No abstract

In the experiment, the filtrate loss of synthetic fluid loss control fluid was recorded in room temperature and high temperature in the composite brine base and sodium chloride brine base slurry, and compared with the filtrate loss before base polymer addition. In this way, the effect of filtration loss and salt resistance and temperature resistance of synthetic polymers were evaluated. The influence of the synthesized polymer on the rheological properties of the composite brine was also evaluated by determining the viscosity of the drilling fluid added to the base slurry and polymer. In the end, the structure of the synthetic polymers was characterized through the infrared spectrum, which initially analyzed through the mechanism of its function in reducing the filter loss. Finally, the products produced according to the recipe are given to the site and added to the two wells to record the drilling fluid performance data.

With the enhancement of environmental protection awareness, the requirements on drilling fluid are increasingly strict, and the use of ordinary oil-based drilling fluid has been strictly restricted. In order to solve the environmental protection and oil-gas reservoir protection problems of offshore oil drilling, a new synthetic basic drilling fluid system is developed. The basic formula is as follows: a basic fluid (80% Linear a-olefin + 20% Simulated seawater) + 2.5% nano organobentonite + 3.5% emulsifier RHJ-5 # + 2.5% fluid loss agent SDJ-1 + 1.5% CaO + the right amount of oil wetting barite to adjust the density, and a multifunctional oil and gas formation protective agent YRZ has been developed. The performance was evaluated using a high-low-high-temperature rheometer, a high-temperature and high-pressure demulsification voltage tester, and a high-temperature and high-pressure dynamic fluid loss meter. The results show that the developed synthetic based drilling fluid has good rheological property, demulsification voltage ≥ 500 V, temperature resistance up to 160˚C, high temperature and high pressure filtration loss < 3.5 mL. After adding 2% -5% YRZ into the basic formula of synthetic based drilling fluid, the permeability recovery value exceeds 90% and the reservoir protection effect is excellent. The new synthetic deepwater drilling fluid is expected to have a good application prospect in offshore deepwater drilling.

We developed a nanocomposite of Fe2O3andTiO2 nanorods (NRs) as a photocatalyst in a photoelectrochemical hydrogen production system through two steps hydrothermal technique. The influence of hydrothermal temperature (100, 120, 150, 180, and 200 o C) was investigated on the physicochemical and photoelectrochemical properties and solar hydrogen production of all photocatalysts by various characterization techniques. At low temperatures, nanorods grow irregularly with low concentration due to the insufficient heat however the samples completely peeled off and nanorods were not detected on the glass substrate at temperature 200 o C. The photocatalyst with the hydrothermal temperature of 150 o C produced the maximum amount of hydrogen (171.6 mmolcm -2 ) under visible light with external potential of 0.7 V in 1M KOH and 5 vol.% methanol solution. Electron Impedance spectroscopy (EIS) results show that this photocatalyst had a reduction in charge transfer resistance and charge carrier recombination rate due to small inner surface area with low reaction sites. Also, its Mott−Schottky data revealed a more negative flat bad potential of -0.9 V with profound ability of proton (H + ) reduction to H2 and a high donor density of 8.45× 10 20 cm -3 with a great photocurrent density.

With the in-depth development of the Sargiz oilfield in Kazakhstan, oil layer protection plays an extremely important role in the development process. The petrological characteristics and pore types of the reservoir were analyzed by X-ray diffraction and electron microscopy. The average face ratio of the reservoir was 19.30%. The main pore type was intergranular pore and the face rate was 17.52%. The total amount of clay minerals in the reservoir core is 7%-10%, and the clay minerals are mainly illite, Yimeng, kaolinite and chlorite; the shale content of the main oil-bearing layer is about 3%-10%. Refer to relevant industry standards for speed, water, stress, acid, and alkali sensitivity experiments to study the potential damage mechanism of the reservoir. According to the above experiments, the oilfield reservoirs have no speed-sensitive damage and are weakly water-sensitive reservoirs; the reservoirs are highly stress-sensitive and easy to produce sand when the stress changes; they have moderately weak acid sensitivity and weak-medium weak alkaline.