Broadband Seismic for Improved Geosciences Integration and Increased End-User Value: Examples Through the E&P Asset Life With an Offshore Africa Focus

Abstract

Geoscientists of all disciplines pursue the same goal: to gain a better understanding of the subsurface by effective integration of the complimentary insights from each specialist discipline. For decades, one of the major obstacles hindering more effective collaboration and integration between geology and geophysics has been the different scales of measurement and resolution between well and seismic data. On the marine seismic side, the measurement of the subsurface has suffered from a band-limited version of the earth response: lacking broader frequencies at both the high and low ends of the signal spectrum. Dual-sensor streamer technology has revolutionized seismic imaging of the subsurface thanks to significantly richer low and high frequency information. These additional frequencies fundamentally change not only the appearance of seismic images, but also the way that seismic interpretation, quantification and assessment is conducted (Reiser and Bird, 2016). Techniques such as quantitative seismic interpretation, integrating geology, pre-stack seismic analysis, and well integration, is now becoming significantly more accurate and trustworthy – with the potential to predict more reliable lithology and fluid properties via elastic properties. These types of seismic data improve collaboration among geologists and geophysicists as the information extracted from seismic measurements starts to approximate the data from well information. West Africa examples are provided in various geological settings from the Ivory Coast; to Nigeria and Angola, that illustrate the ability of dual-sensor seismic to significantly improve geological interpretation that is consistent with well data. A study from Angola pursues mapping of carbonate reservoir variability in the pre-salt province. Cases from Cote d’Ivoire, and Nigeria showcase leads/prospects identification from shallow to deep-water environments. All examples result directly from improved methodologies that have evolved using dual-sensor pre-stack seismic AVO analysis and inversion alongside the traditional seismic interpretation workflow. This allows geologist/interpreters to interpret, develop and improve their geological models with greater confidence, and to describe and de-risk prospects more accurately without imposing a pre-conceived model (more from the data, less from a model).

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018