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

Abstract

Many gas condensate reservoirs suffer a loss in productivity owing to accumulation of liquid in near-wellbore region. Wettability alteration of reservoir rock from liquid-wetting to gas-wetting appears to be a promising technique for elimination of the condensate blockage. In this paper, we report use of a superamphiphobic nanofluid containing TiO2 nanoparticles and low surface energy materials as polytetrafluoroethylene and trichloro(1H,1H,2H,2H-perfluorooctyl)silane to change the wettability of the carbonate reservoir rock to ultra gas-wetting. The utilization of nanofluid in the wettability alteration of carbonate rocks to gas-wetting in core scale has not been reported already and is still an ongoing issue. Contact angle measurements was conducted to investigate the wettability of carbonate core plugs in presence of nanofluid. It was found that the novel formulated nanofluid used in this work can remarkably change the wettability of the rock from both strongly water- and oil-wetting to highly gas-wetting condition. The adsorption of nanoparticles on the rock and formation of nano/submicron surface roughness was verified by Scanning Electron Microscope (SEM) and Stylus Profilometer (SP) analyses. Using free imbibition test, we showed that the nanofluid can imbibe interestingly into the core sample, resulting in notable ultimate gas-condensate liquid recovery. Moreover, we studied the effect of nanofluid on relative permeability and recovery performance of gas/water and gas/oil systems for a carbonate core. The result of coreflooding tests demonstrates that the relative permeability of both gas and liquid phase increased significantly as well as the liquid phase recovery enhanced greatly after the wettability alteration to gas-wetting.

A Complete experimental study of oil/water interfacial properties in the presence of TiO2 nanoparticles and different ions

“…In the EOR processes, the addition of TiO 2 NPs to the injected fluid is capable of altering rock wettability and preventing asphaltene precipitation [18]. However, it has been reported that exceeding the optimum concentration does not necessarily improve the situation.…”

Effect of a synthesized anionic fluorinated surfactant on wettability alteration for chemical treatment of near-wellbore zone in carbonate gas condensate reservoirs

“…As mentioned earlier, wettability alteration to the gas-wetting in the near-wellbore zone is a solution to remove condensate formed in the area. To illustrate the relationship between gas wettability and condensate removal in this area, it should be noted that condensates in this area can be eliminated by increasing the drawdown pressure (viscous forces) or lowering capillary pressure (Esmaeilzadeh et al 2018). The capillary pressure (P c ) is proportional to contact angle (θ), gas-liquid surface tension ( ) and reversely proportional to pore size (r), according to Young-Laplace equation (Eq.…”

“…2): Capillary pressure can be decreased by either reducing the gas-liquid surface tension or increasing the contact angle through wettability alteration. By these interpretations, and by keeping the gas-liquid surface tension constant, the wettability alteration to the gas-wetting reduces capillary pressure and eliminates condensate in the area (Esmaeilzadeh et al 2018).…”

Wettability Alteration in Gas Condensate Reservoirs: A Critical Review of the Opportunities and Challenges

“…They also showed that altering the wettability led to an increment of oil production from 45.6% to 78.4% and consequently the saturation of remaining oil decreased from 29.2% to 17.8%. For altering the tendency of the carbonate rock from highly liquid-wetting toward ultra gaswetting, TiO 2 nanoparticles were modified using PTFE and PFOS by Esmaeilzadeh et al 117 SEM and stylus profilometer (SP) tests were conducted to indicate the adsorption process. Their results indicated an improvement in the productivity of both liquids and gas after treatment.…”