Influence of Grain Size on the Gross Internal Stratigraphic Architecture of the Proximal Parts of Early-stage Unconfined Submarine Terminal Lobes: Insights from Process-Based Modeling

Abstract

The internal architecture of terminal lobes is difficult to predict using conventional approaches due to limited resolution and the complex stratigraphy shaped by interactions between flow dynamics and sediment deposition. Process-based modeling offers a valuable means to explore how turbidity flow properties govern lobe architecture, thereby improving predictive capability. This study uses a stratigraphic forward modeling approach to explore how inflow Rouse number expressed via grain size influences gross internal stratigraphic organization in the proximal zone of early-stage terminal lobes, and to explore how key behaviors such as lateral channel migration and channel persistence affect reservoir characteristics, including net-to-gross ratio and amalgamation ratio. Five models were developed by varying sand grain size across a range spanning fine to medium sand, resulting in mean inflow Rouse numbers ranging from 0.11 to 0.23. Other properties were held constant to isolate autogenic effects. Results show a general but nonlinear reduction in spatial heterogeneity with increasing Rouse number. Low Rouse number conditions produce more lateral channel migration, leading to distributive geometries and compartmentalized sandbodies which leads to lower NTG and AR values. Higher Rouse number scenarios exhibit reduced lateral channel migration, promoting the repeated use of similar flow paths especially in the proximal areas. This behavior generates more confined deposition and vertically amalgamated, sandbodies which enhances NTG and AR. While the results may help predict gross three-dimensional stratigraphic architecture in the proximal parts of early-stage terminal lobes, they represent initial modeling outputs. Future studies will incorporate slope and discharge variability to further assess the robustness and generality of the observed relationships.

Department(s)

Geosciences and Geological and Petroleum Engineering

Comments

American Chemical Society, Grant None

Keywords and Phrases

Stratigraphic architecture; Stratigraphic forward modeling; Submarine fan; Terminal lobes; Turbidity currents

International Standard Serial Number (ISSN)

0264-8172

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Elsevier, All rights reserved.

Publication Date

01 Dec 2025

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