Core Analysis Experience for Fractured Basement Rock at J/V “Vietsovpetro”, Vietnam

Abstract

This study presents a comprehensive methodology for core analysis of fractured basement rock at J/V “Vietsovpetro”. The process begins with a detailed visual description of the core sample, followed by a fracture study to determine fracture density, azimuth, strike, and dip. Probe permeability and radioactivity are measured using traditional methods. The conventional core plug sampling approach is found to be unsuitable for highly heterogeneous fractured basement rock. A new core plug sampling approach is proposed, which involves increasing the core plug diameter and sampling frequency to better preserve vug-macrofractures. Post-cutting core plug analysis includes determining gas permeability, porosity, cut-off porosity, grain density, acoustic velocity, compressibility, capillary pressure curves, and wettability. The study also highlights the need for additional analysis of initial residual water saturation in the reservoir using preserved core, trace element analysis, and determination of radioisotope age. Certain parameters such as electrical properties and cation exchange capacity are deemed unnecessary for fractured basement rock. The findings of this study are crucial for improving the reliability of core analysis results and have significant implications for oil and gas exploration and production.