Sodium Lignosulfonate (SLS) Surfactant Formulation to Improve Oil Recovery


Sodium lignosulfonat is an anionic surfactant that has good potential for enhanced oil recovery (EOR). Surfactants based on sodium lignosulfonate (NaLS) are selected because they can be synthesized from renewable materials, available raw materials, relatively cheaper than other surfactants, and are environmentally friendly.

Previous studies on SLS for the EOR show Sodium lignosulfonate performance not yet optimum, so it needs to be formulated to improve its performance. The formulations applied in this study were the addition of sodium oleate as cosurfactant and ethylene glycol butyl ether (EGBE) as dispersants, with a ratio of 80% of Sodium lignosulfona surfactants: 16% sodium oleate: 4% EGBE. Tests conducted in this study included the Sodium lignosulfona surfactant compatibility test in the laboratory scale and continued to the coreflooding test. The compatibility test consisted of aqueous stability test, phase behavior test, and interfacial tension test (IFT) with three test concentrations. All testing was done for light oil reservoir.

The Sodium lignosulfona surfactant solution before formulation showed the two phases in aqueous stability test and high IFT in 10 -1mN/ m while after formulation the IFT reached 10 -3 mN/ m. The phase behavior before and after formulation showed the same performance, in low concentration had lower phase and in high concentration had middle phase. The incremental recovery from coreflood test using 0.5 % and 1 % concentration of SLS formulation were 34.09 % and 37.5 % respectively. The results showed that SLS surfactant can be good candidate for chemical EOR.

Surfactant injection is one of the enhanced oil recovery (EOR) methods to improve oil recovery. The screening characteristics of reservoir to chemical injection are moderate oil which have օAPI> 20 and its viscosity <35 cp.

Chemical injection is more applicable to sandstone formations with permeability >10 mD, well depth <9000 ft, and temperature <200 oF [1-2]. To improve the optimum recovery of oil, many laboratory studies should be carried out, such as solubility test, phase behavior test, and interfacial tension test. Surfactant or surface-active agent is a chemical compound that can reduce the surface tension between two fluids.

The Sodium lignosulfona surfactant will change the interfacial tension significantly . The type of surfactant that is often used in surfactant injection is anionic and nonionic type. Anionic are used because they are relatively stable and show a low tendency to be absorbed by reservoir rocks.

Nonionic species are often used as co-surfactants to improve surfactant efficiency in surfactant injection processes. Nonionic has greater resistance to high salinity levels, but the ability to reduce its IFT is less efficient than anionic. Cationic is not used in the injection process due to its tendency to be adsorbed by higher
reservoir rocks.

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