MICROSEISMICITY MONITORING IN ENI

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Seisan WorkshopMicroseismicity monitoring in ENI

• Environmental Monitoring: local authorities often requires monitoring programs to control the impact of the production activities even in non seismic areas.

• Reservoir Passive Monitoring: the study of the microseismicity

associated to reservoir behaviour before and during the production. The purpose is to improve the reservoir characterization and/or to check the hydraulic fracturing operations.

Tools need to be installed in active or dedicated wells at the reservoir depth.

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Seisan WorkshopNetworks

• Lago di Patria (1978-1986) 15• Geothermal field

• Sergnano (1979-1981) 7• Gas storage

• Minerbio (1979 -> ) 3• Gas storage

• Cavone (1982 -> ) 4• Oil field

• Malossa (1984-1992) 7• Oil field

• Metanopoli (1986-1988) 5• Geothermal well

• Correggio (1991 -> ) 3• Gas field

• Val d’Agri (2001 -> ) 13• Oil field

• Crotone (2003 -> ) 6• Gas field

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Seisan WorkshopVal D’agri Network - Goals

• 24h seismological monitoring of the Val d’Agri reservoir, located in an active seismic region (area of about 1500 km2)

•Identify seismic events and discriminate between natural and oil production induced seismic activity

• Monitor water and gas injection

• Provide Regione Basilicata with local seismological data

45 km

38 k

m

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Seisan WorkshopVal D’agri Network - Characteristics

• 11 completely autonomous stations + 2 connected to lines

• GSM system for data transmissions to Milan office

• Solar panels supply

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Seisan WorkshopCrotone Network - Goals

• 24h seismological monitoring of the Luna – Hera Lacinia offshore gas field

• Seismological monitoring of the Crotone region

• Monitoring of the human and natural activities in the archaeological area of Capo Colonna

12 km

21 km

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Seisan WorkshopCrotone Network - Characteristics

• 6 stations: 4 onshore and 2 offshore

• GSM data transmissions to Milan office

• Use of the land seismological equipment for easy integration with existing networks

• Full remote control of sensor levelling and heading

• No need for tool recovery to download data or to change batteries

• Applicable to water depths greater than 100 m

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Seisan Workshop

• Network feasibility study

• Network design

• Network installation & maintenance

• Data acquisition

• Data processing

• Data Interpretation

• Studies on seismological items

• Vibrometric measurements

What We Do

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Seisan Workshop

• Lennartz Le-3D: 3 components geophone 1-80 Hz band

• Lennartz Le-3D/5s: 3 components geophone 0.2-40 Hz band

• Lennartz Mars-88: 20 bit recording system with 4 MB RAM memory (3 h continuous recording)

• Lennartz M24: 24 bit recording system with 50 GB memory (6 months

continuous recording)

• Sampling frequency: 62.5 Hz (16 ms) typical

• Frequency band: 1-25 Hz useful for a local network

• Data retrieval every 2 hrs, shorter on contingent

• Data transmission to Milano via analogic or GSM modem

• 11 stations with solar panels, 18 stations with electric line supply

Equipment

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Seisan WorkshopEquipment

Mars-88

Geophone

Battery

GSM modem

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Seisan WorkshopProcessing

Data are checked and events retrieved by using Lennartz m88select

Data are processed for location, magnitude by using Giant and Pitsa software only when identified as Local (d<=10 km).

To locate the Regional ones (100km < d > 10 km) we have to wait for INGV (National Erathquakes Survey) data.

When ML is over 2.0 , distance <10 km and depth near to the reservoir one, an alarm is delivered.

At the end of the month a bulletin for each network is delivered.

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Seisan WorkshopSeisan to locate a local event recorded by Emilia network

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Seisan Workshop2007 Emilia Locations on Google map

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Seisan WorkshopEMILIA SEISMICITY FROM 1982 to 2002

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Seisan Workshop

Many thanks to Jens and Lars for the fruitful First Seisan Workshop, the many coffee breaks and ice-breakings, the walk under the rain and the social dinner.

I’m looking forward to the next one!