Experimental study on the stability of the foamy oil in developing heavy oil reservoirs

Enhanced heavy oil recovery in thin reservoirs using foamy oil-assisted methane huff-n-puff method

“…That is to say, a higher initial solution GOR is achieved prior to the production cycle of the FOAM H-n-P process, which is more beneficial for forming foamy oil and thereby inducing foamy oil flow. The same conclusion was previously obtained in the literature, in which the effect of the initial solution GOR on the performance of primary production in foamy oil reservoirs was studied [29,30,35]. In addition, the foaming agent solution can more readily finger deeper into the heavy oil when the methane slug size is larger, promoting greater contact of the foaming agent solution and fresh heavy oil, and thereby prolonging the functioning time of the foaming agent in the reservoir by avoiding being produced earlier from the production end at the beginning of the production cycle.…”

“…This new experimental procedure allows for visual observation of the foamy oil behavior, convenient evaluation of foamy oil stability, and offers significant advantages over previous methods alluded to in the Introduction, specifically: (1) it does not involve a tedious experimental process (live oil reconstitution and pressure depletion) nor a complex experimental setup (high pressure cell equipped with a glass window); (2) the parameters, such as half-life time, were measured when the foam formation was stopped completely, unlike previous experiments, in which the foamy oil was formed by the release of the solution gas, resulting in continuous foam formation during the foamy oil volume decay period; and, (3) the effect of gas bubble size and degree of dispersion on foamy oil stability can be investigated by this experimental procedure [28][29][30].…”

“…Then, the system pressure was reduced to create gas bubbles, which dispersed in the liquid oil phase, forming a foamy oil. The influence of various factors on foamy oil stability was observed through the visual window of the cell [28][29][30]. The experimental results obtained in previous research show that: (1) foamy oil stability increases with higher oil viscosity, higher dissolved gas content, and higher pressure depletion rate, and decreases with higher temperatures; (2) asphaltene content does not have much impact on foamy oil stability; and, (3) foamy oil appears to be more stable in porous media (actual reservoir conditions) than in a bulk vessel or vessels with larger pore sizes.…”

Diffusion coefficients of natural gas in foamy oil systems under high pressures

“…Once below the equilibrium bubble point pressure, the producing gas-oil ratio (GOR) increases slowly, and a higher primary recovery factor (5 %-25 %) than expected has been reported from some of those reservoirs (Guan et al 2008;Mu et al 2009;Mu 2010;Li et al 2012;Liu et al 2013b). The most plausible explanation of this anomalous behavior appears to be the foamy oil phenomenon.…”

Experimental study and new three-dimensional kinetic modeling of foamy solution-gas drive processes

“…In addition, the oil production rates and oil recovery were reported to be significantly higher than the oil production rates and oil recovery that are expected from solution gas drive theory 5–7 . The most plausible explanation of the unusual production behavior is “foamy-oil” flow 8–12 , which is a different form of two-phase flow, in which the released gas flows in the form of dispersed bubbles instead of flowing as a continuous phase.…”