<i>4D</i>seismic signatures of<i>OWC</i>movement on the Nelson field — Modeling and interpretation

MacBeth, Colin; Reid, Fiona; McInally, A; Garnham, J.; Redondo-López, T.

doi:10.1190/1.1817007

Cited by 7 publications

(7 citation statements)

References 3 publications

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“…The spatial distribution of the 4D signal correlates closely with areas of high net:gross (>0.65), corresponding to the Eastern, Central and Western Channel complexes (Redondo-Lopez et al 2002). However, if no 4D signature is detected within the reservoir interval it may indicate that the reservoir is unswept or is of poor quality.…”

Section: Mapping Owc Movementsmentioning

confidence: 60%

“…Nelson Field a trough/peak 4D signature is observed in the far offset conventional difference (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000) (Fig. 9) (RedondoLopez et al 2002;MacBeth et al 2002). The trough corresponds to the moved OWC and the peak corresponds with the original OWC (Redondo-Lopez et al 2002).…”

Section: Mapping Owc Movementsmentioning

confidence: 95%

“…The seismic isochron from Top Forties to the 4D moved OWC also shows an excellent linear relationship to remaining oil column measured from time-lapse production logs. This has allowed quantitative predictions of the remaining oil column to be made at infill locations (Redondo-Lopez et al 2002). Results from the infill campaign to date have shown these predictions to be accurate to the order of 15 ft (4.5 m).…”

Section: Mapping Owc Movementsmentioning

confidence: 99%

“…9) (RedondoLopez et al 2002;MacBeth et al 2002). The trough corresponds to the moved OWC and the peak corresponds with the original OWC (Redondo-Lopez et al 2002). The trough/peak signature has been mapped throughout the far offset difference volumes for use in the prediction of moved OWC in reservoir simulation history matching and delineation of sweep.…”

Section: Mapping Owc Movementsmentioning

confidence: 99%

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Optimizing 4D fluid imaging

McInally¹,

Redondo-López²,

Garnham³

et al. 2003

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Integrated analysis of 4D seismic data and petrophysical data is used to produce probabilistic fluid and lithology volumes for monitoring reservoir performance on the Nelson Field. Petrophysical analysis of log data shows distinct fields for oil sand, water sand, shale and heterolithic 'lithologies' in acoustic impedance -Poisson's ratio space. Elastic inversion techniques applied to conventional 4D AVO datasets convert the reflectivity data to acoustic impedance, shear impedance, Poisson's ratio and angle impedances. The elastic inversion datasets are used to quantify oil-water contact movements through volume sculpting techniques. Well-derived relationships are used to predict 3D volumes of oil sand probability from three different seismic survey vintages: 1990, 1997 and 2000. Changes in oil sand probability due to production are verified by comparison with repeat production logs. Integrated volume interpretation of 4D far offset inversion difference (oil-water contact (OWC) movement) and oil sand probability shows areas of unswept oil, highlighting infill opportunities. Early results from infill drilling have validated the method, realizing the potential economic benefits of 4D seismic technologies.

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Section: Mapping Owc Movementsmentioning

confidence: 60%

Section: Mapping Owc Movementsmentioning

confidence: 95%

Section: Mapping Owc Movementsmentioning

confidence: 99%

Section: Mapping Owc Movementsmentioning

confidence: 99%

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Optimizing 4D fluid imaging

McInally¹,

Redondo-López²,

Garnham³

et al. 2003

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“…The OWC is characterised in the time-lapse domain by a trough-peak signature which has been shown to be stable for a variety of different geological scenarios (MacBeth et al, 2002). The peak gives the position of the original oil water contact (OOWC), the trough gives the position of the moved oil-water contact (MOWC).…”

Section: Picking the Owc: Sail And Svdmentioning

confidence: 99%

4D signal enhancement using singular value decomposition, application to mapping OWC movement across the Nelson field

Reid¹,

Bertrand²,

McInally

et al. 2003

SEG Technical Program Expanded Abstracts 2003

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In this paper we present a new method for time-lapse signal enhancement using singular value decomposition (SVD). Singular value decomposition is used to separate a 4D signal into its constituent parts: common geology, timelapse response and noise. This signal enhancement technique is used to map out both the original and moved oil-water contact across the Nelson field. The SVD technique allows the oil-water contact (OWC) to be mapped across regions which would have been missed using traditional methods. The oil-water contact is observed to move upwards across the field with the largest movements being associated as anticipated with natural production. The results obtained are consistent with those predicted by the reservoir simulator model. Singular value decomposition is demonstrated to be a useful tool for enhancing the time-lapse signal and for gaining confidence in areas where traditional differencing fails.

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4D signal enhancement using singular‐value decomposition: application to mapping oil–water contact movement across the Nelson Field

Reid¹,

Bertrand²,

McInally³

et al. 2005

Geophysical Prospecting

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A B S T R A C TA new method for time-lapse signal separation and enhancement using singular-value decomposition is presented. Singular-value decomposition is used to separate a 4D signal into its constituent parts: common geology, time-lapse response and noise. Synthetic tests which demonstrate the advantages of the singular-value decomposition technique over traditional differencing methods are also presented. This signal separation and enhancement technique is used to map out both the original and moved oil-water contacts across the Nelson Field. The singular-value decomposition technique allows the oil-water contact to be mapped across regions which would have been missed using traditional differencing methods. In particular, areas toward the edges of the field are highlighted by the technique. The oil-water contact is observed to move upwards across the field, with the largest movements being associated, as anticipated, with natural production. The results obtained are broadly consistent with those predicted by the reservoir simulator model. Singular-value decomposition is demonstrated to be a useful tool for enhancing the time-lapse signal and for gaining confidence in areas where traditional differencing fails. I N T R O D U C T I O NThe differencing of seismic volumes to investigate time-lapse changes poses a variety of problems: simply subtracting one data set from another often has the effect of enhancing noise, with the true reservoir changes being swamped as a consequence. Numerous attempts to combat these problems have been made previously by, for example, Landrø et al. (1999), who computed the robust difference (effectively smoothing prior to differencing), which reduces the rms difference level

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4Dseismic signatures ofOWCmovement on the Nelson field — Modeling and interpretation

Cited by 7 publications

References 3 publications

Optimizing 4D fluid imaging

Optimizing 4D fluid imaging

4D signal enhancement using singular value decomposition, application to mapping OWC movement across the Nelson field

4D signal enhancement using singular‐value decomposition: application to mapping oil–water contact movement across the Nelson Field

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