Advances in Magnetic Resonance Relaxometry for Heavy Oil and Bitumen Characterization

Abstract

This paper offers a summary of the advances in heavy oil and bitumen reservoir characterization and fluid stream monitoring using low field magnetic resonance tools. Both laboratory and field advances are presented. Although the bulk of the work discussed was performed in our laboratory, a selection of other pertinent technologies is also presented. This overview aims at offering the reader a quick reference of what has been achieved in the past ten years and it is hoped that it will be used as a guide for future development in this area.

NMR relaxometry and diffusometry in characterizing structural, interfacial and colloidal properties of heavy oils and oil sands

“…In clay-free sands, the contribution of heavy oil and water is distinct [64]. However, in sands that contain clays the clay-bound water relaxation times are often in the same range as the heavy oil relaxation times.…”

“…This means that the conversion of the de-convoluted oil amplitude to a mass value is not trivial. In order to determine AI b an empirical relationship was found between the de-convoluted T 2gm and the oil RHI using bulk oil, although these are seen to vary depending on the oil properties [50,64].…”

Studies on crude oil‐water biphasic mixtures by low‐field NMR

“…The situation described up to this point (samples from Series I), where the fluids in the mixture have very distinct relaxation behavior, is the simplest one, and similar approaches to the ones reported here can be found in the recent literature. [15] For boundaries to be expanded, experiments were carried out with 17 samples of other biphasic mixtures (Series II), but now using a 360-ppm aqueous Mn 2+ solution as the water-rich phase. Previous tests showed that this concentration of the paramagnetic ions accelerates the relaxation of the 1 H nuclei in the water phase, lowering the corresponding T 2 values to the same range found for the oil phase, which leads to a T 2 distribution for the mixture containing superimposed contributions from both phases (Fig.…”

“…In fact, a proposal of a specific apparatus designed to this end has recently appeared. [15] This work is concerned with the quantification of the fluids present in mixtures of crude oil and water. Sample behaviors, analytical and statistical procedures are investigated, increasing the knowledge and potential application for these on-line tools.…”

Evaluation of the Physicochemical Properties of the Postsalt Crude Oil for Low-Field NMR

“…19 In use since the mid-1980s, the LF NMR technique is very well established in the oil sector due to its ability to determine physicochemical properties of the fluid and the rock formation of the reservoir. 20 Several papers in the literature 21−26 describe the use of the technique for estimating the viscosity based on the T 2 , characterizing the properties of the reservoirs (porosity, permeability, fluid saturation, the potential formation), 27−32 studying emulsions and biphasic mixtures, 33−38 determining the droplet size distribution of emulsions, 38−40 and identifying and classifying crude oil from different reservoirs. 41 Two-dimensional techniques that simultaneously measure T 1 and T 2 and the diffusion coefficient (D) are also used successfully for determining the molecular dynamics of petroleum reservoirs, 42 the chemical composition of molecular groups, 43 and the chain size distribution of oil.…”