3D DAS Full Waveform Inversion (FWI) Case Study for SAGD Steam Chamber Imaging

Abstract

Summary Distributed Acoustic Sensing (DAS) is based on Rayleigh scattering principles used to determine acoustic strain signals over long distances, effectively turning the optic fiber cable into a series of geophones. Once the data is acquired, advanced processing techniques such as Full Waveform Inversion (FWI) can be applied to obtain information for a wide variety of applications. Historically DAS is used as a complementary tool to improve understanding of flow distribution along the entire length of a producing wellbore. It is commonly used in collaboration with DTS to interpret and define flow allocation throughout the life of the well. 3D DAS Vertical Seismic Profiles (VSPs) also can be used as a cost-effective tool for the time-lapse reservoir monitoring due to the finer channel sampling and flexibility in deploying the fiber-optic cables. The application of FWI to 3D DAS is an innovative way to image the steam chamber during the steam-assisted gravity drainage (SAGD) process for Oil Sands. This successful case study demonstrates that 3D DAS FWI can provide a significantly more cost-effective and technically equivalent alternative to conventional 4D seismic programs.