Submarine-fan systems I: characterization and stratigraphic prediction

Submarine-fan and related deep-marine clastic systems such as submarine ramps and slope aprons are important hydrocarbon reservoirs in many parts of the world. The origin and character of these systems reflect a complex interplay between a range of autocyclic and allocyclic controls including sea-level fluctuations, basinal tectonics and the rate, type and nature of sediment supply. These controls are commonly interdependent. This paper reviews the characteristics which distinguish different submarine-fans and their subsurface prediction, then proposes a classification framework for fans which discriminates between different systems on the basis of their fundamental controls. The proposed classification is discussed in terms of its value as a predictive tool in hydrocarbon exploration, development and production. A modus operandi is developed which uses the classification for reservoir description and prediction and involves three stages of investigation: basin screening, fan delineation and fan characterization. Each stage demands the integration of a range of tools and techniques including sequence stratigraphy, seismic facies analysis, seismic redisplay and geophysical modeling. These stages of analysis are linked, in turn, with core and wireline log data to constrain the range of possible fan types within a basin-fill and assess the implications for reservoir seal and trap development. This structured approach to stratigraphic analysis is also valuable in constraining the range of reservoir architectural options in appraisal, development and production.