Identification of fractured-basement reservoir based on integration of FMI Log and seismic attributes in hydrocarbon field “I”, Barito Basin, South Kalimantan

Abstract

As basement has very small matrix porosity, secondary porosity is needed to store hydrocarbon within the basement. Fracture is a secondary porosity, yet not all fracture can be a good secondary porosity. Open fractures have capability to store hydrocabon, also have important roles in productivity and quality of the pre-tertiary basement reservoir. This study is aimed to identify open fractures using FMI log and seismic attributes in the Field “I”, Barito Basin. Interpreted image log (FMI) on two wells gives the azimuth and dip orientation of open fractures are ENE –WSW, NNW-SSE and WNW-ESE and also the horizontal stress orientation. The stress orientation from image log combined with leak-off test (LOT) data and density log used to identify stress fields. Azimuth and dip orientation of the open fracture from FMI log is the input of the stereonet, as an orientation filter for ant-tracking. Ant-track attribute is based on ant-colony optimization algorithm that captures only continuous features and used as edge enhancement methods for fracture-sensitive attributes. Variance is a fracture-sensitive attribute that applied as input data for ant-track algorithm. The results of ant-track map are well correlated and confirmed by image log analysis. Also, by applying ant-track attribute to the fracture-sensitive attributes succesfully able to identify faults and fractures with better resolution and visualization than only using the fracture-sensitive attribute itself, so it makes easier to interpret and get the information.