Sharif Digital Repository

Wettability alteration of rock surfaces toward gas wetting have been recognized as a practical approach for maximizing the production from the gas condensate reservoirs. Most of the reported work in this area applied the so called sessile drop contact angle measurement technique to examine the change in wetting state of a surface. However, the size-dependent wetting behavior of drop which could affect the exact determination of wettability and wettability changes was not well discussed in the previous studies. Therefore, in this work, the size dependency of contact angle for four different liquid-solid-gas systems; i.e., water-calcite-air, water-treated calcite-air (nanofluid treated... 

Dynamic contact angle measurement; as a standard method for surface wettability analysis, is usually conducted through the analysis of sessile drops formed following the low rate injection of fluid from beneath through a drilled hole via an injection needle. However, understanding/characterizing the changes of drop contact angle from the point where the flat solid surface begins is not well discussed yet. Moreover, during the evaluation of size-dependent behavior of contact angle of millimeter-scale drops, the effect of the drilled hole is ignored. In this regard, in the current study, the experimental and thermodynamic characterizations of the sessile drop advancing contact angle... 

Wettability alteration analysis form gas-repellent to gas-wet with the aid of chemical agents has been subjected of numerous studies. However, fundamental understanding of the effect of surface tension of liquid on repellency strength, the change in the intermolecular forces due to the adsorption of nanoparticles onto the rock surfaces, and exposure of treated rock in brine are not well discussed in the available literature. In this study, X-ray diffraction, Atomic Force Microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were applied to characterize the treated and fresh samples. Dynamic and static contact angle measurements were then combined with six methods... 

Recently, super gas wet and gas wet surfaces have been extensively attended in petroleum industry, as supported by the increasing number of publications in the last decade related to wettability alteration in gas condensate reservoirs. In many cases, contact angle measurement has been employed to assess the wettability alteration. Even though contact angle measurement seems to be a straightforward approach, there exist many misuses of this technique and consequently misinterpretation of the corresponding results. In this regard, a critical inspection of the most recent updated concepts and the intervening parameters in the contact angle based wettability evaluation of liquid-solid-gas...