Lignin from paper waste in interefacial tension (IFT) reduction for oil displacement

Abstract

This study focusses on lignin potential in reducing interfacial tension (IFT) where primary and secondary recovery only recovers minimal amount of oil in most cases and leaving behind substantial amount of oil in place unrecovered. Commercial surfactant flooding had been used to address this issue which yielded promising result at the expense of more monetary investment. The preparation of sulfonate based anionic surfactants is complex and costly. Many surfactants have been produced from edible oils, such as soybean and coconut oil, which are more expensive compared with synthetic surfactants. Some studies reported starch as a feedstock for producing surfactants but these surfactants are problematic given they would compete with food source if they became commercialized. Lignosulfonate surfactant ability in reducing the interfacial tension is yet to be tested. Lack of research regarding the effect on lignosulfonate based surfactant or co surfactant at different conditions and also whether lignosulfonate works well with alkali. Hence in case if lignin can reduce IFT then this would be one of the best method for enhanced oil recovery. Lignin extracted from paper waste is a waste product and can be procured with less cost and reduces waste at the same time. The powdered lignin based on the post-extraction treatment will be mixed with alkali to form an alkalized lignin solution. The experiment was conducted at a constant temperature of 500 C and ambient pressure. The temperature is representative of reservoir temperature in Malaysia with neglected pressure effect due to the known fact of IFT independency of pressure. The experiments run by using Goniometer using rising upward method. There are altogether 15 sets of run including base case with no alkalized lignin, lignin without alkalization, alkalized lignin with commercial surfactant which was to test the role of lignin as co-surfactant, lignin with varying alkali concentration and control case of only commercial surfactant. The final cases was brine with only alkali to fully understand that the IFT reduction obtained is contributed by lignin not alkali. Each measurement approximately took 2 hours to complete and gave the mixing of alkali and brine. As a matter of general comparison, there were 5 distinct results. The base case without any surfactant yield. The lignin without alkali. The critical micelle saturation (CMC) was found in this case where further lignin concentration did not cause any decrement in IFT values. The non-alkalized lignin that gives effect for the IFT reduction. Despite of producing lower IFT reduction, the significant difference in manufacturing costs of these two surfactant gave more edge to lignin as an alternative for commercial surfactant. Thus, the proven potential of lignin gave an alternative to costly surfactant and also reduce the amount of harmful waste product as well. The displacement of oil with best IFT is determined and can be applied for the oil and gas industry. Finally the potential of lignosulfonate to act as a co-surfactant also can be practiced and used widely for the benefit of the oil and gas industry.