reservoir induced seismicity

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  • 1. Department of Earth Sciences KFUPM Introduction to Seismology Reservoir Induced Seismicity( Reading Assignment: pp.384-386 ) Introduction to Seismology-KFUPM Ali Oncel [email_address]

2. Earthquake types

  • Natural
    • Volcanic
    • Tectonic
    • Landslide (e.g. Mantaro River, Peru,1974)
  • Anthropogenic
    • Rock burst (e.g. deep South African mines)
    • Reservoir-triggered (e.g. Koyna reservoir, India)
    • Explosion (nuclear & large conventional)

Seismogram: Soviet nuclear blast 1984 Introduction to Seismology-KFUPM Source 3. Volcanic earthquakes

  • Typically swarms
  • Range of seismograms
    • tectonic (short period)
    • long period/tremor
  • Mammoth
    • Long Valley restless caldera
    • May 1980 - 3 M6 quakes
    • By August >6000 small quakes
    • More swarms in late 80s and late 90s
    • accompanying ground deformation & CO 2release

Introduction to Seismology-KFUPM http://www.csupomona.edu/~geology/docs/stop13-3.htm Earthquakes and gas release at Mammoth (California) Source 4. Reservoir-triggered quakes

  • Common when new reservoirs filled (e.g. Vajont, NE Italy)
  • Relevance to dam safety
  • Shivajisagar reservoir, Koyna (India)
    • low seismicity area
    • earthquakes swarms started as reservoir started to fill in 1962
    • M6.5 quake close to dam in 1967 killed200
    • rainfall linked
  • Future: 3 gorges (China) and other major dams

Three Gorges Dam (China) Introduction to Seismology-KFUPM All dams trigger seismicity? 4% of damsin US have triggered M>3 earthquakesSource: 1976 poll of US dams Source 5. Humans induce seismicity

  • Dam filling
  • Waste water injection
  • Oil extraction
  • Hot water extraction
  • Mining
  • Nuclear tests

Introduction to Seismology-KFUPM 6. Koyna Dam, India

  • Filling of dam started in 1962
  • Increase of seismicity noticed in mid-1963
  • Earthquakes clustered
  • near reservoir, shallow depth
  • M 6.3 earthquake in 1967
  • 200 dead,
  • 1500 injured, >5000homeless

Introduction to Seismology-KFUPM 7. Triggered earthquakes at Koyna, India Introduction to Seismology-KFUPM 8.

  • Earthquakesare associated withchange in water level : with large scale filling of the dam, possibly with emptying Seismicityoften tapers off within ten years of water level stabilization Variable timedelays may occur between dam filling and earthquakes

Some characteristics of reservoir triggered seismicity 9. Seismicity in the Oil Field Introduction to Seismology-KFUPM In some regions, hydrocarbon production can induce seismic activity. To help understand how production affects seismicity, a recording network was installed in a producing field in Russia. In a cooperative project between Schlumberger and the Institute of Dynamics of Geospheres at the Russian Academy of Sciences, scientists are analyzing the recorded data to help forecast seismic events, understand reservoir properties and monitor water injection (Adushkin et al., 200, Oiifield Review). Adushkin et al., 2000 10. The Romashkino Oil Field 11. Comparison of smoothed values of seismic activity (red) with variations in volumes of injection, production and imbalance in the four central areas of the Romashkino field. The Romashkino Oil Field Comparison of monthly values of seismic activity (red) with variations in total volumes of injection, production and imbalance in the four central areas (combined) of the Romashkino field.Introduction to Seismology-KFUPM 12. 13. Schematic contours of the Talco reservoir showing the association of microseismic events with channel structure. Monthly injection rates and seismicity rates at Talco. Introduction to Seismology-KFUPM

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