INDUCED SEISMICITY IN PETROLEUM FIELDS: RESERVOIR CHARACTERIZATION, SEISMIC

RISK ASSESSMENT AND MANAGEMENT

M. Nafi ToksözM. Nafi Toksöz

Earth Resources Laboratory,Earth Resources Laboratory,Massachusetts Institute of TechnologyMassachusetts Institute of Technology

Cambridge, MA 02139Cambridge, MA 02139

February, 2006

INVESTIGATORS

MIT: KUWAIT:

Prof. M. Nafi Toksöz KISR- Dr. Dhari Al-Ajmi

(seismologist, team leader) (Kuwait team leader)

Prof. Bradford Hager (geomechanics) Kuwait Oil Company-

Prof. Thomas Herring (GPS network, inSAR) Dr. Adel Al-Abbasi

Prof. Frank Dale Morgan (geotechnical, gravity) Kuwait University- Investigators

Prof. Kenneth Oye (policy, risk management) to be nominated by the university

Prof. Andrew Whittle (soil mechanics) and the Kuwait team

InducedInduced SeismicitySeismicity

Often accompanies fluid injection and Often accompanies fluid injection and production in production in Oil and gas fields; geothermal reservoirs; Oil and gas fields; geothermal reservoirs;

hydraulic fracturing.hydraulic fracturing.

Causes?Causes? Pore pressure changesPore pressure changes Stresses due to volume changes.Stresses due to volume changes.

Why is it Important?Why is it Important?

GIVES INFORMATION ABOUT RESERVOIR GIVES INFORMATION ABOUT RESERVOIR PROPERTIES AND FLUID PRESSURE CHANGESPROPERTIES AND FLUID PRESSURE CHANGES

POTENTIAL FOR DAMAGING EARTHQUAKES POTENTIAL FOR DAMAGING EARTHQUAKES AND RISK TO:AND RISK TO: Surface facilitiesSurface facilities Wells and casingsWells and casings Fault sealsFault seals EnvironmentEnvironment Public acceptance Public acceptance

Seismic Event LocationsSeismic Event Locations

Bou-Rabee, F. and R., M.,Abdel-Fattah, 2004. Kuwait J., Sci., Eng v. 31.

Al-Awadhi, J., V. Midzi,Seism. Res. Lett., V:72, N:4, 2001.

PROPOSED TASKSPROPOSED TASKSAnalyze existing seismic and other data relevant to induced seismicity.Analyze existing seismic and other data relevant to induced seismicity.

Densify the existing seismic network to provide a good coverage over the Densify the existing seismic network to provide a good coverage over the southern and northern oil fields. Include three deep seismic stations and three southern and northern oil fields. Include three deep seismic stations and three strong motion instruments at each region.strong motion instruments at each region.

Install continuous GPS stations at each of the two regions to determine three-Install continuous GPS stations at each of the two regions to determine three-component surface deformations.component surface deformations.

Initiate the inSAR analysis to determine subsidence or other deformations.Initiate the inSAR analysis to determine subsidence or other deformations.

Initiate a reservoir characterization and dynamics (compaction, pore fluid Initiate a reservoir characterization and dynamics (compaction, pore fluid characterization).characterization).

Do an initial probabilistic earthquake hazard assessment using the existing Do an initial probabilistic earthquake hazard assessment using the existing data. Calculate ground motions and site effects.data. Calculate ground motions and site effects.

Develop a plan for the management of potential seismic hazard.Develop a plan for the management of potential seismic hazard.

Update steps 7 and 8 with new data.Update steps 7 and 8 with new data.

USGS Fact Sheet 069-03, December 2003

USGS Fact Sheet 069-03, December 2003

THANK YOUTHANK YOU

SOULTZSOULTZSOULTZSOULTZ

Early Experimental PhaseEarly Experimental Phase

In The Upper Reservoir In The Upper Reservoir

1987 - 19971987 - 1997

Exploration of the Deep Reservoir Exploration of the Deep Reservoir

1988 - 20001988 - 2000

Downhole seismic network

(a) Vertical view and (b) top view of the seismicity associated with the stimulation in 2003

Hydraulic Experiment

Soultz,1993

JHD

Collapsing

P S

fract

ure

Example of multiplet

Time

1

1

3

5

4

2

23

4

5

Aligned waveforms of the master and the slave after adjusting the time delay

P wave

masterslave

Relocated Clusters - Vertical ViewWell GPK3

(Injection)

Well GPK2

(Production)

(a) Azimuth

(b) Dip in degrees of the planes deduced by planarity analysis

Distribution of the events around the GPK3 well (200m around the well). Two major microseismic zones are observed: one at app. 4650 m TVD

and the other one at app. 4900m TVD. If we compare that with the major flow exits, we find a good correlation

between the location of these events and the increases of flow.

Rutledge J. and Phillips S., 2002 – Upper Cotton Valley, TX