ANALYSIS OF TOTAL ORGANIC CARBON (TOC), BRITTLENESS INDEX (BI), MATURITY AND SEISMIC ATTRIBUTES FOR CHARACTERISTICS IDENTIFICATION OF POTENTIAL SHALE OIL: A CASE STUDY OF TALANG AKAR FORMATION, CENTRAL ARDJUNA BASIN

摘要

The reservoir characterization and identification of shale oil in TalangAkar formation has been done by examining the total organic carbon (TOC), brittleness index (BI) and some maturity parameters. Analyzing said parameters, various methods were used to analyze these parameters, including geochemistry, mineralogy, petrophysics, cross plotting and seismic interpretation. Through geochemistry analysis, TOC resulted in a good category with material type of kerogen I-II which usually produces oil with an early maturity window which approximately 7900 ft. The brittleness index of the shale formation of the research area is categorized in less brittle to brittle. The petrophysics analysis resulted in shale thickness between 120-150 ft in the research area and TOC modelling resulted in 0.6986 regression coefficient towards log parameters (gamma ray log, density, Neutron-Porosity, sonic and resistivity). Through seismic analysis and interpretation, we are able to examine the shale distribution of the net shale ratio that is linked with the RMS value from amplitude extraction, with a result of a zone with 20 ms window in the interest zone (TOC 4.1523 %, BI 0.3869 v/v) and 0.5889 regression coefficient. The interest zone that has shale potential exists in the basin with volumetric oil in place value of 46.68 MMBO. The parameters of TOC, BI and maturity do not have any direct correlations, but they does have an important role in determining the potential contained within shale.