Recently, the revolution of nanotechnology has been noticed for its many potential applications in the oil & gas industry such as enhanced oil recovery process and subsurface mapping. Understanding the transport and retention of nanoparticles (NPs) in an oilfield environment, such as high salinity, high temperature, high pressure, and heterogeneous pore distribution is critical to their application. The objective of this study is to investigate the fundamental transport and retention properties of NPs in the challenging oilfield conditions.
In this work, dolomite core material from an oil well in Kuwait and Berea sandstone were used. Carbon NPs were used as model nanomaterials. The core sample was washed with toluene to remove residual oil, ground to 106 – 250 µm grains, and packed into columns. Carbon NP breakthrough curves were collected in synthetic seawater at room temperature. The results showed that the existence of salt ions dramatically delayed NP breakthrough time and increased NP retention. Effects of different types of salts and salt concentrations are discussed. NP transport appears to be highly dependent on the degree of interaction between the NPs, salt ions in solution, and porous medium surface, which affects retardation and retention. NP breakthrough can be significantly improved by avoiding this interaction via NP surface modification. Our preliminary results provided helpful guidelines for NP transport in oil & gas applications. The results are discussed in detail. Furthermore, the experimental results were fitted with a 1-D advective and dispersion equation combined with a first-order removal term to obtain important transport parameters for NPs that did not aggregate. More complicated models are being developed to capture the unusual breakthrough curves associated with NP aggregation.