| AVS 64th International Symposium & Exhibition | |
| Scanning Probe Microscopy Focus Topic | Wednesday Sessions |
| Session SP+SS+TF-WeM |
| Session: | Probing and Manipulating Nanoscale Structure |
| Presenter: | Nancy Burnham, Worcester Polytechnic Institute |
| Authors: | S.L. Eichmann, Aramco Research Center - Boston N.A. Burnham, Worcester Polytechnic Institute |
| Correspondent: | Click to Email |
Oil powers modern economies [1]. Yet only 30% of oil is recovered from a typical reservoir [2]. The reservoirs of Saudi Arabia, which provide over 10% of the world’s oil [3], are unusual . T hey are highly saline, with concentrations of up to 120,000 ppm total dissolved solids (TDS), the temperatures can exceed 100o C, and the emulsion of oil and brine is dispersed within small fissures in carbonate rock. These conditions are challenging for the unhindered diffusion of the nanoparticle tracers that are used to map an oil field from one well to the next [4]. In this study, bare and carboxyl-terminated atomic-force microscope tips and calcite surfaces acted as surrogates for nanoparticle tracers and carbonate rocks, respectively. They were immersed in three fluids: brine (120K ppm TDS), seawater (60K ppm TDS), and calcium-doped seawater (~60K ppm TDS). Surprisingly, the amount of total dissolved solids was not a good predictor of the tip-sample adhesion. Rather, specific ion effects were important; adding calcium to seawater brought the adhesion down to the ~100 pN levels of brine as compared to the ~400 pN levels of seawater . The adhesion for the carboxyl-terminated tips was greater (reaching into the nN-range) than for the bare tips, but the same trends were observed. These results can be used where fresh water for oil recovery is in short supply. The addition of calcium to seawater should mitigate nanoparticle-rock adhesion and allow more efficient diffusion of nanoparticle tracers through a reservoir, which could in turn lead to better oil recovery and help ensure a stable supply of an essential global resource.
1. Marder, Michael, Tadeusz Patzek, and Scott W. Tinker. "Physics, fracking, fuel, and the future." Physics Today 69.7 (2016): 46-52.
2. Lake, Larry W. "Enhanced oil recovery." (1989): 17-39.
3. Key world energy statistics. International Energy Agency: 2016, https://www.iea.org/
4. Berlin, Jacob M., et al. "Engineered nanoparticles for hydrocarbon detection in oil-field rocks." Energy & Environmental Science 4.2 (2011): 505-509.
5. S.L. Eichmann and N.A. Burnham, “Calcium-Mediated Adhesion of Nanomaterials in Reservoir Fluids.” submitted.