Selection of the Effective Enhanced Oil Recovery Method for Highly Viscous Oil Fields on the Basis of Filtration Experiments (on the Example of One Kazakhstani Field)

Abstract

One of the strategic objectives of the modern oil industry is the efficient development of highly viscous oil reserves, which are characterized by low mobility leading to a sharp decline in the oil recovery factor (ORF). The article is devoted to the assessment of the development status of highly viscous oil fields and selection of the most efficient method of enhanced oil recovery (EOR) on the example of one field of the Republic of Kazakhstan.Huge amount of the global oil deposits belongs to deposits with highly viscous scavenger oil with viscosity above 30 mPa*sec. According to international experience most EOR methods applied on highly viscous oil fields the aim to reduce the reservoir fluid viscosity. Another approach based on the use of drainage systems, that provides increase of surface efficiency, is related to improved oil recovery methods. Combination of these two approaches provides a good cumulative effect.This paper presents the results of laboratory filtration experiments on the of highly viscous oil displacement. On fields with scavenger oil recovery factor does not exceed 0.30. The aim of the research was to determine the most effective enhanced oil recovery method in terms of displacement efficiency.Following reservoir stimulation scenarios were considered during the laboratory experiment: the base case (water injection); thermal treatment by hot water injection; polymer flooding; polymer flooding at an elevated temperature. Experiments show that conventional water flooding gives the lowest displacement ratio. According to the research results the maximum displacement ratio is achieved during hot water injection without the use of a polymer. Displacement ratio increased from 12.9% to 30.3%. In the course of special studies displacement efficiency function concerning temperature was obtained. The research results are discussed in detail.