STUDY ON PORE SCALE DISTRIBUTION OF FROZEN WATER AND ITS EFFECT ON RELATIVE PERMEABILITY OF OIL IN PERMAFROST RESERVOIR ROCKS

Permafrost is a regular feature of extreme northern and southern terrain throughout the world, its boundaries dictated by the laws of physics alone. The petroleum reservoir that could produce economically from a frozen ground preferentially contains oil, water, ice, and /or gas. This four‑component system makes the reservoir much more complex than the regular conventional three‑component system (oil, water, and/or gas). The reasons behind this can be analyzed in macro and micro level.The former contributes to the very unusual conditions and the difficulties in completing oil wells in permafrost grounds and the later investigates the effect of freezing of this formation water on the relative permeability of each individuals of this four‑component system in a frozen ground.This present study concentrates on this pore scale distribution of water and ice using Nuclear Magnetic Resonance (NMR) and its effect on the relative permeability of oil. The amount of unfrozen water in a frozen sample has been estimated using NMR and then performed a laboratory study of fluid‑flux permeability measurements of samples, which were frozen below zero centigrade and then, followed by thawing of the core. The effect of frozen water in the pore space on the relative permeability is observed to estimate the production potential of the field. The results experimentally proved the existence of liquid water below zero temperature and changes in the relative permeability of oil while thawing. Further experiments are going on to investigate a best production technique to increase the quantity of "Recoverable reserve" in this ice rich reservoir fields.