The most used technique for controlling high water production in mature oil fields is conformance control agent with high swelling behavior and stability. However, conformance control destabilization often occurs from particle aggregation leading to particle migration (creaming or sedimentation). Coalescence or cluster formation at an early stage of conformance control is crucial for increasing thermal stability and enhancing formulations. The objective of this study was to characterize the colloidal dispersion stability of grafted zeolite copolymers to assess its use as potential conformance control in carbonate reservoirs. In this study, grafting form of bentonite, acrylamide (AM), 2-acrylamino-2-methylpropanesulfonic acid (AMPS), zeolites with anionic surfactants (Sodium Dodecyl Sulphate, SDS) and nonionic surfactants (Span 80 and Tween 80) were prepared. Stability during multiple light scattering analysis of grafted bentonite with and without modification were observed and compared through Turbiscan Classic MA 2000. The results revealed that the multiple light scattering analysis and colloidal dispersion stability all reflect the stability system of the grafted bentonite. Indeed, the multiple light scattering analysis was able to be used to derive the stability for graft zeolite copolymers and showed good agreement with the results from turbidity. The addition of zeolites combined with Span 80 and Tween 80 was observed to enhance stability, maintaining a 1% transmission value over 60 minutes, which is classified as having "good" characteristics for conformance control.
The production of crude oil is always accompanied by water production, which may create severe separation problems. It is important to understand the stabilization mechanism and parameters contributing to the formation of emulsion, specifically the synergy mixing of surfactants. These factors have not been studied primarily in previous studies. The main objective of the current work was to assess the influence of synergy mixing of nonionic surfactants, sorbitan monooleate (hexitol) and polysorbate 80 (glycol), which are mainly affecting the stability of oil-in-water emulsions. Several factors, such as the mixing rate, mixing time, and aging time of the studied emulsions were also investigated. Response surface methodology (RSM), and central composite design (CCD) were employed to design the experiments. Emulsion stability was measured through a static bottle test over a range of time (1-7 days) at a temperature of 60 °C. A model was established with a coefficient of determination value at 0.8814 and the highest emulsion stability achieved was 42.83%. The least water separation was observed at 0.5 v/v% hexitol, 1.5 v/v% glycol, 15 000 rpm mixing rate in 5 minutes, and seven-day ageing time to achieve ∼41.56% emulsion stability. The minimum emulsion stability of ∼25.0% was observed using 0.5 v/v% of sorbitan monooleate and polysorbate 80 at 5000 rpm of mixing rate in 15 min and under seven days of observation. The results also revealed that the mixing time and ageing time do not affect the stability of the prepared emulsions. Hexitol, mixing rate, synergy mixing of nonionic surfactants and polysorbate 80, and mixing speed significantly influence emulsion stability. The R 2 value of 88.14% verified that the model is well-fitted and the optimal values for the input variables were successfully obtained using RSM.