Transgressive successions of the Mahakam Delta Province, Indonesia

Abstract

Sedimentological and stratigraphic analysis of outcrops and subsurface data in the Mahakam Delta province, combined with concepts of transgressive sedimentary processes derived from a study of the modern Mahakam Delta, indicate that a significant portion of the palaeo-Mahakam Delta succession was deposited during transgressive phases. Some of the transgressive successions resulted from major transgressions and are regionally extensive, but many reflect small, short-lived transgressions within dominantly progradational phases.Two sandstone facies with significant reservoir potential are common within the transgressive successions. Backfilled distributary sandstones occur in outcrop as 10–20 m thick, fining-upward channel sands that become more marine upward and in the subsurface as elongate, coastline-perpendicular sand bodies with a back-stepping stratigraphic architecture and highly variable thickness. Transgressive shoreline sandstones also fine upward, but they are shoreline-parallel, their lateral extent is controlled by the pre-transgression delta morphology and their thickness depends on the rate of relative sea-level rise.Both types of transgressive sandstone can be difficult to distinguish from specific progradational sandstones with wireline log data, especially when they occur within predominantly progradational successions. However, their sand body geometries, volumetrics and connectivity are much different from the stratigraphically adjacent sandstones deposited during progradational phases of deltaic deposition.

QFL and Litho Facies: Predicting Reservoir Quality of the Middle Miocene Deep-Water Facies at Kutei and North Makassar Basins

“…The sandstone's litho facies is further subdivided into four classifications: 1) cross-bedded fluvial sandstones (FLU_SX and DC_SX), 2) massive distributary channels (DC_SM), 3) bioturbated distributary channels (DC_SB), 4) bioturbated with mud/clay drapped bars (DF_SC). These are illustrated in the Figure 6, as well as the detailed core-description, core photos, and welllog types (modified from Butterworth et al, 2001;Lambiase et al, 2017;Riadi et al, 2018).…”

“…This study had observed deep-water's litho facies in relationship with their reservoir quality; as shown at Figure 9: (i) a group of high porosity (>22%) with moderate (>35 mD) to high (>100 mD) permeability, which is predominantly well-sorted, fine to medium-grained sandstones; (ii) another group of moderate porosity (17%-22%) with moderate (>11-100 mD) to high permeability (>100 mD) that shows well-sorted, fine-grained sand-Figure 6. Core-facies Type of the Middle Miocene deltaic sandstones (modified from Butterworth et al, 2001;Lambiase et al, 2017, andRiadi et al, 2018), along with their QFL grouping in the ternary diagram.…”

“…Figure 6. Core-facies Type of the Middle Miocene deltaic sandstones (modified from Butterworth et al, 2001;Lambiase et al, 2017, andRiadi et al, 2018), along with their QFL grouping in the ternary diagram. Figure 6.…”

Introduction to the sedimentology of paralic reservoirs: recent advances

“…The resulting patterns of stratigraphic architecture and channelized sediment-body distribution are integrated with vertical facies successions and intra-sediment-body architectural panels in order to develop a generic model of depositional-element distribution within a regressive megafan delta. Lambiase et al (2016) characterize sedimentation patterns in the modern Mahakam Delta, Borneo, which is undergoing transgression via retrogradational stacking and switching of delta lobes. Diagnostic core-based sedimentological criteria are presented for three sharp-based sandstone depositional elements (regressive fluvial distributary channels; transgressively back-filled fluvio-estuarine distributary channels; transgressive wave-dominated shorefaces) that appear similar in wirelinelog data but have distinctly different geometries, spatial distributions and sequence stratigraphic implications.…”

“…In recent years, the stratigraphic architecture of mixed-influence paralic deposits, and the geometry and distribution of the depositional elements that they contain, have been addressed in a new classification scheme (Ainsworth et al 2011), and in case studies of modern and ancient reservoir analogues (e.g. Legler et al 2014;Ainsworth et al 2016;Johnson et al 2016;Lambiase et al 2016;Lane et al 2016). We thank the Geological Society, in particular its Petroleum Group, and the SEPM (Society for Sedimentary Geology) for their support of the conference, the related core workshop and this Special Publication.…”