Abstract
Nanotechnology is one of the modern techniques that can be used for enhancing the oil recovery. Enhanced oil recovery (EOR) is mainly used after oil production declination by chemically altering the injection water. However, it is very important to have an environmentally friendly method to enhance oil recovery. A possible method is to use nanofluids that include nanosilica-polymer (NFs) which contain mainly sandstone ingredients.
This research is mainly an experimental investigation of the usage of several nanofluids with silica particles for enhanced oil recovery. Nanofluid injection is performed in core plugs and the oil recovery is compared with the oil recovery obtained with synthetic sea water (SSW) injection. Both nanofluid and SSW are injected in secondary mode. Five cleaned and dried Berea sandstone cores were used in the core flooding experiments. First, secondary recovery was applied on all cores by SSW injection. Then the cores were re-cleaned and re-dryed to be prepared for the secondary recovery by using 4 different types of nanofluids with the same concentration of 0.1 wt% as NFs.
In this research, it was important to use exactly the same rock in both the SSW and nanofluid flooding to avoid any effect of pore structure on the oil recovery. The research showed that the best nanofluid contained nanoparticles of silica-alumina. This nanofluid gave the highest oil recovery and altered the wettability from water wet to strongly water wet due to the ionic interactions. The ultimate oil recovery was increased to 10.4% of OOIP (original oil in place) compared to SSW injection. In addition to investigating the quantitative effect of the use of several nanofluids with different nanoparticles sizes and surface modifications on oil recovery we also applied Scanning Electron Microscopy (SEM) to study pore blockage, log jamming, and emulsions between NFs and crude oil.
