**4.1 Drainage of film**

In film drainage process the lamella undergoes a thin method. Which goes toward the super thin or rupture of liquid films.it is also called structure of black spot. Gravity drainage and capillary suction can be done by two means. The drainage of gravity is usually occur in lamella that is thick .in this process due to

the gravity the film is moved downward .we can slow this process by decreasing the liquid in the foam and increasing the bulk viscosity. The two indicators are the lamella's time to reach the crucial broadness and the limited broadness beneath which the lamella coalesces. The signals reliant on different factors like viscosity, surfactant solubility, elasticity of surface, adsorption on the plane and ratio of gas to liquid. Usually as the attentiveness of the surfactant extended, the critical thickness decreases [14, 15].

#### **4.2 Gas diffusion**

With the side pressure of lamella could not be equal so the gas is dissolved in lamella the by diffusion it escape .it is common when the porous media trapped the bubbles. When the moving lamella is reshaped continuously then the inter bubble diffusion is complicated. In high flow rates the gas diffusion may be negligible. The main foam film drainage tool is capillary drainage. The reason of the occurrence is the capillary tube (at plateau border suction). The curvature at centre of film is comparatively higher than the radius of the curvature at the plateau border. The reason is the fact at the middle of foam lamella the film border is nearly equal. While, at plateau boundary, the curvature is further curved [16].

#### **4.3 Oil effect**

The oil-foam contacts are significant as the oil occurrence has incompatible belongings on stability of foam. However, the damaging consequence on spume strength by the oil is prevalent. Oil interaction with surfactant creates some problems like it causes in lamellae liquid depletion which brings alteration in wet ability and this scattering of oil on lamella become reasons for destabilisation of the interface. Surfactant and oil solution makes the emulsion and they break the structure of foam. Three coefficients typically used to describe the mechanisms of oil destabilising foam. The spreading coefficient, S: the entering coefficient E, and the bridging coefficient B. Coefficients are described as: [17–21].

Spreading (S), entering (E), and bridging (B) coefficients are described to assess the possibility of oil droplet to enter the gas-water surface. Eqs. 1–3 explaining the foam destabilisation.

$$\mathbf{E} = \boldsymbol{\sigma}\_{\text{gw}} + \boldsymbol{\sigma}\_{\text{ow}} + \boldsymbol{\sigma}\_{\text{og}} \tag{1}$$

$$\mathbf{S} = \boldsymbol{\sigma}\_{\text{gw}} - \boldsymbol{\sigma}\_{\text{ow}} - \boldsymbol{\sigma}\_{\text{og}} \tag{2}$$

$$\mathbf{B} = \boldsymbol{\sigma}^2 \boldsymbol{\ll}\_{\text{gw}} + \boldsymbol{\sigma}^2 \boldsymbol{\ll}\_{\text{ow}} + \boldsymbol{\sigma}^2 \boldsymbol{\ll}\_{\text{og}} \tag{3}$$

**143**

problems.

*CO2-Philic Surfactants Structural Morphology Prerequests for CO2 Philicity for Foam Durability…*

The stability of foam depends on temperature. A high temperature results in decreased foam drainage time and therefore causing the foam stability decrease

The generation is not the serious challenge alone; the important ones are foam quality, form and its stableness mainly when it is in proximity with oil. Surfactants is used for foam spread have low endurance with salinity and results in extreme adsorption on carbonate rocks. The surfactants are capable of playing central roles in enhancement of oil recovery, not only in foam generation but also in IFT reduction. The modern type of surfactants CO2-phillic surfactants are used for CO2 control application movability and for the stability of foam in the creation. As the traditional surfactants, these have two surfactants that have well defined areas, tail and head; nonetheless, surfactants tail has a capability for stabilising the CO2 gas. The reference of foam stability, surfactants that are non-iconic are minor but their stability at high temperatures is a problem. A foam usually absorbs on the rock matrix, deteriorates over time, and has a higher deterioration at high temperatures in the existence of oil. When the Carbon dioxide gas is used the problems become more severe. This phenomena was particularly created to produce fresh surfactants with an affinity for CO2 gas under controlled conditions and to defeat the problems that arise from traditional surfactants. The surfactants novel can produce much balance spume at a higher temperature and in the existence of oil with less adaption

**5. Role of surfactant in foam generation and stability**

**6. Problems with conventional surfactants in foam stability**

The creation of spume, alone, is not a serious problem; the highlighted ones are quality of spume, formation of spume and its balance is particularly when it is in contact with oil. The surfactants used for spume creation have low endurance with salinity and result in extreme adaption on rocks of carbonate. With reference to stability of foam, the surfactants of non-ionic are lesser but the problem is their

*DOI: http://dx.doi.org/10.5772/intechopen.90994*

**4.4 Effect of temperature**

*Oil destabilising foam mechanism.*

**Figure 3.**

with the temperature increase.

where, σgw, σow, and σog stand for gas/water, oil/water, and gas/oil surface.

If the E, entering coefficient is in positive, a drop of oil is predicted to be drawn up in the lamellar area among two bubbles. This will breaching the air/water interface causes the film to drop the foam become stable ability and skinny to rupture point. When bridging coefficient, B, is positive, the oil droplet bridges the lamellar area among the two neighbouring bubbles. When the spreading coefficient, S, is positive, the droplet of oil in the lamella area is predicted to extent like a lens above a foam. The extent of a droplet of oil above a foam lamella reasons the lamella's foam to break (**Figure 3**).

*CO2-Philic Surfactants Structural Morphology Prerequests for CO2 Philicity for Foam Durability… DOI: http://dx.doi.org/10.5772/intechopen.90994*

**Figure 3.** *Oil destabilising foam mechanism.*

*Analytical Chemistry - Advancement, Perspectives and Applications*

ness decreases [14, 15].

**4.2 Gas diffusion**

**4.3 Oil effect**

foam destabilisation.

the gravity the film is moved downward .we can slow this process by decreasing the liquid in the foam and increasing the bulk viscosity. The two indicators are the lamella's time to reach the crucial broadness and the limited broadness beneath which the lamella coalesces. The signals reliant on different factors like viscosity, surfactant solubility, elasticity of surface, adsorption on the plane and ratio of gas to liquid. Usually as the attentiveness of the surfactant extended, the critical thick-

With the side pressure of lamella could not be equal so the gas is dissolved in lamella the by diffusion it escape .it is common when the porous media trapped the bubbles. When the moving lamella is reshaped continuously then the inter bubble diffusion is complicated. In high flow rates the gas diffusion may be negligible. The main foam film drainage tool is capillary drainage. The reason of the occurrence is the capillary tube (at plateau border suction). The curvature at centre of film is comparatively higher than the radius of the curvature at the plateau border. The reason is the fact at the middle of foam lamella the film border is nearly equal.

The oil-foam contacts are significant as the oil occurrence has incompatible belongings on stability of foam. However, the damaging consequence on spume strength by the oil is prevalent. Oil interaction with surfactant creates some problems like it causes in lamellae liquid depletion which brings alteration in wet ability and this scattering of oil on lamella become reasons for destabilisation of the interface. Surfactant and oil solution makes the emulsion and they break the structure of foam. Three coefficients typically used to describe the mechanisms of oil destabilising foam. The spreading coefficient, S: the entering coefficient E, and

Spreading (S), entering (E), and bridging (B) coefficients are described to assess the possibility of oil droplet to enter the gas-water surface. Eqs. 1–3 explaining the

B =σ +σ +σ gw ow og

where, σgw, σow, and σog stand for gas/water, oil/water, and gas/oil surface. If the E, entering coefficient is in positive, a drop of oil is predicted to be drawn up in the lamellar area among two bubbles. This will breaching the air/water interface causes the film to drop the foam become stable ability and skinny to rupture point. When bridging coefficient, B, is positive, the oil droplet bridges the lamellar area among the two neighbouring bubbles. When the spreading coefficient, S, is positive, the droplet of oil in the lamella area is predicted to extent like a lens above a foam. The extent of a droplet of oil above a foam lamella reasons the lamella's foam

E =σ +σ +σ gw ow og (1)

S =σ −σ −σ gw ow og (2)

<sup>222</sup> (3)

While, at plateau boundary, the curvature is further curved [16].

the bridging coefficient B. Coefficients are described as: [17–21].

**142**

to break (**Figure 3**).
