<b>Formation Evaluation of Hydrocarbon Reservoirs of Oil Fields in</b> <b>Geological Basin by the Help of Petrophysical Tools</b>.

The purpose of formation evaluation is to identify the reservoir rock, evaluate the potential hydrocarbon and estimate the volume of those hydrocarbon reserves. Reservoir rock means it should be porous (void space) and permeable to get production of commercial volume of hydrocarbon. Petrophysical tools are to be lowered in the borehole to record continuous log data corresponding to depths within the borehole. Log data recorded from the tools are formation resistivity, resistivity of formation water of the reservoir, porosity, permeability, gamma ray log data for finding volume of shalyness etc. All these log data are used as inputs to the Special software of Electro Log Analysis (ELAN). Archie’s equation for clean sand and Indonesian equation for shaly-sand are used in ELAN software for finding the water saturation in turn hydrocarbon saturation of the reservoir as an output. Also, effective porosity, volume of shalyness and matrix volume of the reservoir are displayed after ELAN processing.