Time-lapse seismic surveys in the North Sea and their business impact

2000 ◽  
Vol 19 (3) ◽  
pp. 286-293 ◽  
Author(s):  
Klaas Koster ◽  
Pieter Gabriels ◽  
Matthias Hartung ◽  
John Verbeek ◽  
Geurt Deinum ◽  
...  
Keyword(s):  
North Sea ◽  
Time Lapse ◽  
Seismic Surveys ◽  
Business Impact ◽  
The North ◽  
The North Sea

CO2-induced seismic time shifts at Sleipner

2015 ◽  
Vol 3 (3) ◽  
pp. SS23-SS35 ◽  
Author(s):  
Anne-Kari Furre ◽  
Anders Kiær ◽  
Ola Eiken
Keyword(s):  
Detailed Analysis ◽  
Layer Thickness ◽  
North Sea ◽  
Time Lapse ◽  
Time Shift ◽  
Seismic Surveys ◽  
Injection Period ◽  
The North ◽  
Distortion Effect ◽  
The North Sea

Since 1996, [Formula: see text] has been injected into the Utsira Formation above the Sleipner Øst field in the North Sea. During the injection period, the [Formula: see text] distribution in the reservoir has been monitored using eight repeated time-lapse seismic surveys. This seismic monitoring has shown that the [Formula: see text] is visible as thin bright reflectors within the Utsira Formation, interpreted to represent [Formula: see text] flooded layers. We show a detailed analysis of the thin [Formula: see text] layers, with respect to amplitude and time shift development. For a fixed location that becomes [Formula: see text] flooded, the amplitude first increased strongly and a small pull-up of the trough amplitude timing was observed. This response is attributed to interference between top and base of the layer, as long as layer thickness is beneath tuning thickness. This pull-up is an effect induced by wavelet distortion and not related to [Formula: see text] in overlying layers. With time the amplitude decreases and the pull-up is reduced to zero. This is attributed to the layer being thick enough for top and base to be separately resolved. Using our time-lapse observations we have estimated this wavelet distortion effect as a function of time of first flood, which has enabled us to correct for it, and estimate time shifts caused by [Formula: see text] in overlying layers. Thickness estimates derived from these time shifts complement previous amplitude derived estimates of [Formula: see text] thickness.

Time-Lapse Seismic Analysis of the North Sea Fulmar Field

1998 ◽  
Author(s):  
D.H. Johnston ◽  
R.S. McKenny ◽  
T.D. Burkhart
Keyword(s):  
North Sea ◽  
Seismic Analysis ◽  
Time Lapse ◽  
The North ◽  
The North Sea

Time‐lapse seismic analysis of the North Sea Fulmar Field

1997 ◽  
Author(s):  
David H. Johnston ◽  
Robert S. McKenny ◽  
Tucker D. Burkhart
Keyword(s):  
North Sea ◽  
Seismic Analysis ◽  
Time Lapse ◽  
The North ◽  
The North Sea

Long-term seafloor tidal gravity and pressure observations in the North Sea: Testing and validation of a theoretical tidal model

Geophysics ◽  
2008 ◽  
Vol 73 (6) ◽  
pp. WA143-WA148 ◽  
Author(s):  
Glenn Sasagawa ◽  
Mark Zumberge ◽  
Ola Eiken
Keyword(s):  
North Sea ◽  
Pressure Gauge ◽  
Earth Tide ◽  
Time Lapse ◽  
Pressure Measurements ◽  
Tidal Model ◽  
Tidal Gravity ◽  
The North ◽  
Ocean Loading ◽  
The North Sea

Seafloor gravity and pressure measurements for 4D reservoir monitoring require precise models of the time-varying tidal signals. Current seafloor instrumentation can resolve [Formula: see text] in time-lapse gravity differences and [Formula: see text] [Formula: see text] in pressure. To verify model accuracy, a seafloor gravimeter and pressure gauge were operated continuously for [Formula: see text] next to the Troll A gas platform in the North Sea (60.64227° north, 3.72417° east) at a depth of [Formula: see text]. The seafloor gravity and pressure time series were filtered and corrected with estimates from the tidal model, which predicts the solid earth tide, ocean loading, and direct gravitational attraction of the varying water level. The rms difference between the observed tidal gravity signal and the prediction is about [Formula: see text] during periods when there are no surface storms. A slight difference is observed for the direct attraction of the water overhead as computed from the tidal prediction versus that computed from direct seafloor pressure measurements when the entire [Formula: see text] record is analyzed; it shows an rms difference of [Formula: see text], equivalent to [Formula: see text] of water-height variation, yielding a gravity effect of [Formula: see text]. We conclude that existing theoretical tide models in combination with in situ pressure records are sufficiently precise for correcting time-lapse gravity observations.

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