Theory on logging interpretation of igneous rocks and its application

Abstract

Based on the summary of theories and methods of well logging interpretation for igneous rock at home and abroad, a complete interpretation process of well logging is formed, which includes lithology identification, quantitative matrix porosity calculation, quantitative saturation calculation, and fluid nature identification. This paper presents a theory and an application model of porosity and saturation calculation for heterogeneous and complex reservoirs, and establishes a framework for interpreting complex volcanic rock reservoirs; proposes a new method combining ECS with FMI logging for 3-D lithology identification of igneous rocks. Based on the study of the micro-fracture simulation well, this paper puts forward a practical quantitative calculation method for calculating the fracture porosity of heterogeneous reservoirs. By experimenting with core of whole diameter under high temperature and high pressure, the authors studied the influence of fracture on saturation calculation through numerical simulation, and proposed a new method of quantitative saturation calculation. The results of the Xujiaweizi area in the Daqing Oilfield and the Ludong-Wucaiwan area in the Xinjiang Oilfield show that the theory and the method are correct and effective. Key words: igneous rock, well-log interpretation, interpretation model, fracture porosity, saturation