Study of Asphaltene Precipitation during CO2 Injection in Light Oil Reservoirs

Abstract

CO2 injection is considered as one of the successful methods used for enhanced oil recovery (EOR) in oil fields to recover residual oil. It increases mobility and reduces viscosity and interfacial tension. Asphaltene precipitation and deposition phenomena appear in petroleum reservoirs due to change in temperature, pressure, and liquid phase compositions; either during the primary production or enhanced oil recovery processes. Asphaltene precipitation might occur due to CO2 injection in light oil (>30° API) reservoirs which may cause blockage of production system, decrease in permeability, wellbore plugging and change in porosity. Experimental data concludes high asphaltenes precipitation and lower asphaltene solubility in light oils. Hence severe damage to formation can happed sue to asphaltene precipitation, in some cases the loss might be irreversible. This paper furnishes the investigation of asphaltene precipitation caused by CO2 injection. In this regards interaction between asphaltene and formation, precipitation quantity under different injection flow rates of CO2 at the constant injection pressure have been investigated. Results conclude that there is direct proportionality between asphaltene precipitation and amount of injected gas in the core sample, whereas inverse proportionality between asphaltene precipitation and increased injection flow rate of the gas at constant injection pressure.

Effect of Cryogenic Liquid Nitrogen on the Morphological and Petrophysical Characteristics of Tight Gas Sandstone Rocks from Kirthar Fold Belt, Indus Basin, Pakistan

“…It is pertinent to measure the conventional petrophysics and rock properties via reservoir characterization in order to quantify hydrocarbon potential. − This can be achieved by proper characterization of the porous media and its lithology. − Our results for petrophysical experiments depict bright difference in properties of tight sandstone rock samples before and after LN 2 treatment, Figure and Table . Liquid nitrogen treatment from 30 to 90 min has enhanced the porosity and permeability of tight sandstone rocks due to induced fractures.…”

Effect of Environment-Friendly Non-Ionic Surfactant on Interfacial Tension Reduction and Wettability Alteration; Implications for Enhanced Oil Recovery

“…It is believed that carbonate rock generally has oil-wetting behavior which attributes to the oil aging effect. After the cleaning process, to simulate the real formation, the thin sections of core samples were placed in a beaker together with crude oil from the Ahwaz oil field in the oven at 80 • C under vacuum conditions for 48 h [10,11], to achieve initial oil saturation. After saturating the core samples with crude oil, the thin section was saturated with formation surfactant (dodecanoyl-glucosamine surfactant) for 24 h to reduce the wettability to more water-wet conditions.…”

A Modified Multiple-Mixing-Cell Method with Sub-Cells for MMP Determinations

“…Gas flooding is one enhanced oil recovery (EOR) method that injects CO 2 or other gases into reservoirs to displace oil. It has been researched and applied in the fields since the 1950s [1][2][3]. Since 2006, the gas flooding projects account for more than half of all the EOR projects worldwide [4], showing the utmost importance of this EOR method.…”

“…Each 𝑛𝑐 𝑗 in the array 𝑁𝐶 corresponds to a recovery factor to be calculated by Equation (3). We can then obtain the dataset {𝑅𝐹 𝑇 , 𝑁𝐶 𝑇 }, where Equation (2) shows that N PT equals two-third of N PT when GOR = 1/3. The use of two sub-cells in each cell leads to a better mixing efficiency because there are two mixing events taking place in each cell.…”