Abstract
In Geological Carbon Sequestration (GCS), mineralization is a secure carbon dioxide (CO2
) trapping mechanism
to prevent possible leakage at a later stage of the GCS project. Modeling the mineralization mechanism during
GCS relies on numerical reservoir simulation, but the computational cost is prohibitively high due to the
complex physical processes. Therefore, deep learning (DL) models can be used as a computationally cheaper
and more reliable at the same time, alternative to conventional numerical simulations. In this work, we
have developed a DL approach to effectively predict the dissolution and precipitation of various essential
minerals, including Anorthite, Kaolinite, and Calcite, during CO2
injection into deep saline aquifers. We have
established a reservoir model to simulate the geological CO2
storage process. Seven hundred twenty-two
numerical realizations were performed to generate a comprehensive dataset for training DL models. Two
convolution neural networks (CNN), Fourier Neural Operator (FNO), and U-Net were trained. The trained
models used reservoir and well properties along with time information as input and predicted the precipitation
and dissolution of minerals in space and time scales. During the training process, root-mean-squared-error
(RMSE) was used as a loss function. To gauge prediction performance, we have applied the trained model to
predict the concentrations of different minerals on the test dataset, which is 15% of the entire dataset, and
two metrics, including the average absolute percentage error (AAPE) and the coefficient of determination (𝑅2
),
were adopted. The FNO model resulted in the 𝑅2 of 0.95 for the Calcite model, 0.94 for the Kaolinite model,
and 0.93 for the Anorthite model. The U-Net model resulted in the 𝑅2 of 0.88 for the Calcite model, 0.89
for the Kaolinite model, and 0.912 for the Anorthite model. The model’s prediction CPU time (0.2 s/case)
was much lower than that of the physics-based reservoir simulator (3600 s/case). Therefore, the proposed
method offers predictions as accurate as our physics-based reservoir simulations while providing a substantial
computational time acceleration.