Some possibilities of fluid typization in core samples at rig site applying nuclear magnetic resonance

Abstract

Copyright 2020, Society of Petroleum Engineers. In the framework of the contract with the Ministry of Education 2010-2012, TNG-Group andKazan Federal University developed a mobile YaMR-Kern unit to acquire information on filtration-capacitive properties of full-sized freshly drilled and extracted core samples, to estimate porosity, to determine free and bound fluids, permeability, residual water saturation, to assess the nature of saturation by analyzing the two-dimensional distribution of relaxation times and diffusion coefficient directly at the wellsite without preliminary core preparation for studies. Efficiency of the unit was tested on more than 1600 m of full-sized core samples taken from sediments of various ages and saturated with oils of various viscosity grades. The core study directly at the wellsite, that is, immediately after its extraction to the surface, allows not to lose the very first information about the studied object as soon as possible, since the study of the core drying process showed that during the first hours the core loses up to a third of fluid-saturated porosity, and 20 days later dries out almost completely. Scanning the NMR properties of the core is carried out with high detail, every 1-2 cm, and does not involve any preparatory work, that is, the core does not break down and can later be used for laboratory studies of both full-sized core and standard samples. Such information is extremely important at the stage of exploratory drilling on poorly studied survey targets, as well as in the study of a thin-layered section of wells.