scholarly journals QFL AND LITHO FACIES: PREDICTING RESERVOIR QUALITY OF THE MIDDLE MIOCENE DEEP-WATER FACIES AT KUTEI AND NORTH MAKASSAR BASINS

2021 ◽  
Vol 36 (1) ◽  
Author(s):  
Kuntadi Nugrahanto Nugrahanto ◽  
Ildem Syafri ◽  
Budi Muljana

As we may all be aware the oil and gas wellbores offshore Kutei and North Makassar have not optimally penetrated the objective strata, which is the Middle Miocene’s deep-water reservoirs.  Therefore, evaluating the quality of these reservoirs with onshore dataset then comparing them with the proven Late Miocene’s deep-water producing reservoirs had been very fundamental.  The study focuses on the assessment of QFL and sandstones litho-facies based on the rock samples from conventional-core and side-wall core, and well-logs data from forty wells onshore and offshore.  These rock samples are bounded by the key biostratigraphy intervals of M40M33, M45M40, M50M45 (Middle Miocene), and M65M50, M66M65, M70M66, M80M70 (Late Miocene).  Subdivisions of the reservoirs considered the sandstone litho facies, NTG ratio, sorting, and grain size, to come up with five groups in the Middle Miocene deltaic facies: FLU_SX, DC_SX, DC_SM, DC_SM, and DF_SC; and four groups in the Late Miocene deep-water facies: SSWS, MSWS, SSPS, and MSPS.  Core-based porosity and permeability further explain the relationship between the reservoir quality with the sandstones’ composition and litho facies, and concluded that high-energy depositional system is mainly associated with the FLU_SX, DC_SX, SSWS and MSWS being the reservoir with best quality.  Oppositely, the DF_SC, SSPS, and MSPS are classified the reservoir with worst to none quality.  A cross plot between core-based porosity and maximum burial depth is able to postulate the relational trend of decreasing reservoir quality with deeper depth.

2018 ◽  
Vol 98 ◽  
pp. 97-115 ◽  
Author(s):  
Daniel Bell ◽  
Ian A. Kane ◽  
Anna S.M. Pontén ◽  
Stephen S. Flint ◽  
David M. Hodgson ◽  
...  

1987 ◽  
Vol 27 (1) ◽  
pp. 318 ◽  
Author(s):  
S.L. Bergmark ◽  
P.R Evans

The major onshore Dongara gas field and a number of adjacent minor gas and oil pools are reservoired in basal Triassic sandstones that are sealed by the overlying Kockatea Shale. Reservoir quality is found to be controlled primarily by the local provenance of the sandstones, by diagenesis and the regional palaeotopography. Sandstones east of Dongara are reworked products of a Late Permian fan delta (Wagina Sandstone) that extended westwards from the basin's eastern, fault controlled margin. Localised high energy streams drained the palaeoslope, depositing thin wedges of mainly fluvial sediments upon and around the flanks of the Permian fan delta during a regional rise in sea level in the Early Triassic. Sandstones to the north of Dongara are localised, low energy offshore bars and strandline deposits derived from Precambrian of the Northampton Block. Diagenetic alterations of the Triassic sandstones, also controlled by the sandstones' provenance, have substantially reduced primary porosity and control permeability. The common presence of the authigenic clay mineral, dickite, is taken as evidence that a fluvial environment of deposition controlled formation of the reservoir rocks.


2017 ◽  
Vol 91 (3) ◽  
pp. 444-466 ◽  
Author(s):  
Steffen Kiel ◽  
Marco Taviani

AbstractEleven species of chemosymbiotic bivalves are reported from middle to late Miocene methane seep deposits (‘Calcari aLucina’) in the Italian Apennines, including seven new species and one new genus. The new species areBathymodiolus(s.l.)moroniaeandB. (s.l.)miomediterraneusamong the Bathymodiolinae andArchivesica aharoni,A.apenninica,A.strigarum, and ‘Pliocardia’italicaamong the Vesicomyidae; specimens from the middle Miocene of Deruta are reported asArchivesicaaff.aharoni.Samiolus iohannesbaptistaenew genus new species is introduced for an unusual mytilid with a commarginally ribbed surface, which might be the first non-bathymodiolin mytilid obligate to the seep environment. The two large lucinid species from which these deposits derived their informal name ‘Calcari aLucina’ are identified asMeganodontia hoernea(Des Moulins, 1868) andLucinoma perusina(Sacco, 1901). WithChanellaxinussp., we report the first thyasirid from a Neogene deep-water seep deposit in Italy and the first fossil occurrence of this genus.


2017 ◽  
Vol 44 (1) ◽  
pp. 17 ◽  
Author(s):  
Aldo Alván De la Cruz ◽  
Astrid Criales ◽  
Hilmar Von Eynatten ◽  
Istvan Dunkl ◽  
Axel Gerdes ◽  
...  

The Camaná-Mollendo Basin is an active-margin depression ~NW-SE elongated, which is located in the forearc of southern Perú and extends from the Coastal Cordillera to the Perú-Chile Trench. This basin consists of a grabens and half-graben complex, filled with deltaic and fluvial sedimentary rocks of the Oligocene-Pliocene Camaná Formation (~500 m thick). An integration of compiled onshore stratigraphic logs, reinterpreted 2D seismic offshore information, sediment provenance data, and previous zircon U-Pb geochronology on volcanic reworked ash supports a refined tectono-chronostratigraphic framework for the whole Camaná-Mollendo Basin fill. To complete this integration we needed firstly to elaborate a geological reinterpretation of seismic offshore data and highlight their most prominent features (i.e., erosive surfaces). This step allowed establishing a first correlation between onshore and offshore deposits of Camaná Formation by means of their sequence boundaries, giving as result a consistent division for Camaná Formation: (i) “CamA Unit” (coarse-grained deltas) and (ii) “CamB Unit” (fluvial deposits). CamA Unit is further subdivided into three subunits based on minor erosive surfaces (i.e., A1: Oligocene, A2: Early Miocene, and A3: Middle Miocene). CamA reflects prograding geometry (subunits A1 and A2) as well as onlapping geometry (subunit A3). CamB Unit (Late Miocene to Pliocene) consists of high-energy hyperpycnal flows composed of fluvial conglomerates in onshore, which very possibly changes to progradational deltaic in offshore. Each one of these units and subunits extends offshore and preserves similarities in depositional geometry and sequence boundaries with Camaná Formation onshore. Subunits A1 and A2 observed in offshore are grouped in this paper as “A1+A2” (Oligocene to Middle Miocene) because they show similar progradational geometry and it is difficult to differentiate them from each other. A regressive systems tract (RST) represents these subunits. These deposits reach up to ~2.5 km thick, and they are intensely affected by normal faulting associated to pinch-out depositional geometry. Strata of subunit A3 (Middle Miocene) reflect a transgressive systems tract (TST), and blanket the entire basin with fine-grained sediments. These deposits are up to ~1 km thick, being less affected by synsedimentary tectonic and show minor effects of synsedimentary tectonics. Finally, deposition of CamB Unit (Late Miocene to Pliocene) occurred during a new regressive systems tract (TST), which turned to progradational geometry similar to deltaic deposits in offshore, and according to seismic lines they are much less affected by synsedimentary faulting. Stratigraphic boundaries between “A1+A2” and A3, and between A3 and CamB observed in onshore outcrops are used here as tools to differentiate, correlate and predict the main depositional geometries in offshore. High-frequency seismic reflectors represent such boundaries and support divisions and subdivisions within Camaná Formation. These boundaries are also used to define depocentres of Camaná Formation along the entire Camaná-Mollendo Basin, where the thickests are located in the proximity of the large river mouths (e.g., Planchada, Camaná, and Punta de Bombón). Strata of subunits “A1+A2” are considered as potential reservoir for hydrocarbon due to their high rate of sediment accumulation. Deposits of A3 are transgressive and they are considered as potential potential seal rock. Structurally, Camaná-Mollendo Basin is composed of graben and half-graben components ~NW-SE-oriented, typical of a trantensional tectonic regime.


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