Wettability Alteration of Reservoir Rocks from Liquid Wetting to Gas Wetting Using Nanofluid

Abstract

Well productivity in gas condensate reservoirs is reduced by condensate banking when the bottom hole flowing pressure drops below the dew point pressure. Among the several methods which have been proposed for condensate removal, wettability alteration of reservoir rock to intermediate gas wetting in the near wellbore region appears to be one of the most promising techniques. In this work, we report use of a nanofluid to change the wettability of the carbonate and sandstone rocks to intermediate gas wetting. Application of nanofluid in the wettability alteration of carbonate and sandstone rocks to gas wetting has not been reported previously and is still an ongoing subject. Static and dynamic contact angle measurements, along with imbibition tests, have been performed to investigate the wettability of carbonate and sandstone rocks in presence of nanofluid. It was found that the nanofluid used in this work can considerably change the wettability of both surfaces to preferentially gas wetting in just one day of ageing time. We also report the effect of initial oil saturation and ageing time on the nanofluid capability for wettability change. Initial oil saturation reduces the impact of the nanofluid on wettability change, and hence, a pre-treatment before using nanofluid is necessary. In addition to these small slab-scale experiments, applicability of nanofluid in wettability alteration of sandstone rocks to gas wetting is also investigated in core scale. The results of core displacement tests confirm the ability of nanofluid to change the rock wettability from liquid wetting to gas wetting in core samples. They also show the effectiveness of chemical treatment in subsurface conditions.

Production improvement in gas condensate reservoirs by wettability alteration, using superamphiphobic titanium oxide nanofluid

“…After the treatment of the core sample with nanofluid, the contact angles of distilled water, brine, n-decane and gas-condensate remarkably increased to 161°, 162°, 144°, and 143°, respectively. Considering these data, it can be deduced that the superamphiphobic TiO 2 nanofluid has increased the water and oil contact angle to a much greater degree than the chemicals reported in the former studies [5,8,9,[13][14][15][16][17]. As it is obvious from the results, no sensible difference could be perceived between the contact angle of distilled water and brine, and the contact angle of n-decane and gas-condensate as well.…”

“…Mousavi et al [16] succeeded to change the wettability of a limestone gas reservoir core from strongly liquid-wetting to intermediate gas-wetting by preparing fluorinated silica nanoparticles with an average diameter of 80 nm. Aminnaji et al [17] experimentally studied the use of a nanofluid containing organofluorine and silicon-based nanoparticles with reasonable capability to change the wettability of the carbonate and sandstone rocks to intermediate gas-wet state. Recently, we have reported for the first time on achieving the wettability alteration of strongly liquid-wet carbonate rocks to ultra gas-wet state using novel TiO 2 , SiO 2 and CNT nanofluids by performing several small-scale slab tests [18].…”

Experimental and modeling study of wettability alteration through seawater injection in limestone: a case study

“…Dynamic contact angle measurements were carried out at different velocities with the Sigma 700 tensiometer in order to deduce the rock characteristics using the MKT model. The Sigma 700 tensiometer was to measure the advancing and receding contact angles using the Wilhelmy plate method (Aminnaji et al 2015). Based on this method, a sensitive balance was used to measure the force exerted by the liquid on the solid when the liquid container moved upward and downward.…”

“…This technique is based on modified Washburn and spontaneous liquid imbibition into porous media. Wettability of powders (Siebold et al 2000;Dang-Vu and Hupka 2005;Yildiz et al 2010) and heterogeneous reservoir rocks (Ghedan et al 2010;Ghedan and Canbaz 2014;Aminnaji et al 2015;Canbaz and Ghedan 2015) could be measured using the RIC technique. The contact angles obtained from the RIC technique match the results measured with Amott and USBM methods (Ghedan et al 2010).…”

Study on Wettability Variation for Removing Liquid Block in Condensate Gas Reservoir

“…In the experimental study of unsteady seepage, core wettability preferred gas wetting [15] or neutral wetting effects on the gas-liquid two-phase flow after using 0.2% sol ? 0.4% FC3721 treating core.…”