Direct correlation of 4D seismic and well activity for dynamic reservoir interpretation

Abstract

A method is proposed which identifies areas in the 4D seismic response which directly correlate with well activity, and hence are consistent with the reservoir engineer's understanding of the field. This approach makes use of the essential requirement for a causal relationship between the seismic difference signatures and the cumulative produced or injected volumes. The method relies upon the use of multiple and frequently shot seismic surveys over a common reservoir area. It is applied to data from the Schiehallion field, West of the Shetland Islands, and the resultant signals are observed to be robust, with a much reduced noise level and to enhance particularly weak 4D seismic signatures. The results may be indicative of regions of connectivity associated with each well.

Correlation of Well Activity to Time-lapsed Signatures in the Valhall Field for Enhanced Dynamic Interpretation

“…There are now many fields for which such datasets have become available. One such example has been shown previously by Huang and MacBeth (2009) for the non-compacting Schiehallion field. Here we show a further application to the Life of Field Seismic (LoFS) data acquired over the compacting chalk of the Valhall field.…”

Direct correlation of 4D seismic with well activity for a clarified dynamic reservoir interpretation

“…Thus, it is natural to assume that at any particular location in the reservoir, the time‐lapse change of a mapped seismic attribute Δ A is a correlatable function of the reservoir's well activity. Indeed, to link cause (seismic) with effect (wells), the pressure‐saturation change equation proposed by MacBeth et al (2006) can be modified to explicitly involve only well data (Huang and MacBeth 2009). Consider the specific case of a pressure‐controlled 4D seismic signature for which the contribution from saturation changes is suppressed relative to the pressure – from our experience to date, in clastic and chalk reservoirs identification of the pressure signal appears possible in most cases.…”