STUDY OF SEDIMENTOLOGY, RESERVOIR PHYSICS AND GEOCHEMISTRY CHARACTERS FOR RESOURCES ESTIMATION OF COAL BED METHANE OF MIOCENE SEAMS 1, 2, 3, 4, 5, AND 6 IN SS FIELD, KUTAI HILIR SUB-BASIN

• Main Author: Tri Setyobudi, Prihatin
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/32193
• Institution: Institut Teknologi Bandung

SS field is a coal bed methane gas field in Kutai Basin. Since 2011 exploration drilling has been done and proven discovery of coal bed methane accumulation by four exploration wells in this area. Integration data of outcrops, shallow coal wells, and coal bed methane wells provide better and accurate information about sedimentology, physical properties, and geochemistry of coal in order to predict paleogeography, thickness, and coal bed methane reservoir quality. The scope of problems to be explained in this study are limited in the sedimentological characters and depositional environment, the distribution of coal which indicated by depth structure and coal isopach maps, the determination of depth and coal maturity by Vr analysis, the relationship between coal type and physico-geochemistry properties of coal, and inter-property of coal physics- geochemistry, reservoir pressure and temperature conditions, modified calculation equation of gas content, the quality and distribution of coal which shown by density and gas content distribution maps, sweet spot map and the resources calculation of gas initial in place of methane in the coal seams 1, 2, 3, 4, 5, and 6 in the SS field. The data analysis methods are analysis of sedimentology and stratigraphy, analysis of the genesis coal bed methane and maturity of coal, analysis of the relationship and the modification formula, subsurface geological mapping, resource calculation methane coal seams 1, 2, 3, 4, 5 and 6 in field SS. Generally, the depositional environment in the field SS is fluvial-deltaic with progradition and bathymetry shallowing upward. Coal in SS field has Ro early mature value about 0.46% at 200 m depth. The value of gas content in SS field is directly proportional with depth, but also influenced by the coal type and physical- geochemistry properties. The formula which used in calculating the value of physical-geochemistry parameters by linear regression of modified formula Mullen (1989) are: ASH = 87,583*D – 112,06 FC = -0,559*ASH + 49,029 VM = -0,3707*ASH + 42,189 M = 100 – AC – FC – VM with ASH = Ash Content (%adb) FC = Fixed Carbon (%adb) VM = Volatile Matter (%adb) M = Moisture (%adb) D = Density (g/cc) The formula of gas content on raw conditions (Vraw) which corresponding with SS field conditions is modified Mullen (1989) formula, namely Vraw = -221.41 * D + 548.36 with Vraw = gas content on raw conditions (scf/ton) and D = coal density (g/cm3). To calculate the gas content with dry conditions (Vdaf) in m3/t unit from the gas content with raw condition (Vraw) in m3/t unit for seams 1, 2, 3, 4, 5, and 6 can be used equation in accordance with the coal type are: - for lithology of coal – high volatile bituminous; Vdaf = 0.961*Vraw + 1,41035 - for lithology of shally coal – lignit; Vdaf = 1.567*Vraw + 2.6523 Total resources of gas initial in-place of coal bed methane derived from six seams which divided into 47 sweet spots in SS field are 149.81 Bcf.