Abstract
A hybrid depth neural network model is proposed to predict the
drillability to increase the drilling speed and reduce the drilling
cost. The drillability of rocks can directly reflect the difficulty of
drilling in the formation. The prediction effects of CNN(Convolutional
Neural Network)-BiGRU(Bidirectional Gated Recurrent Unit)-attention,
CNN-BIGRU, and CNN-GRU-attention models on the evaluation indexes of
rock drillability before and after adding rock properties were compared,
finally, the CNN-BiGRU-attention model with better effect was selected.
The model extracts the features of the data through CNN, then the data
is processed by the BIGRU for time series features to establish a
long-term dependency on the features. Finally, the Attention mechanism
is introduced to focus the data to improve the accuracy of the model
prediction. The coefficient of determination (R2), root mean square
error (RMSE), and mean absolute error (MAE) were used as the evaluation
parameters of the model. The results show that the prediction accuracy
of the deep neural network model is improved by 0.06, 0.08, and 0.1 when
the formation properties are added as input parameters to the model. The
results show that the physical properties of the rock have an important
effect on the drillability of the formation. Therefore, taking the rock
properties as the input of the model can improve the accuracy of the
model, and the CNN-BIGRU-Attention model has a good effect. It is
believed that this method can be popularized in areas similar to this
formation and is conducive to guiding the block to improve drilling
efficiency.