Perpustakaan Digital ITB

Right now, the discovery of giant oil and gas field continued to decline. World demand for oil and gas will continue to rise but production decreases. This leads to the increasing of oil and gas price. Therefore, unconventional hydrocarbon reservoirs become economic to develop. To fulfill the world’s need for hydrocarbons, since a few decades ago the oil and gas industry has started production of unconventional oil and gas, such as extra-heavy oil, bitumen, oil shale, tight gas, coal bed methane, shale gas, and gas hydrates. Unconventional hydrocarbon is more abundant than conventional hydrocarbon, but need specialized technology to produce it. World CBM resources are approximately 9000 TSCF (Jenkins and Boyer, 2008). So far, CBM is produced mainly by US, Canada, and Australia. US started to produce CBM commercially in 1980s. Indonesia has CBM resources of 453 TSCF, mainly deposited in Sumatera and Kalimantan. Currently, there are 54 CBM exploration working areas. XY-1 is a CBM exploration well in one of the working areas. This well has been tested to determine the coal permeability and pore pressure with mini-frac test. Mini-frac test is low injection volume, cost-effective and short duration test that has been used widely in testing tight reservoir. This paper presents the analysis of mini-frac test in XY-1 CBM well that consists of pre-closure analysis to determine leakoff mechanism type and closure pressure; and after-closure analysis to determine pore pressure and permeability. These fracture parameters are very important in designing hydraulic fracturing treatment, which is required for producing gas from unconventional hydrocarbon reservoir.