Seismic reservoir monitoring over the Oseberg Field during period 1989-1992

Johnstad, S.E.; Seymour, R.H.; Smith, Patrick J.

doi:10.3997/1365-2397.1995010

Cited by 30 publications

(15 citation statements)

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“…The results are consistent with an extension of the gas zone during production, as shown for the 1989–1992 period by Johnstad et al . (1995).…”

Section: Discussionsupporting

confidence: 92%

“…A previous feasibility study on synthetic seismic data indicated that variations in the saturation of the reservoir due to production would give rise to subtle but noticeable effects on seismic response, particularly amplitude changes. Previous studies on 4D seismic monitoring from 1989 to 1992 can be found in Johnstad, Seymour and Smith (1995).…”

Section: Introductionmentioning

confidence: 99%

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Seismic preprocessing and amplitude cross‐calibration for a time‐lapse amplitude study on seismic data from the Oseberg reservoir

Stucchi

Mazzotti

Ciuffi

2005

Geophysical Prospecting

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The cross-calibration of different vintage data is an important prerequisite in attempting to determine the time-lapse seismic effects induced by hydrocarbon production in a reservoir. This paper reports the preprocessing and cross-calibration procedures adopted to modify the data of four seismic vintages (1982, 1989, 1992 and 1999) from the Oseberg field in the North Sea, for optimal conditions for a time-lapse seismic amplitude analysis. The final results, in terms of time-lapse variations, of acoustic impedance and of amplitude-versus-offset, are illustrated for selected data sets. The application of preprocessing to each individual vintage data set reduces the effects of the different acquisition and noise conditions, and leads to consistency in the amplitude response of the four vintages. This consistency facilitates the final amplitude cross-calibration that is carried out using, as reference, the Cretaceous horizon reflections above the Brent reservoir. Such cross-calibration can be considered as vintage-consistent residual amplitude correction.Acoustic impedance sections, intercept and gradient amplitude-versus-offset attributes and coherent amplitude-versus-offset estimates are computed on the final cross-calibrated data. The results, shown for three spatially coincident 2D lines selected from the 1982, 1989 and 1999 data sets, clearly indicate gas-cap expansion resulting from oil production. Such expansion is manifested as a decrease in acoustic impedance and a modification of the amplitude-versus-offset trends in the apical part of the reservoir.

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“…The results are consistent with an extension of the gas zone during production, as shown for the 1989–1992 period by Johnstad et al . (1995).…”

Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Seismic preprocessing and amplitude cross‐calibration for a time‐lapse amplitude study on seismic data from the Oseberg reservoir

Stucchi

Mazzotti

Ciuffi

2005

Geophysical Prospecting

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“…and a lower part with faults and tilted blocks (Cretaceous and older) (Johnstad et al 1995). From a geological point of view, we can distinguish a strati®ed overburden, with local 2-D or 3-D structures (shale diapirism?)…”

Section: North Sea Real Datamentioning

confidence: 99%

Two-dimensional velocity macro model estimation from seismic reflection data by local differential semblance optimization: applications to synthetic and real data sets

Chauris¹,

Noble²

2001

Geophysical Journal International

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International audienceThe quality of the migration/inversion in seismic reflection is directly related to the quality of the velocity macro model. We present here an extension of the differential semblance optimization method (DSO) for 2-D velocity field estimation. DSO evaluates via local measurements (horizontal derivatives) how flat events in common-image gathers are. Its major advantage with respect to the usual cost functions used in reflection seismic inverse problems is that it is—at least in the 1-D case—unimodal and thus allows a local (gradient) optimization process. Extension of DSO to three dimensions in real cases involving a large number of inverted parameters thus appears much more feasible, because convergence might not require a random search process (global optimization).Our differential semblance function directly measures the quality of the common-image gathers in the depth-migrated domain and does not involve de-migration. An example of inversion on a 2-D synthetic data set shows the ability of DSO to handle 2-D media with local optimization algorithms. The horizontal derivatives have to be carefully calculated for the inversion process. However, the computation of only a few common-image gathers is sufficient for a stable inversion. As a Kirchhoff scheme is used for migration, this undersampling largely reduces the computational cost.Finally, we present an application to a real North Sea marine data set. We prove with this example that DSO can provide velocity models for typical 2-D acquisition that improve the quality of the final pre-stack depth images when compared to the quality of images migrated with a velocity model obtained by a classical NMO/DMO analysis. Whilst random noise is not a real difficulty for DSO, coherent noise, however, has to be carefully eliminated before or during inversion for the success of the velocity estimation

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“…The results from different 4D seismic case studies so far indicate that the areal consistency of various seismic features is robust with respect to noise, and useful information can be obtained even if the baseline survey is old. Some recent examples from the North Sea are the Oseberg study (Johnstad et al 1995), the Magnus time lapse study (Watts et al 1996), the Fulmar study (Johnston et al 1997). Earlier presentations of the Gullfaks 4D study can be found in Sønneland et al (1997).…”

Section: Introductionmentioning

confidence: 96%

The Gullfaks 4D seismic study

Landrø

Solheim²,

Hilde³

et al. 1999

123

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A time lapse analysis was performed on two 3D seismic datasets (4D seismic) acquired over the northern part of the Gullfaks oilfield in the North Sea. The first survey was acquired in 1985, prior to the production start in 1986, a second survey was acquired in 1995, followed by a third in 1996. The drainage interpretations carried out by means of the repeated seismic datasets are in reasonable agreement with similar interpretations performed the traditional way by reservoir engineers, and have locally resulted in an improved understanding of drainage. The time lapse seismic data are routinely used in well planning projects on Gullfaks. In 1997, two wells were drilled into segments that, based on repeated seismic data, were interpreted to be undrained. Both wells encountered oil-filled reservoirs. Although these wells were not based on time lapse seismic alone, the wells served as a good test of the reservoir management potential associated with the 4D technology. Furthermore, waterfront movements predicted on the basis of time lapse seismic data are confirmed by well observations.

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Seismic reservoir monitoring over the Oseberg Field during period 1989-1992

Cited by 30 publications

References 0 publications

Seismic preprocessing and amplitude cross‐calibration for a time‐lapse amplitude study on seismic data from the Oseberg reservoir

Seismic preprocessing and amplitude cross‐calibration for a time‐lapse amplitude study on seismic data from the Oseberg reservoir

Two-dimensional velocity macro model estimation from seismic reflection data by local differential semblance optimization: applications to synthetic and real data sets

The Gullfaks 4D seismic study

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