Spontaneous Emulsification Aspect Of Enhanced Oil Recovery

Abstract

Recent studies have suggested the possibility of spontaneous emulsification as a mechanism for enhanced oil recovery (EOR). The discussions have, however, remained essentially qualitative. A study was therefore undertaken to estimate quantitatively the contribution of spontaneous emulsification as an EOR mechanism. The tests were conducted on several bulk liquidlliquid systems as well as by displacement experiments in unconsolidated synthetic sand packs. Spontaneous emulsification was found to be a mechanism for EOR: the estimated extra contribution to EOR due to this mechanism was found to be significant in laboratory scale displacement experiments. Tertiary recovery was always greater when spontaneous emulsification was evident than otherwise. Results of tests on bulk liquidlliquid systems indicate that the occurrence or absence of spontaneous emulsification can be correlated with the values of 'partition parameter'. It may be concluded that higher oil recoveries may be achieved in chemical EOR processes where interface mass transfer (and the accompanying spontaneous emulsification) occurs. The evaluation of efficiency of residual oil mobilisation through the capillary number theory (with and without spontaneous emulsification) is also discussed. Displacement tests with spontaneously emulsifying systems showed that residual oil left behind a conventional waterflood was mobilised in a range of capillary numbers much less than that which applies to low-tension waterfloods.

Numerical Simulation of Displacement Mechanisms for Enhancing Heavy Oil Recovery during Alkaline Flooding

“…During the alkaline flooding process, reactions between the acids in the crude oil and alkaline solution result in the generation of surface-active substances, which reduce the interfacial tension at the oil−water interface and, consequently, produce the W/O emulsions in situ . The W/O emulsion lowers mobility of the injected water, delays viscous fingering, and finally blocks the flow of the injected water. ,, The flow blockage leads to a higher pressure gradient to mobile and displace the trapped oil out . The presence of W/O emulsion in the high-permeability zone causes an increase in both pressure drop and oil production. − ,, …”

From Mineral Surfaces and Coreflood Experiments to Reservoir Implementations: Comprehensive Review of Low-Salinity Water Flooding (LSWF)

“…In LSWF studies, AFM can and has been used to investigate surface charges and surface forces such as Van Der Waal forces, Debye interaction, adhesion of polar and nonpolar oil compounds, and hydrophobic interactions . The ζ potential, which is a measure of stability of dispersion in particle suspension and liquid emulsions, can investigate electrokinetic effects, double-layer expansion, colloidal stability, and solid–liquid interfaces. , Moving to the micrometer scale, micromodelling experiments are useful for examining oil–brine interactions, − foam–oil interactions, porous media flow, , and, in some cases, fines migration . These may involve a change in salinity gradient in the presence of an oleic phase, known as osmosis, or the formation and subsequent migration of oil-in-water emulsions from bulk phase to the oil–water interface .…”

Surfactant Stabilized Oil-in-Water Nanoemulsion: Stability, Interfacial Tension, and Rheology Study for Enhanced Oil Recovery Application

“…An in situ surfactant generated by alkali in the reservoir after reacting with the natural acid components of oil partly alters the wettability of rock. , The most probable mechanism of wettability alteration by surfactants is (1) surfactant adsorption (coating mechanism) onto the oil-wet solid surface and (2) surfactant molecules complexing with contaminant molecules from the crude oil which are adsorbed on the rock surface so as to strip them off (cleaning mechanism). , But due to the inconveniences caused in chemical methods such as loss of expensive surfactants in the form of sorption and retention in the reservoir, high project cost and decreasing oil prices affect the process efficiency and pose problems in its application. , Therefore, development of cost-effective EOR techniques is necessary for sustainable recovery. Application of emulsion as an EOR agent has been reported in earlier studies . The low oil recoveries because of poor emulsion stability caused by the coalescence of droplets has limited its use. , Thus, the use of nanotechnology in emulsions can be a breakthrough in EOR, as it has the potential to revolutionize the current scenario of oil production from the matured oil fields .…”