Details of Award
NERC Reference : NE/N009134/1
Distributed acoustic sensors for monitoring microseismicity and CO2 storage
Training Grant Award
- Lead Supervisor:
- Professor M Kendall, University of Bristol, Earth Sciences
- Grant held at:
- University of Bristol, Earth Sciences
- Science Area:
- Earth
- Overall Classification:
- Earth
- ENRIs:
- Environmental Risks and Hazards
- Natural Resource Management
- Pollution and Waste
- Science Topics:
- Carbon Capture & Storage
- Carbon Capture & Storage
- Reservoir technology
- Earth Engineering
- Silicon Technology
- Electronic Devices & Subsys.
- Exploration Technology
- Abstract:
- In the past few decades fibre optic cables have revolutionised the telecommunication industry, as they provide a relatively cheap and efficient means of transmitting broadband data over long distances. More recently though it has been realised that fibre optic cables can act as sensors themselves, transmitting information about a range of properties including temperature, strain and pressure along the cable. This project involves a rapidly growing technology that uses fibre optic cables as sensitive strain meters, or a distributed array of geophones or seismometers. Seismic data from a site of CO2 storage in a geologic reservoir will be used to assess the behaviour and mechanical integrity of a storage site. A drawback of these cables is that impurities in the silica that is used to make them can reduce their strength. However, these impurities lead to Rayleigh scattering in pulsed light (usually a laser) and thereby serve as sensors at a given point in the cable. Any changes in the length of the cable will lead to a phase difference in the backscattered light. The result is a highly sensitive array of broadband sensors distributed along the entire length of a cable - in essence a continual array of geophones or seismometers. These sensors are low cost, can operate in harsh environments (high and low temperatures) and are relatively cheap and easy to operate. Applications include perimeter-fence security, pipeline monitoring, surface seismic recording, and borehole logging of pressure, temperature and strain. Fibre optic technology for monitoring (Distributed Acoustic Sensors - DAS) has been primarily developed in the UK. The case partner for the project - Silixa Limited - is a successful SME with a rapidly growing client base. It works on applications in a range of sectors, but the focus of the proposed research is monitoring seismicity that may be naturally occurring or induced in geologic settings. Induced seismicity is one of the most controversial topics facing the petroleum industry and has implications for waste water management, CO2 sequestration and enhanced oil recovery. This PhD student proposal will investigate the use of Distributed Acoustic Sensors (DAS) to record microseismic activity (small earthquakes) at the Aquistore site in southern Saskatchewan, the world's first commercial carbon capture and storage project. DAS cables have been used successfully by Silixa in recording vertical seismic profiles or VSPs (borehole recordings of controlled-source surface seismic energy). They are currently being used to monitor CO2 injection at Aquistore . Bristol is also a research provider to this project, monitoring seismicity using near-surface seismometers. There are plans to also deploy a DAS cable along the surface at Aquistore. Hence the student will benefit greatly from working within the framework of an existing research project, and will be able to work on cutting-edge technology with an environmental application. Specific aims of the project are testing the use of DAS cables to locate microseismic events and calculate their magnitudes. Methods for migrating signals back to their true locations will be applied to the data. To our knowledge, magnitudes have never been calculated using DAS technology, but given the high sample rates and broadband signals this should be feasible. Time permitting, the student will then investigate recording the full vector wavefield (e.g., P- and S-wave waves on 3-components) using DAS technology (e.g., using a coiled cable). This will open up a broad range of future applications including moment tensor inversions, shear-wave splitting and converted wave detection. The ideal student will have a background in Engineering or Physics, but a keen interest in environmental monitoring.
- NERC Reference:
- NE/N009134/1
- Grant Stage:
- Completed
- Scheme:
- DTG - directed
- Grant Status:
- Closed
- Programme:
- Industrial CASE
This training grant award has a total value of £96,595
FDAB - Financial Details (Award breakdown by headings)
| Total - Fees | Total - Student Stipend | Total - RTSG |
|---|---|---|
| £19,035 | £66,561 | £11,000 |
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