Study on well-log lithofacies classification based on machine learning methods
Machine learning algorithms have been widely applied in the study of lithofacies classification based on well-log data at present.However,with very few drilled cores and a scarcity of lithofacies samples,machine learning algorithms encounter overfitting problems.This leads to poor well-log lithofacies classification.Therefore,the prediction effectiveness of different machine learning algorithms were studied in small sample environment,taking the North American Panoma oil and gas field dataset as an example.Four training models are established by gradually reducing the number of training samples.Meanwhile,three different types of supervised learning algorithms were selected to evaluate the prediction effectiveness,including Linear Regression Classification based on General Gradient Descent(GGD-LRC),Support Vector Machine(SVM),and One-Dimensional Convolutional Neural Networks(1D-CNN).In the comprehensive evaluation of the prediction effectiveness of the algorithms,selected the lithofacies classification accuracy,the overall lithofacies classification Fl value,the individual lithofacies classification Fl value,and the maximum number of effectively identified lithofacies.The results show that the prediction effectiveness of the three algorithms does not present a linear downward trend as the number of training samples decreased,and the 1D-CNN algrithm is more robust than the others.