Upload
devin
View
38
Download
1
Tags:
Embed Size (px)
DESCRIPTION
M onitoring of CO 2 injected at Ketzin using 3D time-lapse seismic data. Alexandra Ivanova 1,2 , Ursula Lengler 1 , Stefan Lüth 1 and Christopher Juhlin 2 GFZ German Research Centre for Geosciences, Germany (2) Uppsala University, Sweden. EGU 2011 5.04.2011, Vienna, Austria. - PowerPoint PPT Presentation
Citation preview
Monitoring of CO2 injected at Ketzin using3D time-lapse seismic data
Alexandra Ivanova1,2, Ursula Lengler1,Stefan Lüth1 and Christopher Juhlin2
(1) GFZ German Research Centre for Geosciences, Germany(2) Uppsala University, Sweden
EGU 2011 5.04.2011, Vienna, Austria
injection wellKtzi 201
observation well
Ktzi 200
observation wellKtzi 202
injection facility
CO2 Pilot Site
Geology of Ketzin
Structural modelV0 Caprock
V1 Aquifer
V0 Auitard
V2
Geology of Ketzin
Structural modelV0 Caprock
V1 Aquifer
V0 Auitard
V2
3D Repeat Survey3D Baseline 2005: 41 Templates~14km2
3D Repeat 2009:20 Templates(after ~20 kilotons CO2 injected)
1 Template:5 lines, 240 geophones12 lines, 180 shotpoints
Start of acquisition 2009:25 Sep 2009
Last shotpoint:6 Nov 2009Ketzin
Repetability
2005baseline
2009repeat
Step:123456789
101112
13
141516171819202122232425
Original parameters:Read raw SEGD dataVertical diversity stackBulk static shift to compensate for source delay: 6 msExtract and apply geometryTrace edit and polarity reversalPick first breaks: offset range 300–500 mRemove 50-Hz noise on selected receiver locationsSpherical divergence correction: v2tBand-pass filter: Butterworth 7–14–150–250 HzSurface consistent deconvolution: filter 120 ms, gap 16 ms, white noise 0.1%Ground roll muteSpectral equalization 20–40–90–120 HzBand-pass filter:0–300 ms:15–30–85–125 Hz 350–570 ms:14–28–80–120 Hz 620–1000 ms: 2–25–70–105 HzZero-phase filterRefraction statics: datum 30 m, replacement velocity 1800 m /s, v0 1000 m/sTrace balance using data windowVelocity analysis: every 20th CDP in the inline and crossline directionResidual staticsNormal moveout correction: 50% stretch muteStackTrace balance: 0–1000 msFX-Decon: Inline and crossline directionsTrace balance: 0–1000 msMigration: 3D FD using smoothed stacking velocitiesDepth conversion: using smoothed stacking velocities
New parameters:
Bandpass filter: Butterworth 7-14-120-200 Hz
Spectral equalization20-35-80-110 HzBand-pass filter:0-300 ms:15-30-75-115 Hz350-570 ms:14-28-70-110 Hz620-1000 ms:12-25-60-95 Hz
Processing steps applied to 3D repeat compared with the original flow
Amplitude change anomaly over the CO2 injection site low fold area for anomaly
1. max change in amplitude ~ amplitude of K2 reflection
2. anomaly ~ centered on injection well
3. positive polarity
VOLUMETRICS
Volumetric estimation of mass of the injected CO2 visible in seismic data will be performed using
- average values of CO2 saturation in reservoir obtained for every well of the Ketzin site witha) Pulsed Neutron-Gamma Well Logging;b) Multiphase Flow Modeling;
- average CO2 density calculated witha) measured temperature and pressure in reservoir at the injection site (in the injection well) to
the time of the repeat survey;b) from Multiphase Flow Modeling for every well of the Ketzin site.
Results show that we can see approximately the same quantity of the injected CO2 in the time-lapse seismic data :
a) Pulsed Neutron-Gamma Well Logging (~ 94%);b) Multiphase Flow Modeling (~91%).
Parameters for volumetric estimationPARAMETER SOURCETime delay Velocity push-downP-Velocities/CO2 and brine saturation
Petrophysics on samples from reservoir saturated with CO2 and brine
CO2 saturation in reservoir
Seismic time-lapse interpretation and:a) PNG Logging in 3 wellsb) Multiphase Flow Modelling
CO2 density in reservoir
a) Temperature and pressure in reservoir on the injection site
b) Multiphase Flow Modelling
Porosity Core analyses and logging
Time Difference for CDP bin Push-Down Effect:
dt = 2h * (1/v2 – 1/v1) => thickness h of CO2 plume
0 25 50 752500
2600
2700
2800
2900
3000
3100
3200
PNG
Modelling
100% brine
Velocitym/s
CO2 saturation%
v2
v1
Parameters for CO2 mass estimation per CDP bin
MOD MIN
MOD MAX
PNG MIN
PNG MAX
0
10
20
30
40
50
60
0.9-1.00.7-0.90.5-0.7
Ampl.Diff.
CO2 Saturation (%)
Ampl.Diff.
MOD MIN
MOD MAX
PNG MIN
PNG MAX
230
240
250
260
270
280
0.9-1.00.7-0.90.5-0.7
Ampl. Diff
CO2 Density (kg/m³)
Distribution of CO2 from 3D time-lapse observaons:
20.5 kTons 23 kTonsMass
of injected CO2 :
22.1-24.2 kTons
20 kTons 22.1 kTons
20.5 kTons 23 kTons
Min
Min
Max
Max
.
.
.
.
a) PNG Well Logging
Massof injected CO2 :
Repeat SurveyBeginning : 22.1 kTons Repeat SurveyEnd: 24.2 kTons
b) Multiphase Flow Modelling
Min
Min
Max
Max
.
. ..
20 kTons 22.1 kTons
23 kTons20.5 kTons
20 kTons
Min
1. Results of seismic interpretation and petrophysical data allowed a satisfactory CO2 mass estimation (91%-94% mass of injected CO2 to the time of the repeat survey) using values of CO2 saturation derived by
a) Pulsed Neutron-Gamma Logging;b) Multiphase-Flow Modeling;
and average CO2 density calculated with c) measured temperature and pressure in reservoir at the injected site
(in the injected well) to the time of the repeat survey;d) Multiphase Flow Modeling for every well of the Ketzin site.
2. Consequences for seismic data of CO2 effect on seismic velocities in reservoir rock (petrophysics) will be illustrated on synthetic seismic models.
3. ‘Predicted’ distributions will be used to generate synthetic seismic data that will be compared directly to seismic field data.
Summary and Outlook
Volumetric estimation based on velocity push-down
Structural modelV0 Caprock
V1 Aquifer
V0 Auitard
V2
Parameter Value
Receiver line spacing / number 96 m / 5
Receiver station spacing / channels 24 m /48
Source line spacing / number 48 m / 12
Source point spacing 24 m or 72 m
CDP bin size 12 m x 12 m
Nominal fold 25
Geophones 28 Hz single
Sampling rate 1 ms
Record length 3 sSource 240 kg accelerated
weight drop, 8 hits persource point
3D Acquisition Parameters
Seismic Interpretation
STACK
STACK MIGRATION
MIGRATION
Volumetric estimation based on velocity push-down
Structural modelV0 Caprock
V1 Aquifer
V0 Aquitard
Top aquifer
Bottom aquifer
Bottom aquitard
Volumetric estimation based on velocity push-down
Structural modelV0 Caprock
V1 Aquifer
V0 Aquitard
Reflectors in time migrated image
Top aquifer
Bottom aquifer
Bottom aquitard
ΔT
V2
CO2 Storage at Ketzin
Start of injection: 30th June, 2008
Food grade CO2 (99.9%)
~ 47,000 tons
Saline aquifer (Stuttgart Formation)
~ 620 m – 650 m
Juni 2008