The demand for energy increases worldwide, while supply from all kinds of alternative energy, nuclear power, renewable energy, as well as the new sources of hydrocarbons still small, so oil and gas still play the key role in the energy market. The resent production technology, including enhanced oil recovery (EOR) can only bring to the surface about 25-30% of the original oil in place (OOIP). The residual oil is trapping in the reservoir due to the surface forces, mainly capillary forces, and partly because of not being swept by injection water. Application of materials and nanotechnology, particularly nano sensors for reservoir surveying and nano liquids, in oil and gas exploration and exploitation is expected to be able to assist in recovering an additional 10-20% of OOIP.

The authors have completed the synthesis and evaluation of various nano-fluid systems on the capabilities in EOR as following:

- The synthesized thermostable nano gel polymer system at 1000 ppm concentration in DNR seawater has showed the EOR potential in ability to improve the viscosity during 31 days aging at temperature of 92oC with increase of > 30% compared to the commercial thermostable polymer AN 125 of SNF, which is being used in RP3 of Vietsovpetro now;

- Have demonstrated that the system of nano-SiO2 dispersion is only capable of lowering the oil-water interfacial tension about 10 times, and the dispersion unstable in the conditions of DNR brine and temperature of 60oC temperature, which is much lower than the DNR reservoir temperature);

- Two systems of nano-SiO2 associated thermostable copolymers were synthesized by the method of reversed microemulsion polymerization. Both are good compatible and having the synergistic impact in IAMS-M2 surfactant solution. The nano- particles are stable dispersed in DNR brine after 31 days aging at temperature of 92oC, the ability to improve the viscosity of the solutions with/without surfactant is higher and more stable than the corresponding commercial polymer AN 125 solution;

- The injection of slug of 1000ppm IAMS-M2 surfactant solution and then continued pumping liquids containing 250ppm of Nano hybrid by volume of 0.25 PV in the DNR core model has given recovery > 20% from the amount of oil trapped in the core after water injection completed, or 6.25% OOIP. In addition to a large amount of additional oil recovered, restored permeability value of about 80%. These results have great potential for applications. In the EOR technology, if after water injection oil residual was <30-35%, will not be applicable any more EOR measures to be technically feasible and economically effective.

- Further study is needed on liquids of nano-hybrid system as well as blend with specific surfactant substance for higher temperature of about 130 ° C, and other reservoir layers as Miocene, Oligoc