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U. S. Behera and J. S. Sangwai
more attractive alternative to replace traditional chemical methods of improved oil
recovery. A new concept for plugging is developed by biomineralization to form
calcite cement layer in carbonate formations (Sheehy 1991). This concept relates to
microbacteria generated from the indigenous reservoir through nutrient manipulation. Field-scale application on this concept needs to improve technically. From this
literature studies, we can say that there is a lot of scopes to research in this field.
An experiment was conducted in the laboratory to see the effect of silica nanoparticles with biosurfactant on interfacial tension. To view the influence, three different
types of solutions were prepared, namely, distilled water-nanosilica, distilled waterbiosurfactant, and distilled water-nanosilica with biosurfactant (Khademolhosseini
et al. 2015). The oil recovery for the individual sample is reported as 19%, 29%, and
52%, respectively. This indicates oil recovery is highly influenced by the presence
of silica nanoparticles with biosurfactant.
6 Gas Injection Method
Gas injection is a type of secondary or tertiary oil recovery method in which miscible
gas is injected into the crude oil reservoirs. Gas injection method is adopted for a
medium pressure reservoir. Miscible gases such as hydrocarbon carbon (methane)
and non-hydrocarbon gases (nitrogen or carbon dioxide) injection into the reservoir
help in maintaining partially or completely the reservoir pressure. In addition to
balancing the reservoir pressure, soluble gases in the oil result in swelling of oil
and increase the oil mobility which expand oil recovery. Gas injection methods are
mostly applicable to the oil reservoir unsaturated with hydrocarbon gas for effective
result. Recovery efficiencies increase with continued gas injection, but the rate of
recovery diminishes after gas breakthrough occurs as the gas–oil ratio increases. Nonhydrocarbon gases can also be used provided they should not have any contribution
in imparting corrosion and should be separable easily.
The most successful immiscible gas injection projects are the vertical gravity
drainage projects in which gas is injected into the crestal primary or secondary gas
cap, with the oil wells producing from as far downdip as possible to maximize this
distance from the gas cap both vertically and laterally. The pictorial view of the gas
injection process is represented in Fig. 12.
Gas injections well are potentially used to inject gas (miscible-CO 2 or immiscibleN 2 ) into the reservoir to push the oil to a producing well. A case study can be
discussed to better understanding the process. Bender and Akin (2017) mentioned
that a field-scale study was conducted for few years to know the production ability
of pure carbon dioxide (CO 2 ) and flue gas (CO 2 + N 2 + SOx + NOx). It was found
that the production rate of CO 2 was more than flue gas due to its solubility over
the same period. According to the authors, pressurizing the reservoir with flue gas
injection followed by pure CO 2 injection may improve the production and can make
the process more economical. For heavy oil reservoir gas injection process is applied
rarely. However, this is one of the best methods in which CO 2 and flue gases can be
U. S. Behera and J. S. Sangwai
more attractive alternative to replace traditional chemical methods of improved oil
recovery. A new concept for plugging is developed by biomineralization to form
calcite cement layer in carbonate formations (Sheehy 1991). This concept relates to
microbacteria generated from the indigenous reservoir through nutrient manipulation. Field-scale application on this concept needs to improve technically. From this
literature studies, we can say that there is a lot of scopes to research in this field.
An experiment was conducted in the laboratory to see the effect of silica nanoparticles with biosurfactant on interfacial tension. To view the influence, three different
types of solutions were prepared, namely, distilled water-nanosilica, distilled waterbiosurfactant, and distilled water-nanosilica with biosurfactant (Khademolhosseini
et al. 2015). The oil recovery for the individual sample is reported as 19%, 29%, and
52%, respectively. This indicates oil recovery is highly influenced by the presence
of silica nanoparticles with biosurfactant.
6 Gas Injection Method
Gas injection is a type of secondary or tertiary oil recovery method in which miscible
gas is injected into the crude oil reservoirs. Gas injection method is adopted for a
medium pressure reservoir. Miscible gases such as hydrocarbon carbon (methane)
and non-hydrocarbon gases (nitrogen or carbon dioxide) injection into the reservoir
help in maintaining partially or completely the reservoir pressure. In addition to
balancing the reservoir pressure, soluble gases in the oil result in swelling of oil
and increase the oil mobility which expand oil recovery. Gas injection methods are
mostly applicable to the oil reservoir unsaturated with hydrocarbon gas for effective
result. Recovery efficiencies increase with continued gas injection, but the rate of
recovery diminishes after gas breakthrough occurs as the gas–oil ratio increases. Nonhydrocarbon gases can also be used provided they should not have any contribution
in imparting corrosion and should be separable easily.
The most successful immiscible gas injection projects are the vertical gravity
drainage projects in which gas is injected into the crestal primary or secondary gas
cap, with the oil wells producing from as far downdip as possible to maximize this
distance from the gas cap both vertically and laterally. The pictorial view of the gas
injection process is represented in Fig. 12.
Gas injections well are potentially used to inject gas (miscible-CO 2 or immiscibleN 2 ) into the reservoir to push the oil to a producing well. A case study can be
discussed to better understanding the process. Bender and Akin (2017) mentioned
that a field-scale study was conducted for few years to know the production ability
of pure carbon dioxide (CO 2 ) and flue gas (CO 2 + N 2 + SOx + NOx). It was found
that the production rate of CO 2 was more than flue gas due to its solubility over
the same period. According to the authors, pressurizing the reservoir with flue gas
injection followed by pure CO 2 injection may improve the production and can make
the process more economical. For heavy oil reservoir gas injection process is applied
rarely. However, this is one of the best methods in which CO 2 and flue gases can be