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Stratigraphic Compartmentalization and Connectivity in Deepwater Slope Valley Reservoirs: Lessons from Block 14 Angola


In Block 14, offshore Angola, the main deepwater reservoirs comprise high-quality Miocene turbidite channel complexes filling erosionally confined slope valleys (up to several hundreds of meters thick and several kilometers wide). These slope-valley reservoirs are extremely heterogeneous owed to vertical and lateral variability in stratigraphy at multiple scales, variability in the facies associations within the channels, remobilized sandstones, both as injections and mass transport deposits, and multiple scales of erosional surfaces. As a result, prediction of reservoir compartmentalization and connectivity between and within the channel complexes is challenging. In order to ensure the successful development of these reservoirs, extensive seismic, well-log, core, production and surveillance data have been collected. Four-dimensional seismic data has also been collected to better understand reservoir connectivity and for optimization of future development wells. Optimal placement of development wells and improved reservoir management are achieved as a result of extremely detailed stratigraphic characterization, which includes mapping of erosional surfaces bounding the slope valleys, a precise identification of where channel elements are located within the valley, and an understanding of the temporal evolution of the valley fill. Furthermore, it is critical that the seismic, well-log, core and production data be fully integrated within the context of stratigraphic concepts of deepwater slope-valley development and evolution. This integrated workflow in reservoir characterization has resulted in a significant improvement in the understanding of reservoir connectivity and resulted in improved reservoir management.