Evaluation of Nanofluids for Selected Malaysian Oilfields with Limited Cores: A Rapid Test Approach

As an emerging technology, nanoparticle offers advanced benefits to be used as a novel improved oil recovery method. The nanoparticle has a much smaller size than pores of rock that can penetrate deeper in the reservoir and it is easily functionalized to change the wettability of rocks. However, the synthesize and screening process of nanofluids will be a laborious task and need a long-term period and numerous cores at rock-fluid tests. It would be a big issue if the research period is short and native cores are limited or even unavailable. This paper presents a rapid test approach to evaluate nanofluids for a Malaysian oilfield with limited cores. Numerous nanofluids: nanopolymer and nanosurfactants, were evaluated using crude oil from a selected oilfield. Rapid measurement tests are proposed based on a parallel bottom-up approach from contact angle, thermal stability, and interfacial tension (IFT) measurement with at reservoir temperature conditions. Glass plate was initially used as the solid media for optimization of nanofluids concentration. Once this is ascertained then it can be used for further analysis on limited native core slab. Rock mineralogy, fluid rheology, and characterization were also determined. The fluid-fluid and rock-fluid measurements were repeated to ensure consistency of results and to estimate deviation in measurements. Based on a rapid test approach, it was observed that the screening process only took several days instead of months to select suitable nanofluids and glass plates that could be used in the screening process to reduce consuming cores for oilfields with a limited core. A series of glass plate experiment showed consistent results with the core slab. It was observed that dynamic optical contact angle using can achieve steady conditions for approximately half an hour. It was also observed that both the glass plate and replicate core slab show consistency of wettability alteration trend and benefits of multiple runs can observe how big the deviation of measurement. As predicted, all nanofluids can alter the rock wetting behavior. A decreasing contact angle showed that the solid media was rendered to be more water-wet, which implies better oil displacement due to residual oil saturation reduction. Surfactant grafted nanoparticles have given marginal effect on IFT reduction at a certain concentration and achieved steady in less than an hour. These results showed the most potential rapidly for further analysis on coreflooding experiments. The rapid test approach can evaluate and screen nanofluids for detailed coreflooding experiments. This approach readily applies for uncored or limited cores and limited research period.