Claim Missing Document
Check
Articles

Found 25 Documents
Search

Quantifying the Impact of Siderite Composition and Reservoir Resistivity (Rt) on Water Saturation Estimation in Low-Resistivity Sideritic Sandstone Reservoirs Using the Graphic Plot Method Sarju Winardi; Sugeng Sapto Surjono; Donatus Hendra Amijaya; Wiwit Suryanto
Scientific Contributions Oil and Gas Vol. 47 No. 2 (2024): SCOG
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The case studies on low-resistivity-low-contrast (LRLC) reservoirs have started using a conductive matrix model approach based on the assumption that the rock matrix is composed of conductive minerals. The previous studies on reservoir resistivity (Rt) against conductive-minerals-rich sandstone were limited to pyritic types without developing the others such as the sideritic which was found in Indonesia. Therefore, there is a need to determine the relationship between siderite volume within the sandstone reservoir and the reduction number of Rt. Relation profiles were applied to accurately estimate the actual water saturation (Sw) while the resistance of the sandstone samples was determined through the voltage (V, volt) and current (I, ampere). The samples were designed as pseudo-core in the laboratory and simulated to have siderite composition in the range of 0-30% followed by the injection of brine at different saturation conditions. The Rt was calculated through the modification of Wenner and Ohm’s Law and later compared graphically with siderite volume of each Sw line. It was observed from the results that siderite led to an exponential reduction in Rt value. Moreover, the threshold volume of siderite required to reduce Rt significantly to 50% of the original value was found to be 6%. The actual Sw was later estimated simply through the application of the Graphic Plot Method from the curves. Keywords: low resistivity, reservoir, LRLC, siderite, sandstone, water saturation
Bioerosion in the Late Eocene Discocyclina discus sowerbyi (Nuttall, 1926) in Bayat Area, Indonesia: Implications for Paleoecology Rahmawati, Diana; Surjono, Sugeng Sapto; Barianto, Didit Hadi; Rahardjo, Wartono
Journal of Tropical Biodiversity and Biotechnology Vol 9, No 4 (2024): December
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jtbb.93779

Abstract

This paper discusses about the bioerosion discovered in carbonate tests of Discocyclina discus sowerbyi (Nuttall, 1926), a large benthic foraminifera from the Priabonian (Late Eocene). The study material was sampled from the Gamping beds in the Wungkal-Gamping Formation in Bayat, Indonesia. We discovered four bioerosional trace fossils from three different ichnogenera demonstrate bioerosion from the surface test analysis. Oichnus simplex and Oichnus paraboloides are ichnogenus Oichnus diagnostic drilling holes that are often found on the surface. Caulostrepsis isp. exhibits the presence of uncomplicated U-shaped borings. The observed formation of drill holes can be mostly linked to the predatory behaviour of gastropods, while other trace fossils are predominantly associated with the burrowing activities of worms. The occurrence of well-preserved individual tests exhibiting no signs of bioerosion is infrequently observed in D. discus sowerbyi. In addition, bioerosion occurs more frequently in the microspheric generation than in the megalospheric generation. This research also demonstrates for the first time in Indonesia that parrotfish bite marks have developed on individual tests of the microspheric generation of D. discus sowerbyi. The taphonomic characteristics exhibited by the bioeroded and encrusted D. discus sowerbyi specimens can serve as reliable paleoecological indicators for sediment deposition occurring at an intermediate to high sedimentation regime. The occurrence of larger foraminifera with some bioerosional trace fossil highly proficient at documenting shallow marine sclerobionts. 
Planktonic Foraminifera Biostratigraphy of the Pliocene Kintom and Bongka Formation, Central Sulawesi, Indonesia Novian, Moch. Indra; Barianto, Didit Hadi; Husein, Salahuddin; Surjono, Sugeng Sapto
Journal of Tropical Biodiversity and Biotechnology Vol 9, No 4 (2024): December
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jtbb.94685

Abstract

The Pliocene sediments exposed in the eastern arm of southern Sulawesi consist of Kintom and Bongka Formations, thought to be the result of collisions in the Middle Miocene. The research area is located along the Matindok – OndoOndolu road, Banggai Regency, Central Sulawesi Province. The aims of the research is to determine the rock units that developed in the Kintom – Bongka Formation and determine the chronological time frame based on planktonic foraminifera biostratigraphy. This research used stratigraphic measurement on a scale of 1:100 and Plio-Pleistocene planktonic foraminifera biostratigraphy. A lithological column along 315 meters divided into three rock units. The marl unit and calcareous sandstone unit show characteristics similar to flysch deposits from the collision and are part of the Kintom Formation. Intergrade conglomerate gravelly sandstone deposited unconformably on top of the previous unit is part of the Bongka Formation. This last unit shows characteristics similar to molasse deposits. In total of 46 rock samples were analyzed for foraminifera biostratigraphy. Seven foraminifera biozones showing the age of rock deposition from the Early Pliocene to the Late Pleistocene.The order of the foraminifera biozone is Globorotalia tumida Brady LOZ (PL1a; 5.59 - 4.45 Ma), Globoturborotalita nepenthes Todd CRZ (PL1b; 4.45 - 4.39 Ma), Globotalia acostaensis Blow PRZ (PL2a; 4.39 – 4.31 Ma), Globotalia margaritae Bolli HOZ (PL2b; 4.31 - 3.85 Ma), Sphaeroidinellopsis seminulina Schwager HOZ (PL 3-4; 3.85 – 3.20 Ma), Globorotalia (M) miocenica Palmer/Globorotalia miocenica Palmer HOZ (PL5–6; 3.20 – 2.30 Ma), and Pulleniatina praecursor Banner & Blow HOZ (PL6–PT1a; 2.30 – 2.26 Ma).
Sebaran Batuan Karbonat Di Cekungan Matarombeo, Lengan Tenggara Sulawesi Samodra, Saptono Budi; surjono, sugeng sapto
Geosfera: Jurnal Penelitian Geografi Vol 3, No 2 (2024): Geosfera: Jurnal Penelitian Geografi
Publisher : Universitas Negeri Gorontalo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37905/geojpg.v3i2.29077

Abstract

Carbonate rocks, especially reef, are an exploration target for sedimentary basins that are still beginning to be explored. In the Matarombeo Basin, there are 5 rock formations composed of carbonate rocks, namely the Tokala Formation, Matano Formation, Tampakura Formation, Eomoiko Formation and Buara Formation. The aims of this research are to determine the distribution of the five carbonate rock formations and their potential as hydrocarbon reservoirs in the study area.. The data used is data from surface geological investigations and seismic data. From the analysis results it is known that carbonate rocks from the Tampakura Formation and the Eomoiko Formation can function as the main reservoir in the Matarombeo Basin. This is based on the physical properties of the rock which has fairly good porosity and permeability, and can be easily recognized in seismic sections as reef growth. The existence of reefs that grow at heights and are connected to the interior which can function as a kitchen area causes the limestone of the Tampakura Formation and the Eomoiko Formation to become the main reservoir targets in the Matarombeo Basin.
Lithofacies, Facies Association, and Depositional Environment of 34-1, 33-6, and 33-4 Sandstone, Wida Field, Gita Member, Talang Akar Formation, Asri Basin, Offshore Southeast Sumatra Saputra, Adi Danu; Surjono, Sugeng Sapto; Winardi, Sarju; Setyadi, Abdul Latif; Ralanarko, Dwandari
Jurnal Ilmiah Geologi PANGEA Vol. 11 No. 1 (2024): Jurnal Ilmiah Geologi Pangea
Publisher : PROGRAM STUDI TEKNIK GEOLOGI FAKULTAS TEKNOLOGI MINERAL UPN VETERAN YOGYAKARTA

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31315/jigp.v11i1.12011

Abstract

Three Gita Member reservoirs 34-1, 33-6, and 33-4 produce from solution gas drive with rapid pressure decline and low recovery factor. After successful oil production enhancements through waterflooding injections prompt the need for a reservoir model in further field development. Before such models were built reservoir characterization was carried out to determine facies and depositional environment for facies modeling. The study integrated core, wireline log, petrophysical logs, seismic attribute, petrography, etc. Next, well correlation was carried out to distribute stratigraphic markers. Finally, seismic attribute and well correlation were integrated to construct pie chart and depositional environment map. External geometry from seismic attribute revealed distributary channel with point bars which act as reservoir and consist of medium-fine grained planar tabular cross bedding sandstone, mud drapes sandstone, and ripple-wavy lamination sandstone. The wireline log showed fining-upward pattern and core displayed abundant channel rip up clasts, sharp or erosional contact with underlying lithology. Frequent mud drapes found within channel sandstone indicate tidal influence in proximity to marine environment probably in lower delta plain. Channels are trending west-east (34-1) and north-south (33-6 and 33-4). Other facies associations are shallow marine, swamp, interdistributary bay, and tidally influenced interdistributary bay. Shallow marine FA consists of skeletal limestone (Lm), calcareous mudstone, and calcareous sandstone (Sc). Rootlet mudstone (Fb) and interlamination of carbonaceous mudstone with very fine-grain sandstone (Fl) formed interdistributary bay FA. Swamp FA consists of coal and coaly mudstone. Tidally influenced interdistributary bay FA consists of carbonaceous laminated mudstone high in carbon (Flb), intensely bioturbated carbonaceous mudstone (Flb), very finely laminated mudstone-very fine grain sandstone (Fl) and black fissile shale (Fm).