Abstract.One of enhanced oil recovery techniques to increase oil production is surfactant flooding. Surfactants are considered as effective chemical agents used in oilfield in Thailand. It is used to reduce the interfacial tension (IFT) of two fluids and to make them flow easier in the reservoir. In this study, Monoethanolamide (MEA) commonly used for carbon dioxide capture, is applied as a surfactant to reduce IFT between oil and brine. Therefore, the aim of this work is to investigate and measure the IFT based on the conditions of subsurface at the oilfield in Thailand. These parameters such as temperature, pressure, salinity as well as the concentration of surfactant are adjusted to investigate the effects on IFT reduction. From the results, it is reported that pressure from 1000 to 2000 psi and temperature varied from 70°C to 90°C can reduce IFT insignificantly. However, salinity and surfactant concentration are the main parameters that impact on the IFT reduction. It can greatly decrease IFT up to 87.13% for surfactant concentration and up to 74.06% for salinity. Finally, the results can be applied to use in the real field for enhanced oil production in Thailand.

Large reserves of feldspar ores exist in the pegmatite veins at Ban Tak district, Tak province. The main impurities of these deposits are muscovite, biotite and garnet which resulted in high Fe-content that does not meet the raw materials specification for ceramic industry. Chemical compositions of the feldspar ores are 75.93 %SiO2, 14.34%Al2O3, 0.63% Fe2O3, 4.01%K2O and 4.34%Na2O with the fire test results of L= 63.10, a = 2.04 and b = 10.56. The typical specifications of the commercialised feldspar require %SiO2, <70%, Al2O3 >17%, Fe2O3 <0.1% with K2O and Na2O both >5%. The traditional method used to remove Fe-bearing minerals is the reverse flotation. However, this method consumes high sulphuric acid which may create the environmental impact for the nearby area if the treatment is not completely done or the accident occurs. The proposed processes combine the typical process of crushing, grinding and classifying, attrition scrubber, with the wet high intensity magnetic separator (WHIMS) and the direct flotation of feldspar. WHIMS is used to remove muscovite, biotite and garnet which are the causes of high Fe-content. The results showed that efficient separation of Fe-bearing minerals could be achieved by WHIMS in the commercial scale and create the environmental friendly manner. The recovery of processed feldspar is 40% and the chemical compositions of feldspar products are 68.29 %SiO2, 18.69% Al2O3, 0.07% Fe2O3, 5.83% K2O and 6.33%Na2O with the fire test results of L= 82.10, a = -0.56 and b = 3.23 which meet the commercial grade of feldspar.

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One of enhanced oil recovery techniques to produce more oil production is surfactant flooding. The surfactants are considered as the effective chemicals used in oilfield in Thailand. It is used to lower the interfacial tension (IFT) of two fluids and to increase mobility in the reservoir. For this study, various chemicals such as amine, fatty alcohol and glycerine are applied as the surfactants to reduce IFT between oil and water. Therefore, the aim of this work is to investigate the potential chemicals and measure the IFT reduction based on the conditions of subsurface at the oilfield in Thailand. These parameters such as temperature, pressure as well as the concentration of surfactant are adjusted to investigate the effects on IFT reduction. From the results, it is reported that pressure from 1, 000 to 2, 000 psi and temperature varied from 70 °C to 90 °C can reduce IFT insignificantly. However, types of chemicals and surfactant concentration are the main parameters that impact on the IFT reduction. Monoethanolamine at 4.0 wt. % can greatly decrease IFT up to 87 % for surfactant concentration. Finally, the results can be applied to use in the real field for enhanced oil production in Thailand.

In petroleum industries, waxy crude oil is normally found in petroleum production. Wax formation and precipitation during pipeline transport of waxy crude oils can cause several challenges, including wax deposition and flow reduction which adversely impacts pipeline performance in oil and gas production. To overcome the wax deposition problem, the small amount of chemicals like wax inhibitors can provide an effective preventative measure. One of this mechanism is to reduce the pour point temperature. In this work, oil from Sirikit Oilfield in Thailand is selected for this study. The wax inhibitors are selected and studied the performance for pour-point reduction. These chemicals are Polyalkyl methacrylate (PAMA), Poly(maleic anhydride-alt-1-octadecane) (PMAO), Polyalkyl methacrylate-co-ethylene glycol (PAMAEG) and Copolymers of maleic anhydride (CPMA) with the concentration ranging from 100 to 1000 ppm. Also, n-pentane with the concentration of 5-20 % by weight is used as a solvent for wax inhibitors. The results from this study show that n-pentane can reduce the pour point to 39.41 % compared to the original oil. Furthermore, among the polymer group, PMAO can reduce the lowest pour point to 52.82 %. In addition, the mixed solvents of polymer with n-pentane can provide relatively less effect on pour-point reduction. The mixture of n-pentane with PMAO can lower the pour point to a certain level of 54.96 % compared to the original oil. This study can be applied to use in the real field to prevent wax deposition in the pipeline transportation for oil production.