Abstract: Over the last few decades, there has been a dispute regarding the ability of colloidal dispersion gels (CDG) to improve sweep efficiency more than polymer flooding. In this study, a numerical model was built using the CMG-STARS simulator to investigate the behavior of injecting 0.1 PV of CDG slug into one quarter of inverted nine-spot pattern. This slug was composed of 0.1 wt. % HPAM polymer solution with a polymer-to-crosslinker ratio (P/X) of 50/1. The model was represented by a thick heterogeneous reservoir with high water cut caused by high heterogeneity and adverse mobility ratio. Different experimental results from published literatures have been implemented in the numerical model to study the effect of these parameters on the propagation of the CDG. The results confirmed that CDG could propagate deep into the thief zones and reduce their permeability more than polymer solution. Moreover, the results showed that the shear-thinning behavior of CDG could assist the selective penetration into the high-permeability streaks only, thus reducing the cost of isolating the thief zones by mechanical methods. In addition, the results showed that the wettability had tremendous effects on the treatment. Therefore, the water-wet system yielded higher results with less damage to the low-permeability layers compared to the oil-wet system. The results showed an overestimation of the performance of post-treatment water when considering irreversible adsorption of CDG. However, the prolonged injection of post-treatment water would not remove the permeability reduction caused by CDG flooding, even with reversible adsorption. The results revealed that the higher the degradation of the CDG, the lower the recovery factor. The results showed the importance of considering a combination injection of polymer and CDG. The results also revealed that the higher the salinity of the reservoir brine and/or the makeup water, the lower the recovery factor. In addition, as the polymer/crosslinker ratio increases, the recovery factor decreases, while as the polymer hydrolysis increases, the recovery factor and residual resistance factor increases.Abstract: Over the last few decades, there has been a dispute regarding the ability of colloidal dispersion gels (CDG) to improve sweep efficiency more than polymer flooding. In this study, a numerical model was built using the CMG-STARS simulator to investigate the behavior of injecting 0.1 PV of CDG slug into one quarter of inverted nine-spot pattern. This...Show More
Abstract: This paper investigates asphaltic concrete core embankment dam in relative to the clay core embankment dam so that it is vital from the perspective of safety and controlling seepage. Plaxis 8.5, finite element based software was employed for analysis of the dam and Geostudio 2012 for seepage analysis. Relatively the result of analysis shows that good result of safety factor has been found in asphalt concrete core dam with regard to the stability of the dam during steady-state condition and end of construction. During steady-state condition, the factor of safety computed for clay core dam was 1.466, and the dam fails to attain the minimum factor of safety recommended by USACE. But, under this similar condition stability analysis result of asphalt concrete core dam gave a good result of 1.661 which is found within the recommended range. Likewise, at the end of construction, the factor of safety computed for clay core dam was 1.553, but, under this loading condition (end of construction) stability analysis result of asphalt concrete core dam gave a good result of 1.600 which keeps the dam more stable. The seepage analysis result of asphaltic concrete core dam is also insignificant. Generally, application of asphalt concrete core in rock fill dam can fulfill the basic requirement and minimum factor of safety under all loading condition, and dam of such types is seepage free as it shown here and approved by many other researchers’ extensive works.Abstract: This paper investigates asphaltic concrete core embankment dam in relative to the clay core embankment dam so that it is vital from the perspective of safety and controlling seepage. Plaxis 8.5, finite element based software was employed for analysis of the dam and Geostudio 2012 for seepage analysis. Relatively the result of analysis shows that go...Show More
