--> Compound Seismic Forward Modeling of the Atiart Submarine Canyon Outcrop, Spain: Application to the Submarine Canyon System on the Subsurface Loppa High, Barents Sea

AAPG ACE 2018

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Compound Seismic Forward Modeling of the Atiart Submarine Canyon Outcrop, Spain: Application to the Submarine Canyon System on the Subsurface Loppa High, Barents Sea

Abstract

The inability to resolve geological details can lead to erroneous seismic interpretation and create higher risk during the prospect evaluation and assessment. Seismic forward modeling of outcrop analogue can provides an important link between the architectural geometries and facies composition observed in the outcrop and in seismic data. The aim of this work is to produce realistic model that can potentially bridge the critical gap in resolution between two different geological datasets and provide improved insight to the interpretation of petroleum targets. This study utilized traditional geological mapping and digital outcrop modeling techniques of the Atiart outcrop in Ainsa, Spain, and was coupled with morphometric analysis of the subsurface canyon systems from the Loppa High, Barents Sea to produce 3-D geometry and facies model. Rock properties have been taken from subsurface Loppa High canyon system with facies comparison to the Atiart sedimentary logs. These kind of integrated outcrop studies was used to create the realistic properties model (gamma, density, shear- and compressional-waves, and velocity). Ray-based convolution method have been performed to produce normal polarity, zero-phase, pre-stack depth migrated seismic model. In addition, gamma model was used to predict net-to-gross for the different facies in the canyon system. Three realizations at 20 Hz, 30 Hz and 40 Hz have been performed to find the specific frequency that matches the interpreted seismic data in the Loppa High (subsurface). The 40 Hz model shows important result that detailed architecture of the canyon system is successfully captured; 1) Single seismic trace indicated stack of several heterogeneous sedimentary layers. 2) Canyon surface not only identified by truncation reflection terminations, but also identified by relatively low amplitude within single seismic trace. 3) Syncline reflector on the canyon-fill might be refer to differential compaction or a seismic artefact. 4) Lateral degradation of the amplitude strength indicate lateral variation on the lithofacies. Our work shows an important result on how to reduce the uncertainty in seismic interpretation of canyon systems. This research also contributes to better constraints on lithology predictions, pit-falls detection, architectural elements, and geometry distribution of canyon systems.