Chemical Enhanced Oil Recovery with Water Soluble Poly Ionic Liquids in Carbonate Reservoirs

Abstract

Recovering oil from carbonate reservoirs by waterflooding is often ineffective due to the combination of ineffective sweep and the originally oil-wet nature of that rocks. Ionic liquid monomers and polymers have recently attracted attention as chemical agents for enhanced oil recovery. 2-acrylamido-2- methylpropane sulfonic acid copolymer with methacrylic acid (AMPSA/MAA) diluted in sea water at 3000 ppm was previously screened among other polyionic liquids (PILs) at different concentrations (Abdullah et. al, 2017) and proved to be the most effective enhanced oil recovery chemical. The PIL AMPSA/MAA was tested with sandstone and proved efficient on enhancing oil recovery. In this study, we extend the work to explore the efficiency of such PIL on carbonates. A post-secondary water flooding was conducted and an incremental tertiary recovery of 6% original oil in place (OOIP) corresponding to 12% residual oil in place (ROIP) was obtained indicating the efficiency of the AMPSA/MAA PIL. This carbonate recovery compares to 10% OOIP in sandstone as reported in previous study (Abdullah et. al, 2017). This difference can be attributed to the low permeability characterizing the carbonate sample used in this work in comparison to the sandstone tested earlier. Seawater-crude oil Interfacial tension and contact angle measurements on carbonate substrate were performed at elevated temperature and pressure to investigate the possible recovery mechanisms. Interfacial tension (IFT) resulted in insignificant IFT drop. On the other hand, contact angle measurements confirmed wettability alteration towards more water wet state indicating it as the main recovery mechanism in carbonates.

Mini-review on Recent Advances in the Application of Surface-Active Ionic Liquids: Petroleum Industry Perspective

“…Currently, ILs as green chemicals have gained wide acceptance for potential application in petroleum industries, because of their remarkable properties and versatility. ILs have shown potential in the petroleum industry to enhance the flowability of viscous and bituminous HCOs that could augment oil production and transportation, inhibit paraffin and asphaltene aggregation and precipitation, and inhibit scale formations and in CEOR . ILs are mostly liquid and nonvolatile in nature, they can be tailor made for specific reservoir conditions, and they have shown high tolerance to harsh conditions such as high salinity and elevated temperatures …”

“…ILs having longer alkyl chain substituents (more than eight alkyl chains) are regarded as a novel group of amphiphiles that possesses combined properties of ILs and surfactants. , The ILs enhanced surface activity and characteristic properties of self-assembly makes them superior candidates to explore over conventional ionic surfactants. ILs have shown potential in the petroleum industry to enhance the flowability of viscous and bituminous HCOs that could augment oil production and transportation, inhibit paraffin and asphaltene aggregation and precipitation, and prevent scale formations, as a desalter and deemulsifier in the refining process, and as an alternative to surfactants in CEOR, drilling fluids, CO 2 capture, etc. ,,,− The amphiphilic nature, self-organization, micelle formation, and surface activity of some ILs are quite similar to behaviors of surfactants and are capable of altering the wettability and lowering the IFT to a noticeable value when the IL is absorbed at the water/oil interface. The lab-scale flooding results suggest their potential as an EOR chemical. − …”