Real-time decision tool to enhance reservoir stimulation and detection of induced seismicity.
Hydraulic Fracturing is a technology to enhance the productivity of oil and gas wells by injecting pressurized fluids into injection wells and thereby creating and opening small fractures or faults within the target zones of a reservoir. Proppants, usually sands, are used to keep these fractures open under subsequent production.
Stimulated reservoir volume
One of the main interests of the operators is to identify the extent and directions of the stimulated reservoir volume (SRV) in real time. The application of microseismic monitoring is currently the only method to obtain such a spatio-temporal image of the SRV.
NORSAR is conducting research on processing methods, analysis and interpretation of microseismic monitoring. Currently, NORSAR is investigating source parameters like stress drops to assist in discriminating wet from dry fractures. In other words, wet fractures being microseismic events that are hydraulically connected to the well and thereby contribute to enhanced production, whereas dry fractures are not hydraulically connected to the well, and thereby do not contribute to enhanced production. This research is funded by the Research Council of Norway and Statoil.
Also, events on dry fractures are more likely to be triggered on pre-existing faults that might lead towards larger faults and thereby pose a seismic hazard. In various states around the world regulations are being drafted on how to permit applications of hydraulic fracturing. In general, a certain minimum criterion of a microseismic network is required that will be able to detect seismicity of a certain magnitude, very similar to cases of waste-water injection, CO₂ storage projects and during generation of enhanced geothermal systems.
NORSAR has broad experience in processing and analysis of microseismic data. Most of the in-house knowledge, processing and analysis competence is originally grown in NORSAR's detection seismology environment.
The main features that NORSAR is working on within hydraulic fracture monitoring are:
- Processing using 3D anisotropic velocity models
- Influence of 3D velocity models on event locations, source parameters and full moment tensors
- Surface data processing of 3-component data for P- and S-wave energy
- Integrated surface and downhole data processing and interpretation using migration-based and phase-picking-based location studies
- Advanced network modelling
- Distinguish between triggered and induced seismicity
- Compliance with regulators on monitoring requirements
NORSAR is used to work with challenging datasets, and we usually provided interesting results where others had to give up. Please contact us if you are interested to work with NORSAR on challenging research topics.