Identification of Thickness and Depth of Volcanic Rocks Layer Using Dar-Zarouk Parameters and Anisotropy Concept on 2D Resistivity Data in Majalengka District

In the region of Majalengka in the area Sukamurni, District Maja, oil seepage that emerged in young volcanic deposits was discovered. The discovery of oil seeps in the the youngest rocks in Bogor Basin, especially in the region of Majalengka, gives an indication of the presence of source rock that can generate oil. The research will be carried out in the border area between Majalengka and Cirebon. In the research area, geophysical survey based on electromagnetic method has been carried out. The inversion and interpretation results showed the presence of geological structures in the form of a normal fault. This fault structure can be interpreted as a hydrocarbons trap in the form of structural traps. In addition, the survey result showed the thickness of the volcanic rocks as thick as 150 m. To improve resistivity resolution, we have performed geoelectric survey. Moreover, geoelectric method can also be used to estimate the depth and thickness of volcanic rocks. The geoelectric data have been processed by using Dar-Zarouk Parameters that assumes the earth is heterogeneous and anisotropy which has resistivity variation in all directions and has irregular shapes. This approach also estimates the value of resistivity of rocks by calculating the longitudinal and transverse resistivity.