Seismic attributes are a fundamental part of seismic interpretation and are routinely used by geoscientists to extract key information and visualize geological features. By combining different findings from each attribute, they can provide a good insight of the area and help overcome many geological challenges. However, individually analyzing multiple attributes to find relevant information can be time-consuming and inefficient, especially when working with large datasets. It can lead to miscalculations, errors in judgement and human bias. This is where Machine Learning (ML) methods can be implemented to improve existing interpretations or find additional information. ML can help by handling large volumes of multi-dimensional data and interrelating them. Methods such as Self Organizing Maps (SOM) allow multi-attribute analysis and help extract more information as compared to quantitative interpretation. SOM is an unsupervised neural network that can find meaningful and reliable patterns corresponding to a specific geological feature (Roden and Chen, 2017).
The purpose of this thesis was to understand how SOM can help make interpretations of direct hydrocarbon indicators (DHI) in the Statfjord Field area easier. Several AVO attributes were generated to detect DHIs and were then used as input for multi-attribute SOM analysis. SOMPY package in Python was used to train the model and generate SOM classification results. Data samples were classified based on BMU hits and clusters in the data. The classification was then applied to the whole dataset and converted to seismic sections for comparison and interpretation.
SOM classified seismic lines were compared with the results of the AVO attributes. Since DHIs are anomalous data, they were expected to be represented by small data clusters and BMUs with low hits. While SOM reproduced the seismic reflectors well, it did not define the DHI features clearly for them to be easily interpreted. Use of fewer seismic attributes and computational limitations of the machine could be some of the reasons behind not achieving desired results.
However, the study has room for improvement and the potential to produce meaningful results. Improvements in model design and training, and also the selection of input attributes are some of the areas that need to be addressed. Furthermore, testing other Python libraries and better handling of large datasets can allow better performance and more accurate results
