OGIP Paper Competition Yogyakarta, 12 th - 14 th February 2013 POTENTIAL EVALUATION OF COALBED METHANE (CBM) BASED ON THE QUALITY AND QUANTITY OF COAL IN SEAM MANGUS MUARAENIM FORMATION, NIBUNG REGION SOUTH SUMATRA BASIN AS ENERGY SUSTAINABILITY INDONESIA Alex Candra 1 , Fajar Ramadhan 1 1 Geological Engineering Department, Diponegoro University, Semarang Jl.Prof.Sudharto,S.H Tembalang, Semarang – 50275 Phone: 081325330169 e-mail : alex.candra15@gmail.com ABSTRACT Indonesia get decrease in oil and gas reserves of about 2.4% per year (Panuju, 2010). Therefore we need energy sustainability for national glory that is CoalBed Methane (CBM). Coalbed methane (CBM) is simply methane found in coal seams. Coal methane is mixture hydrocarbon gases with dominant composition of methane (CH4) by 90 – 95% (Alan A.Bayrak, 2010). The scope of the study is the analysis of seam Mangus late Miocene, Muaraenim Formation (Tmpm) South Sumatra Basin area Nibung Musirawas district. The Reserves of CoalBed Methane (CBM) Indonesia in South Sumatra the potential of CBM is 183 TCF (Steven and Hardiyanto, 2005). Producibility of CBM is influenced by many factors such as geology Condition, depositional environment systems, geometry / distribution of coal, coal rank, the amount of gas content, permeability and tectonics / structural geology, and also by the hydrogeological conditions. The methods used in the evaluation of methane gas is desorption test, the adsorption isotherm analysis, gas chromatograph, and geochemistry method and drilling in the determination of the thickness and depth of coal (Rita Susilawati in geology news, 2008) Based on geochemistry method; desorption test, adsorption isotherm analysis, and gas chromatograph from as many as twenty (20) coal samples tested that contained in seam Mangus on Muaraenim Formation, They are : Methane (CH4) content is about 42.21% (0.48 m 3 /ton); Total gas content 40.10 Scf/ton (1.14 m 3 /ton) and Proximate analysis; Moisture 31.15%; Volatile matter 33.74%; Fixed carbon; Ash content on seam Mangus 2.07%. and Caloric value 5542 – 6346 cal/g. By drilling test in depth 237.58 – 251.22 meter, thickness of coal contained 13.64 meter. For seam mangus has the ability to store gas reached 12.43 m 3 /ton at 474 psi (Sigit Arso, 2011). Coal deposits formed around the coastal plain to the sea in the form of shallow marshes and geological structure of the area is a syncline kelampayan (Sukardi et all, 2001) Based on the analysis method Geochemistry; desorption test, the adsorption isotherm analysis, and gas chromatograph, for seam Mangus Muaraenim Formation is categorized sub-Bituminous class A-B (USA, ASTM) that can produce of methane (CBM), while the results of drilling at depth of 237.58 - 251.22 meters of 13.64 meters and thickness derived methane content is low and depositional environment categorized wetlands will generate biogenic methane, so this seam Mangus potential for CBM (coalbed methane) but the prospect is low. Keywords: CoalBed Methane (CBM), Seam Mangus, Geochemistry method, Muaraenim Formation