Project overview. SleipnerCO 2 plume. Filip Neele, Rob Arts. E T

Transcription

1 Project overview SleipnerCO 2 plume Filip Neele, Rob Arts E filip.neele@tno.nl, rob.arts@tno.nl T

2 Sleipner CO 2 injection CO 2 injection commenced 1996 ~ 1 Mt CO 2 injected per annum > 11 Mt currently in situ Time-lapse monitoring D seismic baseline D seismic D seismic D seismic D seismic D seismic D seismic [2D hi-res] [Seabed gravity] [CSEM] [Seabed imaging] 2 Courtesy CO2STORE

3 Sleipner: the reservoir 3 Courtesy CO2STORE

4 Sleipner: Forward modelling km 4 S N

5 Detailed synthetic modeling of the seismic response Top reservoir Thickness of 127 m Bottom reservoir Top reservoir Tuning effect at the top of the reservoir TWT of 123 ms Bottom reservoir Sand CO 2 Shale 5 Push-down effect below the CO 2 accumulation Amplitude (blue trough) Thickness CO 2 accumulation below the shale barriers (m) Shale - upper CO2 column interface Shale - middle CO2 column interface Shale - low er CO2 column interface

6 Aim (EU CO 2 ReMoVe) Study Sleipner CO 2 plume Development through time Focus on undisturbed top layer Confirm properties of CO 2 filled Utsira reservoir Inline 1838 Method Shot gathers from Inline data (2D) Common Focus Point (CFP) AVP data AVP data rock physics 6

7 CFP work flow (1) Shot gathers DTS Operators - * CFP gathers Grid point g. * After Berkhout 7

8 Local characterization R(-1) R(0) R(1) V int, thickness, rel. dip V int, thickness, rel. dip Gridpoint gather τ - p transform τ = 0 is AVP curve Amplitude (p) After Berkhout; Winthaegen 8 Reflectivity gather

9 CFP work flow (2) Shot gathers DTS Operators - * CFP gathers Grid point g. Amplitude * After Berkhout 9 Velocity

10 Time lapse CFP work flow Baseline Shot gathers Operators DTS CFP gathers Cross focusing (cross equalization: travel time, amplitude) Saturation Stress Pore fluid Time lapse Shot gathers Operators DTS CFP gathers Grid point g. Amplitude Amplitude Grid point g. After Winthaegen 10 Velocity Velocity

11 Cross focusing: travel time Shallow subsurface Changed shallow subsurface Time ( t) Overburden Overburden Redatum source and receivers (new acquisition level) After Winthaegen Reservoir Baseline survey 11 Use the same operator for the monitor survey and update (in case of changes) Changed reservoir Monitor survey Note: focusing includes regularization/interpolation at new datum level

12 Focusing: time correction shot bl Operator (A,t) for overburden DTS Differential time = 0 Reflectivity After Winthaegen 12

13 Cross equalization: time shot bl tl Operator (A,t) for overburden?? T Otl = T Obl Apply kinematic correction using the base line operator to the monitor data (and update) DTS Reflectivity 13

14 Cross equalization: amplitude bl tl bl - tl = diff. shot A Stl = 4A Sbl Operator (A,t) for overburden A Otl = 0.5 A Obl Datum = 0 DTS Changed reservoir 0 Reflectivity (AVP) 14

15 2008 data set 2008 data CFP processing on top Utsira Fm Clear reflection in plume, weak reflection elsewhere Top Utsira Amplitude (p) Reflectivity gather p 0.0 (s/m)

16 2008 data set AVP Top Utsira AVP panel p 0.0 (s/m) Distance along inline (m) AVP curves red: left of plume green: in plume blue: right of plume Data contain interval (approx.) 4e-5 < p < AVP amplitude (a.u.) 0 no data ray parameters in data no data p (s/m)

17 2008 data set Synthetic AVP curves Plume zone higher amplitude Plume zone higher gradient reflection coefficient AVP response, Top Utsira PP (CO2 saturated) PP (water saturated) Zoeppritz ray parameter p AVP amplitude (a.u.) p (s/m) 0 EBN-TNO amplitude conference (p)

18 Plume AVP panels Plume imprint on data increases Consistent results for time lapse surveys

19 AVP curves Red: left of plume Green: in plume Blue: right of plume Data contain interval (approx.) 4e-5 < p < Interference from shallower reflections Restricts validity of results to interval 0<p< (approx.) More far offsets in more recent data sets p (s/m)

20 Future work Interpretation in terms of rock physics Image and analyse deeper parts of the plume (next slide) Top Utsira First reflection inside plume 20

21 First reflections inside plume AVP panels and curves original data original data

22 Sleipner surveys Inline through plume