Education

Ph.D in Computational Geophysics, Rice University, 2022
B.S. in Geophysics, University of Science and Technology of China (USTC), 2016
Exchange student, University of Göttingen, 2015

Work experience

06/2022- : Technical Geophysicist
- Chevron Energy Technology Company
- User support and technical development of scientific seismic imaging software, including Gaussian-beam migration (iGBMig) and least-squares reverse time migration (LSRTM), for the sub-salt imaging problems.
- HPC resource coordinator and manager for the sub-salt imaging team.
06/2020-08/2020: Machine Learning-Earth Science Intern
- Chevron Energy Technology Company
- Code extension of 3D U-nets to multi-class semantic image segmentation for shallow hazards detection in large-scale seismic volumes. Hyperparameters tuning and comparative studies of Focal loss, Tversky loss, Dice loss, Focal-Tversky loss and their combinations. Application on production volumes and quantified results based on validation accuracy, IoU, and Dice coefficient.
09/2019-12/2019: Machine Learning Engineer Intern
- SLB Digtal Foundation Center
- Comparative study of Generative Adversarial Networks (GAN) for seismic impedance inversion, including Cycle-GAN, Least- square GAN, Wasserstein GAN and Wasserstein GAN-GP. Combining Wasserstein loss, cycle-consistent loss and gradient penalty loss and developed Wasserstein Cycle-GAN for improved impedance inversion with an example on 3D seismic volume.
05/2019-08/2019: Machine Learning-Earth Science Intern
- Chevron Energy Technology Company
- Development of machine learning denoise (3D U-nets with dilated convolution) based seismic image optimization workflow.
- Successful applications on Gulf of Mexico field seismic data (~TB scale 3D seismic digital data); created business impact.

Proficiencies & Skills

Programming: Python; C, C++; Java; Fortran; MATLAB; Message Passing Interface (MPI); CUDA; Linux Shell.
Machine Learning: Supervised Learning; Semi-supervised Learning; Neural Networks; TensorFlow; Keras; PyTorch.
Relevant Coursework: Statistical Machine Learning; Deep Learning; Numerical Analysis; Numerical Optimization; Topics in Inverse Problem; Computational Science (OpenMP, MPI, CUDA, OpenCL).

Publications

Data weighted full-waveform inversion with adaptive moment estimation for near-surface seismic refraction data

Cai, Ao, and Colin A. Zelt. "Data weighted full-waveform inversion with adaptive moment estimation for near-surface seismic refraction data." SEG International Exposition and Annual Meeting. SEG, 2019.

Wasserstein cycle-consistent generative adversarial network for improved seismic impedance inversion: Example on 3D SEAM model

Cai, Ao, et al. "Wasserstein cycle-consistent generative adversarial network for improved seismic impedance inversion: Example on 3D SEAM model." SEG technical program expanded abstracts 2020. Society of Exploration Geophysicists, 2020. 1274-1278.

Semi‐supervised Surface Wave Tomography with Wasserstein Cycle‐consistent GAN: Method and Application to Southern California Plate Boundary Region

Cai, A., Qiu, H., & Niu, F. (2022). Semisupervised surface wave tomography with Wasserstein cycle-consistent GAN: Method and application to Southern California plate boundary region. Journal of Geophysical Research: Solid Earth, 127, e2021JB023598. https://doi.org/10.1029/2021JB023598

Advances in seismic time-domain early-arrival waveform inversion and deep-learning-based surface wave tomography

Cai, Ao. Advances in seismic time-domain early-arrival waveform inversion and deep-learning-based surface wave tomography. Diss. Rice University, 2022.

Sensitivity analysis of acoustic waveform inversion to velocity anomalies in the near-surface using the Fréchet derivative

Cai, Ao, and Colin A. Zelt. "Sensitivity analysis of acoustic waveform inversion to velocity anomalies in the near-surface using the Fréchet derivative." Second International Meeting for Applied Geoscience & Energy. Society of Exploration Geophysicists and American Association of Petroleum Geologists, 2022.

Early arrival waveform inversion using data uncertainties and matching filters with application to near-surface seismic refraction data

Cai, Ao, and Colin A. Zelt. "Early arrival waveform inversion using data uncertainties and matching filters with application to near-surface seismic refraction data." Geophysics 87.6 (2022): R465-R486.