Print this pageDeep-Water Reservoir Depositional Models: Early Exploration Experiences and New Observations
Franklin J. Goulding1, Tim Garfield3, Gerrick Jensen3, Richard Lovell1, Kurt W. Rudolph2, Anthony Sprague5, Rick T. Beaubouef1, Michael Porter1, Christine Rossen1, Morgan D. Sullivan4, and Donald K. Sickafoose2
1ExxonMobil Development Company, Houston, TX
2ExxonMobil Exploration Company, Houston, TX
3ExxonMobil Production Company, Houston, TX
4Chevron Energy Technology Company, Houston, TX
5ExxonMobil Upstream Research Company, Houston, TX
In a little more than a decade industry has seen the maturation of the deep-water Oligo-Pliocene plays on the continental slope of West Africa through exploration, development and now into early production. These complex exploration targets presented challenges to industry that necessitated the development of new depositional models and interpretation techniques. The depositional models developed during the exploration phase to predict reservoir distribution have largely stood the test of time, but significant advances have been made in understanding the internal fill architecture and resulting production scale reservoir connectivity.
Seismic stratigraphy and facies analysis, afforded by high quality seismic data, favourable rock properties, integrated with well and outcrop data were key to the development of these depositional models. Mapping the internal architecture of high-frequency sequences yields a high resolution picture of the vertical and lateral distribution of flow-unit scale reservoir elements in the subsurface.
Initial exploration models focused on large scale reservoir-prone channel complexes of three dominant types: leveed channel complexes (LCC), confined channel complexes (CCC) and distributary channel complexes (DCC). Predictions of gross reservoir continuity have also stood the test of time with high net CCC's having markedly different characteristics than DCC's. Local, and significant, production scale variations in sweep have been observed that are largely below the uncertainty limits of seismic mapping. Incorporation of early production data into our models has significantly enhanced understanding of sweep and recovery efficiency.
Emerging 3D seismic analysis techniques, 4D seismic monitoring, and new process based depositional models provide the greatest potential for improving our reservoir predictions in the immediate future.
AAPG International Conference and Exhibition, Cape Town, South Africa 2008 © AAPG Search and Discovery