Investigating the Effect of CO₂Flooding on Asphaltenic Oil Recovery and Reservoir Wettability

Abstract

Miscible and immiscible flooding with CO2 of oils containing asphaltene for chalk reservoir is investigated. Oil recovery from model oil and crude oil (30° API gravity), containing 0.35 and 10 wt % asphlatene, respectively, is addressed. n-Decane is used as a reference oil and showed an increase of recovery from 81 to 89% at 50 °C and 90 bar and 80 °C and 140 bar, respectively. Both model and crude oils showed a reduction in the oil recovery from 78.92 to 70.4% and from 37.6 to 36.6%, respectively, at the same conditions as that for the reference oil. The insignificant change in the oil recovery between the two conditions for the crude oil may be due to the high asphaltene content (10%). A model based on the solubility theory is developed to account for the effect of CO2 flooding and is verified using literature data for CO2 flooding. The average deviations of the model for the miscible flooding from the experimental are 15 and 18% for this study and literature data, respectively. The relative contribution of CO2 on asphaltene precipitation because of miscible CO2 flooding is compared to that for the pressure and temperature effect. On the basis of the approach in this work and available data from literature, CO2 critical content lies between 42 and 17 mol % in the liquid phase, with an average value of about 33 mol %.

Investigation of CO2 Enhanced Oil Recovery Using Dimensionless Groups in Wettability Modified Chalk and Sandstone Rocks

“…In the past five decades, there have been extensive laboratory studies, numerical simulations, and field applications of CO 2 EOR processes [1,[3][4][5][6]. The mechanisms affecting the displacement of oil by CO 2 injection include oil swelling, IFT (interfacial tension), and viscosity reduction as well as increasing the injectivity index due to solubility of CO 2 in water and subsequent reaction of carbonic acid with the minerals [7][8][9].…”

Evaluation of Asphaltene Stability During CO2 Flooding at Different Miscible Conditions and Presence of Light Components

“…Hamouda et al (2009) reported higher oil recovery due to better sweep efficiency in cores with higher deposited asphaltene. Among proposed models, none of them can predict asphaltene precipitation which could results to divergence of CO 2 streamlines and higher sweep efficiency.…”

“…They have shown that at specific pressure and for specific live oil, CO 2 addition increases the asphaltene stability less than the crossover temperature, while above this point, the asphaltene is more unstable when the CO 2 concentration is increased. Hamouda et al (2009) derived a modified solubility equation to take to account the effect of dissolved CO 2 fraction on asphaltene precipitation. The model considers the volume occupied by one mole of CO 2 and fluid as a function of the solubility parameter of the fluid.…”

Experimental Study and Performance Investigation of Miscible Water-Alternating-CO2Flooding for Enhancing Oil Recovery in the Sarvak Formation

“…Theoretical investigations on the application of CO 2 for EOR started in the early 20th century (Rogers and Grigg, 2000). Over the past few decades, extensive laboratory studies, numerical simulations, and field applications of CO 2 -EOR processes have been reported (Burke et al, 1990;Grigg and Schecter, 1993;Idem and Ibrahim, 2002;Moritis, 2006;Chukwudeme and Hamouda, 2009;Hamouda et al, 2009;Manrique et al, 2010;Enick and Olsen, 2012). Several CO 2 -EOR methods have been suggested and developed, such as continuous CO 2 flooding and Water-Alternating-CO 2 (CO 2 -WAG) flooding under immiscible and miscible displacements.…”