Two-Phase Fluid Flow Experiments Monitored by NMR

Thomas Hiller,Norbert Klitzsch,Gabriel Hoder,Norbert Schleifer,Alexandra Amann-Hildenbrand,J Schembre-Mccabe,H Ott

doi:10.1051/e3sconf/202014603005

Abstract

We present a newly developed high-pressure nuclear magnetic resonance (NMR) flow cell, which allows for the simultaneous determination of water saturation, effective gas permeability and NMR relaxation time distribution in two-phase fluid flow experiments. We introduce both the experimental setup and the experimental procedure on a tight Rotliegend sandstone sample. The initially fully water saturated sample is systematically drained by a stepwise increase of gas (Nitrogen) inlet pressure and the drainage process is continuously monitored by low field NMR relaxation measurements. After correction of the data for temperature fluctuations, the monitored changes in water saturation proved very accurate. The experimental procedure provides quantitative information about the total water saturation as well as about its distribution within the pore space at defined differential pressure conditions. Furthermore, the relationship between water saturation and relative (or effective) apparent permeability is directly determined.

Highlights

Petrophysical parameters play an important role in many geological applications and are subject of various research projects
Laboratory fluid flow experiments are crucial in order to determine parameters, which can be used to calculate fluid redistribution in the subsurface
Relaxation time Tlgm, nuclear magnetic resonance (NMR) porosity ΦNMR, Helium porosity ΦHe, Archimedes porosity ΦArch, intrinsic gas permeability k∞, and Klinkenberg slip factor b) of the sample used in this study

Summary

Introduction

Petrophysical parameters play an important role in many geological applications and are subject of various research projects. Core analysis is done under ambient conditions on dry plugs or completely water saturated samples, i.e., single-phase fluid flow is measured in order to derive intrinsic permeability [1, 2]. When it comes to the characterization of low permeable material (tight sandstones, shales) below the mD-range, the experimental procedures need to be adapted for low flow rates and high fluid pressures. The latter is highly important, as gas flow through low permeable (partially) water saturated rocks is usually controlled by capillary pressure, i.e., as water is drained from the pores with increasing differential gas pressure [4]

Methods

Results

Conclusion