The Gullfaks 4D seismic study

Landrø, Martin; Solheim, Odd Arve; Hilde, E.; Ekren, Bjørn Olav; Strønen, L. K.

doi:10.1144/petgeo.5.3.213

Cited by 123 publications

(64 citation statements)

References 9 publications

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“…Time-lapse ͑also known as 4D͒ seismic monitoring is not restricted only to reflection seismic data ͑see Sønneland et al, 1997;Landrø et al, 1999;Boyd-Gorst et al, 2001;Landrø, 2001;Guilbot and Smith, 2002;Bertrand and MacBeth, 2003͒. It is likewise possible to use transmission data recorded at the same location but at different times to assess the 4D changes of the subsurface elastic properties.…”

Section: Introductionmentioning

confidence: 99%

Application of a linear finite-frequency theory to time-lapse crosswell tomography in ultrasonic and numerical experiments

2007

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Time-lapse seismic monitoring is the geophysical discipline whereby multiple data sets recorded at the same location but at different times are used to locate and quantify temporal changes in the elastic parameters of the subsurface. We validate a time-lapse monitoring method by crosswell tomography using two types of wavefield-modeling experiments: ͑1͒ a 3D real ultrasonic waveform experiment and ͑2͒ 2D synthetic finite-difference wavefield simulations. For both wavefield experiments, a time-lapse structure simulating a fluid sweep in a reservoir layer is applied. The timelapse tomographic monitoring approach is based on the standard ray theory and a finite-frequency wavefield theory, where the latter takes into account the finite-frequency properties of recorded wavefields. The inverted time-lapse models compiled with either the ray theory or the finite-frequency wavefield theory locate and correctly quantify the flooding zone in the simulated fluid sweep model. Both wavefield theories provide an adequate result because the flooding zone is comparable in size to the Fresnel volume.

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Section: Introductionmentioning

confidence: 99%

Application of a linear finite-frequency theory to time-lapse crosswell tomography in ultrasonic and numerical experiments

2007

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“…By studying the difference in the data from repeated seismic surveys, useful information from the field can be obtained, such as velocity, pressure, and saturation changes. One of the first commercial successes of time-lapse seismic in the North Sea is the Gullfaks study (Landrø et al, 1999), in which the evident effect of replacing oil with water in the seismic data helps with the successful identification of remaining and untouched oil pockets.…”

Section: Introductionmentioning

confidence: 99%

A new approach to separate seismic time-lapse time shifts in the reservoir and overburden

et al. 2017

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For a robust way of estimating time shifts near horizontal boreholes, we have developed a method for separating the reflection responses above and below a horizontal borehole. Together with the surface reflection data, the method uses the direct arrivals from borehole data in the Marchenko method. The first step is to retrieve the focusing functions and the updown wavefields at the borehole level using an iterative Marchenko scheme. The second step is to solve two linear equations using a least-squares minimizing method for the two desired reflection responses. Then, the time shifts that are directly linked to the changes on either side of the borehole are calculated using a standard crosscorrelation technique. The method is applied with good results to synthetic 2D pressure data from the North Sea. One example uses purely artificial velocity changes (negative above the borehole and positive below), and the other example uses more realistic changes based on well logs. In the 2D case with an adequate survey coverage at the surface, the method is completely data driven. In the 3D case in which there is a limited number of horizontal wells, a kinematic correct velocity model is needed, but only for the volume between the surface and the borehole. Possible error factors related to the Marchenko scheme, such as an inaccurate source wavelet, imperfect surface multiples removal, and medium with loss are not included in this study.

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“…Time-lapse seismic monitoring has emerged as an effective tool for monitoring hydrocarbon reservoirs during production (Landrø et al, 1999;Lumley, 2001). Recently, this method has been adopted for monitoring purposes at CO 2 storage sites (Furre and Eiken, 2014).…”

Section: Introductionmentioning

confidence: 99%

Seismic imaging of the carbon dioxide gas cloud at Sleipner using 3D elastic time-lapse full waveform inversion

Raknes

Weibull

Arntsen

2015

International Journal of Greenhouse Gas Control

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a b s t r a c tA solution to the increasing greenhouse gas emissions is carbon capture and storage. At the Sleipner field, offshore Norway, carbon dioxide is separated from the produced gas and injected into the Utsira formation at approximately 1000 m depth. The Utsira formation is a high porosity saline aquifer that is 200-300 m thick in the injection area. In 1994, two years before the injection started, a seismic survey was acquired. The survey has been followed up by several seismic surveys acquired to monitor the migration of the injected gas. The full waveform inversion (FWI) method is a non-linear inverse method for estimating subsurface elastic parameters. Time-lapse FWI has recently been suggested as a monitoring tool for resolving time-lapse changes directly in the elastic parameter models. This paper presents an application of a three dimensional implementation of isotropic elastic time-lapse FWI applied on time-lapse field data from the Sleipner area. The baseline dataset is the 1994 dataset, whereas the monitor dataset is the survey acquired in 2006 after ten years of injection. Time-lapse FWI is used to estimate separate elastic parameter models for both the baseline and the monitor datasets. The results show that FWI is able to estimate detailed elastic parameter models that produce synthetic data that match the field data. The inverted models are used in a pre-stack depth migration method to yield detailed seismic images of the Sleipner before and after the injection of the gas. The gas cloud after ten years of injection is clearly visible on the monitor seismic images. The baseline and monitor seismic images show events and discontinuities that can explain the migration pathways of the injected gas through the Utsira formation.

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The Gullfaks 4D seismic study

Cited by 123 publications

References 9 publications

Application of a linear finite-frequency theory to time-lapse crosswell tomography in ultrasonic and numerical experiments

Application of a linear finite-frequency theory to time-lapse crosswell tomography in ultrasonic and numerical experiments

A new approach to separate seismic time-lapse time shifts in the reservoir and overburden

Seismic imaging of the carbon dioxide gas cloud at Sleipner using 3D elastic time-lapse full waveform inversion

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