In an effort to increase oil recovery, there are several methods in chemistry that have proven successful, one of which is the application of surfactants flooding. However, the surfactant is limited enough to reach the broader reservoir zone because of sufficient depleted oil at an primary recovery and secondary recovery. So at th condition is a nanosilic additive as a solution that can be used to improve the oil recovery factor. The effect of surfactant concentration and the use of nanosilic additives can be expanded using the spontaneous imbibition test method.
The research in laboratory consists of three main processes: the manufacture of artificial core, the properties of artificial core and crude oil and imbibition test. In the manufacture of the articial core, the core is made up of two
units, the first core consisting of quartz sand, cement and bentonite and a second core with an additive of 0.2 gram of added nanosilic acid added to each artificial core. The imbibilization test was conducted using 10,000 ppm brine combined with five different surfactant concentrations ranging from 0,1%, 0,25%, 0,5%,
0,75%, to 1% in two artificial core.
Based on the results of the research, the artificial nucleus made has excellent porosity and permeability value. In addition, the physical properties of crude oil also exhibit good quality with API values of 32.71 and viscosity of 2.27 cp. The imbibition test carried out using salt water of 10,000 ppm was able to produce a recovery factor of 8.7% followed by surfactant 0.1%, 0.25%, 0.5%,
0.75%, to 1% with RF 11.6 %, 20.6%, 31.8%, 30%, and 26.2% respectively. While the Core with the use of nanosilika additives with the same surfactant concentration produced RF by 13.1%, 21.7%, 34.7%, 33.3%, and 27.1%. 0.5% surfactant solution resulted in an optimum recovery factor of 34.7% on the Core with nanosilic additives and 31.8% at the core with no nanosyllic additives.