**3. Result and discussion**

The analysis of nuclear magnetic resonance (NMR) spectroscopy of SLS surfactant showed that the surfactant consisted of monomer structure having methoxyl and hydroxyl substituted benzene as well as the presence of sulfonate and aliphatic hydroxyl groups. Therefore, according to NMR spectrum analysis, it can be deduced that the monomer of synthesized surfactant has empirical formula of (C11H16O8S)n with relative molecular weight of 308.06. The exact molecular weight

*Surfactant Flooding for EOR Using Sodium Lignosulfonate Synthesized from Bagasse DOI: http://dx.doi.org/10.5772/intechopen.88689*


**Table 4.**

*Enhanced Oil Recovery Processes - New Technologies*

After the core is saturated with crude oil, the first process begins with water injection and then proceeds with injection of surfactant, as shown below

*Scheme of surfactant injection using SLS surfactant synthesized from bagasse [11].*

The analysis of nuclear magnetic resonance (NMR) spectroscopy of SLS surfactant showed that the surfactant consisted of monomer structure having methoxyl and hydroxyl substituted benzene as well as the presence of sulfonate and aliphatic hydroxyl groups. Therefore, according to NMR spectrum analysis, it can be deduced that the monomer of synthesized surfactant has empirical formula of (C11H16O8S)n with relative molecular weight of 308.06. The exact molecular weight

**58**

(**Figure 7**).

**Figure 7.**

**Figure 6.**

*Core flood apparatus [11].*

**3. Result and discussion**

*Results of FTIR of SLS surfactant synthesized from bagasse [2].*

of the synthesized surfactant should be further determined using mass spectrometry measurement. The monomer of the synthesized SLS has a hydrophilic–lipophilic balance value of 11.6 which can be classified as O/W emulsion [12, 13], which means that the SLS surfactant is water soluble. Thus, the SLS surfactant derived from bagasse can be used as an injection fluid and formed middle-phase emulsion that is required in surfactant injection performance.

The results of the Fourier-transform infrared test on bagasse SLS surfactant have shown the existence of components contained in the SLS surfactant which consists of four main components forming lignosulfonic surfactants: alkene stretching groups, sulfonate stretch groups, carboxylic buckling groups, and ester buckling groups with wave numbers from the results of the FTIR [2]. As shown in **Table 4**, it turns out that the wave numbers in the SLS bagasse surfactant component have similarities with the same component wave number for standard lignosulfonic surfactants, namely, standard lignosulfonates from Aldrich and Patricia [14].

Before the characteristics of SLS surfactant synthesized from bagasse was carried out, the physical properties of the SLS surfactant were first measured. The physical properties of the SLS surfactant measured included the viscosity, density, and pH of the SLS surfactant at various proportions of the composition to be used in the injection. The measurement results can be seen in **Table 5**.

From the measurement of physical properties, it turns out SLS surfactant solution in various proportions has physical properties that are almost the same as the viscosity data range 1.5350–1.8375 cP, density 0.9970–1.0657 g/cc, and pH 5.91–6.67. The physical properties of this surfactant are in accordance with the characteristics of the surfactant as described previously.

The characteristic test of the bagasse SLS surfactant consists of:


From the characteristic test, some of the properties of SLS surfactant from bagasse can be known as seen in **Table 6**.


### **Table 5.**

*The physical properties of the SLS surfactant synthesized from bagasse [11].*


### **Table 6.**

*Characteristic test results in various variations of SLS surfactant concentrations [11].*


### **Table 7.**

*IFT and contact angle to recovery oil by SLS surfactant injection of bagasse (concentration of surfactant 1.5%).*

In this research, the surfactant composition of 4.5% of SLS surfactant in 80,000 ppm NaCl gave the lowest IFT value of 1.091 mN/m. From the characteristic test, SLS surfactant synthesized from bagasse has aqueous stability, is clear, and does not cause turbidity. It has a hydrophilic–lipophilic balance value of 11.6 which is classified as oil in water emulsion and can form microemulsion with light oil. This SLS surfactant has middle-phase emulsion with volume fraction of 1–10% microemulsion and IFT of 1.091–6.81 mN/m.

Surfactant injection processes in this research using a variety of concentrations using a variety of concentrations and salinities have shown in **Table 7** and **Figure 8** the contour of relation between salinity and IFT to recovery factor.

### *Surfactant Flooding for EOR Using Sodium Lignosulfonate Synthesized from Bagasse DOI: http://dx.doi.org/10.5772/intechopen.88689*

From **Table 7**, optimal enhanced oil recovery reaches 10.71% at a concentration of surfactant of 1.5% and 80,000 ppm of surfactant solution. From the oil recovery data, the salinity proportion of 10,000 ppm of 1.5% oil recovery with surfactant injection (RF SF) reached 9.25% with stable middle-phase emulsion up to 10% and IFT value of 2.73 mN/m (**Table 6**). This is consistent with the theory that surfactants serve to lower IFT causing a breakdown of the water-to-water interfacial tension resulting in emulsions being formed up to 10% because they are soluble in oil and water. This microemulsions cause the SLS surfactant to produce the lowest value interfacial tension IFT 2.73 mN/m [15].

From **Figure 8**, in the relation contour between salinity and IFT, there are two areas: high recovery factor (red–orange color) and low recovery factor (purple– blue color). **Figure 8** and **Table 7** explain that at low salinity, 10,000 ppm (1.5% surfactant), the recovery factor is 9.25% and at high salinity, 80,000 ppm (1.5% surfactant), the recovery factor is 10.71%. These are the highest recovery factors at this surfactant injection using SLS surfactant synthesized from bagasse. The lowest recovery factor occurs at 40,000 ppm, only 1.80%. The results of injection of core using SLS surfactant from bagasse at concentration of 1.5% can be seen in **Table 7**.

Furthermore, the surfactant with the optimum composition has been tested toward its static and dynamic adsorptions. At the same surfactant concentration in different salt contents, it showed that the higher the salt content, the lower the adsorption value, which means that the surfactant is less absorbed into the rock when the surfactant was injected to the core. Since the less surfactant was

### **Figure 8.**

*Enhanced Oil Recovery Processes - New Technologies*

**Surfactant concentration (%)**

*The physical properties of the SLS surfactant synthesized from bagasse [11].*

*Characteristic test results in various variations of SLS surfactant concentrations [11].*

**Concentration surfactant (%)**

 5000 1.5 6.81 7.00 10,000 1.5 2.73 9.25 20,000 1.5 4.13 8.55 40,000 1.5 4.11 1.80 80,000 1.5 3.61 10.71

**Aqueous stability**

> **IFT (mN/m)**

1. 10,000 1.5 Clear 10.00 2.73 2. 10,000 3.0 Clear 7.50 1.68 3. 20,000 1.5 Clear 5.00 4.13 4. 20,000 4.5 Clear 0.00 1.27 5. 40,000 1.5 Clear 6.00 4.11 6. 40,000 4.0 Clear 0.00 2.72 7. 80,000 1.5 Clear 1.25 3.61 8. 80,000 4.5 Clear 1.00 1.09

**No. Surfactant composition Viscosity (cP) Density (g/cc) pH** 10,000 ppm—1.5% 1.5350 1.0003 6.39 10,000 ppm—3.0% 1.5443 1.0113 6.67 20,000 ppm—1.5% 1.6877 1.0069 5.91 20,000 ppm—4.5% 1.5757 1.0280 6.56 40,000 ppm—1.5% 1.6697 1.0189 6.12 40,000 ppm—4.0% 1.7724 1.0367 6.46 80,000 ppm—1.5% 1.7630 1.0438 5.86 80,000 ppm—4.5% 1.8375 1.0657 4.38

> **Middle emulsion (Stability) %**

**Recovery factor from surfactant flooding (%)**

**IFT (mN/m)**

**No. Salinity (ppm)**

**No. Salinity** 

**(ppm)**

**Table 6.**

**Table 7.**

**Table 5.**

In this research, the surfactant composition of 4.5% of SLS surfactant in 80,000 ppm NaCl gave the lowest IFT value of 1.091 mN/m. From the characteristic test, SLS surfactant synthesized from bagasse has aqueous stability, is clear, and does not cause turbidity. It has a hydrophilic–lipophilic balance value of 11.6 which is classified as oil in water emulsion and can form microemulsion with light oil. This SLS surfactant has middle-phase emulsion with volume fraction of 1–10% micro-

*IFT and contact angle to recovery oil by SLS surfactant injection of bagasse (concentration of surfactant 1.5%).*

Surfactant injection processes in this research using a variety of concentrations using a variety of concentrations and salinities have shown in **Table 7** and **Figure 8**

the contour of relation between salinity and IFT to recovery factor.

**60**

emulsion and IFT of 1.091–6.81 mN/m.

*Relation contour between salinity and IFT to recovery factor [11].*


### **Table 8.**

*The result of static and dynamic adsorption test [15].*

absorbed into the core, it means that more surfactants were available and capable to decrease the interfacial tension between oil and water; therefore the more oil can be produced by the surfactant injection. Wettability test results also showed that the higher salt content produces a larger contact angle which means the system becomes more water wet. These conditions have made the synthesized SLS surfactant derived from bagasse more dissolved in formation water to release grains of oil attached to the core. From the injection process, the composition of surfactant, with a salinity of 1.5% (80,000 ppm), showed the highest oil recovery value up to 10.71%, compared to the other composition. Therefore, the surfactant concentration and salinity affected many factors related to the performance of SLS surfactant of bagasse displacement on light oil.

At the low area recovery factor, the composition of surfactant, with a salinity of 1.5% (40,000 ppm), showed the lowest oil recovery value of 1.80%. At this condition, the value of IFT is 4.11 (mN/m). This value can explain that for this area, they are insoluble for oil and water, so that oil does not move easily. Besides IFT, there are other factors that affect the mechanism surfactant during the surfactant injection process. The other factor is adsorption. **Table 8** indicates the static and dynamic adsorptions of this SLS surfactant on the core surface at the high and the low salinities.

At this salinity of 20,000 ppm, the static adsorption is 20.533%, and the dynamic adsorption is 29.16%. This adsorption is higher than the adsorption at 80,000 ppm. From **Table 7**, recovery factor of the higher adsorption (salinity 40,000 ppm) is 1.80%, and for the lower adsorption (salinity 80,000 ppm), recovery factor is 10.71%. Due to the large amount of adsorption that occurs on the core, the amount of surfactant decreases, so that the surfactant mechanism also decreases. The lower mechanism of surfactant results in a decrease of recovery factor.
