pressure-transient analysis) and flow-rate reconstruction. Both topics are important in PDG-data analysis in practical engineering. The authors have developed a machine-learning model for each problem and have tested the models on different real and synthetic data sets. The test results validated the developed approach, and illustrated the flexibility of the machine-learning framework for different applications by adapting the features and the targets.
Machine Learning Applied to Multiwell-Test Analysis and Flow-Rate Reconstruction
20 April 2016