## 1 Introduction
As a result of the bonding between nanoparticles and surfactant molecules, both remain distributed within the solution, causing a decline in the overall surfactant adsorption [34]. Research findings suggest that most surfactant molecules tend to collide with nanoparticles rather than bonding with the rock surface. This collision phenomenon ultimately leads to a decrease in the amount of surfactant adsorbed on the rock [35]. In the reservoir, nanofluid with a surfactant serves the purpose of generating stable foams and emulsions, consequently reducing the IFT. It works by minimizing the interfacial energy at the interface, resulting in a decrease in IFT. Unlike conventional surfactants that detach from the interface over time, the nanoparticles in the nanofluid prevent the surfactant molecules from desorbing, ensuring a continuous reduction in IFT and ultimately leading to enhanced surfactant efficiency [6; 36]. The aim of this screening study is to select the optimum chemicals for an AS/NS flooding design for an oilfield in Kazakhstan. Field A is a multilayered sandstone reservoir, located in the western Kazakhstan, near the Caspian Sea [37]. It was discovered in the early 1960s and reached a stable oil production during the early years of field development. The field was water flooded with Caspian seawater (CSW) in the late 1960s under several five spot square patterns [38]. The peak of oil production in the field was reached in 1975. The field is still producing oil by waterflooding; however, the oil production has considerably decreased with a field-wide water cut of above 90% [39]. In addition to high water cut, the field also faces problem of a high asphaltene and paraffin content in the crude oil which crystallizes at temperatures ranging from 50-60 \({}^{\circ}\)C. The remaining oil saturation in the field is 59%, but due to water breakthrough and the presence of high permeable layers, the remaining oil cannot be produced with waterflooding [39]. As a result of high S\({}_{\text{or}}\) in the field, chemicals such as surfactant and alkali are needed to detach the residual oil. The Field A reservoir and fluid characteristics are similar to the fields where ASP proved to be effective, as can be seen in Table 1. Therefore, low TAN and high paraffin content are not the main limitations, and chemical flooding can be successfully conducted in Field A.  
ASP flooding is proposed as a tertiary recovery method for the Field A, given its success in fields with similar characteristics, including the Daqing field in China and the Mangala field in India. However, the available literature suggests that surfactants, alkalis, and nanoparticles have not been tested for Field A. While polymer flooding has been reviewed as an EOR method for this field, no laboratory studies have been conducted for selection of chemicals design under field conditions. In this context, several experiments should be conducted considering the reservoir rock and fluid properties to design a chemical flooding recipe for maximum oil recovery from the target field [40; 41; 42]. For this reason, surfactant, alkali, nanoparticles, and polymer screening should be conducted to design a proper chemical flooding project. Screening includes aqueous stability tests to select stable chemical concentration, phase behavior studies to observe Winsor type III microemulsion and IFT reduction, and adsorption studies to select optimum alkali and NPs concentration. The Linear Isotherm model for surfactant adsorption is employed in this work due its simplicity, ease of use, and reasonably accurate estimation for surfactant concentrations used in current study.