Miscible CO2 Flooding for EOR in the Presence of Natural Gas Components in Displacing and Displaced Fluids

Abstract

Carbon dioxide (CO 2) flooding is a complicated process as it involves phase behavior. The objective of this work was to understand the mass transfer mechanisms during flooding with CO 2 and CO 2 /C1/C3 (CO 2 /HC) based on experimental and simulated composition changes. Three model oil compositions were used (n-C10, n-C10/C1, and n-C10/C1/C3). For a comparison, crude oil from a North Sea field was included. The second part of the investigation was to compare the effect of the combined light components (C1/C3) with CO 2 as a displacing fluid on enhanced oil recovery (EOR). Equation of State EOS SRK-Peneloux was used for the simulations to predict composition changes. The highest recovery was obtained from model oil (n-C10) displaced with CO 2 compared to model oil containing light components with the highest recovery recorded from model oil/C1 (live oil A) compared to model oil/C1/C3 at all of the tested temperatures. The presence of light components (C1/C3) in the injected CO 2 at miscible conditions increased the oil recovery for crude oil compared to flooding only with CO 2. Transverse dispersion of CO 2 helps in eliminating/reducing the effect of viscous instabilities by shortening fingering travel/widening the fingers. The collected samples contained water, although the flooding was done on dry sandstone cores. Possible mechanisms are discussed in a later section.

Experimental Investigation of Polymer Injection in High Permeability Conduits for Material Sustainability and Behavior in Oil Reservoirs

“…Different chemical methods are used to enhance oil recovery based on the basic principles of improving sweep and displacement efficiencies. The chemical methods used are polymer-augmented waterflooding [1,2], surfactant flooding [3], alkaline flooding [4], CO 2augmented water flooding [5], and miscible/immiscible CO 2 displacement [6]. Polymers have been utilized in the hydrocarbon industry for many years [1,2].…”

Experimental Investigation of Polymer Reinjection in Long Conduits for Material Sustainability and Cost Reduction of Enhanced Oil Recovery

“…Different chemical methods are used to enhance oil recovery based on the basic principles of improving sweep and displacement efficiencies. Chemical methods used are: polymer augmented waterflooding [27,29]; surfactant flooding [28]; alkaline flooding [30]; CO2-augmented water flooding [31]; and Miscible/immiscible CO2 displacement [32]. Polymers have been utilized in the hydrocarbon industry for many years [27,29].…”

“…Polymer injection has also been coupled with other EOR methods [27][28][29][30][31][32][33]. In most of the researches, polymer injection was combined with other chemical EOR methods, such as alkaline or surfactant flooding.…”

Molecular Insights into Asphaltene Aggregation in Gas Flooding

“…The heavy oil with high viscosity is hard to spontaneously flow, and various tertiary oil recovery technologies have been well developed for heavy oil recovery. Among these technologies, the injecting gas method is of superb performance thanks to its high miscible displacement efficiency. − Gases like CO 2 , N 2 , and CH 4 were generally adopted as injecting gases for enhanced oil recovery (EOR). ,,− The injected CO 2 can not only increase the oil saturation beyond the residual saturation, but also reduce the viscosity, thereby endowing the heavy oil additional fluidity . Generally, the injecting gas is supercritical fluid under the reservoir conditions with high pressure and temperature, and have excellent dissolubility to crude oil and extraordinary diffusivity.…”