Seismic Monitoring of a Small Scale Supercritical CO 2 /CH 4 Injection: CO2CRC Otway project Case Study

Transcription

1 Seismic Monitoring of a Small Scale Supercritical CO 2 /CH 4 Injection: CO2CRC Otway project Case Study R. Pevzner 1,2, M. Urosevic 1,2, K. Tertyshnikov 1,2, B. Gurevich 1,2, S. V. Shulakova 2,4, S. Glubokovskikh 1,2, D. Popik 1,2, J. Correa 1,2, A. Egorov 1,2, H. AlNasser 1,2, A. Kepic 1,2, B.M. Freifeld 3, M. Robertson 3, T. Wood 3, T.M. Daley 3 and R. Singh 1 1 CO2CRC, 2 Curtin University, 3 Lawrence Berkeley National Lab, 4 CSIRO 11 th IEAGHG Monitoring Network Meeting Traverse City, Michigan June 13 th 15 th, 2017

2 ACKNOWLEDGEMENTS We would like to acknowledge the funding provided by the Australian government to support this CO2CRC research project. We also acknowledge funding from ANLEC R&D and the Victorian Government for the Stage 2C project. Funding for LBNL was provided through the Carbon Storage Program, U.S. DOE, Assistant Secretary for Fossil Energy, Office of Clean Coal and Carbon Management through the NETL. We thank the National Geosequestration Laboratory (NGL) for providing the seismic sources (INOVA Vibrators) for this project. Funding for NGL was provided by the Australian Federal Government.

3 Otway Basin Pilot Project (Victoria, Australia) Paaratte Stage II injection Stage I injection STAGE I: An 80/20 % of CO 2 /CH 4 stream produced from Buttress, transported and injected into CRC 1 well (previous CH 4 production well) 65 Kt. STAGE II: CO 2 /CH 4 stream injected into CRC 2 well 15 Kt.

4 Stage 2C Project goals Detect injected Buttress gas in the subsurface: ascertain minimum seismic detection limit Observe the gas plume development using time lapse seismic Verify stabilisation of the plume in the saline formation using time lapse seismic

5 Otway site aerial photo Naylor 1 CRC 1 CRC 2

6 Seismic Otway site D seismic 3D&4D seismic Curdie Vale Sodas Ln, 7 surveys, various sources and seasons Baseline, Otw 4D Otw 4D, M1 Source tests Otw 4D, M2 PROTECT, SH, several lines Shallow 3D/3C survey 4D with buried receivers Test array, Soda Rd Geophon es + idas Stage 2C, baseline Stage 2C, 3xMonit or surveys, M1 M3) Stage 2C, M4 Zero offset and offset VSP Naylor 1, Z, O, WA CRC 1 (Z, O, 4D Baseline) CRC 2 (Z) CRC 1 (Z, O, 4D Monitor) CRC 1 (Z, O, Hydroph ones) CRC2 (idas) CRC 1 4x Offsets CRC 2 (idas) CRC 1 4x Offsets CRC 2 (idas) CRC 1 4x Offsets CRC 2 (idas) Walk away and 3D/4D VSP CRC2 (idas) CRC 1 (4D/3C Baseline) CRC 2 (idas) CRC 1 (4D/3C Monitor) CRC 2 (idas) CRC 1 (4D/3C Monitor) CRC 2 (idas) Near surface Various refraction and micro VSP surveys Site characterization Stage 1 Stage 2 prepar Stage 2C

7 Stage 2C monitoring strategy Full 4D finite difference time domain (FDTD) synthetic dataset was generated prior commencement of the first monitor survey and used to predefine and validate processing flows (Glubokovskikh et al., IJGGC 49, 2016) 4D seismic with buried receiver array acquired concurrently with 4D VSP Baseline: March 2015 Monitor surveys: 5 kt, 10kt, 15 kt of injection (January April 2016), 1&2 years post injection (January 2017&2018) Offset VSPs Passive seismic using buried receiver array LBNL group lead: Trialing 4D seismic with buried DAS array, 4D VSP in CRC 2 (optical fiber on the tubing) and continuous seismic sources

8 Timeline February 2015 Receiver array installed March 2015 Baseline data acquired September 2015 LBNL installs permanent vibroseis sources on site, baseline acquired; passive seismic acquisition tested November 2015 Passive seismic data acquisition commences, including idas (8000 s / day) January 2016 Monitor 1 (5122 tco 2 ) acquired, new foundations for permanent vibes built February 2016 Both permanent vibes became operational Monitor 2 (10000 t) acquired April 2016 Monitor 3 (15000 t) acquired January 2017 Monitor 4 (1 year post injection) acquired

9 Acquisition geometry 1 km General Survey Parameters Total Number of Source 26+1 Lines Lines Total Number of Sources 3003 Points Source Line Spacing from 50 m to 100 m Source Point Spacing 15 m Total Number of 11 Lines Receiver Lines Total Number of 909 Points Receivers Receiver Line Spacing 100 m Receiver Point Spacing 15 m Max Offset 2480 m Sample Interval 1 ms

10 Receivers geophone RECEIVER PARAMETERS Receiver Type Sercel SG 5 Recording Orthogonal Pattern cross spread pattern Receiver Line 100 m Spacing Receiver Point 15 m Spacing Receiver 4 m Depth Cables Depth 0.8 m

11 Receivers FDU trench crossline unit

12 6 wireless stations above the buried geophones on line 5

13 Source SOURCE PARAMETERS Source Type Sweep frequency Tapers Sweep Length Listening Time INOVA UniVibe lbs Hz 0.5 s 24 s 5s

14 Line 5, receiver 46, common receiver gather Buried Surface

15 Noise floor reduction ~ 25 db

16 Fast track processing flowchart Procedure Parameters DataInput SEG D data input Correlation with sweep signal Linear sweep Hz, length of sweep 24 s, output trace length 5 s Binning Bin size 7.5 m x 7.5 m Trace Editing Kill bad traces/seismograms Elevation Statics Final datum elevation 30 m (MSL),Replacement Velocity 1800 m/s Radon Filtering Number of P values 700, Modelled noise subtraction, Applied in cone window Automatic Gain Control 500 ms, applied before radon filter and removed after Statics 500 ms shift, applied before radon filter and removed after Air Blast Attenuation Energy with velocity of 330 m/s was attenuated Surface Waves Noise Attenuation 900 m/s, 6 35 Hz Spiking Deconvolution Zero phase spiking, Decon Operator length 200 ms, Operator white noise level 0.1 % Automatic Gain Control 500 ms, applied before deconvolution and removed after Interactive Velocity Analysis 2 iterations, VA Grid 100 m x 100 m, 30% NMO muting Residual Static Correction 2 iterations, Max Power Autostatics Automatic Gain Control and NMO AGC window 500 ms, NMO muting 30% CDP stacking Stacking method Mean, Power scalar for stack normalization 0.5 Pad 3D Stack Volume INLINES 1 219, XLINES FXY deconvolution Wiener Levinson filter, Hz FK Filter Applied in polygon Migration Phase shift Time Migration / Explicit FD Time Migration

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18 Buried receiver array preliminary results Buried array higher resolution ~25 db ambient noise floor reduction Virtually all weather acquisition Lower impact on the land occupiers with no cables on the ground Overall higher quality of the data higher resolution better source + sensitivity of the geophones more energy compared to 2009/2010 surveys

19 Time shifts computed between B and (top left to bottom right): M1, M2, M3, M4

20 Histograms of the time shifts

21 Histograms of NRMS values computed between the baseline image and each of monitor images: M1 (red), M2 (blue), M3 (green), and M4 (black). Computations: 200 ms window centred at 1000 ms Distribution density of NRMS values computed in (from left to right): 60 ms window centred at 1136 ms, 200 ms window centred at 1000 ms and 400 ms window centred at 900 ms.

22 Survey area map

23 Intersection along the arbitrary line

24 Intersection along the arbitrary line

25 RMS amplitudes of the differences computed in 24 ms window centred at the plume level (1210 ms). The differences are computed between B and (top left to bottom right): M1, M2, M3, M4

26 VSP in CRC 1 Sercel SlimWave 3C VSP tool (10 levels, 15 m spacing) 3D VSP with m MD 4 offset VSPs

27 Comparison of baseline 4D VSP and surface seismic data CRC 1 T (ms) Target interval 3D surface seismic 3D surface seismic 3D VSP

28 Stage 2C 4D VSP results, xline 122 B M2 M3 M2 B M3 B

29 Offset VSP, SP1, M2 B Baseline Monitor 2 Difference ~1500 m MD

30 Distributed Acoustic Sensing Standard optical fibre acts as the sensor array Typical sampling at 10kHz on 10,000m fibre Standard gauge length of 10m Spatial sampling of 25cm DAS measures change in average elongation per 10m gauge length per 0.1ms acoustic time sample, sampled every 0.25 m in distance z, t Parker et al., Distributed Acoustic Sensing a new tool for seismic applications, first break (32), February Copyright Silixa Ltd 2016

31 FAT Helical Wound Cable Anderson and Shapiro HWC on soft mandrel 1980 US Patent Hornman et al. ( th EAGE) introduced a helical wound FO cable LBNL trialed multiple designs with varying physical properties Line 5 installed one length of HWC for comparison to straight fiber Normal Telecom Cable used in all trenches 30 spiral wound on 58 Shore A rubber mandrel. Lessons learned acoustic impedance of cable and surrounding soil is important

32 Surface Orbital Vibrator VFD Controlled AC Induction Motor Max Frequency 80 Hz, Force 10 T f Phase stability is not maintained. Operate 2.5 hr/d Force is adjustable F=mω 2 r

33 Deconvolved SOV Data Helical Cable shows good sensitivity to reflected P. Straight telecom less sensitivity

34 DAS 3D cube DAS after Post Stack Time Migration Strong reflection at 500 ms (related to a carbonate layer) DAS Monitor 2 Geophone Monitor 2 Far offsets were included in the stack (due to directionality)

35 Stage 2C of the Otway project Conclusions 15,000 t were injected into the subsurface and an extensive seismic monitoring program was rolled out to detect it The data is likely to be sufficient to claim detection & observation of the plume evolution Buried receiver array Better S/N, higher repeatability Lower impact on landowners Passive recording capability + ability to pair it with permanent sources VSP data is inline with the surface seismic data idas (in trenches) can be used to image subhorizontal reflectors Permanent vibes operational

36 Next steps for DAS Improving sensitivity Stage 3: Comparison Carina DAS cable vs standard telcom in CRC 3, SP0, 700 m offset, 5 sweeps Geophones, Z component idas v2 Carina

37 Government, Industry and Research Partners