Sharif Digital Repository

In reservoirs that have been water flooded or gas injected, it is still a significant amount of the remaining oil. Water alternative gas injection is a tertiary oil recovery method which was used for the first time in Canada for recovering remained oil in place of reservoir. The pore-scale mechanisms of this process are not fully understood yet. Such knowledge is essential for accurate modelling of reservoir. In this study various experiments on the WAG process is carried out by means of high pressure glass type micromodel instrument. The micromodel apparatus in this experiment was capable to operate at pressures up to 3500 Psi and temperatures up to 85°C which is similar to conventional... 

Gas injection process for more oil recovery and in particular CO2 injection is well-established method to increment oil recovery from underground oil reservoirs. CO2 sequestration which takes place during this enhanced oil recovery (EOR) method has positive impact on reducing the greenhouse gas emission which causes global warming. Direct gas injection into depleted oil reservoirs, encounters several shortcomings such as low volumetric sweep efficiency, early breakthrough (BT) and high risk of gas leakage in naturally fractured carbonate oil reservoirs. Carbonated water injection (CWI) has been recently proposed as an alternative method to alleviate the problems associated with gas... 

Microbial enhanced oil recovery (MEOR) process is divided into two main categories, namely in-situ and ex-situ techniques. It utilizes reservoir microorganisms or specially selected bacteria to use their metabolites for more oil recovery from depleted oil reservoirs. In the present study, the potential of two biosurfactant-producing strains of Enterobacter cloacae and Bacillus stearothermophilus SUCPM#14 were investigated on tertiary oil recovery efficiency in carbonated cores using different designed injection protocols. The required operational time, process cost and proper selection of bacterial formulation during the MEOR process were the main objectives of this study. The results of... 

Naturally fractured reservoirs (NFRs) contribute in large extent to oil and gas production to the ever increasing market demand of fossil energy. It is believed that the vertical displacement of oil during gas injection assisted by gravity drainage (GAGD) is one of the most efficient methods for oil recovery in these reservoirs. Hence, in this work, unconsolidated packed models of cylindrical geometry surrounded by fracture were utilized in order to perform a series of flow visualization experiments during which the contribution of different parameters such as the extent of matrix permeability, physical properties of oil (viscosity, density, and surface tension) and the withdrawal rate was... 

During any microbial enhanced oil recovery process, both cells and the metabolic products of bacteria govern the tertiary oil recovery efficiency. However, very accurate examination is needed to find the functionality of these tiny creatures at different reservoir conditions. In this regard, the effect of cell structure on ultimate microbial recovery efficiency which is the most dominant mechanism based on the microorganism types (gram-negative or gram-positive) was systematically investigated. At the first stage, possible different active mechanisms using Bacillus stearothermophilus SUCPM#14 strain were tested using specially designed injection protocol, in situ and ex situ core flooding... 

The amount of residual oil trapped in the matrix of a fractured reservoir after water drive, either natural water drive or water injection, depends on the wettability of the matrix rocks. Gas oil gravity drainage (GOGD) has been proposed as the tertiary oil recovery process for this type of oil reservoir. The current work focuses on experimental investigation of tertiary GOGD in fractured porous media under different types of matrix wettability. Results of a set of experiments performed in artificial porous media composed of sand packs and glass beads of different wettability have been used to check the GOGD rate and the ultimate oil recovery for previously waterflooded models. A novel...