Global Geomorphological Relationships of Source to Sink Segments and Implications for Predicting Subsurface Reservoir Characteristics

Abstract

Production, transport and deposition of siliclastic sediment occur in different segments along sediment routing paths known as the source-to-sink (S2S) system. Key controlling factors in different segments, such as climatically and tectonically induced variations in sediment deposition, bypass and erosion leaves morphological characteristics that may be analyzed to provide valuable insights when reconstructing the sink evolution. These characteristics and their relation to one another as observed from modern S2S systems, such as drainage area, channel length, shelf width, shelf gradient and deep-water fan geometry can be used as an analog to allow us to predict similar relationships in ancient S2S systems. Previous research on modern S2S systems has quantified geomorphological relationships on selected worldwide analogs; however a global comprehensive study that integrates the full range of autogenic and allogenic controls, that uniquely influence individual systems, has not been undertaken. Many S2S studies have dealt with S2S systems where the first preserved “sink” is assumed to be the shallow marine environment. In cases, such as in the Mississippi, Ganges, and Niger Delta, large sedimentary basins are also providing storage for significant accumulations of alluvial sediments. This leads to several sub-catchments, all with their own properties and sediment routing systems, which are all important to understand distribution of alluvial fans, channel belts, floodplains and deltas. To quantify the morphological characteristics of global S2S systems on different scales and controls, a new methodology has been developed to define 239,831 watersheds depicting global S2S drainage patterns to modern terrestrial sedimentary basins. The results suggest that the source region area in relation to the full drainage area to the marginal marine for foreland and intracratonic settings is significantly less with numerous smaller source drainage areas contributing to the sedimentary basin as compared to passive and fore-arc tectonic regimes. Catchment area and river length show strong a correlation and are related to shelf width and distance to submarine canyon. The observed geomorphological relationships in the current study provide new insight into the application of modern S2S systems for predictive subsurface reservoir characterization.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017