About microseismic reservoir monitoring

17-01-2006

Microearthquakes (aka "microseismics", "passive seismics", "microseismicity" or "AE") are induced during hydrocarbon and geothermal fluid production and reservoir development operations. A microearthquake typically results from shear stress release on pre existing faults and fractures due to production or injection induced perturbations to the effective stress conditions. These stress changes may be due to reservoir depletion, water flooding or reservoir stimulation (ie hydraulic frac) operations.

Microseismic frac monitoring

After being a niche technology for many years microseismic monitoring has now emerged as a valuable tool for evaluating the effectiveness of hydraulic-fracturing operations. In particular in the USA it is becoming a routine diagnostic technique for frac monitoring in unconventional gas (ie shale-gas or CBM) plays. Specific examples include development of the;

• tight shale-gas plays such as Barnett Shale and Fayetteville Shale, where microseismic monitoring has had a direct impact on both hydraulic fracturing strategy and the reduction in horizontal well spacings
• tight gas-sand plays such as the Bossier sands and Cotton Valley sands in East Texas
• tight gas-sand plays in the Piceance basin and Pinedale-Jonah in the Green River Basin

Illustrations of this growing use include;

Barnett Shale monitoring: Society of Petroleum Engineers ATCE 2005

Bossier sandstone frac monitoring: World Oil Magazine Bossier sands article

Cotton Valley sandstone monitoring: SEG Geophysics paper

Cotton Valley sands monitoring: Bulletin Seismological Society America (SSA) paper

Piceance basin monitoring: Society of Petroleum Engineers (SPE) ATCE 2005

Microseismic reservoir monitoring

Over a number of years it has also been shown that permanent microseismic monitoring (or "passive listening") has the potential to provide valuable time-lapse 3D seismic (ie 4D seismic) information on the longer-term hydraulic and geomechanical processes taking place within a reservoir. In other words microseismicity has considerable potential for permanent 4D seismic reservoir monitoring and contribution to reservoir management processes.

These processes include the distribution of fluid flow and pressure fronts within naturally fractured systems, production related compaction and the re-activation of faults.

Illustrations of this come from;

Ekofisk field, Offshore Norway: Reservoir microseismicity at the Ekofisk oil field

Valhall field, Offshore Norway: Microseismic survey of a North Sea reservoir

Ekofisk field, Offshore Norway: Microseismic Logging of the Ekofisk Reservoir

With the advent of enhanced permanent reservoir monitoring systems (eg intelligent wells, fibre optics, MEM's sensors) microseismic monitoring has become a practicable means of time-lapse seismic imaging of hydrocarbon reservoir processes remote from production/injection boreholes.

Why Microseis.net?

Microseis.net is a new online news and information service focussing on the rapidly developing technology of microseismic reservoir monitoring. It will meet the growing requirement for independent and up-to-date information on microseismic R&D, hardware and software, service provision, IP, training and field applications.

Microseis.net recognises that passive-seismic monitoring is outside the mainstream of oil industry geophysics and also that end-users want high quality information and expert guidance. Microseis.net fills this knowledge gap, by providing information, training and virtual networking services to E&P companies, service providers and research organisations around the world.

Microseis.net is a subscription service, but you can gain FREE access to a limited set of sample content by registering for a FREE login ID.

Obtain a FREE login ID - no obligation to subscribe

You can also look at a preview of Microseis.net using the link below.

Visit the website preview without registering

Thank you for visiting Microseis.net