VOLCANIC RESERVOIR CHARACTERIZATION OF JATIBARANG FORMATION BASED ON AN INTEGRATED STUDY OF PETROGRAPHY, CORE, FMI, AND WELL LOG

摘要

The volcanic reservoir of the Jatibarang Formation has been studied extensively. The Jatibarang is a naturally fractured reservoir. It is divided into three facies: massive tuffaceous sandstone, laminated tuffaceous sandstone, and conglomerate. Realistic characterization of volcanic reservoirs by downhole logs is a problem because the nature of the rock overwhelms the tools.An integrated study of petrography, Scanning Electron Microscope (SEM), Side Wall Cores (SWC), Full bore Formation Micro Imager (FMI), and well logs is required to define the characteristics of Jatibarang volcanics. Matrix density and porosity type are important parameters to calculate appropriate porosity values in each facie. Well test data are used to determine water resistivity which is influenced by the value of saturation water. A permeability model was derived from Wyllie-Rose formula for each facie.The purpose of this study was to determine the characteristics of the Jatibarang volcanic reservoir in order to construct a model or parameter for each facie based on integrated well data. Well analysis must be done for each facie of the reservoir. Lithology of the reservoir is very complex, causing not insignificant difficulty for reservoir engineers and petrophysicists to arrive at realistic reservoir parameters. Matrix density, porosity and permeability are important parameters for characterization of volcanic reservoirs; good results mean good models to use in un-cored wells.