Application Of Ferrofluids For Enhanced Surfactant Flooding In IOR

Kothari, Nikita (Maharashtra Institute Of Technology) | Raina, Bhavna (Maharashtra Institute Of Technology) | Chandak, Krishna Bijay (U. of Pune) | Iyer, Venkat (U. of Pune) | Mahajan, Hrishikesh Prakash (Pune)

OnePetro 

Abstract:
Improved Oil Recovery (IOR), techniques offer prospects that enhance the displacement of oil from the reservoir, ultimately producing 30 to 60 percent, or more, of the reservoir's original oil in place. The most important criteria in IOR- Surfactant Flooding is to determine if the interfacial tension (IFT) can be reduced enough to produce incremental oil.

One of the key recovery problems in oil-wet reservoir is overcoming the surface tension forces that tend to bind the oil to the rock. In water wet reservoirs, surface tension forces act to create bubbles of oil, which can block pore passages as the bubble resists movement in the increased surface area associated with squeezing through the passages. These surface tension forces are the primary reason why reservoirs become increasingly impermeable to oil, relative to water, as the water saturation increases.

Ferrofluids are a special category of smart nano-materials, in particular magnetically controllable nanofluids. The ferromagnetic nano-particles are coated with a surfactant to prevent their agglomeration. As a result of their composition, Ferrofluids possess a unique combination of fluidity and the capability to interact with a magnetic field. The addition of a surfactant will greatly reduce the Interfacial Tension and in water-wet reservoirs, where oil globules are formed, ferrofluid shatters it. Also, as ferrofluid comes in contact with the reservoir fluid, it interacts with the crude in the reservoir & due to the presence of dipole moment, the reservoir fluid molecules align, thus reducing the resistance to the flow.

To sum up, reduction in Interfacial tension, thus reducing resistance to the flow, can be easily achieved by making use of Ferrofluid-enhanced surfactant. Oil can be made even more polar using Ferrofluid which will act as a better solvent for the surfactant.

Introduction:
Ferrofluid:

A ferrofluid (FF) is a type of smart fluid. It is a suspension of nano-sized magnetic particles in a carrier fluid, usually a type of oil, or water. When subjected to a magnetic field, the fluid greatly increases its apparent viscosity, to the point of becoming a viscoelastic solid. Importantly, the yield stress of the fluid when in its active ("on") state can be controlled very accurately by varying the magnetic field intensity. Although the name may suggest otherwise, ferrofluids do not display ferromagnetism, since they do not retain magnetization in the absence of an externally applied field. In fact, ferrofluids display (bulk-scale) paramagnetism, and are often referred as being "superparamagnetic" due to their large magnetic susceptibility. Permanently magnetized fluids are difficult to create at present.