The Maturity Estimation of Material Organic in CaCO₃ with Determining T _max and Energy Activation Using Pyrolysis Method

Shale material is shale oil that is clay or carbonate material contain excessively immature organic. When heated to a certain temperature, the organic content changed to mature and changed in physics and chemistry, so it can produce energy materials such as oil and gas. The testing of TOC that produced carbonates-organic showed excellent quality as shale oil (TOC ≥ 12.0%). The results of thermogravimetric analysis showed activation energy of carbonates was 749–1339 kJ/mol and the temperature of the reaction process was 75–740 °C. Organic composition that was larger than carbonate can caused a smaller activation energy. The carbonate content of OD7-Asl2 had E_a = 1083.7 kJ/mol smaller than OD7-Asl1 with E_a = 1338.1 kJ/mol. A very large TOC value affected the activation energy to be smaller, as the carbonate of OD7-Asl2 was smaller than OD7-Asl1. The maturity of the OD7-Asl2 shale occurred at T = (380–445) °C, E_a = 1083.7 kJ/mol and T_max = 415 °C, better than OD7-Asl1. The Rock Eval Pyrolisis test results showed shale carbonate had a high potential to produce oil and gas. Shale material heating result reinforced by FTIR testing that the compounds with specific functional groups apart and a new peak appeared at wavenumber 2900 cm⁻¹ which indicate the presence of hydrocarbons single bonds.