An Introduction to DAS: Using Fiber Optics for Geoscience Applications
Society of Exploration Geophysicists (SEG)
Monday, 27 September 2021, 1:20 p.m.–5:20 p.m. | Denver, Colorado
The first Distributed Acoustic Sensing DAS VSP paper was presented at the SEG conference ten years ago (Mestayer el al 2011). Early adoption of DAS was focused on borehole seismic but quickly evolved into other areas of surveillance including production and completions monitoring. The flexibility of the technology proved that geophysics with DAS could extend into other areas like earthquake seismology, near surface geophysics as well as emerging fields like smart city monitoring and ocean bottom seismics that take advantage of existing fiber optic networks.
The goal of this session is to provide a general overview of the technology to new practitioners. The first part of the session gives a quick overview of the fundamentals of the technology, from the physics of the measurement, the fiber architecture and deployment as well as the interrogator unit.
The second half of this session focuses on representative applications of the technology in different fields. Borehole seismic is represented by studies of 4D reservoir monitoring in both land and offshore settings. Repeatability and sensitivity of the measurements is validated by showing progression of fluid movement images by DAS data in CO2 storage facilities and deep water waterflood reservoirs.
An important application of DAS for completions and unconventional reservoir focuses on fracture network monitoring. Here the focus is on the use of DAS as an injection monitoring tool, a strain meter and as a microseismic sensor to assess the development of unconventional resources. The final set of applications included in this session are those that take advantage of fibers on the surface or on the ocean floor that are intended for other telecommunication uses. Taking advantage of these dark fibers it is shown how researchers are using DAS for near surface geophysics studies using surface waves, traditional earthquake seismology with long and dense receiver apertures, as well as sensing of the oceans. Special emphasis throughout this session is put on the specific technological advantages that DAS presents over other available technologies while providing great flexibility in its deployment.
- Rayleigh DAS Strain vs Strain Rate IU; Brillouin DSS – Discussion on Different Types of IU’s Multiphysics With DS: Strain, Temperature, Seismics, DAS and Geophones
- Basics of Fiber Optic – Enhanced Fibers and DAS
- Deployment Methods – Seismic Modeling of DAS and Field QC
- 4DVSP Applications – Waterflood and Production Monitoring (Offshore); CO2 Storage Monitoring (Land)
- DAS for Fracture Monitoring: Strain From Fractures and Near Field Injection Monitoring
- DAS Microseismic – Single and Multifiber DAS Analysis for Microseismic
- Earthquake Monitoring
- Near Surface Geophysics – Surface Wave Analysis and Shallow Subsurface
- Ocean Bottom Fiber Sensing
Colorado Convention Center
700 14th St