Fluid loss can be defined as the lost of mud filtrate into a porous permeable formation due to high hydrostatic pressure compared to the formation pressure. This phenomenon may cause some major problems to the workover operation such as formation damage, stuck pipe, and poor cementing job. Thus, in order to prevent fluid loss into formation, an environmentally safe, non-toxic, high biodegradability and low cost of polymer additive in drilling mud was prepared from corn starch as the fluid loss control agent. The purpose of this study is to investigate the potential of utilizing natural polymer-corn starch acting as fluid loss control agents in water-based drilling mud. The filtration and rheological properties of the water-based mud were analyzed at 170 to 200 °F temperature range with 0 to 10 g of corn starch concentration. Experimental results showed that the higher concentration of corn starch gave better fluid loss control behavior. Therefore, there is high potential of corn starch to be used as fluid loss control agent in drilling mud.

Foam flooding is an established approach in Enhanced Oil Recovery (EOR) to recover a significant quantity of the residual oil left in the reservoir after primary and secondary recovery. However, foam flooding faces various problems due to low viscosity effect, which reduces its efficiency in recovering oil. Using surfactant to stabilize CO2foam may reduce mobility and improve areal and vertical sweep efficiency, but the potential weaknesses are such that high surfactant retention in porous media and unstable foam properties under high temperature reservoir conditions. Nanoparticles have higher adhesion energy to the fluid interface, which potentially stabilize longer lasting foams. Thus, this paper is aimed to investigate the CO2foam stability and mobility characteristics at different concentration of nanosilica, brine and surfactant. Foam generator has been used to generate CO2foam and analyze its stability under varying nanosilica concentration from 100 - 5000 ppm, while brine salinity and surfactant concentration ranging from 0 to 2.0 wt% NaCl and 0 – 10000 ppm, respectively. Foam stability was investigated through observation of the foam bubble size and the reduction of foam height inside the observation tube. The mobility was reduced as the concentration of nanosilica increased with the presence of surfactant. After 150 minutes of observation, the generated foam height reduced by 10%. Liquid with the presence of both silica nanoparticles and surfactant generated more stable foam with lower mobility. It can be concluded that the increase in concentration of nanosilica and addition of surfactant provided significant effects on the foam stability and mobility, which could enhance oil recovery.

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Foam stability can be uttered in foamability measurement and bubble size dispersal. The higher the foamability, the more stable it is. The addition of nanosilica particle to the foam system will further improve the rigidity of the lamellae interface by providing stickiness force between foam lamellae and its surface, halting the film thinning and prevent it from rupture. This paper aims to investigate the stability of CO2 foam with addition of nanoparticle, to find the optimum surfactant and nanoparticle concentration that achieved higher foam stability, to determine the relationship between the foamability and the nanoparticle concentration within the carbon dioxide foam system and also to analyze the effect of crude oil on foam stability. For this experiment, foam generator was used. The concentrations of surfactant were prepared at ranges from 500 ppm to 5000 ppm. The foam stability test was conducted at constant pressure, temperature and flowrate. The nanoparticle was used with set of different concentrations such as 1000 ppm, 3000 ppm and 5000 ppm. It was found that the increases in both surfactant and nanoparticle concentration have boosted up the stability of the foam produced from 92% to 100% foamability and foam durability extended to maximum of 5 hours. The optimum concentration of both surfactant and nanoparticle was 5000 ppm. It is important to determine the relationship between foamability and nanoparticle concentration, so that foam stability, mobility and the morphology of the foam produced can be forecasted with the newly breakthrough nanoparticles technology.

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