Enhanced imaging using bandwidth extending operators and pre-stack Q-inversion over the northwest European volcanic margin

Abstract

Extensive sequences of flood basalts dominate the northwest European Atlantic margin. The basalt flows absorb and scatter the higher frequencies present in any source wavelet through intrinsic and apparent seismic attenuation. Successful sub-basalt imaging therefore tends to focus on the generation of low frequencies in acquisition and retention in processing. Conversely, the Rosebank discovery in the Faroe-Shetland Basin of oil bearing sequences interbedded within the Basalt illustrates that high frequencies need to be recovered in order to delineate subtle stratigraphic plays. For this we require broad bandwidth, a robust approach to signal to noise improvement and accurate knowledge of the seismic quality factor (Q) to compensate for locally strong attenuation effects. We show that the required bandwidth can be obtained from conventionally acquired seismic data through the use of low and high frequency boosting operators and application of a horizon consistent Q field. The latter is derived using the pre-stack Q-inversion (PSQI) method to determine effective Q in defined intervals from the data itself. Through a combination of both techniques a substantial uplift in resolution is demonstrated for the highly prospective intra-basalt units with useable frequencies up to 50Hz.

Lava-Sediment Interaction and Drainage-System Development In A Large Igneous Province: Columbia River Flood Basalt Province, Washington State, U.S.A

“…In addition, these aspects become important in hydrocarbon exploration in LIPs. Interdisciplinary studies which provide comprehensive models of lava-drainage interplay and drainage development help to better predict distribution and dimensions of potential hydrocarbon reservoirs in volcanic terrains such as the FaroeShetland Basin in the North Atlantic Igneous Province (Helland-Hansen 2009;Hardwick et al 2012;Schofield and Jolley 2013).…”

“…Volcanic terrains are becoming areas of increased interest for hydrocarbon exploration such as the Faroe-Shetland Basin (Helland-Hansen 2009;Hardwick et al 2012;Schofield and Jolley 2013), the Cretaceous Paraná-Etendeka Province in Brazil and offshore Namibia (Jerram et al 1999;Scherer 2000;Waichel et al 2008). This requires adequate models describing the distribution and dimensions of potential reservoirs in lava fields.…”