Facies Heterogeneity and Lobe Facies Multiscale Analysis of Deep-Marine Sand-Shale Complexity in the West Crocker Formation of Sabah Basin, NW Borneo

Abstract

Deepwater lobes constitute a significant volume of submarine fans and are primarily believed to exhibit a simple sheet geometry. However, recent studies interpret the geometries of these deep-marine lobes as distinct with respect to the complexity of the facies and their distribution. Hence, a conceptual model of deep-marine sediments is essential to discuss the deep-marine sediments associated with the fan and lobe architecture. The present study highlights the facies heterogeneity and distribution of various lobe elements at a multiscale level by considering a case study of the West Crocker Formation of Sabah in northwest Borneo. The formation was logged on a bed-to-bed scale from recently well-exposed sections, with a total vertical thickness of more than 300 m. The lithological characteristics, bed geometry, sedimentary textures and structures of individual beds were used to categorize the rock units into nine sedimentary lithofacies: five sandstone lithofacies (S1–S5), one hybrid bed facies (H), two siltstone facies (Si1 and Si2) and one shale or mudstone facies (M). These facies were grouped into four facies associations (FA1–FA4), which were interpreted as lobe axis (FA1), lobe off-axis (FA2), lobe fringe (FA3) and distal fringe to interlobe (FA4) facies associations. This study is applicable for the distribution of lobes and their subseismic, multiscale complexities to characterize the potential of hydrocarbon intervals in deep-marine sand-shale system around the globe.

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

“…The presence of water‐escape features, which occasionally coexist with amalgamation, is an indication of the rapid dewatering process (Jamil, Siddiqui, Umar, et al, 2021; Stow & Johansson, 2000). This process is interpreted as large influx of sand during a brief time span in the sedimentary basin (Jamil, Siddiqui, Rahman, et al, 2021; Stow & Smillie, 2020).…”

“…These beds are also termed as fluxoturbidites, which are typically deposited in the proximal part of deep‐marine fan (Górska, 2019). They are mostly associated with landslide, slump basin floors, and classic Bouma turbidites where these massive sandstones are relatively coarse‐grained than classic Bouma facies (Jamil, Siddiqui, Rahman, et al, 2021; S. Li et al, 2020). However, some of the Bouma facies (Ta and Tb) with higher flow regimes are also present in these massive beds (S. Li et al, 2020).…”

“…Our results show that the DWMS of the West Crocker Formation exposed in NW Borneo were mainly deposited by sandy debris flow and high‐density turbidity currents. Sandy debris flow is concentrated in sand‐dominated proximal fan settings while higher sand content with minor argillaceous sediments was formed by high‐density turbidity currents in proximal to middle submarine fan (Cao et al, 2021; Jamil, Siddiqui, Rahman, et al, 2021). This indicates that massive sandstones can be developed by multiple depositional processes in a larger broader area of deep‐marine sedimentary environments.…”

“…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).…”

Automated Fault Detection and Extraction under Gas Chimneys Using Hybrid Discontinuity Attributes

“…Geologically and seismically, it represents a layer cake model with compressive anticlinal inversion structures. This is one of the deepest (12 KMs at center) basins in SE Asia and is highly petroliferous and has already witnessed an extensive hydrocarbon exploration and production [15][16][17][18][19][20]. Keeping this context in view, this study has been carried out to device efficient and optimized techniques to understand the structural framework better.…”