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Both theory and experiments demonstrate that gas-wetness cannot always be overlooked and the gas-wet degree affects gas-well production greatly in gas condensate reservoirs. In the study, two quantitative methods have been introduced, the sessile drop and the captive bubble, and the corresponding wettability indexes, including gas-wetting parameter in the sessile drop method and gas contact angle in the captive bubble method. Gas-wetness of various substrates, such as Paraffin wax, plastics, glass, and iron plate, has been compared. Experimental results show that with the decrease of surface free energy, the hydrophobic and oleophobic and aerophily property gets enhanced. Particularly, air against water was preferentially wet on the Paraffin wax surface ( = 0.258, = 70.53°). Moreover, gas-wetness against water on the substrate surface is stronger than gas-wetness against oil on the same surface. The study is of great importance for study on gas-wetness.

The oxidation state of the surfaces of titanium-based biomaterials strongly depends on their previous history. This factor affects the titanium wettability and it probably conditions the success of the implanted biomaterials. However, the separate role of the pollution and oxidation states of metallic titanium surfaces remains still controversial. To elucidate this, it is required to standardize the initial surface state of titanium in terms of roughness and surface chemistry, and then, to monitor its wettability after the corresponding treatment. In this work, we studied finely polished surfaces of commercially pure titanium (cpTi) which were subjected to cleaning surface treatments. X-Photoelectron spectroscopy was used to characterize the surface chemistry and the oxide film thickness. The contact angle hysteresis in underwater conditions was measured with the growing/shrinking captive bubble method, which allowed for mimicking the real conditions of implantable devices. The water wettability of smooth...

Gas-well production will be increased greatly after altering the wettability of porous media from preferential liquid-wetting to preferential gas-wetting in gas-condensate reservoirs. Moreover, the degree of gas wetness strongly affects the production. Thus, the study of gas-wet quantitative measurement methods is of great significance. The wetting ability parameter of gas versus liquid ζG-L is calculated from the proposed formula in the sessile drop method, and the gas contact angle θ G in the captive bubble method was separately used to measure gas wettability and propose the wettability criteria. Also, the concept of gas wettability was defined. After treated by fluorocarbon polymer (Zonyl8740), glass slides, and glass capillary tubes got tested on gas wetness. The results show that with the increase of the concentration of Zonyl8740 solution, the surface free energy of glass slides decreases and gas-wetness of them is enhanced. And capillary tube rise tests showed the same conclusion, demonstrating th...