Facies Analysis and Sedimentary Architecture of Hybrid Event Beds in Submarine Lobes: Insights from the Crocker Fan, NW Borneo, Malaysia

Abstract

Hybrid event beds represent the combined effect of multiple geological processes, which result in complex depositional geometries and distinct facies distribution in marine environments. Previous work on hybrid event beds highlights the classification, origin, and types of hybrid facies. However, in the present study, we discuss the development of hybrid event beds in submarine lobes with an emphasis on the analysis of proximal to distal, frontal to lateral relationships and evolution during lobe progradation. Detailed geological fieldwork was carried out in the classical deep-marine Late Paleogene Crocker Fan to understand the relationship between the character of hybrid bed facies and lobe architecture. The results indicate that hybrid facies of massive or structureless sandstone with mud clasts, clean to muddy sand, and chaotic muddy sand with oversized sand patch alternations (H1–H3) are well developed in proximal to medial lobes, while distal lobes mainly contain parallel to cross-laminated clean to muddy hybrid facies (H3–H5). Furthermore, lateral lobes have less vertical thickness of hybrid beds than frontal lobes. The development of hybrid beds takes place in the lower part of the thickening upward sequence of lobe progradation, while lobe retrogradation contains hybrid facies intervals in the upper part of stratigraphy. Hence, the development of hybrid beds in submarine lobe systems has a significant impact on the characterization of heterogeneities in deep-marine petroleum reservoirs at sub-seismic levels.

Facies analysis and distribution of Late Palaeogene deep‐water massive sandstones in submarine‐fan lobes, NW Borneo

“…The heterogeneities in lithofacies of massive sand are the result of soft‐sediment deformation, amalgamation, flow behaviour of non‐Newtonian fluids, and erosional processes (Purvis et al, 2002; Rubi et al, 2018). Sedimentary facies like structureless massive beds, beds with an erosional base or floating mud‐clasts are restricted to the proximal fan where the flow has high‐energy conditions erode the underlying strata (Jamil, Siddiqui, Ahmed, et al, 2021; Zavala, 2020). Additionally, the slumped sandstones are also present at the slope or in the most proximal fan deposition (Jamil, Siddiqui, Umar, et al, 2021; Stow & Johansson, 2000).…”

“…Borneo is associated with tectonic subduction coupled with obduction of ophiolites and closure of palaeo‐basins (Hall, 2013; Mathew et al, 2014; Ramkumar et al, 2021; Siddiqui et al, 2019; Usman et al, 2021; Usman, Siddiqui, Mathew, et al, 2020). The northern part of Borneo is comprised of the Sabah Basin (Figure 1a), which was filled by the Late Cretaceous to Tertiary sediments (Jamil, Siddiqui, Ahmed, et al, 2021; Siddiqui et al, 2020). Tectonically, the Sabah Basin lies at a complex geological junction between the Sunda Sea, Celebes Sea, Sulu Sea, and the South China Sea, the closure of which resulted in the Sabah orogenic belt (Figure 1) (Hall, 2013; Murtaza et al, 2018; Ramkumar et al, 2018; Suggate & Hall, 2014; Usman, Siddiqui, Mathew, et al, 2020).…”

“…Deep‐marine massive sandstones in the West Sabah Basin were recognized as single lithofacies and interpreted as rapid sedimentation by high‐density turbidity currents (Jackson et al, 2009; Jamil, Siddiqui, Rahman, et al, 2021; Lambiase et al, 2008; Zakaria et al, 2013). The literature also encompasses hybrid event beds and aseismic and seismic sedimentary deformation structures in the Crocker Fan (Jamil, Siddiqui, Ahmed, et al, 2021; Jamil, Siddiqui, Umar, et al, 2021). However, a detailed investigation of massive sandstone is required for various types of lithofacies and facies associations.…”

Reservoir Characterization of Alluvial Glutenite in the Guantao Formation, Bohai Bay Basin, East China

“…The various lithofacies, sedimentary microfacies, and diagenesis processes have significant impact on the quality of alluvial glutenite reservoirs [4,10,13,14]. Clarifying reservoir characteristics and assessing the role of depositional factors and diagenetic processes is critical to evaluate reservoir quality [15][16][17][18].…”

Data-Driven Classification and Logging Prediction of Mudrock Lithofacies Using Machine Learning: Shale Oil Reservoirs in the Eocene Shahejie Formation, Bonan Sag, Bohai Bay Basin, Eastern China

“…Lithofacies are inherent properties of rocks or rock combinations formed under certain sedimentary conditions that reflect specific processes or environments. Lithofacies can reflect the sedimentary environment for facies analysis, and determine the fundamental properties of subsurface reservoirs [1][2][3][4]. Determining the lithofacies type and distribution is critical for shale oil exploration and development [5,6].…”