Barito Basin Research Articles

Microfacies and Paleomire Reconstruction of Coal in the Warukin Formation, Barito Basin, Kandangan Area, South Kalimantan

Abstract The Barito Basin is one of the basins in South Kalimantan and serves as a coal-producing region. One of the coal-bearing formations present in the Barito Basin is the Miocene Warukin Formation. The purpose of this research is to understand the characteristics of coal macerals, including the dominance of macerals and their microfacies, as well as the type and development of the mire where coal is deposited. This information is crucial for the coal geological study in the Kandangan region, South Kalimantan. The methods employed include organic petrography analysis, proximate and ultimate analysis on seams L8, L5, L5B, M16, and MS02 collected using the ply-by-ply method.The results of the subbituminous coal petrography examination in this formation show the dominance of vitrinite ranging between 41.34-74.04% vol, liptinite between 11.61-38.24% vol, inertinite between 2.21-32.32% vol, and mineral matter ranging from 0.17-1.98% vol, predominantly composed of pyrite. The ash content data ranges from 1.36-15.45 (% wt, adb). The sulfur content data ranges from 0.1-0.45 (% wt, daf). Based on the distribution of maceral abundance, coal microfacies can be categorized into five groups: (1) gelovitrinite-rich group, (2) telovitrinite-rich group, (3) liptinite-telovitrinite-rich group, (4) inertinite-rich group, and (5) telovitrinite-inertinite-rich group. The lower section is predominantly characterized by the telovitrinite-inertinite-rich group. In the middle section, the inertinite-rich group takes precedence, alternating with the liptinite-telovitrinite-rich group. The upper segment is primarily marked by the gelovitrinite-rich and telovitrinite-rich groups. The developed paleomire includes repetitions of topogenous mire and ombrogenous mire. The paleomire type is a wet forest swamp under limnic and telmatic conditions. The dominant original vegetation consists of woody plants, although shrubby plants are also found in significant amounts. Moderate to high gelification levels indicate that the peat was constantly inundated with water.

Microfacies and Paleomire Reconstruction of Coal in the Tanjung Formation, Barito Basin, Kandangan Area, South Kalimantan

Abstract The occurrence of the Tanjung Formation as a coal-bearing formation that has thick coals and is laterally distributed along in Barito Basin causes it to be well-known as one of the biggest coal-producing basins in Indonesia. The genesis of Eocene coal formed in terrestrial depositional environment influenced by freshwater and marine transgression is the uniqueness of this coal and interesting to examine maceral’s characteristic and its microfacies, and the evolution of paleomire seam AGM-B3, AGM-B4, AGM-B5, and AGM-B6 in Kandangan area by organic petrography’s analysis and coal’s chemical analysis. The result of subbituminous coal’s petrography show vitrinite is the most abundant maceral ranging from 56,.6% - 80.36% vol, liptinite (15.27% - 39.45% vol), inertinite (0.55% - 15.18% vol), and mineral matter (0.18% - 4.36% vol) which is dominated by pyrite. Based on maceral’s assemblages, coal’s microfacies divided into four groups are (1) telovitrinite-rich group, (2) detrovitrinite-rich group, (3) telovitrinite-liptinite-rich group, (4) inertinite-rich group. The basal section of seam AGM-B6 is characterized by detrovitrinite-rich group while seam AGM-B3, AGM-B4, and AGM-B5 are characterized by telovitrinite-liptinite-rich group. The middle section only represented the inertinite-rich group in seam AGM-B3, and the top section of the coal seams, except AGM-B6, is typically represented by the telovitrinite-rich group. The vertical profile of paleomire evolution shows a repetition of topogenous mire changing into ombrogenous mire and then back to topogenous mire. The paleomire type developed includes wet forest swamp, forested peatlands, and intermittently dry forested swamp and the environmental conditions are telmatic. The correlation between paleomire’s type and coal maceral’s abundance in the Kandangan area reflects that the type of vegetation from woody plants that underwent high degradation, moderate gelification, and intensive oxidation processes triggered by a short dry season.

Association and textural-compositional evolution of pyrite-organic matter in coals of the Tarakan, Barito, and Pasir Basins, Kalimantan, Indonesia

The Barito, Pasir, and Tarakan Basins in Kalimantan Island is the most extensive coal-bearing sedimentary basin in Indonesia, mined since 1989. The coal is notable in having high sulfur coal content, exceeding >10% in some cases, contributed by the presence of pyrite. The latter issue contributed to interest in the coal, forming economic mineral deposits hosted by the sedimentary pyrite and organic matter. Novel findings of this research providing valuable information of trace element behavior during the diagenetic conditions. This paper documents the textural and compositional evolution of pyrite-organic matter of coals using coal petrographic, proximate, ultimate, total sulfur content, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), electron probe micro analyser (EPMA), and Raman spectroscopy. Coals from Kalimantan are mainly characterized by medium-high sulfur content (>3%) and the maximum temperatures reached by organic matter during diagenesis are 166 ± 10 °C for the Pasir Basin, 136 ± 11 °C for the Barito Basin, and 132 ± 12 °C for the Tarakan Basin. Pyrite is mainly found as large size framboids (mostly >5 μm), indicating formation in the sedimentary layer with dysoxic bottom water conditions during early–late diagenetic stages. The framboidal pyrite was likely formed in detrovitrinite and gelovitrinite under topogenous mire conditions, due to the degradation of macerals and biochemical gelification, which provided the organic templates. High concentrations of trace elements (TE) of framboidal pyrite, such as 1) Cu, Ni, and Co in the Pasir Basin and 2) As in the Barito Basin, likely reflect the local sedimentary provenance and underlying basement rocks. Pyrite texture evolved with increasing diagenetic temperatures from 1) framboidal pyrite, 2) recrystallized framboidal pyrite rims, and 3) anhedral, anhedral-euhedral pyrite transition, and euhedral massive pyrite. This study shows a similar average TE concentrations of various pyrite texture, suggesting that the TEs are not remobilized during the evolution of pyrite at the diagenetic stages.

Signature characteristics of coal geochemistry from the Eocene Tanjung Formation and the Miocene Warukin Formation, Barito Basin: Insights into geological control on coal deposition and future critical element prospection

In conjunction with implementing the Indonesian Act on coal downstream research and development, the geochemical characterization of the Barito Basin coals and an evaluation of the critical elements in coal and coal ashes compared with those found in conventional deposits must be fulfilled. This study documented the signature characteristics of the coal geochemistry in the Barito Basin. Coals from Tanjung Formation mainly comprise huminite macerals and inorganic constituents are mainly dominated by kaolinite, pyrite, quartz, carbonate minerals (i.e., calcite, Sr-bearing carbonate), Ti-oxide minerals (anatase or rutile), chlorite, and apatite. Meanwhile, the Warukin Fm is characterized by high contents of inertinite and inorganic materials comprising kaolinite, pyrite, and quartz. Moreover, the B3 seam from the Tanjung Fm shows normal slight enrichments for Hf, Zr, and V, demonstrating the highest REY content of up to 194.56 ppm. Meanwhile, coal samples from the Warukin Fm show depletion in all the trace elements and REY.The provenance source of the Barito Basin coals is derived from epiclastic mafic–intermediate volcaniclastic rocks, including the Early Cretaceous Pitap and Haruyan Fm, which are mainly derived from low-Ti mafic magmas. Subsequently, marine water infiltration during peat accumulation is subjected to the influence of the geochemical characteristics of coals from the Eocene Tanjung Fm, showing the transgressive settings. On the other hand, the Miocene Warukin Fm. represents a non-marine regressive setting during peat accumulation. Furthermore, local geological controls in the Eocene Tanjung Fm. may lead some roof, floor, parting and coals from B3 seam to critical elements enrichment (such as REY, Zr, Hf, and V), and their affinity is related to Ti-oxide minerals, aluminosilicates, and organic matter.

Organic geochemistry and petrography of Miocene ombrotrophic coals in the tropical Asem-Asem Basin (Kalimantan, Indonesia): Comparison to coeval subtropical coals in the Eastern Alps

Abstract The middle Miocene Warukin Formation in the Asem-Asem Basin (Kalimantan) contains a 20-m-thick coal seam (BL1) that is mined at the Jumbang mine. The seam, formed in a tropical peat, was studied to reconstruct the peat-forming environment and to compare its characteristics with those of similarly aged tropical coals from the Tutupan mine in the Barito Basin (Kalimantan) and similarly aged (~15 Ma) subtropical coal from the Leoben Basin in the Eastern Alps (Austria). Although all coals were formed in ombrotrophic peatlands, the comparison reveals differences in biomarker and maceral composition due to the different climate and flora. The study is based on 22 coal and three non–coal samples, each representing a stratigraphic interval of 0.2 to 1.0 m. The samples were analyzed for ash yield, carbon and sulphur contents, and maceral composition. Organic geochemical parameters were obtained on eight coal samples to obtain information on the peat-forming vegetation. The low-ash, low-sulphur BL1 seam was deposited in an ombrotrophic basinal (coastal) mire. Locally increased sulphur contents in the lower coal bench BL1L demonstrate brackish influence and a near-shore environment. The vegetation was dominated by angiosperms including abundant dammar resin producing Dipterocarpaceae, while the contribution of gymnosperms was negligible. The Tutupan seams T110 and T210, which were formed in kerapah (inland) ombrotrophic mires, have similar ash yields and sulphur contents but contain higher, although still low, concentrations of gymnosperm-derived diterpenoids. In addition, lower amounts of cadinane-type biomarkers and resinite suggest that Dipterocarpaceae were less dominant in kerapah peats. While differences between tropical coals from Kalimantan are minor, major differences exist between the tropical coals and the subtropical ombrotrophic Leoben coal. These include significantly higher concentrations of gymnosperm-derived biomarkers in subtropical peat, lower amounts of resinite due to the absence of Dipterocarpaceae, as wells as lower amounts of leaf- and rootlet-derived macerals. Apparently, fungal activity was also reduced in the sub-tropical Leoben peat. Surprisingly, the average amount of oxidized plant remains is also lower in the subtropical peat.

The Role of Fractal Micro-Pore to Absorption of Methane Gas, Case Study: Coal of Tanjung Formation, Arang Alus Area, Banjar District, South Kalimantan, Indonesia

The Tanjung Formation is one of the coal bearing formations in the Barito Basin, South Kalimantan. The coal seams in the Tanjung Formation in the Arang Alus area have 4 (four) seams,there are seam A, B, C, and D. The age of these coal seams are Eocene - Oligocene with a thickness between 0.5 - 2 meters. This study aims to determine the characteristics of micropore fractal and methane gas absorption from coal samples taken by channel sampling on exposed coal in the open pit. The method used is SEM analysis, vitrinite reflectance (Ro,max), adsorption isotherm, and fractal calculation. The four coal seams based on vitrinite reflectance values (0.52 %- 0.62 belong to the sub-bituminous rank. Based on the methane gas absorption capacity for coal seam C of 450 SCF/ton while coal seams A, B and D of 308 SCF/ton, 336 SCF/ton and 407 SCF/ton, the fractal pore dimension value in seam coal C = 1.963 is higher than seam coal A = 1.933, B = 1.940 , and D = 1.943. The small size of the fractal pore dimension value caused by the degree of regularity of the micropore distribution in each coal seam methane differences.

Coal deposition in the Barito Basin (Southeast Borneo): The Eocene Tanjung Formation compared to the Miocene Warukin Formation

Coal seams of Late Eocene (Tanjung Formation) and middle Miocene age (Warukin Formation) are present in the Barito Basin of Borneo. The seams are laterally continuous and can be traced over at least 20 km. The thickness of three Eocene seams in the TAJ Pit–1D mine ranges from 1.4 to 3.4 m. These seams (from base to top: D, C, B) were studied to reconstruct their peat–forming environment and to compare the characteristics of Eocene and Miocene coals. The comparison reveals differences in peat types, flora and climate. The study is based on 38 Eocene coal and six non–coal samples, each representing a stratigraphic interval of 0.2 m. The samples were analyzed for ash yield, carbon and sulphur contents, and maceral composition. Organic geochemical parameters (incl. biomarkers) were obtained on every second coal sample to obtain information on the peat-forming vegetation and its diagenetic alteration.The Eocene seams were deposited in rheotrophic mires with palm/fern–dominated vegetation. Transitions to local ombrotrophic mires cannot be excluded. Very low to low sulphur contents (max. 0.9 wt%) speak against a marine influence, despite a general coastal plain setting. Upward increasing sulphur contents in the lower seam D and the upper seam B are interpreted to reflect transgression, which ended peat accumulation. The seam C formed in a rheotrohpic seam with a relatively high water level. This favored the accumulation of aquatic plants.Miocene coals from the Warukin Formation in the Barito Basin were studied recently in a companion paper. The comparison of Eocene and Miocene coals shows major differences, which include: Miocene coals are significantly thicker (up to 50 m) and display a cyclic structure. Miocene coals accumulated in ombrotrophic mires dominated by more decay resistant angiosperm trees (and subordinate gymnosperms). Therefore, preserved plant tissues are more abundant in Miocene coals. In addition, Miocene coals contain a significantly higher amount of root–derived macerals (suberinite). Leaf–derived macerals (cutinite, fluorinite) and resinite are ubiquitous in Miocene coals, but even slightly more abundant in Eocene coals. At least part of the resinite in Miocene coals, but not in Eocene coals, is derived from dammar resin produced by Dipterocarpaceae. Fungal activity, recorded by high funginite percentages, was high in low-ash ombrotrophic and high-ash rheotrophic mires both in Eocene and Miocene times.

THE POTENTIAL OF USING THE EARLY EOCENE-OLIGOCENE COAL’S FORMATION IN TANJUNG BARITO BASIN

Research on the development of coal utilization for Indonesia is very important considering that Indonesia is a country that has large amounts of coal reserves, so it can use its coal not only as a source of energy for power plants but also needs to incentivize coal conversion for increased added value. To analyze the potential of using the early Eocene-Oligocene coal's formation in Tanjung Barito basin. In this study, data sources derived from laboratory test results will be analyzed by descriptive methods with quantitative approaches. The results of this study were obtained through proximate tests on coal samples TIAN-0 1 and TIAN-0 2 total value moisture of 9.1 4% weight as-received basis (arb) and Moisture in the Analysis sample worth 3.67%, value ash content 7.35%, flying substance value 36.11%, tethered carbon value 52.86% with air-dried base (ADB) basis % weight and total sulfur value 0.36% with air-dried base (ADB) % weight. Based on the gross calorific value with an average caloric value of 7353 Kcal/kg, sample coal is classified as high volatile coal A bituminous. The results of testing on the potential of sample coal caking also indicate the potential utilization of Early Eocene-Oligocene coal Tanjung Formation to be used in the metallurgical industry with the results of testing the value of the Free Swelling Index sample showing the swelling ability of the coal with a value of 6 and 2.5 and G indexes 66 and 92.

Organic geochemistry and petrography in Miocene coals in the Barito Basin (Tutupan Mine, Indonesia): Evidence for astronomic forcing in kerapah type peats

In the Barito Basin of Borneo, there are extensive coal seams in the Miocene Warukin Formation. The net thickness of subbituminous C coal exceeds 100 m in the Tutupan mine. Three coal seams (from bottom to top: T110, T210, T300) were studied to explore the paleo-peat type and the factors controlling paleo-peat accumulation. The study is based on 93 coal and 7 non-coal samples, each representing a stratigraphic interval of 1 m. The samples were analyzed for ash yield, moisture, carbon and sulphur contents. All samples were analyzed using the Rock-Eval method and maceral analysis. Every second coal sample was used for detailed organic geochemical analysis.The coal in the T110 (46 m thick) and T210 (24 m) seams are very low in ash and sulphur, suggesting peat formation in an ombrotrophic mire. Accumulation of seam T300 (24 m), which contains a higher amount of detrital minerals, is interpreted to have occurred in rheotrophic and ombrotrophic settings. n-Alkane and biomarker ratios indicate that accumulation of seam T110 began in a mire with a relatively high contribution of grassland vegetation. Apart from this early stage, angiosperms (including dipterocarps) dominated the forest swamp vegetation. The presence of gymnosperms, albeit at lesser extent, indicates that coal formation occurred in a kerapah (watershed) type peat. The geochemical data reveal a cyclic structure in the T110 and T210 seams, possibly controlled by climatic fluctuations. Five cycles were recognized in the T110 seam and three cycles in the T210 seam, each 6 to 13 m thick. Using accumulation rates of tropical peat in SE Asia and the compaction of low-rank coal, the duration of a single cycle was estimated to be 10.8 kyr (P10) to 61.1 kyr (P90), with a 50% probability that the true value is 22.7 kyr. A causal relationship between the climatic variability and the precession index (17–24 kyr) is suspected.The maceral composition of the Tutupan coals is characterized by moderately high tissue preservation and low gelification, which is typical for tropical ombrotrophic mires. Huminite is the most important maceral group. Liptinite macerals (including resinite, cutinite, fluorinite and suberinite) are abundant, while inertinite macerals are rare. Funginite is one of the main inertinite macerals.

MIOCENE PALYNOLOGY OF THE BARITO BASIN, SOUTH KALIMANTAN PALINOLOGI UMUR MIOSEN DI CEKUNGAN BARITO, KALIMANTAN SELATAN

This study has succesfully disclosed the rich assemblage of palynomorph within the Miocene sediment ofthe Barito Basin, South Kalimantan. It is characterised by the the last occurrence of Florschuetzia trilobata(Middle/ Late Miocene boundary) and the fi rst occurrence of F. meridionalis (Early/ Middle Mioceneboundary). In addition, other Miocene markers appear to mark this age such as spores of Stenochlaeniditespapuanus (Late Miocene) and Scolocyamus magnus (Early/ Middle Miocene). Mean while, the regularoccurrence of brackish palynomorphs along the studied sections indicates marine infl uence during depositionincluding Zonocostites ramonae, Florschuetzia meridionalis (mangrove pollen), Florschuetzia levipoli andSpinizonocolpites echinatus (back-mangrove pollen). The depositional environment initially occurs in thefreshwater environment of delta plain during Early to Middle Miocene (lower well sections) as suggestedby domination of freshwater pollen in the absence of marine micro-fossils. It gradually shifts in to deepermarine setting in delta front to pro delta (with possible shallow marine environment) during Middle toLate Miocene (upper well sections) as indicated by the increase of brackish palynomorphs combined withmarine micro-fossils. This study identifi es peak of riparian pollen Myrtaceidites sp. which is potential forwell correlation. This pollen is common within the lower well sections suggesting the presence of riverdeposits. On the other hand, considerable appearance of freshwater palynomorphs may be an indication ofwell development of low land forests under wet climate condition.

Reservoir Quality Assessment Based on The Occurrence of Burial Diagenesis: Sandstone Case Study From Tanjung Formation, Barito Basin, South Kalimantan

Barito Basin is known as one of hydrocarbon producing basin which is located in the Southeast Kalimantan. One of its prolific reservoir comes from sandstone facies of Tanjung Formation in the Paleo-Oligocene time. The sandstone undergone diagenesis, subsequently after deposition due to burial process. Burial diagenesis promotes further compaction, cementation and alteration which affect the reservoir quality. This study aims to assess the reservoir quality and its sensitivity against the diagenesis products. Research method was carried out by examine the core samples and scrutiny laboratory observation, such as Scanning Electron Microscope (SEM). X-ray Diffraction (XRD), porosity, permeability, grain density measurement and surface gamma-ray. The results show that the amount and type of alteration is vary by depth, age and lithofacies. Sandstones of sublitharenites and litharenites were buried to depths of 848.29 – 849.80 m and contained significant amounts of authigenic grain-coating and pore-lining clay as well as pore-filling zeolite cements. However, the underlying sandstones from 969.19 – 970.14 m depths exhibit less extensive alteration. In the early burial process, the reservoir quality is modified by the formation of secondary dissolution pores and minerals as a result of silicate dissolution during shallow burial diagenesis. The subsequent burial has reduced the pore spaces through mechanical compaction and cementtion. This study certainly valuable addition to our understanding about reservoir quality in correspond to the burial diagenesis.

Selective mine plan based on coal quality distribution of Batu Ayau formation, Murung Raya-Central Kalimantan

Coal quality, which eventually controlling coal’s behavior during preservation, combustion, and other forms of utilization, are defined by the depositional environment in which the peat was formed. Batu Ayau Formation is a well-known coal-bearing formation of Barito Basin and has been thoroughly explored. The aim of this study, which differs from previous studies, is to figure out the correlation of depositional environment to the coal quality of Batu Ayau Formation and anticipate the less desired coal quality from being mined. The depositional environment is determined through the stratigraphic section compared to Horne model, supported by coal facies determination using Tissue Preservation Index (TPI) vs Gelification Index diagram. Ash and sulphur content (weight %) data from 4 seams are integrated to the lithostratigraphic column. The coal quality distribution is defined from good correlation. The coal-bearing depositional environment of the studied area is transitional – upper delta plain. The ash content is ranging in 5.20-8.64wt% and total sulphur is ranging in 0.34-1.28%. The position of depositional environment that is closer to open marine, which is dipping westward, is preferable in terms of quality. Hence, coal on the center part of the research has preferable coal quality to be mined.

Statistical Downscaling for the Projection of the Keetch Byram Drought Index in the Barito Basin

Over the last few decades, prolonged drought in Indonesia has led to a catastrophic wildfire hazard, including on Kalimantan Island. The Barito River basin is one of the major river basins on the island, located in South and Central Kalimantan Provinces. According to The Indonesian National Board for Disaster Management (BNPB), the drought hazard index in the southern part of Kalimantan is mostly at the medium to high-risk level. In terms of Integrated Water Resources (IWRM), more detailed drought risk analysis needs to be conducted at the river basin level, so that drought adaptation and mitigation strategies can be integrated into long-term river basin management plans. In this study, a drought projection of the Barito River basin was simulated by using the Coupled Model Intercomparison Project 5 (CMIP5). A coarse grid of CMIP5 data was statistically downscaled to a smaller grid over the basin area. Data from climatology observation stations and Climate Forecast System Reanalysis (CFSR) were used to calibrate the bias correction function of the CMIP5 data. This function for rainfall data was developed based on the rainfall probability curve, while the bias correction function for temperature data was developed based on the elevation-temperature relation. The bias-corrected rainfall and temperature data were used as input for the Keetch-Byram Drought Index (KBDI) analysis. The study shows that the potential for drought hazard may increase in the future. Drought projection in the Barito basin for 2050 using KBDI shows that the potential areas with medium and high drought risk may cover around 50% and 2%, respectively, or about 35,000km2 and 1,400km2. The occurrence of wildfires also has a strong correlation with the drought index. A comparison between 1998 and 2015 fire hotspot data shows that most hotspots were located in areas in the medium and high drought risk categories. The study shows the importance of climate change impact analysis to prevent more catastrophic hazards in the future, especially in the Barito River basin, Kalimantan Island.

ANALISIS RESERVOAR MIGAS (SANDSTONE) MENGGUNAKAN MULTIATRIBUT SEISMIK PADA LAPANGAN TG12, CEKUNGAN BARITO, KALIMANTAN SELATAN

The study using multi attribute seismic has been done on TG12 field which situated at Lower Foreland Formation, Barito Basin dominated by sandstone on layer area of the target X. The objective of the study is to map the sandstone reservoir by predict distribution value of gamma ray log, neutron porosity, and density which goes through wells such as FM1, FM2, FM3, and FM4 on seismic data. Total attribute that is being used by step wise regression method by considering validation error. Multiattribute process only applied on FM2, FM3, and FM4 wells, whereas FM1 is used as a test well to determine the correlation value between seismic data and log data that is being used. In addition, from well test correlation showing great correlation result of neutron porosity log and density log both obtain the correlation around 0.6322 and 0.6557 while the gamma ray log obtain low correlation that is 0.1647 towards multi attribute result. The processing result of multi attribute obtained distribution of sandstone with gamma ray estimation range value of 65-75.8API, neutron porosity estimation range value 0.15-0.2262, while density estimation range value 2.4308-2.77gr/cc.

Occurrence of rare earth element and yttrium (REY) in Tanjung formation coking coal from Sekako area, Central Kalimantan

Inorganic geochemistry of coal become a point of interest on coal study, especially relating with the occurrence of rare earth element. Tanjung Formation is one of coking coal bearing deposits in Barito Basin, Central Kalimantan. The aims of this study to determine the occurrence of Rare Earth Element and Yttrium (REY) especially in term of concentration and enrichment type in coal seam A and B of Tanjung Formation in Sekako Area, Central Kalimantan. A number of 10 coal samples were collected from both seams. Inductively Coupled Plasma-Atomic Spectroscopy (ICP-AES) analysis was conducted to determine the REY in coal. Based on this study, coal seam A and B generally have very low concentration of REY elements deposits. The REY elements of coal seam A and B in the study area are typically characterized with M and H-type enrichment, which might be caused by the mafic basalt rocks in the surroundings.

Total Sulfur and Ash Yield of Tanjung Formation Coal in Sekako, Barito Basin, Central Kalimantan: Implication of Depositional Process

Tanjung Formation is one of the major coal-bearing deposit in the Barito Basin, Central Kalimantan. The distribution of total sulfur and ash yield in coal is closely related to the depositional environment. This study was to determine the total sulfur and ash yield and the interpretation of the dynamics of depositional process. Coal seam A and B generally have low to medium ash yield 2.82 to 9.23 (wt.%, db) and low total sulfur content of <1 (wt.%, db), except for the 6PLY1 coal sample which has total sulfur content that relatively high at 1.55 (wt.%, db). Coal samples 5PLY1A, 5PLY1B, 5PLY3, 5PLY5, 6PLY2, 6PLY4, 6PLY5, 6PLY7, and 6PLY9 which have low to medium ash yield and low total sulfur content <1% (wt.%, db) are formed in the topogeneous mire (freshwater swamp) in a fluvial environment. The total sulfur content was interpreted to be derived mainly from the parent plant materials. Meanwhile, the 6PLY1 coal sample which has an ash yield of 5.83 (wt.%, db) and total sulfur content of 1.55 (wt.%, db) formed in topogeneous mire in an environment that is invaded by sea water, and the total sulfur content were interpreted coming from the parent plant materials and the effect of seawater invasion which is rich in sulfate (SO4) compounds. It is also supported by the occurrence of syngenetic mineral content (framboidal pyrite) and epigenetic pyrite of 1.23 (vol.%).

LATE CRETACEOFS SEDIMENTARY ROCK IN BARITO BASIN, INDONESIA: LITHOLOGY, PALEONTOLOGY, AND PALEOENVIRONMENT

The Barito Basin so far known as back-arc basin that formed by the rifting in Early Tertiary, which the oldest sedimentary rock in this basin is believed has a Middle Eocene to Early Oligocene age. However, this research will present new evidence regarding the existence of sedimentary rocks that are older than Cenozoic age in the Barito Basin. This research was carried out on Bongkang-2 well, as the main data, and other five wells which have an indication of the discovery of Pre-Tertiary sedimentary rocks, which are generally located in the northern part of the Barito Basin. Integration of mud log data, petrography, paleontology, and dip-meter data, resulting the identification of lithology, age and depositional environment, and then interpretation of the paleoenvironment of the Barito Basin in the Late Cretaceous is carried out. Based on the analysis of data, it is show that Pre-Tertiary sedimentary rocks found in the six wells analyzed has Cenomanian age, which is indicated by the presence of large foraminifera fossils in the form of Sulcoperculina sp. and Orbitolina sp. in Bongkang-2, Hayup-1 and Hayup-3 wells, as well as palynomorph fossils in the form of Cicatrico- sisporites dorogensis, A. tricornitatus, Aquilapollenites sp., Distaverrusporites margaritus and Classopolis cf. classoidesin Bagok-1 and Bagok-2 wells. In addition, based on lithological analysis, in the Bongkang-2, Hayup-1 and Hayup-2 wells lithology develops in the form of limestone, shale and sandstone, while in the Didi-1, Bagok-1 and Bagok-2 wells lithology develops in the form of shale with sandstone and pyroclastic volcaniclastics rock intercalation. Then, based on the integration of lithology and paleontology analysis, it is known that in the Cenomanian age, terrestrial environments developed in the western part of the Barito Basin, while in the eastern part the shallow marine environment developed.

Identification of fractured-basement reservoir based on integration of FMI Log and seismic attributes in hydrocarbon field “I”, Barito Basin, South Kalimantan

As basement has very small matrix porosity, secondary porosity is needed to store hydrocarbon within the basement. Fracture is a secondary porosity, yet not all fracture can be a good secondary porosity. Open fractures have capability to store hydrocabon, also have important roles in productivity and quality of the pre-tertiary basement reservoir. This study is aimed to identify open fractures using FMI log and seismic attributes in the Field “I”, Barito Basin. Interpreted image log (FMI) on two wells gives the azimuth and dip orientation of open fractures are ENE –WSW, NNW-SSE and WNW-ESE and also the horizontal stress orientation. The stress orientation from image log combined with leak-off test (LOT) data and density log used to identify stress fields. Azimuth and dip orientation of the open fracture from FMI log is the input of the stereonet, as an orientation filter for ant-tracking. Ant-track attribute is based on ant-colony optimization algorithm that captures only continuous features and used as edge enhancement methods for fracture-sensitive attributes. Variance is a fracture-sensitive attribute that applied as input data for ant-track algorithm. The results of ant-track map are well correlated and confirmed by image log analysis. Also, by applying ant-track attribute to the fracture-sensitive attributes succesfully able to identify faults and fractures with better resolution and visualization than only using the fracture-sensitive attribute itself, so it makes easier to interpret and get the information.

The dynamic changes of Barito basin peat land ecosystem in South Borneo, Indonesia

The dynamic changes of aquatic ecosystem have an important role in order to maintain the sustainability of peat land ecosystem. The aquatic ecosystem is the main supply of freshwater in the Barito basin region, contribute to the water quality for consumption and production, habitat for aquaculture. Therefore, the spatial modelling of inundation changes is a pre-requisite for future peat land management. This study employed GIS and Remote Sensing techniques to monitored land cover/land use changes for observed inundation in Barito basin, South Borneo, Indonesia using multispectral satellite data obtained from Landsat at 1994, 1996, 2013 and 2015 respectively. The Barito peat basin areas, based on object dominance, were classified into five cover classes/dry land use compilation namely swamp bushes, open areas, transportation, galam vegetation (Melaleuca sp) and water bodies. The truth value was 88.48% for Overall Accuracy and 0.8 for Kappa which belonged to the substantial category. Land cover/land use resulting from spatial analysis showed a significant increase in water bodies totally 24% from 14% in 1994. Inundations that were close to the Barito river flow had a typical permanent compared to those that were far from the river. Regarding inundations throughout the season contributed to the management and development of the socio-economic area.

A preliminary study of Indonesian coal basins for underground coal gasification development

The energy needs in Indonesia are continuing to increase, however, the production of oil and gas declines. This problem can be minimized by developing alternativ e energy such as underground coal gasification (UCG) by utilizing deep seated coal at 200 to 1 . 000 m below surface . The objective of this study is to evaluate coal characteristic in the basins for UCG purpose depends on several coal properties such as its rank (below bituminous), thickness (5m), depth (up to 200m), and ash content plus total moisture (below 60%). Based on coal analysis of 11 coal basins from previous exploration drilling, there were several coal layers in four selected basins to be applied for the UCG project, namely 7 coal layers in South Sumatra Basin , 7 coal layers in Barito Basin , 2 coal layers in Asam- a sam Basin and 5 coal layers in Kutai Basin . Based on the SNI No. 5015-2011, the coal resources was calculated and converted into a gas by a simulation procedure. Total UCG coal in South Sumatera Basin is 80 1 million tons , meanwhile, the Barito Basin has 436 million tons, Asam-asam 136 million tons, and Kutai 289.7 million tons. The total hypothetical syngas is 8.38 TSCF. The UCG facilities in South Sumatra Basin should be designed to produce the syngas as the natural gas within this area is in deficit condition and the basic cost for electricity supply belongs to low situation, however, the UCG plants in Kalimantan should produce electricity as its cost ratio of electricity is high and this area retains surplus natural gas supply.