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All Journal IJOG : Indonesian Journal on Geoscience Journal of Geosciences and Applied Geology
Nana Suwarna
Geological Agency, Jln. Diponegoro 57 Bandung - 40122
Earth & Planetary Sciences Engineering

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Permian Mengkarang coal facies and environment, based on organic petrology study Suwarna, Nana
Indonesian Journal on Geoscience Vol 1, No 1 (2006)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (101.393 KB) | DOI: 10.17014/ijog.v1i1.3

Abstract

http://dx.doi.org/10.17014/ijog.vol1no1.20061aThe Permian Mengkarang Coal Measures is situated in the middle part of Sumatera Island. Some fresh outcrop samples of the Permian Mengkarang coals have been analyzed both macroscopically and microscopically, to asses their depositional environment. On the basis of organic-petrological analysis, the coal seams show variation in the predominance of some macerals, indicating successions of environmental changes. The dominant maceral group is vitrinite, present in very low to very high values; whilst the minor one is inertinite showing low amount. Environmental information derived from the organic facies study shows that the coals were deposited in wet zone of mire, ranges from wet limnic-telmatic zone to telmatic wet forest swamp under rapid burial condition, due to rapid basin subsidence. The organic facies concept is thus applicable in basin studies context and has potential to become an additional tool for interpretation of depositional environment.    
Coalbed methane potential and coal characteristics in the Lati region, Berau basin, East Kalimantan Suwarna, Nana; Hermanto, Bambang; Sihombing, Torkis; Kusumah, Kusdji Darwin
Indonesian Journal on Geoscience Vol 1, No 1 (2006)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (933.643 KB) | DOI: 10.17014/ijog.v1i1.5

Abstract

http://dx.doi.org/10.17014/ijog.vol1no1.20063aA geological research was performed in the Berau Basin, to provide a better understanding on the potential and resources of coalbed methane (CBM) in Berau Regency, East Kalimantan Province, particularly in the Lati Coalfield. Field observation conducted in the coalfield, shows that the banded to bright banded Lati coal is dominated by the bright banded one. Petrographically, the coal consists of vitrinite comprising typical telocollinite and desmocollinite; with rare to sparse exinite, and minor inertinite, and mineral matter. Geochemical analysis shows the range of volatile matter content is from 32.65–39.60%, total sulfur from 0.35–3.04%, ash varies between 2.78–14.50%, and moisture from 12.23–19.98%. Vitrinite reflectance values (Rv), varying from 0.42–0.57%, tend to indicate that the Lati coal rank ranges from sub-bituminous B to high volatile bituminous C category, with low ash content in general. Moreover, the coal maturity level, thermally immature to early mature, leads to the assumption that the expected gas present is suggested to be of biogenic origin. The fairly well cleated Lati coal shows cleat orientations trending north - northeastward, perpendicular to nearly oblique to the syncline axis. Furthermore, coal microcleat occurs as open tensional, sub-curved to curved lines microcracks, diagonally to perpendicular to bedding plane, but some are parallel to the bedding plane. An in-situ coal gas calculation tends to indicate a low to moderate methane content level, with a value of 44.20–47.08 scf/t. However, the Q1 plus Q2 calculation exhibits the gas content ranging from 41.69 to 78.71 scf/t. Moreover, total calculated gas in-place of the P, Q, and R Seams =  5.33 m3/t = 191.56 scf/t.    
Berau coal in East Kalimantan; Its petrographics characteristics and depositional environment Suwarna, Nana; Hermanto, Bambang
Indonesian Journal on Geoscience Vol 2, No 4 (2007)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (891.333 KB) | DOI: 10.17014/ijog.v2i4.38

Abstract

http://dx.doi.org/10.17014/ijog.vol2no4.20071To asses the characteristics of the Early to Middle Miocene Berau coal in the Berau Basin, leading to interpretation of coal depositional environments, some fresh outcrop and subcrop samples and also drill cores of the coals have been analyzed microscopically. Coal petrographic analysis was performed on twenty four coal samples from the Middle Miocene Lati Formation. Vitrinite, present in a high value, and ranging between 66.2 - 96.2%, is dominated by vitrinite B. On the other hand, inertinite and exinite, showing a similar value, exist in a low to moderate amount. Vitrinite reflectance, present in a low value, varies from 0.40 - 0.58%. Low mineral matter content is dominated by clay minerals (0.4 - 6.6%) with minor pyrite. Transitions from wet and very wet forested swamps to drier conditions with lower tree density are indicated by the higher content of vitrinite B, whilst a reverse trend is indicated by the lower content of vitrinite A. Petrographic indices obtained from facies diagnostic macerals show that an accumulation of the ancient peats under prevailing relatively wet limited influx clastic marsh to very wet forest swamps or moors is considered. The composition of the coal samples supports the interpretation of a system of fluvial to meandering streams in an upper delta plain environment. The original peat-forming vegetation was composed mainly of cellulose rich, shrub-like plants, tree ferns, herbaceous plant communities, with minor amount of trees. Thereby, the organic facies concept is thus applicable in basin studies context and has potential to become an additional tool for depositional environment interpretation.  
Macroscopic, Microscopic, and Paleo-depositional Features of selected Coals in Arahan, Banjarsari, Subanjeriji, and South Banko Regions, South Sumatra Suwarna, Nana; Kusumahbrata, Y.
Indonesian Journal on Geoscience Vol 5, No 4 (2010)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (999.255 KB) | DOI: 10.17014/ijog.v5i4.110

Abstract

DOI: 10.17014/ijog.v5i4.110The Arahan, Banjarsari, Subanjeriji, and Banko Regions, parts of the Bukit Asam coalfield, is situated in the Lematang Depression of South Palembang Sub-basin, South Sumatera Basin. Twenty two fresh outcrop and subcrop samples of Seam B, A, Benuang, Enim, and Jelawatan of the Mio-Pliocene Muaraenim coals have been analyzed macroscopically and microscopically, to assess the characteristics and depositional environment of the coal present. On the basis of lithotype analysis, accompanied by organic-petrological and SEM analyses, the coal seams of the Muaraenim Formation show variations in the predominance of some macerals, indicating successions of environmental changes. Petrographically, the dominant maceral group is vitrinite, present in high to very high values (69.4 – 97.4 %); whilst the minor one is inertinite showing a low to moderate amount (0.4 – 22.0 %), followed by low to moderate value of exinite (0.4 – 18.2 %). Vitrinite reflectance values are present in a low to moderate level, varying from 0.34 to 0.55 %, with one sample showing value of 0.59 %. Mineral matter dominated by clay minerals, with minor pyrite and carbonate, displays a low degree (0.4 – 5.4 %), with one sample of 12.0 %. Organic facies study tends to indicate that the coals were deposited in a wet forest swamp to limnic zone, within lower delta plain to transgressive area. This condition has supported the depositional setting interpreted from sedimentary facies associations that shows a shallow-water continental margin sequence, varying from a fluvial to deltaic environment. The organic facies concept is thus applicable in basin studies context and has potential to become an additional tool for interpretation of depositional environment.
SOURCE ROCK POTENTIAL AND DEPOSITIONAL ENVIRONMENT OF OIL SHALE BASED ON PETROGRAPHY CHARACTERISTICS AND ORGANIC GEOCHEMISTRY IN KAPUR IX, WEST SUMATRA Rahmola, Wiryadi Rizkiputra; Syafri, Ildrem; Winantris, Winantris; Suwarna, Nana
Journal of Geological Sciences and Applied Geology Vol 2, No 6 (2018): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v2i6.20868

Abstract

The research area were located in the Kapur IX District, Lima Puluh Kota Regency, West SumatraProvince. The research focused on Kapur IX Intramontane Sub-basin filled with oil shale. Theanalysis was carried out on shale samples of the Kapur IX Intramontane Sub-basin collected fromoutcrops to evaluate the source rock characteristics, including type of oil shale, depositionalenvironment, and dispersed organic matter. Geochemical analyses include total organic carbon(TOC) and Rock-Eval Pyrolysis, while organic petrographic analysis comprises organic materialcomposition and vitrinite reflectance. Based on the results the oil shale of the study area has lowto excellent quality and richness, type II and II kerogen content, with the maturity level of lateimmature to early mature. The dominant lamalginite maceral content in the sample tends toindicate the oil shale in the research area is a Green River type. The liptinite maceral group isdirectly proportional to the value of Potential Yield (PY) indicating that the maceral group, especiallyalginite plays a role in producing hydrocarbons in the oil shale of the study area. Based on thecomposition of maceral data, the depositional environment of oil shale of the Kapur IXIntramontane Sub-basin is interpreted to be a lacustrine environment with brackish watercondition.
Co-Authors Bambang Hermanto Ildrem Syafri Kusdji Darwin Kusumah Rahmola, Wiryadi Rizkiputra Torkis Sihombing Winantris Winantris Y. Kusumahbrata