AAPG Europe Regional Conference, Global Analogues of the Atlantic Margin

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The use of seismic amplitude in analysing the proprieties of an offshore reservoir


The main purpose of this paper is the physical interpretation of seismic amplitude for the purpose of hydrocarbon exploration and exploitation. In the right geological scenarios, the interpretation of seismic amplitude can have a significant impact in reservoir characterization. The numerous developments in seismic and amplitude interpretation over the years have made it clear that seismic amplitude technologies have more of a role to play in establishing proven reserves. An accurate understanding of seismic amplitude signatures is critical in the recognition of direct hydrocarbon indicators (DHIs) in the exploration phase and even in the development phase. The purpose of the current study is to evaluate hydrocarbon potentials of an offshore miocene siliciclastic reservoir and to minimise the differences in the amplitude phase and timing for non-reservoir reflections and thereby enhance the signals related to production differences. The data on which the current study is based are well logs from an exploration well and both 2D and 3D seismic data acquired through geophysical prospecting from depths ranging from 100 to 1500 m. To achieve that purpose, a number of techniques were applied. The results of the preliminary 3D seismic map were encouraging, with a high potential for hydrocarbons in the studied miocene formation and in the neighbouring area, and were consistent with the results obtained from the exploration well. Further evidence on the reliability of the seismic data comes from the assessment of data quality. In this case study, the seismic data interpretation was in accordance with the actual well results, demonstrating a reasonable level of certainty in the interpretation of seismic amplitudes. In conclusion, the past years have witnessed significant developments in the way seismic data is used in oil and gas exploration and production, 3D seismic use being the most important, not only to map structures in detail but also to determine reservoir proprieties from the analysis of seismic amplitude and other attributes.