Process-Based Sand Prediction: Eastern Gulf of Mexico
Hudson, Sam; Armitage, Dominic; Granjeon, Didier; Wu, Xinxia; Blackerby, Jim; Mornet, Christopher
Depositional patterns of Tertiary deep-water sediment, on the Gulf of Mexico slope to the abyss, are complicated by the pervasive influence of syndepositional salt tectonics. Net sand prediction for the eastern Gulf of Mexico is made based on integrating well control and seismic-reflection interpretation. Significant variation in sand distribution is well documented due to the abundance of wireline log data, and conventional core drilled in this area.
Despite decades of hydrocarbon exploration there is still significant temporal and spatial uncertainty regarding the depositional distribution and preservation of clastic sediments. Stratigraphic forward modeling is used as an important tool to aid prediction in these data-poor areas. Multiple realizations of sand distribution are created using diffusion-based process modeling. Favored realizations compare well with data-rich areas in the Gulf of Mexico, adding confidence to areas modeled with little or no hard data.
Calibrating the model to well control, and regional predictive sand maps, allows the relative importance of different assumptions such as salt relief during deposition, sediment sources, and flow concentration to be tested. While forward modeling provides non-unique solutions, there is great value in understanding the relative sensitivity of the model to variations in control parameters and in finding which reasonable inputs can be used to approximate what is known from subsurface data. Through the scenarios tested, it has been shown that the models are less sensitive to relative salt relief; results are very similar whether using 5m relief of salt or 50m relief. In addition, sediment sources from the NNW consistently provide the best matches to control data, which is consistent with regional assumptions. Work is ongoing to better understand sediment distribution from the slope to the abyss. Through this workflow, exploration can be directed by defining areas of potential sand accumulation, and a more developed understanding of likely sediment fairways is gained.
AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013